General Description
The MAX1586/MAX1587 power-management ICs are
optimized for devices using Intel XScale®microproces-
sors, including Smart Phones, PDAs, internet appli-
ances, and other portable devices requiring substantial
computing and multimedia capability at low power.
The ICs integrate seven high-performance, low-operating-
current power supplies along with supervisory and
management functions. Included are three step-down
DC-DC outputs, three linear regulators, and a seventh
always-on output. DC-DC converters power I/O, DRAM,
and the CPU core. The I/O supply can be preset to
3.3V or adjusted to other values. The DRAM supply on
the A and C devices is preset for 1.8V or 2.5V, while the
MAX1586B DRAM supply is preset for 3.3V or 2.5V. The
DRAM supply on all parts can also be adjusted with
external resistors. The CPU core supply is serial pro-
grammed for dynamic voltage management and, on C
devices, can supply up to 0.9A. Linear-regulated out-
puts are provided for SRAM, PLL, and USIM supplies.
To minimize quiescent current, critical power supplies
have bypass “sleep” LDOs that can be activated when
output current is very low. Other functions include sep-
arate on/off control for all DC-DC converters, low-bat-
tery and dead-battery detection, a reset and power-OK
output, a backup-battery input, and a two-wire serial
interface.
All DC-DC outputs use fast, 1MHz PWM switching and
small external components. They operate with fixed-fre-
quency PWM control and automatically switch from
PWM to skip-mode operation at light loads to reduce
operating current and extend battery life. The core out-
put can be forced into PWM mode at all loads to mini-
mize noise. A 2.6V to 5.5V input voltage range allows
1-cell lithium-ion (Li+), 3-cell NiMH, or a regulated 5V
input. The MAX1587 is available in a tiny 6mm x 6mm,
40-pin thin QFN package. The MAX1586 features an
additional linear regulator (V6) for VCC_USIM and low-
battery and dead-battery comparators. The MAX1586 is
available in a 7mm x 7mm, 48-pin thin QFN package.
Applications
PDA, Palmtop, and Wireless Handhelds
Third-Generation Smart Cell Phones
Internet Appliances and Web-Books
Features
♦Six Regulators in One Package
Step-Down DC-DC for I/O at 1.3A
Step-Down DC-DC for Memory at 0.9A
Step-Down Serial-Programmed DC-DC for CORE
Up to 0.9A
Three LDO Outputs for SRAM, PLL, and USIM
Always-On Output for VCC_BATT
♦Low Operating Current
60µA in Sleep Mode (Sleep LDOs On)
130µA with DC-DCs On (Core Off)
200µA All Regulators On, No Load
5µA Shutdown Current
♦Optimized for XScale Processors
♦Backup-Battery Input
♦1MHz PWM Switching Allows Small External
Components
♦Tiny 6mm x 6mm, 40-Pin and 7mm x 7mm, 48-Pin
Thin QFN Packages
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
________________________________________________________________
Maxim Integrated Products
1
Ordering Information
MAX1586
MAX1587
V1
V2
V3
V4
V5
V6
V7
VCC_IO 3.3V
VCC_MEM 2.5V
VCC_CORE
0.8V TO 1.3V
VCC_USIM
0V, 1.8V, 3.0V
MAIN BATTERY
VCC_PLL 1.3V
VCC_SRAM 1.1V
BACKUP
BATTERY
IN
BKBT
MR
RSO
VCC_BATT
POK
nRESET
nVCC_FAULT
SYS_EN
PWR_EN
ON1-2
ON3-6
nBATT_FAULT DBO
Simplified Functional Diagram
19-3089; Rev 4; 4/09
EVALUATION KIT
AVAILABLE
Pin Configurations and Selector Guide appear at end of
data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX1586AETM -40°C to +85°C 48 Thin QFN 7mm x 7mm
MAX1586BETM -40°C to +85°C 48 Thin QFN 7mm x 7mm
MAX1586CETM -40°C to +85°C 48 Thin QFN 7mm x 7mm
MAX1587AETL -40°C to +85°C 40 Thin QFN 6mm x 6mm
MAX1587CETL -40°C to +85°C 40 Thin QFN 6mm x 6mm
Intel XScale is a registered trademark of Intel Corp.
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim's website at www.maxim-ic.com.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
IN, IN45, IN6, MR, LBO, DBO, RSO, POK, SCL, SDA,
BKBT, V7, SLP, SRAD, PWM3 to GND...............-0.3V to +6V
REF, CC_, ON_, FB_, DBI, LBI, V1, V2, RAMP, BYP,
MR to GND ...........................................-0.3V to (VIN + 0.3V)
PV1, PV2, PV3, SLPIN to IN...................................-0.3V to +0.3V
V4, V5 to GND ..........................................-0.3V to (VIN45 + 0.3V)
V6 to GND ..................................................-0.3V to (VIN6 + 0.3V)
PV1 to PG1 ............................................................-0.3V to +6.0V
PV2 to PG2 ............................................................-0.3V to +6.0V
PV3 to PG3 ............................................................-0.3V to +6.0V
LX1 Continuous Current....................................-1.30A to +1.30A
LX2 Continuous Current........................................-0.9A to +0.9A
LX3 Continuous Current........................................-0.9A to +0.9A
PG1, PG2, PG3 to GND.........................................-0.3V to +0.3V
V1, V2, V4, V5, V6 Output Short-Circuit Duration.......Continuous
Continuous Power Dissipation (TA = +70°C)
6mm x 6mm 40-Pin Thin QFN
(derate 26.3mW/°C above +70°C)...........................2105mW
7mm x 7mm 48-Pin Thin QFN
(derate 26.3mW/°C above +70°C)...........................2105mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
PV1, PV2, PV3, SLPIN, IN Supply
Voltage Range
PV1, PV2, PV3, IN, and SLPIN must connect together
externally 2.6 5.5 V
IN45, IN6 Supply Voltage Range 2.4 5.5 V
VIN rising 2.25 2.40 2.55
IN Undervoltage-Lockout (UVLO)
Threshold VIN falling 2.200 2.35 2.525 V
MAX1586 32
Only V7 on, VIN below
DBI threshold VIN = 3.0V MAX1587 5
MAX1586 130
REG1 and REG2 on in
switch mode, REG3 off MAX1587 130
MAX1586 60
REG1 and REG2 on in
sleep mode, REG3 off MAX1587 60
MAX1586 225
Quiescent Current
No load (IPV1 +
IPV2 + IPV3 + IIN +
ISLPIN + IIN45 +
IIN6)
All REGs on MAX1587 200
µA
ON1 = 0 4
BKBT Input Current ON1 = IN 0.8 µA
REF Output Voltage 0 to 10µA load 1.2375 1.25 1.2625 V
SYNCHRONOUS-BUCK PWM REG1
REG1 Voltage Accuracy FB1 = GND, 3.6V ≤ VPV1 ≤ 5.5V, load = 0 to 1300mA 3.25 3.3 3.35 V
FB1 Voltage Accuracy FB1 used with external resistors, 3.6V ≤ VPV1 ≤ 5.5V,
load = 0 to 1300mA 1.231 1.25 1.269 V
FB1 Input Current FB1 used with external resistors 100 nA
Error-Amplifier Transconductance Referred to FB 87 µS
Load = 800mA 180 280
Dropout Voltage (Note 1) Load = 1300mA 293 450 mV
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
_______________________________________________________________________________________ 3
PARAMETER CONDITIONS MIN TYP MAX UNITS
ILX1 = -180mA 0.18 0.3
p-Channel On-Resistance ILX1 = -180mA, VPV1 = 2.6V 0.21 0.35
Ω
ILX1 = 180mA 0.13 0.225
n-Channel On-Resistance ILX1 = 180mA, VPV1 = 2.6V 0.15 0.25
Ω
Current-Sense Transresistance 0.5 V/A
p-Channel Current-Limit Threshold -1.55 -1.80 -2.10 A
PWM Skip-Mode Transition Load
Current Decreasing load current (Note 2) 30 mA
OUT1 Maximum Output Current 2.6V ≤ VPV1 ≤ 5.5V (Note 3) 1.3 A
LX1 Leakage Current VPV1 = 5.5V, LX1 = GND or PV1, VON1 = 0V -20 +0.1 +20 µA
SYNCHRONOUS-BUCK PWM REG2
FB2 = GND, 3.6V ≤ VPV2 ≤ 5.5V, load = 0 to 900mA 2.463 2.5 2.537
MAX1586A, MAX1587A, FB2 = IN, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 1.773 1.8 1.827
REG2 Voltage Accuracy
MAX1586B, FB2 = IN, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 3.25 3.3 3.35
V
FB2 Voltage Accuracy FB2 used with external resistors, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 1.231 1.25 1.269 V
FB2 Input Current FB2 used with external resistors, VFB2 = 1.25V 100 nA
Error-Amplifier Transconductance Referred to FB 87 µS
Dropout Voltage Load = 900mA (Note 1) 243 380 mV
ILX2 = -180mA 0.225 0.375
p-Channel On-Resistance ILX2 = -180mA, VPV2 = 2.6V 0.26 0.425
Ω
ILX2 = 180mA 0.15 0.25
n-Channel On-Resistance ILX2 = 180mA, VPV2 = 2.6V 0.17 0.275
Ω
Current-Sense Transresistance 0.7 V/A
p-Channel Current-Limit Threshold -1.1 -1.275 -1.50 A
PWM Skip-Mode Transition Load
Current Decreasing load current (Note 2) 30 mA
OUT2 Maximum Output Current 2.6V ≤ VPV2 ≤ 5.5V (Note 3) 0.9 A
LX2 Leakage Current VPV2 = 5.5V, LX2 = GND or PV2, VON2 = 0V -10 +0.1 +10 µA
SYNCHRONOUS-BUCK PWM REG3
MAX1586A, MAX1586B, MAX1587A,
load = 0 to 500mA -1.5 +1.5
REG3 Output Voltage Accuracy
REG3 from 0.7V to
1.475V, 2.6V ≤
VPV3 ≤ 5.5V MAX1586C, MAX1587C,
load = 0 to 900mA -1.5 +1.5
%
Error-Amplifier Transconductance 68 µS
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
4 _______________________________________________________________________________________
PARAMETER CONDITIONS MIN TYP MAX UNITS
ILX3 = -180mA 0.225 0.375
p-Channel On-Resistance ILX2 = -180mA, VPV3 = 2.6V 0.26 0.425
Ω
ILX3 = 180mA 0.15 0.25
n-Channel On-Resistance ILX3 = 180mA, VPV3 = 2.6V 0.17 0.275
Ω
MAX1586A, MAX1586B, MAX1587A 1.1
Current-Sense Transresistance MAX1586C, MAX1587C 0.55 V/A
MAX1586A, MAX1586B, MAX1587A -0.60 -0.7 -0.85
p-Channel Current-Limit Threshold MAX1586C, MAX1587C -1.125 -1.35 -1.700 A
PWM Skip-Mode Transition Load
Current Decreasing load current (Note 2) 30 mA
MAX1586A, MAX1586B, MAX1587A 0.5
OUT3 Maximum Output Current 2.6V ≤ VPV3 ≤ 5.5V
(Note 3) MAX 1586C, MAX1587C 0.9 A
