MAX8888EZK15-TG24 - Maxim Integrated Products, Inc.

General Description

The MAX8887/MAX8888 low-dropout linear regulators

operate from a 2.5V to 5.5V input and deliver up to

300mA continuous (500mA pulsed) current. The

MAX8887 is optimized for low-noise operation, while the

MAX8888 includes an open-drain POK ouput flag. Both

regulators feature exceptionally low 100mV dropout at

200mA. These devices are available in a variety of pre-

set output voltages in the 1.5V to 3.3V range.

An internal PMOS pass transistor allows the low 55µA

supply current to remain independent of load, making

these devices ideal for portable battery-powered equip-

ment such as personal digital assistants (PDAs), cellu-

lar phones, cordless phones, and notebook computers.

Other features include a micropower shutdown mode,

short-circuit protection, thermal shutdown protection,

and an active-low open-drain power-OK (POK) output

that indicates when the output is out of regulation. The

MAX8887/MAX8888 are available in a thin 5-pin SOT23

package that is only 1mm high.

________________________Applications

Notebook Computers

Wireless Handsets

PDAs and Palmtop Computers

Digital Cameras

PCMCIA Cards

Hand-Held Instruments

Features

♦Guaranteed 300mA Output Current (500mA for

Pulsed Loads)

♦Low 100mV Dropout at 200mA Load

♦POK Output (MAX8888)

♦42µVRMS Output Noise (MAX8887)

♦Preset Output Voltages (1.5V, 1.8V, 2.85V, and

3.3V)

♦55µA No-Load Supply Current

♦Thermal Overload and Short-Circuit Protection

♦Foldback Output Current-Limit Protection

♦60dB PSRR at 1kHz

♦0.1µA Shutdown Current

♦Thin 5-Pin SOT23 Package, 1mm High

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

________________________________________________________________ Maxim Integrated Products 1

GND

BPSHDN

15OUTIN

MAX8887

TOP VIEW

GND

POKSHDN

15OUTIN

MAX8888

Pin Configurations

MAX8887

MAX8888

OFF

INPUT

2.5V TO 5.5V

SHDN

GND

(BP)

POK

OUT

VOUT

300mA

CIN

2.2μF

COUT

2.2μF

CBP

0.01μF

( ) ARE FOR MAX8887 ONLY.

Typical Operating Circuit

19-1859; Rev 3; 11/06

Ordering Information

PART TEMP

RANGE

PIN-

PACKAGE

TOP

MARK

M A X8 8 8 7 E Z K15+ T -40°C to +85°C 5 SOT23-5 ADQD

MAX8887EZK18+ T -40°C to +85°C 5 SOT23-5 ADPX

MAX8887EZK29+ T -40°C to +85°C 5 SOT23-5 ADPY

MAX8887EZK33+ T -40°C to +85°C 5 SOT23-5 ADPZ

MAX8887EZKxy+ T* -40°C to +85°C 5 SOT23-5 —

M A X8 8 8 8 E Z K15+ T -40°C to +85°C 5 SOT23-5 ADQE

MAX8888EZK18+ T -40°C to +85°C 5 SOT23-5 ADQA

MAX8888EZK29+ T -40°C to +85°C 5 SOT23-5 ADQB

MAX8888EZK33+ T -40°C to +85°C 5 SOT23-5 ADQC

MAX8888EZKxy+ T* -40°C to +85°C 5 SOT23-5 —

*Other versions (xy) between +1.5 and +3.3V are available in

100mV increments. Contact factory for other versions. Minimum

order quantity is 25,000 units.

+Denotes lead-free availability.

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.

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN = VOUT + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)

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, SHDN, POK, to GND...........................................-0.3V to +7V

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

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

Continuous Power Dissipation (TA= +70°C)

5-Pin SOT23 (derate 9.1mW/°C above +70°C)............727mW

Operating Temperature Ranges..........................-40°C to +85°C

Junction Temperature......................................................+150°C

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

Lead Temperature (soldering, 10s) .................................+500°C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Voltage VIN 2.5 5.5 V

