MAX8902AATA+ - Hytronics

General Description

The MAX8902A/MAX8902B low-noise linear regulators

deliver up to 500mA of output current with only

16µVRMS of output noise in a 100kHz bandwidth. These

regulators maintain their output voltage over a wide

input range, requiring only 100mV of input-to-output

headroom at full load.

These LDOs maintain a low 80µA typical supply cur-

rent, independent of the load current and dropout volt-

age. The regulator control circuitry includes a

programmable soft-start circuit and short circuit,

reverse current, and thermal-overload protection. Other

features include an enable input and a power-OK out-

put (MAX8902B only).

The MAX8902A output voltage can be set to 1.5V, 1.8V,

2.0V, 2.5V, 3.0V, 3.1V, 3.3V, 4.6V, or 4.7V using the

SELA and SELB inputs. The MAX8902B output voltage

can be set between 0.6V and 5.3V with an external

resistor voltage-divider.

Applications

Notebook Computers

MP3 and Portable Media Players

Wireless Headphones

GPS Portable Navigation Devices

Smartphones

Features

o1.7V to 5.5V Input Voltage Range

o0.6V to 5.3V Output Voltage Range

o16µVRMS Output Noise, 10Hz to 100kHz

o80µA Operating Supply Current

o92dB PSRR at 5kHz

oGuaranteed 500mA Output Current

o±1.5% Output Accuracy Over Load, Line, and

Temperature

o100mV (max) Dropout at 500mA Load

o< 1µA Shutdown Supply Current

o700mA Short-Circuit Protection

oThermal-Overload Protection

oOutput-to-Input Reverse Current Protection

o2mm x 2mm x 0.8mm TDFN Package

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

EVALUATION KIT AVAILABLE

For pricing, delivery, and ordering information, please contact Maxim Direct at

1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.

19-0990; Rev 5; 10/12

Ordering Information

OUT

BYP

OFF

OUTPUT

4.6V

SELB

SELA

OUTS

GND

10μF

INPUT

4.7V TO 5.5V

0.01μF10μF

MAX8902A

Typical Operating Circuits

PART FEATURES TOP

MARK

MAX8902AATA+ Pin-selectable output

voltage ABG

MAX8902BATA+ Adjustable output voltage ABH

MAX8902BATA/V+ Adjustable output voltage ADL

Denotes a lead(Pb)-free/RoHS-compliant package.

/V denotes an automotive qualified part.

Note: All devices are in an 8-pin, 2mm x 2mm TDFN package

with an exposed paddle and operate over the -40°C to +125°C

automotive temperature range.

OUT

BYP

OFF

OUTPUT ADJUSTABLE

0.6V TO 5.3V

POK

GND

10μF

INPUT

1.7V TO 5.5V

0.01μF10μF

MAX8902B

LOGIC

SUPPLY

100kΩ

TO μC

Pin Configurations appear at end of data sheet.

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

2 Maxim Integrated

ABSOLUTE MAXIMUM RATINGS

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.

BYP, EN, IN, OUT, SELA, SELB, POK to GND, GS to GND, FB,

OUTS to GND .....................................................-0.3V to +6.0V

Output Short-Circuit Duration.....................................Continuous

Continuous Power Dissipation (TA= +70°C)

TDFN (derate 11.9mW/°C above +70°C)...................953.5mW

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature Range ............................-40°C to +150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Soldering Temperature (reflow) .......................................+260°C

ELECTRICAL CHARACTERISTICS

(VIN = VEN = 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA= -40°C to +125°C, unless otherwise

noted.) (Note 1)

