MAX8891EXK18+T - Maxim Integrated

General Description

The MAX8891/MAX8892 low-dropout (LDO) linear regu-

lators are designed to deliver up to 150mA continuous

output current. These regulators achieve a low 120mV

dropout for 120mA load current.

The MAX8891 only requires an input/output capacitor,

hence achieving the smallest PCB area. The

MAX8892’s output voltage can be adjusted with an

external divider.

The MAX8891 is preset to a variety of voltages in the

1.5V to 4.5V range. Designed with a p-channel

MOSFET series pass transistor, the MAX8891/MAX8892

maintain very low ground current (40µA).

The regulators are designed and optimized to work with

low-value, low-cost ceramic capacitors. The MAX8891/

MAX8892 require only 1µF (typ) of output capacitance

for stability with any load. When disabled, current con-

sumption drops to below 1µA.

These regulators are available in a tiny 5-pin SC70

package.

Applications

Cellular and Cordless Phones

PDA and Palmtop Computers

Base Stations

Bluetooth Portable Radios and Accessories

Wireless LANs

Digital Cameras

Personal Stereos

Portable and Battery-Powered Equipment

Features

♦Space-Saving SC70 Package

♦65dB PSRR at 10kHz

♦120mV Dropout at 120mA Load

♦Stable with 1µF Ceramic Capacitor for Any Load

♦Guaranteed 150mA Output

♦Only Need Input and Output Capacitors (MAX8891)

♦Output Voltages: 1.5V, 1.8V, 2.5V, 2.6V, 2.7V, 2.8V,

2.85V, 3V, 3.3V, 4.5V (MAX8891) and Adjustable

(MAX8892)

♦Low 40µA Ground Current

♦Excellent Load/Line Transient

♦Overcurrent and Thermal Protection

High PSRR, Low-Dropout, 150mA

Linear Regulators

MAX8891/MAX8892

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.

GND

N.C. (MAX8891)

FB (MAX8892)

SHDN

OUT

MAX8891/

MAX8892

SC70

TOP VIEW

Pin Configuration

MAX8891

OUTPUT PRESET

1.5V TO 4.5V

INPUT

2V TO 6V

OFF SHDN COUT = 1μF

CIN = 1μF

OUT

GND

MAX8892

OUTPUT ADJUSTABLE

1.5V TO 4.5V

INPUT

2V TO 6V

OFF SHDN

COUT = 1μF

CIN = 1μF

OUT

ON FB

GND

Typical Operating Circuits

Ordering Information

19-4537; Rev 1; 12/11

xy is the output voltage code (see Output Voltage Selector

Guide). Other versions between 1.5V and 4.5V are available in

100mV increments. Contact factory for other versions.

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

/V denotes an automotive qualified part.

PART* TEMP RANGE PIN-PACKAGE

MAX8891EXKxy+T -40°C to +85°C 5 SC70

MAX8891EXKxy/V+T -40°C to +85°C 5 SC70

MAX8892EXK+T -40°C to +85°C 5 SC70

Output Voltage Selector Guide appears at end of data sheet.

High PSRR, Low-Dropout, 150mA

Linear Regulators

2 Maxim Integrated

MAX8891/MAX8892

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN = VOUT + 0.5V, TA = -40°C to +85°C, unless otherwise noted. CIN = 1µF, COUT = 1µF. Typical values are at TA= +25°C; the

MAX8892 is tested with 2.45V output, unless otherwise noted.) (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 +7V

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

OUT, SHDN to GND ....................................-0.3V to (VIN + 0.3V)

FB, BP, N.C. to GND ................................-0.3V to (VOUT + 0.3V)

Continuous Power Dissipation (TA= +70°C)

5-Pin SC70 (derate 3.1mW/°C above +70°C)..............0.247W

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

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

PACKAGE THERMAL CHARACTERISTICS (Note 1)