LX3 Leakage Current VPV3 = 5.5V, LX3 = GND or PV2, VON3 = 0V -10 +0.1 +10 µA
LDOS V4, V5, V6, V1 SLEEP, V2 SLEEP, AND V7 OUTPUT
V4, V5, V6, V1 SLEEP, V2 SLEEP
Output Current 35 mA
V7 Output Current 30 mA
REG4 Output Voltage Load = 0.1mA to 35mA 1.261 1.3 1.339 V
REG4 Noise With 1µF COUT and 0.01µF CBYP 15 µVRMS
REG5 Output Voltage Load = 0.1mA to 35mA 1.067 1.1 1.133 V
IN45, IN6 Input Voltage Range 2.4 5.5 V
0V setti ng ( ei ther ON 6 l ow or ser i al p r og r am m ed ) 0
1.8V setting, load = 0.1mA to 35mA 1.746 1.8 1.854
2.5V setting, load = 0.1mA to 35mA 2.425 2.5 2.575
REG6 Output Voltage (POR Default
to 0V, Set by Serial Input) MAX1586
3.0V setting, load = 0.1mA to 35mA 2.91 3.0 3.09
V
V1 on and in regulation VV1
V7 Output Voltage V1 off VBKBT
V
V1 and V2 SLEEP Output Voltage
Accuracy Set to same output voltage as REG1 and REG2 -3.0 +3.0 %
V1 and V2 SLEEP Dropout Voltage LOAD = 20mA 75 150 mV
V6 Dropout Voltage M AX 1586 3V m od e, l oad = 30m A, 2.5V m od e, l oad = 30m A 110 200 mV
V7 Switch Voltage Drop LOAD = 20mA, VBKBT = VV1 = 3.0V 100 200 mV
V4, V5, V6 Output Current Limit 40 90 mA
BKBT Leakage 1 µA
OSCILLATOR
PWM Switching Frequency 0.93 1 1.07 MHz
SUPERVISORY/MANAGEMENT FUNCTIONS
Rising 92 94.75 97
POK Trip Threshold (Note 4) Falling 88.5 90.5 92.5 %
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
_______________________________________________________________________________________ 5
PARAMETER CONDITIONS MIN TYP MAX UNITS
LBI = IN (for preset) 3.51 3.6 3.69
LBI Threshold (Falling) MAX1586 hysteresis is
5% (typ) With resistors at LBI 0.98 1.00 1.02 V
DBI = IN (for preset) 3.024 3.15 3.276
DBI Threshold (Falling) MAX1586 hysteresis is
5% (typ) With resistors at LBI 1.208 1.232 1.256 V
RSO Threshold (Falling) Voltage on REG7, hysteresis is 5% (typ) 2.25 2.41 2.56 V
RSO Deassert Delay 61 65.5 70 ms
LBI Input Bias Current MAX1586 -50 -5 nA
DBI Input Bias Current MAX1586 15 50 nA
Thermal-Shutdown Temperature TJ rising +160 °C
Thermal-Shutdown Hysteresis 15 °C
LOGIC INPUTS AND OUTPUTS
LBO, DBO, POK, RSO, SDA Output
Low Level 2.6V ≤ V7 ≤ 5.5V, sinking 1mA 0.4 V
LBO, DBO, POK, RSO Output Low
Level V7 = 1V, sinking 100µA 0.4 V
LBO, DBO, POK, RSO Output-High
Leakage Current Pin = 5.5V 0.2 µA
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input High Level 2.6V ≤ VIN ≤ 5.5V 1.6 V
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input Low Level 2.6V ≤ VIN ≤ 5.5V 0.4 V
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input Leakage Current Pin = GND, 5.5V -1 +1 µA
SERIAL INTERFACE
Clock Frequency 400 kHz
Bus-Free Time Between START and
STOP 1.3 µs
H ol d Ti m e Rep eated S TART C ond i ti on 0.6 µs
CLK Low Period 1.3 µs
CLK High Period 0.6 µs
S etup Ti m e Rep eated S TART C ond i ti on 0.6 µs
DATA Hold Time 0µs
DATA Setup Time 100 ns
Maximum Pulse Width of Spikes that
Must be Suppressed by the Input
Filter of Both DATA and CLK Signals
50 ns
Setup Time for STOP Condition 0.6 µs
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = 0°C to +85°C, unless otherwise noted. Typical values
are at TA= +25°C.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
6 _______________________________________________________________________________________
PARAMETER CONDITIONS MIN MAX UNITS
PV1, PV2, PV3, SLPIN, IN Supply
Voltage Range
PV1, PV2, PV3, IN, and SLPIN must connect together
externally 2.6 5.5 V
IN45, IN6 Supply Voltage Range 2.4 5.5 V
VIN rising 2.25 2.55
IN Undervoltage-Lockout (UVLO)
Threshold VIN falling 2.200 2.525 V
SYNCHRONOUS-BUCK PWM REG1
FB1 = GND, 3.6V ≤ VPV1 ≤ 5.5V, load = 0 to 1300mA 3.25 3.35
REG1 Voltage Accuracy FB1 = IN, 3.6V ≤ VPV1 ≤ 5.5V, load = 0 to 1300mA 2.955 3.045 V
FB1 Voltage Accuracy FB1 used with external resistors, 3.6V ≤ VPV1 ≤ 5.5V,
load = 0 to 1300mA 1.231 1.269 V
FB1 Input Current FB1 used with external resistors 100 nA
Load = 800mA (Note 1) 280
Dropout Voltage Load = 1300mA (Note 1) 450 mV
ILX1 = -180mA 0.3
p-Channel On-Resistance ILX1 = -180mA, VPV1 = 2.6V 0.35
Ω
ILX1 = 180mA 0.225
n-Channel On-Resistance ILX1 = 180mA, VPV1 = 2.6V 0.25
Ω
p-Channel Current-Limit Threshold -1.55 -2.10 A
OUT1 Maximum Output Current 2.6V ≤ VPV1 ≤ 5.5V (Note 3) 1.30 A
LX1 Leakage Current VPV1 = 5.5V, LX1 = GND or PV1, VON1 = 0V -10 +10 µA
SYNCHRONOUS-BUCK PWM REG2
FB2 = GND, 3.6V ≤ VPV2 ≤ 5.5V, load = 0 to 900mA 2.463 2.537
MAX1586A, MAX1587A, FB2 = IN, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 1.773 1.827
REG2 Voltage Accuracy
MAX1586B, FB2 = IN, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 3.25 3.35
V
FB2 Voltage Accuracy FB2 used with external resistors, 3.6V ≤ VPV2 ≤ 5.5V,
load = 0 to 900mA 1.231 1.269 V
FB2 Input Current FB2 used with external resistors, VFB2 = 1.25V 100 nA
Dropout Voltage Load = 900mA (Note 1) 380 mV
ILX2 = -180mA 0.375
p-Channel On-Resistance ILX2 = -180mA, VPV2 = 2.6V 0.425
Ω
ILX2 = -180mA 0.25
n-Channel On-Resistance ILX2 = -180mA, VPV2 = 2.6V 0.275
Ω
p-Channel Current-Limit Threshold -1.1 -1.50 A
OUT2 Maximum Output Current 2.6V ≤ VPV2 ≤ 5.5V (Note 3) 0.9 A
LX2 Leakage Current VPV2 = 5.5V, LX2 = GND or PV2, VON2 = 0V -10 +10 µA
ELECTRICAL CHARACTERISTICS
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = -40°C to +85°C, unless otherwise noted.) (Note 5)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
_______________________________________________________________________________________ 7
PARAMETER CONDITIONS MIN MAX UNITS
SYNCHRONOUS-BUCK PWM REG3
MAX1586A, MAX1586B, MAX1587A,
load = 0 to 500mA -1.5 +1.5
REG3 Output Voltage Accuracy
REG3 from 0.7V to
1.475V, 2.6V ≤
VPV3 ≤ 5.5V MAX1586C, MAX1587C,
load = 0 to 900mA -1.5 +1.5
%
ILX3 = -180mA 0.375
p-Channel On-Resistance ILX2 = -180mA, VPV3 = 2.6V 0.425
Ω
ILX3 = 180mA 0.25
n-Channel On-Resistance ILX3 = 180mA, VPV3 = 2.6V 0.275
Ω
MAX1586A, MAX1586B, MAX1587A -0.60 -0.85
p-Channel Current-Limit Threshold MAX1586C, MAX1587C -1.125 -1.700 A
MAX1586A, MAX1586B, MAX1587A 0.5
OUT3 Maximum Output Current 2.6V ≤ VPV3 ≤ 5.5V
(Note 3) MAX1586C, MAX1587C 0.9 A
LX3 Leakage Current VPV3 = 5.5V, LX3 = GND or PV2, VON3 = 0V -10 +10 µA
LDOs V4, V5, V6, V1 SLEEP, V2 SLEEP, AND V7 OUTPUT
V4, V5, V6, V1 SLEEP, V2 SLEEP
Output Current 35 mA
V7 Output Current 30 mA
REG4 Output Voltage Load = 0.1mA to 35mA 1.254 1.346 V
REG5 Output Voltage Load = 0.1mA to 35mA 1.061 1.139 V
IN45, IN6 Input Voltage Range 2.4 5.5 V
1.8V setting, load = 0.1mA to 35mA 1.737 1.863
2.5V setting, load = 0.1mA to 35mA 2.412 2.588
REG6 Output Voltage (POR Default
to 0V, Set by Serial Input) MAX1586
3.0V setting, load = 0.1mA to 35mA 2.895 3.105
V
V1 and V2 SLEEP Output Voltage
Accuracy Set to same output voltage as REG1 and REG2 -3.5 +3.5 %
V1 and V2 SLEEP Dropout Voltage Load = 20mA 150 mV
V6 Dropout Voltage M AX 1586 3V m od e, l oad = 30m A; 2.5V m od e, l oad = 30m A 200 mV
V7 Switch Voltage Drop Load = 20mA, VBKBT = VV1 = 3.0V 200 mV
V4, V5, V6 Output Current Limit 40 mA
BKBT Leakage 1 µA
OSCILLATOR
PWM Switching Frequency 0.93 1.07 MHz
SUPERVISORY/MANAGEMENT FUNCTIONS
Rising 92 97
POK Trip Threshold (Note 4) Falling 88.5 92.5 %
LBI = IN (for preset) 3.51 3.69
LBI Threshold (Falling) MAX1586,
hysteresis is 5% (typ) With resistors at LBI 0.98 1.02 V
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = -40°C to +85°C, unless otherwise noted.) (Note 5)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
8 _______________________________________________________________________________________
PARAMETER CONDITIONS MIN MAX UNITS
DBI = IN (for preset) 2.993 3.307
DBI Threshold (Falling) MAX1586,
hysteresis is 5% (typ) With resistors at LBI 1.208 1.256 V
RSO Threshold (Falling) Voltage on REG7, hysteresis is 5% (typ) 2.25 2.60 V
RSO Deassert Delay 62 69 ms
LBI Input Bias Current MAX1586 -50 nA
DBI Input Bias Current MAX1586 75 nA
LOGIC INPUTS AND OUTPUTS
LBO, DBO, POK, RSO, SDA Output
Low Level 2.6V ≤ V7 ≤ 5.5V, sinking 1mA 0.4 V
LBO, DBO, POK, RSO, SDA Output
Low Level V7 = 1V, sinking 100µA 0.4 V
LBO, DBO, POK, RSO Output-High
Leakage Current Pin = 5.5V 0.2 µA
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input High Level 2.6V ≤ VIN ≤ 5.5V 1.6 V
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input Low Level 2.6V ≤ VIN ≤ 5.5V 0.4 V
ON_, SCL, SDA, SLP, PWM3, MR,
SRAD Input Leakage Current Pin = GND, 5.5V -1 +1 µA
SERIAL INTERFACE
Clock Frequency 400 kHz
Bus-Free Time Between START and
STOP 1.3 µs
Hold Time Repeated START
Condition 0.6 µs
CLK Low Period 1.3 µs
CLK High Period 0.6 µs
Setup Time Repeated START
Condition 0.6 µs
DATA Hold Time 0µs
DATA Setup Time 100 ns
Setup Time for STOP Condition 0.6 µs
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 3.6V, VBKBT = 3.0V, VLBI = 1.1V, VDBI = 1.35V, circuit of Figure 5, TA = -40°C to +85°C, unless otherwise noted.) (Note 5)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
_______________________________________________________________________________________ 9
Note 1: Dropout voltage is guaranteed by the p-channel switch resistance and assumes a maximum inductor resistance of 45mΩ.