PARAMETER CONDITIONS MIN TYP MAX UNITS

Input Voltage Range 1.7 5.5 V

Input Undervoltage Lockout VIN rising, 100mV typical hysteresis 1.5 1.6 1.7 V

OUT

Output Voltage Range VIN  VOUT + 0.1V 0.6 5.3 V

Output Voltage Accuracy

VIN = 1.7V to 5.5V for VOUT  1.4V,

VIN = (VOUT + 0.3V) to 5.5V for VOUT > 1.4V,

IOUT = 0.1mA to 500mA

-1.5 +1.5 %

Load Regulation IOUT = 0.1mA to 500mA 0.02 %

Line Regulation

VIN = 1.7V to 5.5V for VOUT  1.4V,

VIN = (VOUT + 0.3V) to 5.5V for VOUT > 1.4V,

IOUT = 200mA

0.04 %

VIN  3.6V, TA +85°C 50 100

VIN  3.6V, TA +125°C 120

Dropout Voltage

(Note 2) IOUT = 500mA

VIN = 1.7V 150

Current Limit VOUT = 95% of regulation, VIN = VOUT + 0.5V 600 700 800 mA

Output Noise IOUT = 100mA, f = 10Hz to 100kHz, CBYP = 0.01μF 16 μVRMS

f = 5kHz 92

f = 10kHz 85

Power-Supply Rejection Ratio IOUT = 10mA

f = 100kHz 62

OUTS (MAX8902A only)

OUTS Input Bias Current In regulation 0.5 7.0 μA

FB (MAX8902B only)

FB Threshold Accuracy VIN = 1.7V to 5.5V, IOUT = 0.1mA to 500mA 0.591 0.600 0.609 V

TA = +25°C -0.1 0.02 +0.1

FB Input Bias Current VFB = 0.6V TA = -40°C 0.03 μA

BYP

BYP Capacitor Range Regulator remains stable 1 100 nF

BYP Startup Current From BYP to GND during startup 50 μA

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

Maxim Integrated 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN = VEN = 5V, OUTS = OUT, circuit of Figure 2 (MAX8902A) and Figure 3 (MAX8902B), TA= -40°C to +125°C, unless otherwise

noted.) (Note 1)

PARAMETER CONDITIONS MIN TYP MAX UNITS

GND

TA < +85°C 80 120

GND Supply Current IOUT = 0mA TA < +125°C 160 μA

TA = +25°C 0.001 +1

GND Shutdown Current VIN = 5.5V, EN = 0V TA = +85°C 0.01 μA

SELA/SELB (MAX8902A only)

When shorted to GND or VIN 500 

Select Input Resistance When open 1 M

Select Input Capacitance When open 10 pF

EN rising 0.8 1.2

EN falling, TA < +85°C 0.4 0.7 Enable Input Threshold VIN = 1.7V to 5.5V

EN falling, TA < +125°C 0.38 0.7

TA = +25°C -1 0.001 +1

Enable Input Bias Current VEN = 0V to 5.5V TA = +85°C 0.01 μA

POK (MAX8902B only)

OUT rising 88 91 94 %

POK Threshold OUT voltage when POK

switches OUT falling 88 %

POK Voltage, Low IPOK = 1mA 10 100 mV

TA = +25°C -1 0.001 +1

POK Leakage Current POK = 5.5V, VEN = 0V TA = +85°C 0.01 μA

THERMAL SHUTDOWN

TJ rising 165

Thermal Shutdown Threshold TJ falling 150 °C

OUTPUT TRANSIENT

Load Transient IOUT = 50mA to 500mA to 50mA, tRISE = tFALL= 1μs 25 mV/P-P

Line Transient VIN = 4V to 5V to 4V, tRISE = tFALL = 5μs, IOUT = 500mA 3 mV/P-P

IN-to-OUT Reverse Voltage

Turnoff Threshold IN falling below OUT 10 mV

Note 1: All devices are production tested at TA= +25°C. Specifications over the operating temperature range are guaranteed by

design and characterization.

Note 2: The dropout voltage is defined VIN - VOUT, when VOUT is 5% lower than the value of VOUT when VIN = VOUT + 0.5V.

Typical Operating Characteristics

(MAX8902A, VIN = 3.6V, VOUT = 2.5V, TA= +25°C, unless otherwise noted.)