SC70

Junction-to-Ambient Thermal Resistance (θJA) .........324°C/W

Junction-to-Case Thermal Resistance (θJC) ..............115°C/W

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Voltage Range VIN 2 6 V

Output Voltage Accuracy IOUT = 100μA to 80mA -3 +3 %

Maximum Output Current IOUT 150 mA

Current Limit ILIM I

OUT = 90% of nominal value 200 mA

VOUT  3V, IOUT = 120mA 120

2.5V  VOUT < 3V, IOUT = 120mA 135

Dropout Voltage (Note 3)

2V  VOUT < 2.5V, IOUT = 120mA 180

Ground Current IQ I

OUT = 0.05mA 40 μA

Line Regulation VLNR V

IN = (VOUT + 0.5V) to 6V, IOUT = 0.1mA 0.001 %/V

Load Regulation VLDR I

OUT = 1mA to 80mA 0.003 %/mA

TA = +25°C 0.003 1

Shutdown Supply Current ISHDN V

SHDN = 0V TA = +85°C 0.05 μA

Ripple Rejection PSRR f = 10kHz, IOUT = 10mA 65 dB

Output Noise Voltage (RMS) f = 100Hz to 100kHz, ILOAD = 80mA 230 μV

SHDN Logic-Low Level VIN = 2V to 6V 0.4 V

SHDN Logic-High Level VIN = 2V to 6V 1.5 V

TA = +25°C

SHDN Input Bias Current VIN = 6V,

VSHDN = 0V or 6V TA = +85°C 0.01 μA

TA = +25°C 0.006 0.1

FB Input Bias Current

(MAX8892)

VIN = 6V,

VFB = 1.3V TA = +85°C 0.01 μA

Thermal Shutdown 160 °C

Thermal-Shutdown Hysteresis 10 °C

Note 2: Limits are 100% tested at TA= +25°C. Limits over operating temperature range are guaranteed by design.

Note 3: Dropout is defined as VIN - VOUT when VOUT is 100mV below the value of VOUT for VIN = VOUT + 0.5V.

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer

board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.

High PSRR, Low-Dropout, 150mA

Linear Regulators

DROPOUT VOLTAGE vs. LOAD CURRENT

MAX8891/2 toc04

LOAD CURRENT (mA)

DROPOUT VOLTAGE (mV))

125100755025

120

160

200

100

140

180

0150

TA = +85°C

TA = +25°C

TA = -40°C

DROPOUT VOLTAGE vs. OUTPUT VOLTAGE

MAX8891/2 toc05

OUTPUT (V)

DROPOUT VOLTAGE (mV)

3.02.82.62.42.2

100

150

200

250

2.0 3.2

IOUT = 80mA

GROUND PIN CURRENT vs. INPUT VOLTAGE

MAX8891/2 toc06

INPUT VOLTAGE (V)

GROUND PIN CURRENT (μA)

4321

150

200

100

250

300

350

IOUT = 0mA

GROUND PIN CURRENT vs. LOAD CURRENT

MAX8891/2 toc07

LOAD CURRENT (mA)

GROUND PIN CURRENT (μA)

125100755025

100

150

200

250

300

350

0 150

VIN = 3.8V

VIN = 5.5V

GROUND PIN CURRENT vs. TEMPERATURE

MAX8891/2 toc08

TEMPERATURE (°C)

GROUND PIN CURRENT (μA)

603510-15

-40 85

Maxim Integrated 3

MAX8891/MAX8892

Typical Operating Characteristics

(VIN = VOUT + 0.5V, CIN = 1µF, COUT = 1µF, TA= +25°C, unless otherwise noted.)