Input Undervoltage Lockout VIN rising

(2% typical hysteresis) 2.15 2.4 V

TA = +25°C, IOUT = 100mA -1.2 +1.2

IOUT = 100µA to 300mA,

TA = 0°C to +85°C-2 +2

Output Voltage Accuracy

IOUT = 100µA to 300mA -3 +3

Continuous 300

Maximum Output Current 10ms pulse 500 mA

VOUT = 0 300

Current Limit VOUT > 93% of nominal value 420 mA

No load 55 100

Ground-Pin Current IOUT = 300mA 65 µA

IOUT = 1mA 0.5

IOUT = 200mA 100 200

Dropout Voltage (Note 2) VOUT = +3.3V

IOUT = 300mA 150

Line Regulation VIN = 2.5V or (VOUT + 0.4V) to 5.5V,

IOUT = 5mA -0.15 0 0.15 %/V

MAX8887 10Hz to 100kHz, CBP = 0.01µF,

COUT = 2.2µF, ESRCOUT < 0.1Ω42

Output Noise

MAX8888 10Hz to 100kHz, COUT = 2.2µF,

ESRCOUT < 0.1Ω360

µVRMS

MAX8887 f < 1kHz, CBP = 0.01µF,

COUT = 4.7µF, ESRCOUT < 0.1Ω60

PSRR

MAX8888 f < 1kHz, COUT = 2.2µF,

ESRCOUT < 0.1Ω40

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

_______________________________________________________________________________________ 3

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SHUTDOWN

Shutdown Supply Current SHDN = GND, VIN = 5.5V 0.1 2 µA

VIH 2.5V ≤ VIN ≤ 5.5V 1.6

SHDN Input Threshold VIL 2.5V ≤ VIN ≤ 5.5V 0.6 V

SHDN Input Bias Current SHDN = IN or GND 10 100 nA

OUT Discharge Resistance in

Shutdown SHDN = GND 650 1100 Ω

POK (MAX8888 ONLY)

POK Trip Level, Referred to OUT

Set Point

VOUT falling

(1% typical hysteresis) 90 92.5 95 %

Operating IN Voltage Range for

Valid POK 1.0 5.5 V

POK Output Voltage Low VOL ISINK = 1mA 0.1 V

POK Output Leakage Current VPOK = 5.5V, SHDN = IN 100 nA

THERMAL PROTECTION

Thermal Shutdown Temperature 170 °C

Thermal Shutdown Hysteresis 20 °C

ELECTRICAL CHARACTERISTICS (continued)

(VIN = VOUT + 1V, SHDN = IN, TA = -40°C to +85°C, unless otherwise noted.) (Note 1)

Note 1: All parts are 100% tested at TA= +25°C. Limits over the operating temperature range are guaranteed by design.

Note 2: Typical and maximum dropout voltage for different output voltages are shown in the Typical Operating Characteristics

curve.

Typical Operating Characteristics

(Typical Operating Circuit, TA = +25°C, unless otherwise noted.)

1.0

0.5

2.0

1.5

3.0

2.5

3.5

2.0 3.0 3.52.5 4.0 4.5 5.0 5.5

OUTPUT VOLTAGE vs. INPUT VOLTAGE

MAX8887/8 toc01

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

IOUT = 0

IOUT = 300mA

-1.0

-0.6

-0.8

0.0

-0.2

-0.4

0.2

0.4

0.8

0.6

1.0

10050 150 200 250 300

OUTPUT VOLTAGE ACCURACY

vs. LOAD CURRENT

MAX8887/8 toc02

LOAD CURRENT (mA)

% DEVIATION (%)

-0.05

-0.02

-0.03

-0.04

-0.01

0.0

0.01

0.02

0.03

0.04

0.05

-40 10-15 35 60 85

OUTPUT VOLTAGE ACCURACY

vs. TEMPERATURE

MAX8887/8 toc03

TEMPERATURE (°C)

% DEVIATION

IOUT = 0

VIN = VOUT + 500mV

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

4 _______________________________________________________________________________________

100

120

140

160

0 10050 150 200 250 300

DROPOUT VOLTAGE vs. LOAD CURRENT

MAX8887/8 toc04

LOAD CURRENT (mA)

VDROPOUT (mV)

TA = +25°C

TA = +85°C

TA = -40°C

100

150

200

250

300

2.5 2.7 2.9 3.1 3.3

DROPOUT VOLTAGE vs. OUTPUT VOLTAGE

MAX8887/8 toc05

VOUT (V)

VDROPOUT (mV)

IOUT = 200mA

MAXIMUM

TYPICAL

0 1.0 2.0 3.0 4.0 5.0

INPUT VOLTAGE (V)

100

125

150

GROUND-PIN CURRENT vs. INPUT VOLTAGE

MAX8887/8 toc06

GROUND-PIN CURRENT (μA)

ILOAD = 300mA

ILOAD = 0

100

0 10050 150 200 250 300

GROUND-PIN CURRENT vs. LOAD CURRENT

MAX8887/8 toc07

LOAD CURRENT (mA)

GROUND-PIN CURRENT (μA)

VIN = 5.5V

VIN = 3.8V

-40 10-15 35 60 85

GROUND-PIN CURRENT vs. TEMPERATURE

MAX8887/8 toc08

TEMPERATURE (°C)

GROUND-PIN CURRENT (μA)