Note 2: The PWM-skip-mode transition has approximately 10mA of hysteresis.
Note 3: The maximum output current is guaranteed by the following equation:
where:
and RN = n-channel synchronous rectifier RDS(ON)
RP = p-channel power switch RDS(ON)
RL = external inductor ESR
IOUT(MAX) = maximum required load current
f = operating frequency minimum
L = external inductor value
ILIM can be substituted for IOUT(MAX) (desired) when solving for D. This assumes that the inductor ripple current is
small relative to the absolute value.
Note 4: POK only indicates the status of supplies that are enabled (except V7). When a supply is turned off, POK does not trigger
low. When a supply is turned on, POK immediately goes low until that supply reaches regulation. POK is forced low when all
supplies (except V7) are disabled.
Note 5: Specifications to -40°C are guaranteed by design, not production tested.
DVI RR
VI RR
OUT OUT MAX N L
IN OUT MAX N P
=++
+−
()
()
()
()
I
IVD
xfxL
RR D
OUT MAX
LIM OUT
NL
()
()
()
()
=
−−
++ −
1
2
11
22xfxL
ELECTRICAL CHARACTERISTICS (continued)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
10 ______________________________________________________________________________________
Typical Operating Characteristics
(Circuit of Figure 6, VIN = 3.6V, TA = +25°C, unless otherwise noted.)
100
0.1 1 10 100 1000 10,000
90
80
70
60
50
40
REG1 3.3V OUTPUT EFFICIENCY
vs. LOAD CURRENT
MAX1586A/86B/87A toc01
LOAD CURRENT (mA)
EFFICIENCY (%)
VIN = 3.6V
VIN = 4.0V VIN = 5.0V
100
40
0.1 10 1001 1000
REG2 2.5V OUTPUT EFFICIENCY
vs. LOAD CURRENT
MAX1586A/86B/87A toc02
LOAD CURRENT (mA)
EFFICIENCY (%)
50
60
70
80
90 VIN = 3.6V
VIN = 4.0V VIN = 5.0V
100
40
0.1 10 1001 1000
REG3 1.3V OUTPUT EFFICIENCY
vs. LOAD CURRENT
MAX1586A/86B/87A toc03
LOAD CURRENT (mA)
EFFICIENCY (%)
50
60
70
80
90 VIN = 3.6V
VIN = 4.0V VIN = 5.0V
100
40
30
20
10
0.1 10 1001 1000
REG3 1.3V OUTPUT EFFICIENCY
vs. LOAD CURRENT
MAX1586A/86B/87A toc03B
LOAD CURRENT (mA)
EFFICIENCY (%)
50
60
70
80
90 VIN = 3.6V
VIN = 4.0V
VIN = 5.0V
L3 = 4.7μH
C17 = 44μF
MAX1586C
MAX1587C
0.1 10 1001 1000
REG3 1.3V OUTPUT WITH FORCED-PWM
EFFICIENCY vs. LOAD CURRENT
MAX1586A/86B/87A toc04B
LOAD CURRENT (mA)
EFFICIENCY (%)
VIN = 3.6V
VIN = 5.0V
VIN = 4.0V
L3 = 4.7μH
C17 = 44μF
100
40
30
20
10
50
60
70
80
90
MAX1586C
MAX1587C
0.1 10 1001 1000
REG3 1.3V OUTPUT WITH FORCED-PWM
EFFICIENCY vs. LOAD CURRENT
MAX1586A/86B/87A toc04
LOAD CURRENT (mA)
EFFICIENCY (%)
VIN = 3.6V
VIN = 5.0V
VIN = 4.0V
100
40
50
60
70
80
90
REG1 SLEEP LDO 3.3V OUTPUT
EFFICIENCY vs. LOAD CURRENT
MAX1586A/86B/87A toc05
LOAD CURRENT (mA)
EFFICIENCY (%)
100
40
50
60
70
80
90
0.1 1 10
VIN = 3.6V
VIN = 4.0V
VIN = 5.0V
REG2 SLEEP LDO 2.5V OUTPUT
EFFICIENCY vs. LOAD CURRENT
MAX1586A/86B/87A toc06
LOAD CURRENT (mA)
EFFICIENCY (%)
90
30
40
50
60
70
80
0.1 1 10
VIN = 3.6V VIN = 4.0V
VIN = 5.0V
0
20
140
100
180
220
021345
QUIESCENT CURRENT
vs. SUPPLY VOLTAGE
MAX1586A/86B/87A toc07
INPUT VOLTAGE (V)
INPUT CURRENT (μA)
BKBT BIASED AT 3.6V
V1, V2, AND V3 ON
V1 AND V2 ON
V1 ON
V1 AND V2 SLEEP
V1 SLEEP
ALL BUT V7 OFF
200
160
40
60
80
120
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
0
100
50
200
150
250
300
0 400200 600 800 1000 1200
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX1586A/86B/87A toc08
LOAD CURRENT (mA)
DROPOUT VOLTAGE (mV)
REG1 3.3V OUTPUT
-100
0
-50
100
50
150
200
0 400200 600 800 1000 1200
CHANGE IN OUTPUT VOLTAGE
vs. LOAD CURRENT
MAX1586A/86B/87A toc09
LOAD CURRENT (mA)
CHANGE IN OUTPUT VOLTAGE (mV)
VIN = 3.6V
REG1 3.3V OUTPUT
REG3 1.3V OUTPUT
REG2 2.5V OUTPUT
1.225
1.265
1.260
1.255
1.250
1.245
1.240
1.235
1.230
-40 -15 10 35 60 85
REFERENCE VOLTAGE
vs. TEMPERATURE
MAX1586A/86B/87A toc11
TEMPERATURE (°C)
REFERENCE VOLTAGE (V)
REG1 SWITCHING WAVEFORMS
WITH 800mA LOAD
MAX1586A/86B/87A toc12
400ns/div
0
0
500mA/div
10mv/div
AC-COUPLED
2V/div
VLX1
IL1
V1
REG1 SWITCHING WAVEFORMS
WITH 10mA LOAD
MAX1586A/86B/87A toc13
20μs/div
0
0
500mA/div
50mv/div
AC-COUPLED
2V/div
VLX1
V1
IL1
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________
11
Typical Operating Characteristics (continued)
(Circuit of Figure 6, VIN = 3.6V, TA = +25°C, unless otherwise noted.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
12 ______________________________________________________________________________________
REG3 SWITCHING WAVEFORMS
WITH 250mA LOAD
MAX1586A/86B/87A toc14
400ns/div
0
0
500mA/div
10mv/div
AC-COUPLED
2V/div
V3
IL3
VLX3
REG3 PULSE-SKIP SWITCHING
WAVEFORMS WITH 10mA LOAD
MAX1586A/86B/87A toc15
10μs/div
0
0
500mA/div
10mv/div
AC-COUPLED
2V/div
VLX3
V3
IL3
REG3 FORCED-PWM SWITCHING
WAVEFORMS WITH 10mA LOAD
MAX1586A/86B/87A toc16
400ns/div
0mA
0V
500mA/div
10mv/div
AC-COUPLED
2V/div
VLX3
V3
IL3
V7 AND RSO
STARTUP WAVEFORMS
MAX1586A/86B/87A toc17
10ms/div
0V
2V/div
0V
2V/div
0V
2V/div
RSO
VIN
V7
SYS_EN STARTUP WAVEFORMS
MAX1586A/86B/87A toc18
2ms/div
2V/div
2V/div
2V/div
2V/div
V2
V1
VEN1
AND
VEN2
VPOK
PWR_EN STARTUP WAVEFORMS
MAX1586A/86B/87A toc19
1ms/div
2V/div
2V/div
2V/div
2V/div
2V/div
V5
V4
V3
VEN3
AND
VEN45
VPOK
Typical Operating Characteristics (continued)
(Circuit of Figure 6, VIN = 3.6V, TA = +25°C, unless otherwise noted.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________
13
REG1 LOAD-TRANSIENT RESPONSE
MAX1586A/86B/87A toc20
200μs/div
0A
V1
100mV/div
AC-COUPLED
ILOAD1
200mA/div
REG2 LOAD-TRANSIENT RESPONSE
MAX1586A/86B/87A toc21
200μs/div
0A
V2
100mV/div
AC-COUPLED
ILOAD2
200mA/div
REG3 LOAD-TRANSIENT RESPONSE
MAX1586A/86B/87A toc22
200μs/div
0A
V3
100mV/div
AC-COUPLED
ILOAD3
200mA/div
REG3 LOAD-TRANSIENT RESPONSE
MAX1586A/86B/87A toc22B
100μs/div
850mA
50mA
V3
100mV/div
ILOAD3
500mA/div
MAX1586C
MAX1587C
REG3 OUTPUT VOLTAGE CHANGING FROM
1.3V TO 1.0V WITH DIFFERENT VALUES OF CRAMP
MAX1586A/86B/87A toc23
200μs/div
CRAMP = 2200pF
CRAMP = 1500pF
CRAMP = 1000pF
CRAMP = 330pF
REG6 USIM TRANSITIONS
MAX1586A/86B/87A toc24
10μs/div
0
500mV/div
V6
2.5V TO 3.0V
V6
1.8V TO 2.5V
V6
0 TO 1.8V
Typical Operating Characteristics (continued)
(Circuit of Figure 6, VIN = 3.6V, TA = +25°C, unless otherwise noted.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
14 ______________________________________________________________________________________
Pin Description
PIN
MAX
1586
MAX
1587
NAME
FUNCTION
1
— LBI
Dual Mode™, Low-Battery Input. Connect to IN to set the low-battery threshold to 3.6V (no resistors
needed). Connect LBI to a resistor-divider for an adjustable LBI threshold. When VIN is below the set
threshold, LBO output switches low. LBO is deactivated and forced low when VIN is below the dead-battery
(DBI) threshold and when all REGs are disabled.
