________________General Description
The MAX1615/MAX1616 are micropower, SOT23-5 lin-
ear regulators that supply always-on, keep-alive power
to CMOS RAM and microcontrollers (µCs) in systems
with high-voltage batteries. Key features include wide
input voltage range, low dropout voltage, and low qui-
escent supply current.
Despite a miserly 8µA (max) no-load supply current, the
MAX1615/MAX1616 have excellent line-transient
response and AC power-supply rejection ratio. They
provide a clean, fixed 5V or 3.3V output (MAX1615) or
an adjustable 1.24V to 28V output (MAX1616), even
when subjected to fast supply-voltage changes that
occur during the switchover from battery to AC adapter
input power. The space-saving SOT23-5 package has
excellent thermal characteristics and tolerates up to
571mW of power dissipation. Fault protection is provid-
ed by internal foldback current limiting and thermal-
shutdown circuitry. The MAX1615/MAX1616 are now
available in lead-free packages.
________________________Applications
CMOS/RTC Backup Power
Microcontroller Power
Notebook Computers
Smart-Battery Packs
PDAs and Handy-Terminals
Battery-Powered Systems
____________________________Features
♦4V to 28V Input Range
♦8µA (max) Quiescent Supply Current
♦<1µA Shutdown Supply Current
♦3.3V or 5V, Pin-Selectable Output (MAX1615)
Adjustable 1.24V to 28V Output (MAX1616)
♦30mA Output Current
♦±2% Initial Output Accuracy
♦Thermal-Overload Protection
♦5-Pin SOT23 Package
♦Low Cost
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
________________________________________________________________ Maxim Integrated Products 1
GND
5/3 (FB)
OUT
( ) ARE FOR MAX1616.
15SHDN
IN
MAX1615
MAX1616
SOT23-5
TOP VIEW
2
34
___________________Pin Configuration
IN OUT
SHDN
GND 5/3
BATTERY CIN
0.1µF
COUT
4.7µF
OUTPUT
VOLTAGE
MAX1615
____________Typical Operating Circuit
19-1225; Rev 3; 9/04
PART
MAX1615EUK-T -40°C to +85°C
TEMP RANGE PIN-
PACKAGE
5 SOT23-5
_______________Ordering Information
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
SOT
TOP MARK
ABZD
MAX1616EUK-T ABZE-40°C to +85°C 5 SOT23-5
+Denotes lead-free package.
MAX1615EUK-T+ ABZD-40°C to +85°C 5 SOT23-5
MAX1616EUK-T+ ABZE-40°C to +85°C 5 SOT23-5
V
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VIN = 15V, SHDN = VIN, ILOAD = 5µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)
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 to GND .................................................................-0.3V to 30V
Terminal Voltages to GND
SHDN to GND...........................................-0.3V to (VIN + 0.3V)
5/3to GND ............................................-0.3V to (VOUT + 0.3V)
FB (MAX1616) to GND .........................-0.3V to (VOUT + 0.3V)
OUT to GND...........................................................-0.3V to 30V
OUT Short-Circuit to GND ...............................................30sec
Continuous OUT Current.....................................................40mA
Continuous Power Dissipation (TA= +70°C) (Note 1)
SOT23-5 (derate 7.1mW/°C above +70°C)...................571mW
Operating Temperature Range
MAX161_EUK-T ...............................................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: See Operating Region and Power Dissipation section.