OUTPUT VOLTAGE vs. INPUT VOLTAGE

MAX8891/2 toc01

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

54321

0.5

1.0

1.5

2.0

2.5

3.0

0.0

IOUT = 120mA

IOUT = 0mA

OUTPUT VOLTAGE ACCURACY

vs. LOAD CURRENT

MAX8891/2 toc02

LOAD CURRENT (mA)

% DEVIATION (%)

125100755025

-0.4

-0.2

0.2

0.4

0.6

-0.6

0150

OUTPUT VOLTAGE ACCURACY

vs. TEMPERATURE

MAX8891/2 toc03

TEMPERATURE (°C)

% DEVIATION (%)

603510-15

-0.8

-0.6

-0.4

-0.2

0.2

0.4

0.6

0.8

1.0

-1.0

-40 85

IOUT = 1mA

PSRR vs. FREQUENCY

MAX8891/2 toc09

FREQUENCY (kHz)

PSRR (dB)

0.1 1 10 100

0.01 1000

ILOAD = 10mA

High PSRR, Low-Dropout, 150mA

Linear Regulators

LOAD TRANSIENT RESPONSE

dl/dt = 0.5mA/μs

MAX8891/2 toc10

200

s/div

VIN = 3.5V

ILOAD

25mA/div

VIN

10mV/div

VOUT

10mV/div

50mA

dl/dt = 0.5mA/μs10mA10mA

LOAD TRANSIENT RESPONSE

dl/dt = 5mA/μs

MAX8891/2 toc11

s/div

VIN = 3.5V

ILOAD

25mA/div

VIN

10mV/div

VOUT

10mV/div

50mA

dl/dt = 0.5mA/μs10mA10mA

LOAD TRANSIENT RESPONSE

dl/dt = 20mA/μs

MAX8891/2 toc12

s/div

VIN = 3.5V

ILOAD

25mA/div

VIN

10mV/div

VOUT

10mV/div

50mA

dl/dt = 20mA/μs

10mA10mA

STARTUP WAVEFORM

MAX8891/2 toc13

s/div

VIN = 3.5V

RLOAD = 30ΩVSHDN

2V/div

VOUT

500mV/div

OFF

SHUTDOWN WAVEFORM

MAX8891/2 toc14

s/div

VIN = 3.5V

RLOAD = 30Ω

VOUT

500mV/div

VSHDN

2V/div

OFF

4 Maxim Integrated

MAX8891/MAX8892

LINE TRANSIENT RESPONSE

dv/dt = 500mV/μs

MAX8891/2 toc15

s/div

RLOAD = 30Ω

VIN

500mV/div

VOUT

10mV/div

3.5V

dv/dt = 500mV/μs4V4V

LINE TRANSIENT RESPONSE

dv/dt = 200mV/μs

MAX8891/2 toc16

s/div

RLOAD = 30Ω

VIN

1V/div

VOUT

10mV/div

3.5V

dv/dt = 200mV/μs5V5V

REGION OF STABLE COUT ESR

vs. LOAD CURRENT

MAX8891/2 to17

LOAD CURRENT (mA)

COUT ESR (Ω)

75 10025 12550

0.1

100

0.01

0 150

STABLE REGION

Typical Operating Characteristics (continued)

(VIN = VOUT + 0.5V, CIN = 1µF, COUT = 1µF, TA= +25°C, unless otherwise noted.)

High PSRR, Low-Dropout, 150mA

Linear Regulators

Maxim Integrated 5

MAX8891/MAX8892

Detailed Description

The MAX8891/MAX8892 are low-dropout, low-quies-

cent current linear regulators designed for space-

restricted applications. The parts are available with

preset output voltages ranging from 1.5V to 4.5V in

100mV increments. These devices can supply loads up

to 150mA. As shown in the

Functional Diagram

, the

MAX8891 consists of an innovative bandgap core, error

amplifier, p-channel pass transistor, and internal feed-

back voltage-divider. The MAX8892 allows for

adjustable output with an external feedback network.

Additional blocks include a current limiter, thermal sen-

sor, and shutdown logic.

The 1.225V bandgap reference is connected to the

error amplifier’s inverting input. The error amplifier com-

pares this reference with the feedback voltage and

amplifies the difference. If the feedback voltage is lower

than the reference voltage, the pass-transistor gate is

pulled low. This allows more current to pass to the out-

put and increases the output voltage. If the feedback

voltage is too high, the pass transistor gate is pulled

high, allowing less current to pass to the output. The

output voltage is fed back through an internal (external

for the MAX8892) resistor voltage-divider connected to

the OUT pin.