2
40 CC1
REG1 Compensation Node. Connect a series resistor and capacitor from CC1 to GND to compensate the
regulation loop. See the Compensation and Stability section.
31
FB1
REG1 Feedback Input. Connect FB1 to GND to set V1 to 3.3V. Connect FB1 to external feedback resistors
for other output voltages.
42
BKBT
Input Connection for Backup Battery. This input can also accept the output of an external boost converter.
53V7
Also known as VCC_BATT. V7 is always active if main or backup power is present. It is the first regulator
that powers up. V7 has two states:
1) V7 tracks V1 if ON1 is high and V1 is in regulation.
2) V7 tracks VBKBT when ON1 is low or V1 is out of regulation.
64V1
REG1 Voltage-Sense Input. Connect directly to the REG1 output voltage. The output voltage is set by FB1
to either 3.3V or adjustable with resistors.
75
SLPIN
Inp ut to V 1 and V 2 S l eep Reg ul ator s. The i np ut to the stand b y r eg ul ator s at V 1 and V 2. C onnect S LP IN to IN .
86V2
REG2 Voltage-Sense Input. Connect directly to the REG2 output voltage. The output voltage is set by FB2
to either 1.8V/2.5V (MAX1586A, MAX1587A), 3.3V/2.5V (MAX1586B), or adjustable with resistors.
97
FB2
REG2 Feedback Input. Connect to GND to set V2 to 2.5V on all devices. Connect FB2 to IN to set V2 to
1.8V on the MAX1586A and MAX1587A. Connect FB2 to IN to set V2 to 3.3V on the MAX1586B. Connect
FB2 to external feedback resistors for other voltages.
10
8
CC2
REG2 Compensation Node. Connect a series resistor and capacitor from CC2 to GND to compensate the
regulation loop. See the Compensation and Stability section.
11
9
POK
Power-OK Output. Open-drain output that is low when any of the V1–V6 outputs are below their regulation
threshold. When all activated outputs are in regulation, POK is high impedance. POK maintains a valid low
output with V7 as low as 1V. POK does not flag an out-of-regulation condition while REG3 is transitioning
between voltages set by serial programming. POK also does not flag for any REG channel that has been
turned off; however, if all REG channels are off (V1–V6), then POK is forced low. If VIN < VUVLO, then POK is
low. POK is expected to connect to nVCC_FAULT.
12
10 SCL
Serial Clock Input
13
11 SDA
Serial Data Input. Data is read on the rising edge of SCL. Serial data programs the REG3 (core) and REG6
(VCC_USIM) voltage. REG3 and REG6 can be programmed even when off, but at least one of the ON_ pins
must be logic-high to activate the serial interface. On power-up, REG3 defaults to 1.3V and REG6 defaults
to 0V.
14
12 PWM3
Force V3 to PWM at All Loads. Connect PWM3 to GND for normal operation (skip mode at light loads). Drive
or connect high for forced-PWM operation at all loads for V3 only.
15
—LBO
Low-Battery Output. Open-drain output that goes low when VIN is below the threshold set by LBI.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 15
Pin Description (continued)
PIN
MAX
1586
MAX
1587
NAME
FUNCTION
16
13 PV2
REG2 Power Input. Bypass to PG2 with a 4.7µF or greater low-ESR capacitor. PV1, PV2, PV3, and IN must
connect together externally.
17
14 LX2
REG2 Switching Node. Connects to REG2 inductor.
18
15 PG2
REG2 Power Ground. Connect directly to a power-ground plane. Connect PG1, PG2, PG3, and GND
together at a single point as close as possible to the IC.
19
16
IN Main Battery Input. This input provides power to the IC.
20
17 RAMP
V3 Ramp-Rate Control. A capacitor connected from RAMP to GND sets the rate-of-change when V3 is
changed. The output impedance of RAMP is 100kΩ. FB3 regulates to 1.28 x VRAMP.
21
18 GND
Analog Ground
22
19 REF
Reference Output. Output of the 1.25V reference. Bypass to GND with a 0.1µF or greater capacitor.
23
20 BYP
Low-Noise LDO Bypass. Low-noise bypass pin for V4 LDO. Connect a 0.01µF capacitor from BYP to GND.
24
—DBO
Dead or Missing Battery Output. DBO is an open-drain output that goes low when VIN is below the
threshold set by DBI. DBO does not deactivate any MAX1586/MAX1587 regulator outputs. DBO is
expected to connect to nBATT_FAULT on Intel CPUs.
25
21 ON2
On/Off Input for REG2. Drive high to turn on. When enabled, the REG2 output soft-starts. ON2 has
hysteresis so an RC can be used to implement manual sequencing with respect to other inputs. It is
expected that ON1, ON2, and ON6 are connected to SYS_EN.
26
— ON4
On/Off Input for REG4. Drive high to turn on. When enabled, the REG4 output activates. ON4 has hysteresis
so an RC can be used to implement manual sequencing with respect to other inputs. It is expected that
ON4 is connected to PWR_EN.
27
23
V4 Also Known as VCC_PLL. 1.3V, 35mA linear-regulator output for PLL. Regulator input is IN45.
28
24 IN45
Power Input to V4 and V5 LDOs. Typically connected to V2, but can also connect to IN or another voltage
from 2.5V to VIN.
29
25
V5 Also Known as VCC_SRAM. 1.1V, 35mA linear-regulator output for CPU SRAM. Regulator input is IN45.
30
— ON5
On/Off Input for REG5. Drive high to turn on. When enabled, the MAX1586/MAX1587 soft-starts the REG5
output. ON5 has hysteresis so an RC can be used to implement manual sequencing with respect to other
inputs. It is expected that ON5 is connected to PWR_EN.
31
26 PG3
REG3 Power Ground. Connect directly to a power-ground plane. Connect PG1, PG2, PG3, and GND
together at a single point as close as possible to the IC.
32
27 LX3
REG3 Switching Node. Connects to the REG3 inductor.
33
28 PV3
REG3 Power Input. Bypass to PG3 with a 4.7µF or greater low-ESR ceramic capacitor. PV1, PV2, PV3, and
IN must connect together externally.
34
34 ON3
On/Off Input for REG3 (Core). Drive high to turn on. When enabled, the REG3 output ramps up. ON3 has
hysteresis so an RC can be used to implement manual sequencing with respect to other inputs. It is
expected that ON3 is driven from CPU SYS_EN.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
16 ______________________________________________________________________________________
Pin Description (continued)
PIN
MAX
1586
MAX
1587
NAME
FUNCTION
35
29 SRAD
Serial Address Bit. SRAD allows the serial address of the MAX1586/MAX1587 to be changed in case it
conflicts with another serial device. If SRAD = GND, A1 = 0. If SRAD = IN, A1 = 1.
36
30 RSO
Open-Drain Reset Output. Deasserts when V7 exceeds 2.55V (typ rising). Has 65ms delay before release.
RSO is expected to connect to nRESET on the CPU.
37
31 MR
Manual Reset Input. A low input at MR causes the RSO output to go low and also resets the V3 output to its
default 1.3V setting. MR impacts no other MAX1586/MAX1587 functions.
38
32 CC3
REG3 Compensation Node. Connect a series resistor and capacitor from CC3 to GND to compensate the
regulation loop. See the Compensation and Stability section.
39
33 FB3
REG3 Feedback-Sense Input. Connect directly to the REG3 output voltage. Output voltage is set by the
serial interface.
40
— ON6
On/Off Input for REG6. Drive high to turn on. When enabled, the REG6 output activates. ON6 has hysteresis
so an RC can be used to implement manual sequencing with respect to other inputs. It is expected that
ON1, ON2, and ON6 are connected to SYS_EN.
41
—
V6 Also known as VCC_USIM. Linear-regulator output. This voltage is programmable through the I2C interface
to 0V, 1.8V, 2.5V, or 3.0V. The default voltage is 0V. REG6 is activated when ON6 is high.
42
— IN6
Power Input to the V6 LDO. Typically connected to V1, but can also connect to IN.
43
36 PG1
REG1 Power Ground. Connect directly to a power-ground plane. Connect PG1, PG2, PG3, and GND
together at a single point as close as possible to the IC.
44
37 LX1
REG1 Switching Node. Connects to the REG1 inductor.
45
38 PV1
REG1 Power Input. Bypass to PG2 with a 4.7µF or greater low-ESR ceramic capacitor. PV1, PV2, PV3, and
IN must connect together externally.
46
35 ON1
On/Off Input for REG1. Drive high to turn on REG1. When enabled, the REG1 output soft-starts. ON1 has
hysteresis so an RC can be used to implement manual sequencing with respect to other inputs. It is
expected that ON1, ON2, and ON6 connect to SYS_EN.
47
39 SLP
Sleep Input. SLP selects which regulators ON1 and ON2 turn on. SLP = high is normal operation (ON1 and
ON2 are the enables for the V1 and V2 DC-DC converters). SLP = low is sleep operation (ON1 and ON2 are
the enables for the V1 and V2 LDOs).
48
— DBI
Dual Mode, Dead-Battery Input. Connect DBI to IN to set the dead-battery falling threshold to 3.15V (no
resistors needed). Connect DBI to a resistor-divider for an adjustable DBI threshold.
—
22 ON45
On/Off Input for REG4 and REG5. Drive high to turn on. When enabled, the REG4 and REG5 outputs
activate. ON45 has hysteresis so an RC can be used to implement manual sequencing with respect to
other inputs. It is expected that ON45 is connected to PWR_EN.