FB Input Current (MAX1616) IFB -10 12 30 nAVFB = 1.3V
FB Threshold (MAX1616)
(Note 3) VFBT
1.215 1.240 1.265
V
FB = OUT,
VIN = 6V to 28V
TA= +25°C,
ILOAD = 1mA
1.18 1.28
TA= TMIN to TMAX,
ILOAD = 5µA to 30mA
Output Voltage (MAX1615)
(Note 3) 3.15 3.48
ILOAD = 5µA to 30mA,
TA= TMIN to TMAX,
VIN = 6V to 28V
5/3= GND
4.75 5.25
5/3= OUT
4.95 5.05 5.15
5/3= OUT
3.26 3.33 3.40
ILOAD = 1mA,
TA= +25°C,
VIN = 6V to 28V
5/3= GND
Dropout Supply Current 70 µA
Output set to 5V,
VIN = 4V TA= +25°C
TMIN = TMIN to TMAX
TA= +25°C
Start-Up Overshoot VOSH 0.5 %VOUT
RL= 500Ω, COUT = 10µF within 90% of nominal
output voltage
PARAMETER SYMBOL MIN TYP MAX UNITS
Shutdown Supply Current IIN 3µA
1.5
Minimum Load Current 5µA
Input Voltage Range VIN 428V
6.2 8
Supply Current IIN 15 µA
Output Current Limit 100 mA
OUT Reverse Leakage
Current 70 µA
Capacitive Load
Requirements (Note 5)
0.16 µF/mA
Start-Up Time Response 1ms
CONDITIONS
SHDN = GND
(shutdown mode)
VIN = 6V
IN = unconnected, VOUT forced to 5V
SHDN = IN, TA= +25°C
MAX1615
SHDN = IN, VIN = 6V to 28V, TA= TMIN to TMAX
Rising edge of IN or SHDN to OUT within specifi-
cation limits, RL= 500Ω, COUT = 6.8µF,
VOUT set to 5V
MAX1616 0.23
Dropout Voltage ∆VDO 350 mVILOAD = 30mA (Note 4)
V
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN = 15V, SHDN = VIN, ILOAD = 5µA, TA= TMIN to TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 2)
Note 2: Limits are 100% production tested at TA= +25°C. Limits over the operating temperature range are guaranteed through
correlation using standard quality-control (SQC) methods.
Note 3: Pulse tested at VIN = 28V, ILOAD = 30mA to avoid exceeding package power-dissipation limits.
Note 4: Guaranteed by design. Tested with VOUT set to 5V. Dropout voltage is tested by reducing the input voltage until VOUT drops
to 100mV below its nominal value, measured with VIN starting 2V above VOUT.
Note 5: Use at least 1µF minimum for light loads. Add 0.125µF/mA (0.2µF/mA for the MAX1616) for loads greater than 100µA,
not production tested. See Capacitor Selection in the Applications Information section.
60
0
030
SAFE LOAD-CURRENT
OPERATING AREA
vs. SUPPLY VOLTAGE
20
10
50
MAX1615-01
SUPPLY VOLTAGE (V)
OUTPUT CURRENT (mA)
105252015
40
30
POWER-
DISSIPATION
LIMIT REGION
VOUT = 5V
8
0
530
GROUND CURRENT
vs. SUPPLY VOLTAGE
AT VARIOUS LOADS
2
3
1
6
7
MAX1615-02
SUPPLY VOLTAGE (V)
GROUND CURRENT (mA)
10 252015
5
4
65mA
55mA
45mA
35mA
15mA
5mA
25mA
9.0
5.0
530
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
6.0
6.5
5.5
8.0
8.5
MAX1615-03
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
25201510
7.5
7.0
TA = +85°C
TA = +25°C
TA = -40°C
__________________________________________Typical Operating Characteristics
(VOUT set to 5V, TA = +25°C, unless otherwise noted.)
SHDN Input Threshold
Voltage
CONDITIONS
V
0.25VIL
UNITSMIN TYP MAXSYMBOLPARAMETER
SHDN Input Current VSHDN = 0V or 15V µA-1 1
Thermal-Shutdown
Temperature VSHDN = 0V or 15V, hysteresis = +20°C °C150TSHDN
VIH 1.4
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
4_______________________________________________________________________________________
100µs/div
LOAD-TRANSIENT RESPONSE
IOUT
30mA/div
VOUT
50mV/div
MAX1615-08
____________________________Typical Operating Characteristics (continued)
(VOUT set to 5V, TA = +25°C, unless otherwise noted.)