IOUT = 0

VIN = VOUT + 500mV

0.01 0.1 1 10 100 1000

POWER-SUPPLY REJECTION RATIO

vs. FREQUENCY

MAX8887/8 toc09

FREQUENCY (kHz)

PSRR (dB)

COUT = 2.2μF

CBP = 0.01μF

VOUT = 3.30V

ILOAD = 30mA MAX8887 ONLY

MAX8887

OUTPUT NOISE DC TO 1MHz

VOUT

50μV/div

MAX8887/8 toc10

40ms/div

VOUT = 1.8V, VIN = 3.8V, ILOAD = 15mA

LOAD-TRANSIENT RESPONSE

50mV/div

AC-COUPLED

MAX8887/8 toc11

300mA

10mA

VOUT

IOUT

VOUT = 3.3V

VIN = 3.8V

10μs/div

Typical Operating Characteristics (continued)

(Typical Operating Circuit, TA = +25°C, unless otherwise noted.)

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

_______________________________________________________________________________________ 5

LINE-TRANSIENT RESPONSE

MAX8887/8 toc13

20mV/div

AC-COUPLED

4.5V

VOUT

VIN

VOUT = 3.3V

ILOAD = 100mA

100μs/div

SHUTDOWN WAVEFORM

MAX8887/8 toc14

VSHDN

1V/div

DC-COUPLED

2V/div

VOUT

VOUT = 3.3V, RLOAD = 10Ω

20μs/div

POK WAVEFORM

MAX8887/8 toc15

2V/div

VOUT

VPOK

VIN

VOUT = 3.3V, RLOAD = 100Ω

20ms/div

Pin Description

MAX8887 MAX8888 NAME FUNCTION

11IN

Regulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with 2.2µF

capacitor to GND (see the Capacitor Selection and Regulator Stability section).

2 2 GND Ground

33SHDN Active-Low Shutdown Input. A logic low reduces the supply current to below 0.1µA.

In shutdown, POK and OUT are driven low. Connect to IN for normal operation.

—4POK

Open-Drain Active-Low POK Output. POK remains low while the output voltage (VOUT) is

below the reset threshold. Connect a 100kΩ pullup resistor to OUT to obtain a logic level

output. POK is driven low in shutdown. If not used, leave this pin unconnected.

4 — BP Reference Bypass. Bypass with a low-leakage 0.01µF ceramic capacitor.

5 5 OUT Regulator Output. Sources up to 300mA guaranteed. Bypass with 2.2µF (<0.2Ω typical

ESR) ceramic capacitor to GND.

LOAD-TRANSIENT RESPONSE

NEAR DROPOUT

MAX8887/8 toc12

50mV/div

AC-COUPLED

300mA

10mA

VOUT

IOUT

VOUT = 3.3V

VIN = 3.4V

10μs/div

Typical Operating Characteristics (continued)

(Typical Operating Circuit, TA = +25°C, unless otherwise noted.)

Detailed Description

The MAX8887/MAX8888 are low-dropout, low-quies-

cent-current linear regulators designed primarily for

battery-powered applications. The devices supply

loads up to 300mA and are available in several fixed

output voltages in the 1.5V to 3.3V range. The

MAX8887 is optimized for low-noise operation, while

the MAX8888 includes an open-drain POK output flag.

As illustrated in Figure 1, the MAX8888 consists of a

1.25V reference, error amplifier, P-channel pass tran-

sistor, and internal feedback voltage divider.

Internal P-Channel Pass Transistor

The MAX8887/MAX8888 feature a 0.5ΩP-channel

MOSFET pass transistor. Unlike similar designs using

PNP pass transistors, P-channel MOSFETs require no

base drive, which reduces quiescent current. PNP-

based regulators also waste considerable current in

dropout when the pass transistor saturates and use

high base drive currents under large loads. The

MAX8887/MAX8888 do not suffer from these problems

and consume only 55µA of quiescent current under

heavy loads as well as in dropout.

Output Voltage Selection

The MAX8887/MAX8888 are supplied with various fac-

tory-set output voltages ranging from 1.5V to 3.3V. The

part number’s two-digit suffix identifies the nominal out-

put voltage. For example, the MAX8887EZK33 has a

preset output voltage of 3.3V (see the Ordering Infor-

mation).

Shutdown

Drive SHDN low to enter shutdown. During shutdown,

the output is disconnected from the input and supply

current drops to 0.1µA. When in shutdown, POK and

OUT are driven low. SHDN can be pulled as high as

6V, regardless of the input and output voltages.

Power-OK Output

The power-OK output (POK) pulls low when OUT is less

than 93% of the nominal regulation voltage. Once OUT

exceeds 93% of the nominal voltage, POK goes high

impedance. POK is an open-drain N-channel output.