EP
EP
EP Exposed Metal Pad. Connect the exposed pad to ground. Connecting the exposed pad to ground does not
remove the requirement for proper ground connections to the appropriate ground pins.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 17
MAIN
BATT
PV1
BATT
STEP-DOWN
PWM
REG1
SLEEP
LDO
LX1
PG1
V1
FB1
V2
FB2
PV2
ON
SLPININ
ON STEP-DOWN
PWM
REG2
SLEEP
LDO
LX2
PG2
FB3
ON3
IN45
V4
BYP
ON4
ON5
V6
ON6
IN6
V5
PV3 TO BATT
TO V2
TO V2
TO BATT
PWM
LDO
REG
4
LDO
REG
5
STEP-DOWN
PWM
REG3 LX3
PG3
LDO
REG
6
V2, VCC_MEM
2.5V WITH FB2 = GND,
1.8V WITH FB2 = IN (MAX1586A, MAX1587A)
3.3V WITH FB2 = IN (MAX1586B)
OR ADJ WITH RESISTORS
V1, VCC_IO
3.3V WITH FB1 = GND,
OR ADJ WITH RESISTORS
VCC_USIM
0V, 1.8V, 3.0V (DEF = 0V)
V4, VCC_PLL
1.3V, 35mA
V5, VCC_SRAM
1.1V, 35mA
V3, VCC_CORE
0.7V TO 1.475V
500mA (MAX1586A, MAX1586B, MAX1587A)
900mA (MAX1586C, MAX1587C)
FROM CPU
PWR_EN
FROM CPU
SYS_EN
ON1
RUN
SLEEP
ON2
DBI (3.15V OR ADJ)
LBO
REF
1.25V
REF
UVLO
AND
BATT
MON
LBI (3.6V OR ADJ)
BKBT
DBO
SLP
TO V1
REG1 OK
POK
SCL SDA
GND
I2C
SERIAL
CC1
V7, VCC_BATT
(1ST SUPPLY, ALWAYS ON)
FROM CPU
SYS_EN
V7
V1–V6
POWER-
OK
CC2
CC3
TO CPU
nRESET
TO CPU
nVCC_FAULT
RSO
MR
RESET INPUT
Li+
BACKUP
BATTERY
OPEN-DRAIN LOW-BATT OUT
OPEN-DRAIN DEAD-BATT OUT
TO nBATT_FAULT
V3
DAC
RAMP
SRAD
PWM3
FORCE REG3
TO PWM
V7
RESET
2.425V
65ms
ADJ ON
MAX1586
100kΩ
Figure 1. MAX1586 Functional Diagram (The MAX1587 omits some features. See the Pin Description section.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
18 ______________________________________________________________________________________
Detailed Description
The MAX1586/MAX1587 power-management ICs are
optimized for devices using Intel XScale microproces-
sors, including third-generation smart cell phones,
PDAs, internet appliances, and other portable devices
requiring substantial computing and multimedia
capability at low power. The MAX1586A/MAX1586B/
MAX1587A comply with Intel Processor Power
specifications.
The ICs integrate seven high-performance, low-operat-
ing-current power supplies along with supervisory and
management functions. Regulator outputs include three
step-down DC-DC outputs (V1, V2, and V3), three lin-
ear regulators (V4, V5, and V6), and one always-on out-
put, V7 (Intel VCC_BATT). The V1 step-down DC-DC
converter provides 3.3V or adjustable output voltage for
I/O and peripherals. The V2 step-down DC-DC convert-
er on the MAX1586A and MAX1587A is preset for 1.8V
or 2.5V, while the MAX1586B V2 supply is preset for
3.3V or 2.5V. V2 can also be adjusted with external
resistors on all parts. The V3 step-down DC-DC con-
verter provides a serial-programmed output for power-
ing microprocessor cores. The three linear regulators
(V4, V5, and V6) provide power for PLL, SRAM, and
USIM.
To minimize sleep-state quiescent current, V1 and V2
have bypass “sleep” LDOs that can be activated to
minimize battery drain when output current is very low.
Other functions include separate on/off control for all
DC-DC converters, low-battery and dead-battery
detection, a power-OK output, a backup-battery input,
and a two-wire serial interface.
All DC-DC outputs use fast, 1MHz PWM switching and
small external components. They operate with fixed-fre-
quency PWM control and automatically switch from
PWM to skip-mode operation at light loads to reduce
operating current and extend battery life. The V3 core
output is capable of forced-PWM operation at all loads.
The 2.6V to 5.5V input voltage range allows 1-cell Li+,
3-cell NiMH, or a regulated 5V input.
The following power-supply descriptions include the
Intel terms for the various voltages in parenthesis. For
example, the MAX1586/MAX1587 V1 output is referred
to as VCC_IO in Intel documentation. See Figure 1.
V1 and V2 (VCC_IO, VCC_MEM)
Step-Down DC-DC Converters
V1 is a 1MHz current-mode step-down converter. The V1
output voltage can be preset to 3.3V or adjusted using a
resistor voltage-divider. V1 supplies loads up to 1300mA.
V2 is also a 1MHz current-mode step-down converter.
The V2 step-down DC-DC converter on the MAX1586A
and MAX1587A is preset for 1.8V or 2.5V, while the
MAX1586B V2 supply is preset for 3.3V or 2.5V. V2 can
also be adjusted with external resistors on all parts. V2
supplies loads up to 900mA.
Under moderate to heavy loading, the converters operate
in a low-noise PWM mode with constant frequency and
modulated pulse width. Switching harmonics generated
by fixed-frequency operation are consistent and easily fil-
tered. Efficiency is enhanced under light loading (< 30mA
typ), by assuming an Idle Mode™during which the con-
verter switches only as needed to service the load.
Synchronous Rectification
Internal n-channel synchronous rectifiers eliminate the
need for external Schottky diodes and improve efficien-
cy. The synchronous rectifier turns on during the sec-
ond half of each cycle (off-time). During this time, the
voltage across the inductor is reversed, and the induc-
tor current falls. In normal operation (not forced PWM),
the synchronous rectifier turns off at the end of the
cycle (at which time another on-time begins) or when
the inductor current approaches zero.
100% Duty-Cycle Operation
If the inductor current does not rise sufficiently to sup-
ply the load during the on-time, the switch remains on,
allowing operation up to 100% duty cycle. This allows
the output voltage to maintain regulation while the input
voltage approaches the regulation voltage. Dropout
voltage is approximately 180mV for an 800mA load on
V1 and 220mV for an 800mA load on V2. During
dropout, the high-side p-channel MOSFET turns on,
and the controller enters a low-current-consumption
mode. The device remains in this mode until the regula-
tor channel is no longer in dropout.
Sleep LDOs
In addition to the high-efficiency step-down converters,
V1 and V2 can also be supplied with low-quiescent cur-
rent, low-dropout (LDO) linear regulators that can be
used in sleep mode or at any time when the load current
is very low. The sleep LDOs can source up to 35mA. To
enable the sleep LDOs, drive SLP low. When SLP is high,
the switching step-down converters are active. The out-
put voltage of the sleep LDOs is set to be the same as
the switching step-down converters as described in the
Setting the Output Voltages
section. SLPIN is the input to
the V1 and V2 sleep LDOs and must connect to IN.
Idle Mode is a trademark of Maxim Integrated Products, Inc.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 19
V3 (VCC_CORE) Step-Down
DC-DC Converter
V3 is a 1MHz current-mode step-down converter. The
MAX1586A, MAX1586B, and MAX1587A supply loads
up to 500mA from V3 while the MAX1586C and
MAX1587C supply loads up to 1A.
The V3 output is set by the I2C serial interface to
between 0.7V and 1.475V in 25mV increments. The
default output voltage on power-up and after a reset is
1.3V. See the
Serial Interface
section for programming
details. See the
Applications Information
for instructions
on how to increase the V3 output voltage.
Forced PWM on REG3
Under moderate to heavy loading, the V3 always operates
in a low-noise PWM mode with constant frequency and
modulated pulse width. Switching harmonics generated by
fixed-frequency operation are consistent and easily filtered.
With light loads (< 30mA) and PWM3 low, V3 operates
in an enhanced-efficiency Idle Mode during which the
converter switches only as needed to service the load.
With PWM3 high, V3 operates in low-noise forced-PWM
mode under all load conditions.
Linear Regulators (V4, V5, and V6)
V4 (VCC_PLL)
V4 is a linear regulator that provides a fixed 1.3V output
and supplies loads up to 35mA. The power input for the
V4 and V5 linear regulators is IN45, which is typically
connected to V2. To enable V4 on the MAX1586, drive
ON4 high, or drive ON4 low for shutdown. On the
MAX1587, the enable pins for V4 and V5 are combined.
Drive ON45 high to enable V4 and V5, or drive ON45 low
for shutdown. V4 is intended to connect to VCC_PLL.
V5 (VCC_SRAM)
V5 is a linear regulator that provides a fixed 1.1V output
and supplies loads up to 35mA. The power input for the
V4 and V5 linear regulators is IN45, which is typically
connected to V2. To enable V5 on the MAX1586, drive
ON5 high, or drive ON5 low for shutdown. On the
MAX1587, the enable pins for V4 and V5 are combined.
Drive ON45 high to enable V4 and V5, or drive ON45 low
for shutdown. V5 is intended to connect to VCC_SRAM.
V6 (VCC_USIM—MAX1586 Only)
V6 is a linear regulator on the MAX1586 that supplies
loads up to 35mA. The V6 output voltage is pro-
grammed with the I2C serial interface to 0V, 1.8V, 2.5V,
or 3.0V. The power-up default for V6 is 0V. See the
Serial Interface
section for details on changing the volt-
age. The power input for the V6 linear regulator is IN6,
which is typically connected to V1. To enable V6, drive
ON6 high, or drive ON6 low for shutdown. V6 is intend-
ed to connect to VCC_USIM.
V7 Always-On Output (VCC_BATT)
The V7 output is always active if V1 is enabled and in
regulation or if backup power is present. When ON1 is
high and V1 is in regulation, V7 is sourced from V1 by
an internal MOSFET switch. When ON1 is low or V1 is
out of regulation, V7 is sourced from BKBT by a second
on-chip MOSFET. V7 can supply loads up to 30mA. V7
is intended to connect to VCC_BATT on Intel CPUs.
Due to variations in system implementation, BKBT and
V7 can be utilized in different ways. See the
Backup-
Battery and V7 Configurations
section for information on
how to use BKBT and V7.
Quiescent Operating Current
in Various States
The MAX1586/MAX1587 are designed for optimum effi-
ciency and minimum operating current for all typical
operating modes, including sleep and deep sleep.
These states are outlined in Table 1.
Table 1. Quiescent Operating Current in Various States
OPERATING
POWER MODE DESCRIPTION TYPICAL MAX1586/MAX1587
NO-LOAD OPERATING CURRENT
RUN All supplies on and running
IDLE All supplies on and running, peripherals on
SENSE All supplies on, minimal loading, peripherals monitored
STANDBY All supplies on, minimal loading, peripherals not monitored
200µA MAX1587,
225µA MAX1586
SLEEP P W R_E N contr ol l ed vol tag es ( V 3, V 4, V 5) ar e off. V 1 and V 2 on. 60µA if V1 and V2 SLEEP LDOs on;
130µA if V1, V2 step-down DC-DCs enabled
DEEP SLEEP All supplies off except V7. V7 biased from backup battery.