Internal P-Channel Pass Transistor

The MAX8891/MAX8892 feature a 1Ω(typ) p-channel

MOSFET pass transistor. This provides several advan-

tages over similar designs using a PNP pass transistor,

including longer battery life. The p-channel MOSFET

requires no base drive, which considerably reduces qui-

escent current. PNP-based regulators waste consider-

able current in dropout when the pass transistor

saturates. They also use high base-drive current under

heavy loads. The MAX8891/MAX8892 do not suffer from

these problems and consume only 40µA of quiescent

current in light load and 220µA in dropout (see the

Typical Operating Characteristics

Output Voltage Selection

The MAX8891 is supplied with factory-set output volt-

ages from 1.5V to 4.5V, in 100mV increments (see the

Ordering Information

). The MAX8892 features a user-

adjustable output through an external feedback net-

work (see the

Typical Operating Circuits

To set the output of the MAX8892, use the following

equation:

where R2 is chosen to be less than 240kΩand VREF =

1.225V. Use 1% or better resistors.

Shutdown

The MAX8891/MAX8892 feature a low-power shutdown

mode that reduces quiescent current less than 1µA.

Driving SHDN low disables the voltage reference, error

amplifier, gate-drive circuitry, and pass transistor (see

the

Functional Diagram

), and the device output enters a

high-impedance state. Connect SHDN to IN for normal

operation.

Current Limit

The MAX8891/MAX8892 include a current limiter, which

monitors and controls the pass transistor’s gate volt-

age, limiting the output current to 200mA. The output

can be continuously shorted to ground without damag-

ing the part.

RR V

OUT

REF

12 1=×

⎛

⎝

⎜⎞

⎠

⎟

Pin Description

MAX8891

MAX8892

NAME FUNCTION

1 1 IN Unregulated Input Supply

2 2 GND Ground

33SHDN Shutdown. Pull low to disable the regulator.

— 4 FB Adjustable Output Feedback Point

4 — N.C. Not Internally Connected

5 5 OUT Reg ul ated Outp ut V ol tag e. Byp ass w i th a cap aci tor to GN D . S ee the C ap aci tor S el ecti on

and Reg ul ator S tab i l i ty secti on for m or e d etai l s.

Thermal-Overload Protection

Thermal-overload protection limits total power dissipation

in the MAX8891/MAX8892. When the junction tempera-

ture exceeds TJ= +160°C, the thermal sensor signals

the shutdown logic, turning off the pass transistor and

allowing the IC to cool down. The thermal sensor turns

the pass transistor on again after the IC’s junction tem-

perature drops by 10°C, resulting in a pulsed output dur-

ing continuous thermal-overload conditions.

Thermal-overload protection is designed to protect the

MAX8891/MAX8892 in the event of a fault condition. For

continual operation, do not exceed the absolute maxi-

mum junction temperature rating of TJ = +150°C.

Operating Region and Power Dissipation

The MAX8891/MAX8892 maximum power dissipation

depends on the thermal resistance of the case and cir-

cuit board, the temperature difference between the die

junction and ambient, and the rate of airflow. The power

dissipation across the device is:

P = IOUT (VIN - VOUT)

The maximum power dissipation is:

PMAX = (TJ- TA)/(θJC + θCA)

where TJ- TAis the temperature difference between the

MAX8891/MAX8892 die junction and the surrounding air,

θJC is the thermal resistance of the package, and θCA is

the thermal resistance through the PCB, copper traces,

and other materials to the surrounding air.

The GND pin of the MAX8891/MAX8892 performs the

dual function of providing an electrical connection to

ground and channeling heat away. Connect the GND

pin to ground using a large pad or ground plane.