120

100

140

023145

QUIESCENT CURRENT

EN = HIGH, NO LOAD

MAX8902A/02B toc01

INPUT VOLTAGE (V)

INPUT CURRENT (μA)

2.500

2.502

2.501

2.504

2.503

2.505

2.506

0 200100 300 400 500

LOAD REGULATION

MAX8902A/02B toc02

LOAD CURRENT (mA)

OUTPUT VOLTAGE (V)

3.6V INPUT

2.490

2.496

2.494

2.492

2.498

2.500

2.502

2.504

2.506

2.508

2.510

1.5 2.5 3.5 4.5 5.5

LINE REGULATION

MAX8902A/02B toc03

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

200mA LOAD

40ms/div

LOAD TRANSIENT RESPONSE

50mA TO 500mA TO 50mA

VOUT 100mV/div

200mA/div

MAX8902A/02B toc04

IOUT

tRISE = tFALL = 1μs

10μs/div

LINE TRANSIENT RESPONSE

VIN 2V/div

2mV/div

MAX8902A/02B toc05

VOUT

2.5V OUTPUT

5Ω LOAD

100μs/div

STARTUP WAVEFORM

VEN

500mV/div

2V/div

200mA/div

MAX8902A/02B toc06

IIN

VOUT

5Ω LOAD

CBYP = 0.01μF

0 100 200 300 400 500

DROPOUT VOLTAGE vs. LOAD CURRENT

MAX8902A/02B toc07

LOAD CURRENT (mA)

DROPOUT VOLTAGE (mV)

3.6V INPUT, 4.6V OUTPUT PRESET

THE SLOPE OF THE LINE INDICATES

A 129mΩ ON-RESISTANCE IN

DROPOUT

PSRR vs. FREQUENCY

MAX8902A/02B toc08

10k1k10010 100k

FREQUENCY (Hz)

-10

-20

-30

-40

-50

-60

-70

-80

-90

-100

PSRR (dB)

MAX8902A LDO OUTPUT-NOISE SPECTRAL

DENSITY vs. FREQUENCY

MAX8902A/02B toc09

FREQUENCY (Hz)

100k10k1k100

100E+0

1E+3

10E+3

10E+0

10 1M

NOISE DENSITY (nV √Hz)

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

4 Maxim Integrated

Detailed Description

The MAX8902A/MAX8902B low-noise, low-dropout lin-

ear regulators deliver up to 500mA of output current

with only 16µVRMS of output noise in a 100kHz band-

width. These regulators maintain their output voltage

over a wide input range, requiring only 100mV of input-

to-output headroom at full load.

The MAX8902 maintains a low 80µA typical supply cur-

rent, independent of the load current and dropout volt-

age. The regulator control circuitry includes a

programmable soft-start circuit and short circuit,

reverse current, and thermal-overload protection. Other

features include an enable input and a power-OK

(POK) output (MAX8902B only). A simplified functional

diagram is shown in Figure 1.

The MAX8902A output voltage can be set to 1.5V, 1.8V,

2.0V, 2.5V, 3.0V, 3.1V, 3.3V, 4.6V, or 4.7V using the

SELA and SELB inputs. The MAX8902B output voltage

can be set between 0.6V and 5.3V with an external

resistor voltage-divider.

Enable (EN)

The MAX8902A/MAX8902B include an enable input,

EN. Pull EN low to shut down the output, or drive EN

high to enable the output. If shutdown is not needed,

connect EN to IN.

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

Maxim Integrated 5

Pin Description

NAME

PIN MAX8902A MAX8902B FUNCTION

1 IN IN

Regulator Power Input. Connect IN to a supply from 1.7V to 5.5V. Bypass IN with a 10μF

ceramic capacitor to GND.

2 GND GND Ground

3 EN EN

Enable Input. A logic-low drives the output low through a 3k resistor and reduces the supply

current to less than 1μA. Drive logic-high or connect to IN for normal operation.

SELA —

Output Voltage Select Input. Connect SELA to GND, IN, or leave unconnected. The states of

SELA and SELB are sampled when the regulator turns on and the output voltage is set as

shown in Table 2.

— GS Internally Used. Connect GS to GND.

SELB —

Output Voltage Select Input. Connect SELB to GND, IN, or leave unconnected. The states of

SELA and SELB are sampled when the regulator turns on and the output voltage is set as

shown in Table 2.