5µA MAX1587 if VIN > DBI threshold;
32µA MAX1586 if VIN > DBI threshold;
4µA if VIN < DBI threshold
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
20 ______________________________________________________________________________________
Voltage Monitors, Reset, and
Undervoltage-Lockout Functions
Undervoltage Lockout
When the input voltage is below 2.35V (typ), an under-
voltage-lockout (UVLO) circuit disables the IC. The
inputs remain high impedance while in UVLO, reducing
battery load under this condition. All serial registers are
maintained with the input voltage down to at least 2.35V.
Reset Output (RSO) and MR Input
The reset output (RSO) is low when the MR input is low
or when V7 is below 2.425V. V7 is powered from V1
(when enabled) or the backup-battery input (BKBT).
RSO normally goes low:
1) When power is first applied in configurations with no
separate backup battery (external diode from IN to
BKBT).
2) When power is removed in configurations with no
separate backup battery (external diode from IN to
BKBT).
3) If the backup battery falls below 2.425V when V1 is
off or out of regulation.
4) When the manual reset button is pressed (MR goes
low).
If VIN is > 2.4V, an internal timer delays the release of
RSO for 65ms after V7 rises above 2.3V. However, if VIN
< 2.4V when V7 exceeds 2.3V, or if VIN and V7 rise at the
same time, RSO deasserts immediately with no 65ms
delay. There is no delay in the second case because the
timer circuitry is deactivated to minimize operating cur-
rent during VIN undervoltage lockout.
If it is desired to have a 65ms RSO release delay for any
sequence of VIN and V7, the circuit in Figure 2 may be
used. An RC connected from IN to MR delays the rise of
MR until after VIN powers up. The 65ms timer is valid for
either sequence of V7 and VIN and does not release until
65ms after both are up. The only regulator output that
affects RSO is V7. RSO will not respond to V1–V6, which
are monitored by POK. Also, RSO is high impedance
and does not function if BKBT is not powered.
MR is a manual reset input for hardware reset. A low
input at MR causes the RSO output to go low for at least
65ms and also resets the V3 output to its default 1.3V set-
ting. MR impacts no other MAX1586/MAX1587 functions.
Dead-Battery and Low-Battery Comparators—
DBI, LBI (MAX1586 Only)
The DBI and LBI inputs monitor input power (usually a
battery) and trigger the DBO and LBO outputs. The
dead-battery comparator triggers DBO when the battery
(VIN) discharges to the dead-battery threshold. The
factory-set 3.15V threshold is selected by connecting
DBI to IN, or the threshold can be programmed with a
resistor-divider at DBI. The low-battery comparator has
a factory-set 3.6V threshold that is selected by connect-
ing LBI to IN, or its threshold can be programmed with a
resistor-divider at LBI.
One three-resistor-divider can set both DBI and LBI
(R1, R2, and R3 in Figure 3) according to the following
equations:
1) Choose R3 to be less than 250kΩ.
323 1)RR
V
V
V
V
DBITH
LBITH
LB
DB
=× −
⎛
⎝
⎜⎞
⎠
⎟
2131)RR
V
V
V
V
LB
LBITH
DBITH
DB
=−
⎛
⎝
⎜⎞
⎠
⎟
MAX1586
MAIN BATTERY
R1
438kΩ
R2
62kΩ
R3
200kΩ
IN
DBI (1.232V THRESHOLD)
LBI (1.00V THRESHOLD)
Figure 3. Setting the Low-Battery and Dead-Battery Thresholds
with One Resistor Chain. The values shown set a DBI threshold
of 3.3V and an LBI threshold of 3.5V (no resistors are needed
for the factory preset thresholds).
IN
100kΩ
0.22μF
MAX1586
MAX1587
MR
Figure 2. An RC delay connected from IN to MR ensures that
the 65ms RSO release delay remains in effect for any
sequence of VIN and V7.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 21
where VLB is the desired low-battery detection voltage
and VDB is the desired dead-battery detection voltage.
VLBITH is the LBI threshold (1.0V typ) and VDBITH is the
DBI threshold (1.232V typ).
Alternately, LBI and DBI can be set with separate two-
resistor-dividers. Choose the lower resistor of the divider
chain to be 250kΩor less (R5 and R7 in Figure 4). The
equations for upper divider-resistors as a function of
each threshold are then:
When resistors are used to set VLB, the threshold at LBI
is 1.00V. When resistors are used to set VDB, the
threshold at DBI is 1.232V. A resistor-set threshold can
also be used for only one of DBI or LBI. The other
threshold can then be factory set by connecting the
appropriate input to IN.
If BKBT is not powered, DBO does not function and is
high impedance. DBO is expected to connect to
nBATT_FAULT on Intel CPUs. If BKBT is not powered,
LBO does not function and is high impedance.
Power-OK Output (POK)
POK is an open-drain output that goes low when any
activated regulator (V1–V6) is below its regulation
threshold. POK does not monitor V7. When all active
output voltages are within 10% of regulation, POK is
high impedance. POK does not flag an out-of-regula-
tion condition while V3 is transitioning between voltages
set by serial programming or when any regulator chan-
nel has been turned off. POK momentarily goes low
when any regulator is turned on, but returns high when
that regulator reaches regulation. When all regulators
(V1–V6) are off, POK is forced low. If the input voltage
is below the UVLO threshold, POK is held low and
maintains a valid low output with VIN as low as 1V. If
BKBT is not powered, POK does not function and is
high impedance.
Connection to Processor
and Power Sequencing
Typical processor connections have only power-control
pins, typically labeled PWR_EN and SYS_EN. The
MAX1586/MAX1587 provide numerous on/off control
pins for maximum flexibility. In a typical application,
many of these pins are connected together. ON1, ON2,
and ON6 typically connect to SYS_EN. ON3, ON4, and
ON5 typically connect to PWR_EN. V7 remains on as long
as the main or backup power is connected. Sequencing
is not performed internally on the MAX1586/MAX1587;
however, all ON_ inputs have hysteresis and can connect
to RC networks to set sequencing. For typical connec-
tions to Intel CPUs, no external sequencing is required.
Backup-Battery Input
The backup-battery input (BKBT) provides backup
power for V7 when V1 is disabled. Normally, a primary
or rechargeable backup battery is connected to this
pin. If a backup battery is not used, then BKBT should
connect to IN through a diode or external regulator. See
the
Backup-Battery and V7 Configurations
section for
information on how to use BKBT and V7.
Serial Interface
An I2C-compatible, two-wire serial interface controls
REG3 on the MAX1587, and REG3 and REG6 on the
MAX1586. The serial interface operates when VIN
exceeds the 2.40V UVLO threshold and at least one of
ON1–ON6 is asserted. The serial interface is shut down
to minimize off-current drain when no regulators are
enabled.
RR V
V
LB
LBITH
67 1=× −
⎛
⎝
⎜⎞
⎠
⎟
RR V
V
DB
DBITH
45 1=× −
⎛
⎝
⎜⎞
⎠
⎟
MAX1586
MAIN BATTERY
R6
500kΩ
R7
200kΩ
IN
DBI (1.232V THRESHOLD)
LBI (1.00V THRESHOLD)
R5
200kΩ
R4
334kΩ
Figure 4. Setting the Low-Battery and Dead-Battery Thresholds
with Separate Resistor-Dividers. The values shown set a DBI
threshold of 3.3V and an LBI threshold of 3.5V (no resistors are
needed for factory-preset thresholds).
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
22 ______________________________________________________________________________________
Table 2. V3 and V6 Serial Programming Codes
D7 D6
D5
0 = PROG V3
1 = PROG V6
D4 D3 D2 D1 D0 OUTPUT
(V) DESCRIPTION
0 000000.700
0 000010.725
0 000100.750
0 000110.775
0 001000.800
0 001010.825
0 001100.850
0 001110.875
0 010000.900
0 010010.925
0 010100.950
0 010110.975
0 011001.000
0 011011.025
0 011101.050
0 011111.075
0 100001.100
0 100011.125
0 100101.150
0 100111.175
0 101001.200
0 101011.225
0 101101.250
0 101111.275
0 110001.300
0 110011.325
0 110101.350
0 110111.375
0 111001.400
0 111011.425
0 111101.450
0 111111.475
V3, CORE
VOLTAGES
1 XXX0 0 0
1 XXX011.8
1 XXX102.5
XX
1 XXX113.0
V6, USIM
VOLTAGES
[MAX1586
ONLY]
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 23
The serial interface consists of a serial data line (SDA)
and a serial clock line (SCL). Standard I2C-compatible
write-byte commands are used. Figure 5 shows a tim-
ing diagram for the I2C protocol. The MAX1586/
MAX1587 are slave-only devices, relying upon a master
to generate a clock signal. The master (typically a
microprocessor) initiates data transfer on the bus and
generates SCL to permit data transfer. A master device
communicates to the MAX1586/MAX1587 by transmit-
ting the proper address followed by the 8-bit data code
(Table 2). Each transmit sequence is framed by a
START (A) condition and a STOP (L) condition. Each
word transmitted over the bus is 8 bits long and is
always followed by an acknowledge clock pulse.
Table 2 shows the serial data codes used to program
V3 and V6. The default power-up voltage for V3 is 1.3V
and for V6 is 0V.
Bit Transfer
One data bit is transferred during each SCL clock
cycle. The data on SDA must remain stable during the
high period of the SCL clock pulse. Changes in SDA
while SCL is high are control signals (see the
START
and STOP Conditions
section). Both SDA and SCL idle
high when the bus is not busy.
START and STOP Conditions
When the serial interface is inactive, SDA and SCL idle
high. A master device initiates communication by issu-
ing a START condition. A START condition is a high-to-
low transition on SDA with SCL high. A STOP condition
is a low-to-high transition on SDA while SCL is high
(Figure 5). A START condition from the master signals
the beginning of a transmission to the MAX1586/
MAX1587. The master terminates transmission by issu-
ing a not acknowledge followed by a STOP condition
(see the
Acknowledge Bit (ACK)
section). The STOP
condition frees the bus.
When a STOP condition or incorrect address is detect-
ed, the MAX1586/MAX1587 internally disconnect SCL
from the serial interface until the next START condition,
minimizing digital noise and feedthrough.
Acknowledge Bit (ACK)
The acknowledge bit (ACK) is the ninth bit attached to
every 8-bit data word. The receiving device always
generates ACK. The MAX1586/MAX1587 generate an
ACK when receiving an address or data by pulling SDA
low during the ninth clock period. Monitoring ACK
allows for detection of unsuccessful data transfers. An
unsuccessful data transfer occurs if a receiving device
is busy or if a system fault has occurred. In the event of
an unsuccessful data transfer, the bus master should
reattempt communication at a later time.
Serial Address
A bus master initiates communication with a slave
device by issuing a START condition followed by the
7-bit slave address (Table 3). When idle, the
MAX1586/MAX1587 wait for a START condition fol-
lowed by its slave address. The serial interface com-
pares each address value bit by bit, allowing the
interface to power down immediately if an incorrect
address is detected.