Applications Information

Capacitor Selection

and Regulator Stability

Use a 1µF capacitor on the MAX8891/MAX8892 input

and a 1µF capacitor on the output. Larger input capacitor

values and lower ESRs provide better noise rejection and

line-transient response. Reduce output noise and

improve load-transient response, stability, and power-

supply rejection by using large output capacitors. Note

that some ceramic dielectrics exhibit large capacitance

and ESR variation with temperature. With dielectrics such

as Z5U and Y5V, it may be necessary to use a 2.2µF or

larger output capacitor to ensure stability at temperatures

below -10°C. With X7R or X5R dielectrics, 1µF is sufficient

at all operating temperatures. A graph of the region of

stable COUT ESR vs. load current is shown in the

Typical

Operating Characteristics

PSRR and Transient Response

The MAX8891/MAX8892 are designed to deliver high

PSRR as well as low dropout and low quiescent currents

in battery-powered systems. The MAX8891/MAX8892

power-supply rejection is 65dB at 10kHz.

When operating from sources other than batteries,

improved supply-noise rejection and transient response

can be achieved by increasing the values of the input

and output bypass capacitors, and through passive fil-

tering techniques. The

Typical Operating Characteristics

show the MAX8891/MAX8892 line- and load-transient

responses.

Dropout Voltage

A regulator’s minimum dropout voltage determines the

lowest usable supply voltage. In battery-powered

systems, this determines the useful end-of-life battery

voltage. Because the MAX8891/MAX8892 use a

p-channel MOSFET pass transistor, their dropout volt-

age is a function of drain-to-source on-resistance

(RDS(ON)) multiplied by the load current (see the

Typical

Operating Characteristics

High PSRR, Low-Dropout, 150mA

Linear Regulators

6 Maxim Integrated

MAX8891/MAX8892

High PSRR, Low-Dropout, 150mA

Linear Regulators

Maxim Integrated 7

MAX8891/MAX8892

OUT

FB**

*MAX8891 ONLY

**MAX8892 ONLY

MAX8891/

MAX8892

ERROR

AMP

SHDN

GND

SHUTDOWN AND

POWER-ON CONTROL

THERMAL

SENSOR

MOS DRIVER

WITH ILIMIT

1.225V REFERENCE

Functional Diagram

Chip Information

PROCESS: BiCMOS

Package Information

For the latest package outline information and land patterns

(footprints), go to www.maximintegrated.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.

Output Voltage Selector Guide

PART VOUT (V) TOP MARK

MAX8891EXK15+T 1.5 ATI

MAX8891EXK18+T 1.8 ATJ

MAX8891EXK25+T 2.5 ATL

MAX8891EXK26+T 2.6 ATM

MAX8891EXK28+T 2.8 ATO

MAX8891EXK29+T 2.85 ATP

MAX8891EXK89+T 2.9 ATV

MAX8891EXK30+T 3.0 ATQ

MAX8891EXK31+T 3.1 ATR

MAX8891EXK33+T 3.3 ATS

MAX8891EXK33/V+T 3.3 AUR

MAX8891EXK45+T 4.5 ATU

MAX8892EXK+T Adjustable ATW

Note: Standard output voltage options, shown in bold, are

available. Contact the factory for other output voltages between

1.5V and 4.5V. Minimum order quantity is 15,000 units.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

5 SC70 X5+1 21-0076 90-0188

High PSRR, Low-Dropout, 150mA

Linear Regulators

MAX8891/MAX8892

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 3/09 Initial release —

1 12/11

Added the /V option to the Ordering Information table and the Output Voltage Selector

Guide; updated the Package Information table 1, 7

Mouser Electronics

Authorized Distributor

Click to View Pricing, Inventory, Delivery & Lifecycle Information:

Maxim Integrated:

MAX8891EXK33/V+T MAX8891EXK15+T MAX8891EXK18+T MAX8891EXK19+T MAX8891EXK25+T

MAX8891EXK26+T MAX8891EXK27+T MAX8891EXK28+T MAX8891EXK29+T MAX8891EXK30+T

MAX8891EXK31+T MAX8891EXK33+T MAX8891EXK35+T MAX8891EXK45+T MAX8891EXK89+T

MAX8892EXK+T