0
10
20
30
40
50
60
70
80
90
4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0
DROPOUT SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX1615-09
SUPPLY VOLTAGE (V)
DROPOUT SUPPLY CURRENT (µA)
TA = +85°C
TA = +25°C
TA = 0°C
TA = -40°C
0
0.05
0.10
0.15
0.20
0.25
0.30
05101520 25 30 35 40
DROPOUT VOLTAGE
vs. LOAD CURRENT
MAX1615-10
LOAD CURRENT (mA)
VIN - VOUT (V)
50µs/div
LINE-TRANSIENT RESPONSE
+20V
VOUT
50mV/div
VIN
COUT
4.7µF
CIN
10µF
MAX1615-07
+10V
500µs/div
TIME TO EXIT SHUTDOWN
+5V
+5V
OUT
0V
SHDN
MAX1615-06
VIN = 10V
0V
1.6
0
428
SHUTDOWN SUPPLY CURRENT
vs. SUPPLY VOLTAGE
0.4
0.6
0.2
1.2
1.4
MAX1615-04
SUPPLY VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (µA)
242016128
1.0
0.8
-70
0
0.01 100
RIPPLE REJECTION vs. FREQUENCY
-20
-30
-10
-50
-60
MAX1615-05
FREQUENCY (kHz)
RIPPLE REJECTION (dB)
1010.1
-40
ILOAD = 10mA
_______________Detailed Description
The MAX1615/MAX1616 low-quiescent-current linear
regulators are designed primarily for high input voltage
applications. The MAX1615 supplies a preselected 3.3V
or 5.0V output for loads up to 30mA. The MAX1616
provides an adjustable voltage from 1.24V to 28V. The
maximum output current is a function of the package’s
maximum power dissipation for a given temperature. A
5µA load is required to maintain output regulation.
The MAX1615’s output voltage is fed back through an
internal resistor voltage divider connected to OUT. Set
the output voltage to either 3.3V or 5.0V with the 5/3pin.
Select the 5V output by connecting 5/3to OUT, or the
3.3V output by connecting 5/3to GND.
The MAX1616 uses external feedback, allowing the out-
put voltage to be set by external resistors (see Setting
the MAX1616 Output Voltage section). The typical FB
threshold is at 1.24V.
Shutdown
The device enters shutdown mode when SHDN is low.
In shutdown mode, the pass transistor, control circuit,
reference, and all biases turn off, reducing the supply
current to below 1µA. Connect SHDN to IN for automatic
start-up.
Current Limit
Output current is limited to 100mA (typical). The current
limit exceeds the 30mA (max) safe operating limit. The
output can be shorted to ground for 30 seconds without
damaging the part.
Thermal-Overload Protection
When the junction temperature exceeds TJ= +150°C,
the thermal sensor sends a signal to the shutdown
logic, turning off the pass transistor and allowing the IC
to cool. The thermal sensor turns the pass transistor on
again after the IC’s junction temperature cools by
+20°C (typical), resulting in a pulsating output during
continuous thermal-overload conditions.
Operating Region and Power Dissipation
Maximum power dissipation depends on the thermal
resistance of the case and circuit board, the tempera-
ture difference between the die junction and ambient
air, and the rate of air flow. The device’s power dissipa-
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
_______________________________________________________________________________________ 5
______________________________________________________________Pin Description
1IN Positive Input Voltage. Connect to a +4V to +28V supply.
2GND Ground
45/3Preset Output Voltage Select. Connect to GND for 3.3V output or to OUT
for 5.0V output.
5SHDN Shutdown, active low input. Connect to IN for automatic start up.