—POK

Power-OK Output. Open-drain output that goes low when the output is above 91% of the

nominal regulation voltage. POK is high impedance in shutdown or when the output is below

the regulation voltage.

OUTS —

Output Sense Input. Connect OUTS to the load at a point where accurate regulation is

required, or connect OUTS directly to OUT.

— FB

Feedback Input. Connect FB to the center of a resistor voltage-divider connected between

OUT and GND to set the output voltage. VFB regulates to 0.6V.

7 BYP BYP

Bypass Input. Connect a 0.01μF ceramic capacitor from BYP to OUT to achieve 16μVRMS

output noise. Adjust the value of this capacitor to control the output slew rate during startup.

Slew Rate = (5V / ms) x (0.01μF / CBYP)

8 OUT OUT

Regulator Output. Sources up to 500mA at the output regulation voltage. Bypass with a 10μF

(< 0.03 ESR) capacitor to GND.

— EP EP Exposed Paddle. Connect the exposed paddle to a ground plane to provide heat sinking.

Bypass (BYP)

The capacitor connected from BYP to OUT filters the

noise of the reference, feedback resistors, and regula-

tor input stage and provides a high-speed feedback

path for improved transient response. A 0.01µF capaci-

tor rolls off input noise at approximately 32Hz.

The slew rate of the output voltage during startup is

also determined by the BYP capacitor. A 0.01µF

capacitor sets the slew rate to 5V / ms. This startup rate

results in a 50mA slew current drawn from the input at

startup to charge the 10µF output capacitance.

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

6 Maxim Integrated

VOLTAGE

SELECT

SELA

SELB

990kΩ

OUTS

BYP

OUT

GND

REF

0.6V

BYP

MAX8902A ONLY

CONTROL

THERMAL

PROTECTION

POK

CURRENT

LIMIT

REVERSE

CURRENT

PROTECTION

MAX8902B ONLY

0.54V

MAX8902A

MAX8902B

Figure 1. Simplified Functional Diagram

The BYP capacitor value can be adjusted from 0.001µF

to 0.1µF to change the startup slew rate according to

the following formula:

Startup slew rate = (5V / ms) x (0.01µF / CBYP)

Note that this slew rate applies only at startup, and that

recovery from a short circuit occurs at a slew rate

approximately 500 times slower.

Also note that, being a low-frequency filter node, BYP is

sensitive to leakage. BYP leakage currents above 10nA

cause measurable inaccuracy at the output and should

be avoided.

Protection Features

The MAX8902A/MAX8902B are fully protected from an

output short circuit by a current-limiting and thermal-

overload circuit. If the output is shorted to GND, the

output current is limited to 700mA (typ). Under these

conditions, the part quickly heats up. When the junction

temperature reaches +165°C, a thermal-limit circuit

shuts off the output device. When the junction cools to

+150°C, the output turns back on in an attempt to

reestablish regulation. While the fault persists, the out-

put current cycles on and off, as the junction tempera-

ture slews between +150°C and +165°C.

The MAX8902A/MAX8902B are also protected against

reverse current when the output voltage is higher than

the input. In the event that extra output capacitance is

used at the output, a power-down transient at the input

would normally cause a large reverse current through a

conventional regulator. The MAX8902A/MAX8902B

include a reverse voltage detector that trips when IN

drops 10mV below OUT, shutting off the regulator and

opening the pMOS body diode connection, preventing

any reverse current.

Thermal Considerations

The MAX8902A/MAX8902B are packaged in an 8-pin,

2mm x 2mm TDFN package with an exposed paddle.

The exposed paddle is the main path for heat to leave

the IC, and therefore, must be connected to a ground

plane with thermal vias to allow heat to dissipate from

the device. Thermal properties of the IC package are

given in Table 1.

Selecting the Output Voltage (MAX8902A)

The MAX8902A output can be set to one of nine volt-

ages by shorting or opening the SELA and SELB

inputs, as shown in Table 2. SELA and SELB should be

connected to GND, IN, or left unconnected.