SCL
AB CDEFG HIJK
SDA
tSU:STA tHD:STA
tLOW tHIGH
tSU:DAT tHD:DAT tSU:STO tBUF
A = START CONDITION
B = MSB OF ADDRESS CLOCKED INTO SLAVE
C = LSB OF ADDRESS CLOCKED INTO SLAVE
D = R/W BIT CLOCKED INTO SLAVE
E = SLAVE PULLS SMB DATA LINE LOW
L M
F = ACKNOWLEDGE BIT CLOCKED INTO MASTER
G = MSB OF DATA CLOCKED INTO SLAVE (OP/SUS BIT)
H = LSB OF DATA CLOCKED INTO SLAVE
I = SLAVE PULLS SMB DATA LINE LOW
J = ACKNOWLEDGE CLOCKED INTO MASTER
K = ACKNOWLEDGE CLOCK PULSE
L = STOP CONDITION, DATA EXECUTED BY SLAVE
M = NEW START CONDITION
Figure 5. I2C-Compatible Serial-Interface Timing Diagram
Table 3. Serial Address
SRAD A7 A6 A5 A4 A3 A2 A1 A0
RD/W
0 0010100 0
1 0010101 0
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
24 ______________________________________________________________________________________
The LSB of the address word is the read/write (R/W) bit.
R/Windicates whether the master is writing or reading
(RD/W0 = write, RD/W1 = read). The MAX1586/
MAX1587 only support the SEND BYTE format; there-
fore, RD/Wis required to be 0.
After receiving the proper address, the MAX1586/
MAX1587 issue an ACK by pulling SDA low for one
clock cycle. The MAX1586/MAX1587 have two user-
programmed addresses (Table 3). Address bits A7
through A2 are fixed, while A1 is controlled by SRAD.
Connecting SRAD to GND sets A1 = 0. Connecting
SRAD to IN sets A1 = 1.
V3 Output Ramp-Rate Control
When V3 is dynamically changed with the serial inter-
face, the output voltage changes at a rate controlled by
a capacitor (CRAMP) connected from RAMP to ground.
The voltage change is a conventional RC exponential
described by:
Vo(t) = Vo(0) + dV(1 – exp(-t/(100kΩCRAMP)))
A useful approximation is that it takes approximately 2.2
RC time constants for V3 to move from 10% to 90% of
the voltage difference. For CRAMP = 1500pF, this time
is 330µs. For 1V to 1.3V change, this equates to
1mV/µs. See the
Typical Operating Characteristics
for
examples of different ramp-rate settings.
The maximum capacitor value that can be used at
RAMP is 2200pF. If larger values are used, the V3 ramp
rate is still controlled according to the above equation,
but when V3 is first activated, POK indicates an “in reg-
ulation” condition before V3 reaches its final voltage.
The RAMP pin is effectively the reference for REG3.
FB3 regulates to 1.28 times the voltage on RAMP.
Design Procedure
Setting the Output Voltages
The outputs V1 and V2 have preset output voltages, but
can also be adjusted using a resistor voltage-divider. To
set V1 to 3.3V, connect FB1 to GND. V2 can be preset to
1.8V or 2.5V on the MAX1586A and MAX1587A. To set
V2 to 1.8V on the MAX1586A and MAX1587A, connect
FB2 to IN. To set to 2.5V, connect FB2 to GND. V2 can
preset to 3.3V or 2.5V on the MAX1587B. To set V2 to
3.3V on the MAX1587B, connect FB2 to IN. To set to
2.5V, connect FB2 to GND.
To set V1 or V2 to other than the preset output voltages,
connect a resistor voltage-divider from the output volt-
age to the corresponding FB input. The FB_ input bias
current is less than 100nA, so choose the low-side
(FB_-to-GND) resistor (RL) to be 100kΩor less. Then cal-
culate the high-side (output-to-FB_) resistor (RH) using:
RH= RL[(VOUT/1.25) – 1]
The V3 (VCC_CORE) output voltage is set from 0.7V to
1.475V in 25mV steps by the I2C serial interface. See
the
Serial Interface
section for details.
Linear regulator V4 provides a fixed 1.3V output volt-
age. Linear regulator V5 provides a fixed 1.1V output
voltage. V4 and V5 voltages are not adjustable.
The output voltage of linear regulator V6 (VCC_USIM) is
set to 0V, 1.8V, 2.5V, or 3.0V by the I2C serial interface.
See the
Serial Interface
section for details.
Linear regulator V7 (VCC_BATT) tracks the voltage at
V1 as long as ON1 is high and V1 is in regulation. When
ON1 is low or V1 is not in regulation, V7 switches to the
backup battery (VBKBT).
Inductor Selection
The external components required for the step-down
are an inductor, input and output filter capacitors, and a
compensation RC network.
The MAX1586/MAX1587 step-down converters provide
best efficiency with continuous inductor current. A rea-
sonable inductor value (LIDEAL) is derived from:
LIDEAL = [2(VIN) x D(1 - D)]/(IOUT(MAX) x fOSC)
This sets the peak-to-peak inductor current at 1/2 the
DC inductor current. D is the duty cycle:
D = VOUT/VIN
Given LIDEAL, the peak-to-peak inductor ripple current
is 0.5 x IOUT. The peak inductor current is 1.25 x
IOUT(MAX). Make sure the saturation current of the
inductor exceeds the peak inductor current and the
rated maximum DC inductor current exceeds the maxi-
mum output current (IOUT(MAX)). Inductance values
larger than LIDEAL can be used to optimize efficiency or
to obtain the maximum possible output current. Larger
inductance values accomplish this by supplying a
given load current with a lower inductor peak current.
Typically, output current and efficiency are improved
for inductor values up to about two times LIDEAL. If the
inductance is raised too much, however, the inductor
size may become too large, or the increased inductor
resistance may reduce efficiency more than the gain
derived from lower peak current.
Smaller inductance values allow smaller inductor sizes,
but also result in larger peak inductor current for a
given load. Larger output capacitance may then be
needed to suppress the increase in output ripple
caused by larger peak current.
Capacitor Selection
The input capacitor in a DC-DC converter reduces cur-
rent peaks drawn from the battery or other input power
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 25
source and reduces switching noise in the controller.
The impedance of the input capacitor at the switching
frequency should be less than that of the input source
so high-frequency switching currents do not pass
through the input source.
The output capacitor keeps output ripple small and
ensures control-loop stability. The output capacitor
must also have low impedance at the switching fre-
quency. Ceramic, polymer, and tantalum capacitors
are suitable, with ceramic exhibiting the lowest ESR
and lowest high-frequency impedance.
Output ripple with a ceramic output capacitor is
approximately:
VRIPPLE = IL(PEAK) [1/(2πx fOSC x COUT)]
If the capacitor has significant ESR, the output ripple
component due to capacitor ESR is:
VRIPPLE(ESR) = IL(PEAK) x ESR
Output capacitor specifics are also discussed in the
Compensation and Stability
section.
Compensation and Stability
The relevant characteristics for REG1, REG2, and
REG3 compensation are:
1) Transconductance (from FB_ to CC_), gmEA
2) Current-sense amplifier transresistance, RCS
3) Feedback regulation voltage, VFB (1.25V)
4) Step-down output voltage, VOUT, in V
5) Output load equivalent resistance, RLOAD = VOUT/
ILOAD
The key steps for step-down compensation are:
1) Set the compensation RC zero to cancel the RLOAD
COUT pole.
2) Set the loop crossover at or below approximately
1/10th the switching frequency.
For example, with VIN(MAX) = 5V, VOUT = 2.5V for
REG2, and IOUT = 800mA, then RLOAD = 3.125Ω. For
REG2, RCS = 0.75V/A and gmEA = 87µS.
Choose the crossover frequency, fC≤fOSC/10. Choose
100kHz. Then calculate the value of the compensation
capacitor, CC:
CC= (VFB/VOUT) x (RLOAD/RCS) x (gmEA/(2πx fC))
= (1.25/2.5) x (3.125/0.75) x (87 x 10-6/(6.28
x 100,000)) = 289pF
Choose 330pF, the next highest standard value.
Now select the compensation resistor, RC, so transient-
droop requirements are met. As an example, if 3% tran-
sient droop is allowed for the desired load step, the
input to the error amplifier moves 0.03 x 1.25V, or
37.5mV. The error-amplifier output drives 37.5mV x
gmEA, or IEAO = 37.5mV x 87µS = 3.26µA across RCto
provide transient gain. Find the value of RCthat allows
the required load-step swing from:
RC= RCS x IIND(PK)/IEAO
where IIND(PK) is the peak inductor current. In a step-
down DC-DC converter, if LIDEAL is used, output cur-
rent relates to inductor current by:
IIND(PK) = 1.25 x IOUT
So for an 800mA output load step with VIN = 3.6V and
VOUT = 2.5V:
RC= RCS x IIND(PK)/IEAO = (0.75V/A) x
(1.25 x 0.8A)/3.26µA = 230kΩ
We choose 240kΩ. Note that the inductor does not limit
the response in this case since it can ramp at (VIN -
VOUT)/L, or (3.6V - 2.5V)/3.3µH = 242mA/µs.