CURRENT
LIMIT
VREF
OUT
GND
SHDN
5/3
(MAX1615)
FB
(MAX1616)
IN
MAX1615
MAX1616
Figure 1. Functional Diagram
1
2
PIN
—
5
NAME FUNCTION
MAX1615 MAX1616
3OUT Regulator Output3
—FB Feedback Input. Regulates to 1.24V nominally.4
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
6_______________________________________________________________________________________
___________________Chip Information
TRANSISTOR COUNT: 386
tion is P = IOUT (VIN - VOUT). The power dissipation at
+70°C ambient is 571mW (see Absolute Maximum
Ratings). The thermal resistance junction-to-case of the
SOT23-5 package is 81°C/W, and the maximum safe
junction temperature is +150°C.
The GND pin performs the dual function of providing an
electrical connection to ground and channeling heat
away. Connect GND to ground using a large pad or
ground plane.
__________Applications Information
Setting the MAX1616 Output Voltage
Set the MAX1616’s output voltage with two resistors, R1
and R2 (Figure 2). Choose R2 = 250kΩto maintain a
5µA minimum load and calculate R1 using the following
equation:
where VFBT = 1.24V (typical).
Capacitor Selection
Use a 0.1µF minimum capacitor on the input. Higher
values will improve line-transient response.
Use 1µF minimum on the output, or 4.7µF for the full
30mA load current (6.8µF, MAX1616). Otherwise, use
1µF plus 0.125µF/mA (0.2µF/µA, MAX1616). For output
voltages less than 3.3V, use 15µF instead of 6.8µF. The
output capacitor’s effective series resistance (ESR) must
be less than 1Ωfor stable operation.
Output Voltage Noise
The MAX1615/MAX1616 typically exhibit 5mVp-p of
noise during normal operation. This is negligible in
most applications. In applications that include analog-
to-digital converters (ADCs) of more than 12 bits, con-
sider the ADC’s power-supply-rejection specifications.
Transient Response
The Typical Operating Characteristics show the
MAX1615/MAX1616’s load-transient response. Two of
the output response’s components can be observed on
the load-transient graph: a DC shift from the output
impedance due to the different load currents, and the
transient response. Typical step changes in the load
current from 10mA to 20mA produce 50mV transients.
Increasing the output capacitor’s value attenuates tran-
sient spikes.
R1 = R2 V
V
OUT
FBT
−
1
Table 1. Surface-Mount Capacitor
Manufacturers
MANUFACTURER CAPACITOR
Sprague 593D, 595 series
Electrolytic
AVX TPS series
TYPE
Matsuo 267 series
Ceramic
AVX X7R
Matsuo X7R
Table 2. Component Suppliers
PHONE FAX
(803) 626-3123
(714) 960-6492
(603) 224-1430
AVX (803) 946-0690
Sprague
SUPPLIER
Matsuo (714) 969-2491
(603) 224-1961
IN OUT
FB
SHDN
GND
6V TO
28V 0.1µF6.8µF*
R1
R2
OUTPUT
VOLTAGE
MAX1616
*15µF for VOUT <3.3V
Figure 2. MAX1616 Typical Application Circuit
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
_______________________________________________________________________________________ 7
__________________________________________________Tape-and-Reel Information
P
D
E
F
W
P2
P0
D1
A0
B0
K0
t
±0.102
±0.102
A0
B0
D
D1
3.200
3.099
1.499
0.991
±0.102
±0.051
±0.102
±0.102
1.753
3.505
1.397
3.988
E
F
K0
P
+0.102
+0.000
NOTE: DIMENSIONS ARE IN MM.
AND FOLLOW EIA481-1 STANDARD.
+0.305
-0.102
+0.254
+0.000
P0 3.988 ±0.102
P010 40.005 ±0.203
P2 2.007 ±0.051
t 0.254 ±0.127
W 8.001
5 SOT23-5
MAX1615/MAX1616
High-Voltage, Low-Power Linear Regulators
for Notebook Computers
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.
8_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
©2004 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
SOT-23 5L .EPS
E
1
1
21-0057
PACKAGE OUTLINE, SOT-23, 5L
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