Alternatively, they may be driven high, low, or open with

external logic; however, the states of SELA and SELB

are sampled only at startup. The regulation voltage can

be set to a different level by cycling EN or IN momen-

tarily to GND.

Setting the Output Voltage (MAX8902B)

The MAX8902B uses external feedback resistors to set

the output regulation voltage as shown in Figure 3. The

output can be set from 0.6V to 5.3V. Set the lower feed-

back resistor (R2) to 120kΩor less to minimize FB input

bias current error. Then calculate the value of the upper

feedback resistor (R1) as follows:

where VFB is the feedback regulation voltage of 0.6V.

Power-OK (MAX8902B)

The MAX8902B includes an additional open-drain out-

put, POK, that pulls low to indicate the output voltage is

in regulation. During startup, POK is high impedance

until the output voltage rises to 91% of its regulation

level. If an overload occurs at the output, or the output

is shut down, POK is high impedance.

RR V

OUT

12 1=× −

⎛

⎝

⎜⎞

⎠

⎟

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

Maxim Integrated 7

CONTINUOUS POWER

DISSIPATION

953.5mW DERATE 11.9mW/°C

ABOVE +70°C

JA* 83.9°C/W

JC 10.8°C/W

Table 1. 2mm x 2mm TDFN Package

Thermal Characteristics

OUTPUT VOLTAGE

(V) SELA STATE SELB STATE

1.5 IN Unconnected

1.8 Unconnected GND

2.0 Unconnected IN

2.5 Unconnected Unconnected

3.0 GND GND

3.1 GND IN

3.3 GND Unconnected

4.6 IN GND

4.7 IN IN

Table 2. MAX8902A Output Voltages

θJA is specified according to the JESD51 standard with the

part mounted on a multilayer PCB.

Input Capacitor

A 10µF ceramic capacitor is recommended for the

input. Select a capacitor that maintains its capacitance

over temperature and DC bias. Capacitors with X5R or

X7R temperature characteristics generally perform well.

Output Capacitor

A minimum of 10µF of capacitance is required at OUT

to ensure stability. Select a ceramic capacitor that

maintains its capacitance over temperature and DC

bias. Capacitors with X5R or X7R temperature charac-

teristics generally perform well.

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

8 Maxim Integrated

OUT

BYP

OFF

OUTPUT

4.6V

SELB

SELA

OUTS

GND

10μF

INPUT

4.7V TO 5.5V

0.01μF10μF

MAX8902A

Figure 2. MAX8902A Fixed-Output Application Circuit

OUT

BYP

OFF

OUTPUT ADJUSTABLE

0.6V TO 5.3V

POK

GND

10μF

INPUT

1.7V TO 5.5V

0.01μF10μF

MAX8902B

LOGIC

SUPPLY

100kΩ

TO μC

Figure 3. MAX8902B Adjustable-Output Application Circuit

Chip Information

PROCESS: BiCMOS

TDFN

(2mm x 2mm)

TOP VIEW

OUTS

SELB

SELA

OUT

BYP

GND

MAX8902A

TDFN

(2mm x 2mm)

POK

OUT

BYP

GND

MAX8902B

EP = EXPOSED PADDLE.

Pin Configurations

Package Information

For the latest package outline information and land patterns

(footprints), go to www.maxim-ic.com/packages. Note that a

“+”, “#”, or “-” in the package code indicates RoHS status only.

Package drawings may show a different suffix character, but

the drawing pertains to the package regardless of RoHS status.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

8 TDFN-EP T822+1 21-0168 90-0064

MAX8902A/MAX8902B

Low-Noise 500mA LDO Regulators

in a 2mm x 2mm TDFN Package

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent

licenses are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and

max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000

Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 9/07 Initial release —

1 1/08 Changed input capacitor value from 4.7μF to 10μF 1, 5, 8

2 2/08 Changed BP to BYP 2, 4–8

3 5/08 Updated TOC 5 title 4

4 4/11 Added the MAX8902BATA/V+ part to the Ordering Information table 1

5 10/12 Updated JC specification in Table 1 7