The output filter capacitor is then selected so that the
COUT RLOAD pole cancels the RCCCzero:
COUT x RLOAD = RCx CC
For the example:
RLOAD = VOUT x ILOAD = 2.5V/0.8A =
3.125Ω
COUT = RC x CC/RLOAD = 240kΩx 330pF/
3.125Ω= 25µF
PARAMETER REG1 REG2 REG3
Error-Amplifier
Transconductance, gmEA 87µS 87µS 68µS
Current-Sense Amp
Transresistance, RCS 0.5V/A 0.75V/A 1.25V/A
Table 4. Compensation Parameters
COMPONENT OR
PARAMETER REG1 REG2 REG3
VOUT 3.3V 2.5V 1.3V
Output Current 1300mA 900mA 500mA
Inductor 3.3µH 6.8µH 10µH
Load-Step Droop 3% 3% 3%
Loop Crossover Freq (fC) 100kHz 100kHz 100kHz
CC330pF 270pF 330pF
RC240kΩ240kΩ240kΩ
COUT 22µF 22µF 22µF
Table 5. Typical Compensation Values
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
26 ______________________________________________________________________________________
MAIN
BATT
PV1
BATT
TO
BATT STEP-DOWN
PWM
REG1
SLEEP
LDO
LX1
C12
4.7μF
C11
10μF
C19
0.1μF
C25
1μF
C24
1μF
C28
330pF
C27
270pF
C26
330pF
R20
1MΩ
R21
240kΩ
R18
1MΩ
R22
240kΩR23
240kΩ
R19
1MΩC15
22μF
C16
22μF
C17
22μF
C13
4.7μF
C14
4.7μF
C20
0.01μF
C23
1μF
C22
1μF
C21
1μF
L1
3.3μH
L2
6.8μH
L3
10μH
PG1
V1
FB1
V2
FB2
PV2
ON
SLPININ
ON STEP-DOWN
PWM
REG2
SLEEP
LDO
LX2
PG2
FB3
ON3
IN45
V4
BYP
ON4
ON5
IN6
ON6
V5
V6
PV3 TO BATT
TO V2
TO V2
TO BATT
PWM
LDO
REG
4
LDO
REG
5
STEP-DOWN
PWM
REG3 LX3
PG3
LDO
REG
6
V1
VCC_IO
3.3V
1300mA
V2
VCC_MEM
2.5V
900mA
V6
VCC_USIM
0V, 1.8V, 3.0V (DEF = 0V)
35mA
V4, VCC_PLL
1.3V, 35mA
V5
VCC_SRAM
1.1V, 35mA
V3
VCC_CORE
0.7V TO 1.475V
500mA (MAX1586A, MAX1586B, MAX1587A)
900mA (MAX1586C, MAX1587C)
FROM CPU
PWR_EN
FROM CPU
SYS_EN
ON1
RUN
SLEEP
ON2
DBI (3.2V OR ADJ)
LBO
REF
1.25V
REF
UVLO
AND
BATT
MON
LBI (3.6V OR ADJ)
BKBT
DBO
SLP
TO V1
TO V1
TO V1
REG1 OK
POK
ADJ ON
SCL SDA
GND
I2C
SERIAL
CC1
V7, VCC_BATT
(ALWAYS ON)
FROM CPU
SYS_EN
V7
V1–V6
POWER-
OK
CC2
CC3
TO CPU
nRESET
TO CPU
nVCC-FAULT
RSO
MR
RESET INPUT
Li+
BACKUP
BATTERY
LOW-BATT
WARNING
TO CPU
nBATT_FAULT
V3
DAC
RAMP
C18
1500pF
SRAD
PWM3
V7
RESET
2.3V
65ms
MAX1586
100kΩ
Figure 6. MAX1586 Typical Applications Circuit (The MAX1587 omits some features. See the Pin Description section.)
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 27
We choose 22µF.
Recalculate RCusing the selected COUT.
RC= COUT x RLOAD/CC = 208kΩ
Note that the pole cancellation does not have to be
exact. RCx CCneed only be within 0.75 to 1.25 times
RLOAD x COUT. This provides flexibility in component
selection.
If the output filter capacitor has significant ESR, a zero
occurs at:
ZESR = 1/(2πx COUT x RESR)
If ZESR > fC, it can be ignored, as is typically the case
with ceramic or polymer output capacitors. If ZESR is
less than fC, it should be cancelled with a pole set by
capacitor CPconnected from CC_ to GND:
CP= COUT x RESR/RC
If CPis calculated to be < 10pF, it can be omitted.
Optimizing Transient Response
In applications that require load-transient response to
be optimized in favor of minimum component values,
increase the output filter capacitor to increase the R in
the compensation RC. From the equations in the previ-
ous section, doubling the output cap allows a doubling
of the compensation R, which then doubles the tran-
sient gain.
Applications Information
Extending the Maximum Core
Voltage Range
The V3 output can be serially programmed to supply
from 0.7V to 1.475V in 25mV steps. In some cases, a
higher CPU core voltage may be desired. The V3 volt-
age range can be increased by adding two resistors as
shown in Figure 7.
R24 and R25 add a small amount of gain. They are set
so that an internally programmed value of 1.475V
results in a higher actual output at V3. The resistors
shown in Figure 7 set a maximum output of 1.55V, 1.6V,
or 1.65V. All output steps are shifted and the step size
is also slightly increased.
The output voltage for each programmed step of V3 in
Figure 7 is:
V3 = V3PROG + R24[(V3PROG/R25) +
(V3PROG/185.5kΩ)]
where V3 is the actual output voltage, V3PROG is the
original programmed voltage from the "OUTPUT (V)"
column in Table 2, and 185.5kΩis the internal resis-
tance of the FB3 pin.
Backup-Battery and V7 Configurations
The MAX1586/MAX1587 include a backup-battery con-
nection, BKBT, and an output, V7. These can be utilized
in different ways for various system configurations.
Primary Backup Battery
A connection with a primary (nonrechargeable) lithium
coin cell is shown in Figure 6. The lithium cell connects to
BKBT directly. V7 powers the CPU VCC_BATT from either
V1 (if enabled) or the backup battery. It is assumed
whenever the main battery is good, V1 is on (either with
its DC-DC converter or sleep LDO) to supply V7.
No Backup Battery (or Alternate Backup)
If no backup battery is used, or if an alternate backup
and VCC_BATT scheme is used that does not use the
MAX1586/MAX1587, then BKBT should be biased from
IN with a small silicon diode (1N4148 or similar, as in
Figure 8). BKBT must still be powered when no backup
battery is used because DBO, RSO, and POK require
this supply to function. If BKBT is not powered, these
outputs do not function and are high impedance.
PV3
STEP-DOWN
PWM
REG3
**OTHER R24 VALUES:
R24 = 5.5kΩ, V3: 0.759V TO 1.60V
R24 = 7.7kΩ, V3: 0.783V TO 1.65V
LX3
PG3
FB3
185.5kΩ
V3
VCC_CORE
1.55V MAX
TO BATT
R25
100kΩ
R24**
3.3kΩ
MAX1586
MAX1587
Figure 7. Addition of R24 and R25 increases maximum core
voltage. The values shown raise the maximum core from
1.475V to 1.55V.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
28 ______________________________________________________________________________________
Rechargeable Li+ Backup Battery
If more backup power is needed and a primary cell has
inadequate capacity, a rechargeable lithium cell can be
accommodated as shown in Figure 9. A series resistor
and diode charge the cell when the 3.3V V1 supply is
active. In addition to biasing V7, the rechargeable bat-
tery may be required to also power other supplies.
Rechargeable NiMH Backup Battery
In some systems, a NiMH battery may be desired for
backup. Usually this requires multiple cells because
the typical NiMH cell voltage is only 1.2V. By adding a
small DC-DC converter (MAX1724), the low-battery
voltage is boosted to 3V to bias BKBT (Figure 10). The
DC-DC converter’s low operating current (1.5µA typ)
allows it to remain on constantly so the 3V BKBT bias is
always present. A resistor and diode trickle charge the
NiMH cell when the main power is present.
PCB Layout and Routing
Good PCB layout is important to achieve optimal perfor-
mance. Conductors carrying discontinuous currents and
any high-current path should be made as short and wide
as possible. A separate low-noise ground plane contain-
ing the reference and signal grounds should connect to
the power-ground plane at only one point to minimize the
effects of power-ground currents. Typically, the ground
planes are best joined right at the IC.
Keep the voltage feedback network very close to the
IC, preferably within 0.2in (5mm) of the FB_ pin. Nodes
with high dV/dt (switching nodes) should be kept as
small as possible and should be routed away from
high-impedance nodes such as FB_. Refer to the
MAX1586 or MAX1587 evaluation kit data sheets for a
full PCB example.
MAX1586
MAX1587
MAIN
POWER
D1
1N4148
IN
BKBT
V7
4.7μF
1μF
Figure 8. BKBT connection when no backup battery is used, or
if an alternate backup scheme, not involving the
MAX1586/MAX1587, is used.
MAX1586
MAX1587
MAIN
POWER
1-CELL
Li+ RECHARGEABLE
BACKUP BATTERY
IN
BKBT
1kΩ
V7
V1
4.7μF
1μF
4.7μF
Figure 9. A 1-cell rechargeable Li+ battery provides more back-
up power when a primary cell is insufficient. The cell is charged
to 3.3V when V1 is active. Alternately, the battery can be
charged from IN if the voltages are appropriate for the cell type.
MAX1586
MAX1587
MAX1724
EZK30
MAIN
POWER
1N4148
MURATA
LQH32C 10μH
1-CELL
NiMH
RECHARGEABLE
BACKUP BATTERY
10kΩ
IN
BKBT
GND
BATT LX
SHDN
OUT V7
4.7μF
4.7μF
1μF
10μF
3.0V
Figure 10. A 1-cell NiMH battery can provide backup by boost-
ing with a low-power DC-DC converter. A series resistor-diode
trickle charges the battery when the main power is on.
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
______________________________________________________________________________________ 29
TOP VIEW
RSO
SRAD
LX3
PG3
V4
ON45
ON2
V5
IN45
PV3
V7
V1
SLPIN
V2
FB2
CC2
POK
SCL
BKBT
FB1 1
2
3
4
5
6
7
8
9
10
11 12 13 14 15 16 17 18 19 20 13 14 15 16 17 18 19 20 21 22 23 24
48 47 46 45 44 43 42 41 40 39 38 37
40 39 38 37 36 35 34 33 32 31
30
29
28
27
26
25
24
23
22
21
PG2
IN
RAMP
REF
BYP
LX2
PV2
PWM3
SDA
SLP
PV1
LX1
PG1
ON1
ON3
FB3
CC3
MR
CC1
THIN QFN
6mm × 6mm
MAX1587AETL
MAX1587CETL
GND
RSO
SRAD
LX3
PG3
V4
ON4
ON2
ON5
ON3
V5
IN45
PV3
V7
V1
SLPIN
V2
FB2
CC2
CC1
POK
SCL
BKBT
FB1
LB1
PG2
IN
RAMP
REF
BYP
LX2
PV2
LBO
PWM3
SDA
SLP
PV1
LX1
PG1
IN6
V6
ON6
ON1
FB3
CC3
MR
DBI
THIN QFN
7mm × 7mm
MAX1586AETM
MAX1586BETM
MAX1586CETM
GND
DBO
1
2
3
4
5
6
7
8
9
10
11
12
36
35
34
33
32
31
30
29
28
27
26
25
Pin Configurations
Selector Guide
PART REG2 PRESET VOLTAGE
(ALSO ADJUSTABLE)
REG3 (VCC_CORE)
OUTPUT CURRENT OTHER FUNCTIONS
MAX1586A 1.8V, 2.5V 0.5A
MAX1586B 3.3V, 2.5V 0.5A
MAX1586C 1.8V, 2.5V 0.9A
VCC_USIM (V6) linear regulator,
LBO and DBO battery monitors
MAX1587A 1.8V, 2.5V 0.5A
MAX1587C 1.8V, 2.5V 0.9A —
Package Information
(For the latest package outline information and land patterns,
go to www.maxim-ic.com/packages.)
Chip Information
PROCESS: BiCMOS
PACKAGE TYPE PACKAGE CODE DOCUMENT NO.
40 Thin QFN T4066-5 21-0141
48 Thin QFN T4877-6 21-0144
MAX1586A/MAX1586B/MAX1586C/MAX1587A/MAX1587C
High-Efficiency, Low-IQPMICs with
Dynamic Core for PDAs and Smart Phones
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
30
____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
3 12/08 Corrected equations to calculate resistors in the Dead-Battery and Low-Battery
Comparators—DBI, LBI (MAX1586 Only) section. 20, 21
4 4/09 Corrected typos 20, 21, 23,
25, 27