To obtain a logic level output, connect a pullup resistor

from POK to OUT. A 100kΩresistor works well for most

applications. POK can be used as a power-on-reset

(POR) signal to a microcontroller (µC) or to drive other

logic. Adding a capacitor from POK to ground creates

POK delay. When the MAX8887 is shut down, POK is

held low independent of the output voltage. If unused,

leave POK grounded or unconnected.

Current Limit

The MAX8887/MAX8888 monitor and control the pass

transistor’s gate voltage, limiting the output current to

0.8A (typ). This current limit is reduced to 500mA (typ)

when the output voltage is below 93% of the nominal

value to provide foldback current limiting.

Thermal Overload Protection

Thermal overload protection limits total power dissipa-

tion in the MAX8887/MAX8888. When the junction tem-

perature exceeds TJ =+170°C, a thermal sensor turns

off the pass transistor, allowing the device to cool. The

thermal sensor turns the pass transistor on again after

the junction temperature cools by 20°C, resulting in a

pulsed output during continuous thermal overload con-

ditions. Thermal overload protection protects the

MAX8887/MAX8888 in the event of fault conditions. For

continuous operation, do not exceed the absolute maxi-

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

Operating Region and Power Dissipation

The MAX8887/MAX8888’s maximum power dissipation

depends on the thermal resistance of the IC package

and circuit board. The temperature difference between

the die junction and ambient air, and the rate of air flow.

The power dissipated in the device is P = IOUT ✕(VIN-

VOUT). The maximum allowed power dissipation is

727mW or:

PMAX = (TJ(MAX) - TA) / (θJC + θCA)

where TJ(MAX)-TAis the temperature difference

between the MAX8887/MAX8888 die junction and the

surrounding air; θJC is the thermal resistance from the

junction to the case; and θCA is the thermal resistance

from the case through PC board, copper traces, and

other materials to the surrounding air.

Refer to Figure 2 for the MAX8887/MAX888 valid oper-

ating region.

Noise Reduction

For the MAX8887 only, an external 0.01µF bypass

capacitor at BP creates a lowpass filter for noise reduc-

tion. The MAX8887 exhibits 42µVRMS of output voltage

noise with CBP = 0.01µF and COUT = 2.2µF (see the

Typical Operating Characteristics).

Applications Information

Capacitor Selection and Regulator

Stability

Connect a 2.2µF ceramic capacitor between IN and

ground and a 2.2µF ceramic capacitor between OUT

and ground. The input capacitor (CIN) lowers the

source impedance of the input supply. Reduce noise

and improve load-transient response, stability, and

power-supply rejection by using a larger ceramic out-

put capacitor such as 4.7µF.

The output capacitor’s (COUT) equivalent series resis-

tance (ESR) affects stability and output noise. Use out-

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

6 _______________________________________________________________________________________

put capacitors with an ESR of 0.1Ωor less to ensure sta-

bility and optimum transient response. Surface-mount

ceramic capacitors have very low ESR and are com-

monly available in values up to 10µF. Connect CIN and

COUT as close to the MAX8887/MAX8888 as possible to

minimize the impact of PC board trace inductance.

Noise, PSRR, and Transient Response

The MAX8887/MAX8888 are designed to operate with

low dropout voltages and low quiescent currents in bat-

tery-powered systems while still maintaining excellent

noise, transient response, and AC rejection. See the

Typical Operating Characteristics for a plot of power-

supply rejection ratio (PSRR) versus frequency. When

operating from noisy sources, improved supply-noise

rejection and transient response can be achieved by

increasing the values of the input and output bypass

capacitors and through passive filtering techniques.

Input-Output (Dropout) Voltage

A regulator’s minimum input-to-output voltage differen-

tial (dropout voltage) determines the lowest usable sup-

ply voltage at which the output is regulated. In

battery-powered systems, this determines the useful

end-of-life battery voltage. The MAX8887/MAX8888 use

a P-channel MOSFET pass transistor. Its dropout volt-

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

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

Typical Operating Characteristics).

VDROPOUT = VIN - VOUT = RDS(ON) ✕IOUT

Chip Information

TRANSISTOR COUNT: 620

PROCESS: BiCMOS

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

_______________________________________________________________________________________ 7

SHUTDOWN

LOGIC

ERROR

AMP

1.25V

REF

95%

REF

OUT

POK

GND

SHDN

MAX8888

THERMAL

SENSOR

MOS DRIVER

WITH ILIMIT

POK

Figure 1. Functional Diagram

100

200

300

400

0 1.0 2.0 3.00.5 1.5 2.5 3.5 4.0

MAXIMUM OUTPUT CURRENT

vs. INPUT VOLTAGE

(POWER DISSIPATION LIMIT)

(VIN - VOUT) (V)

MAXIMUM OUTPUT CURRENT (mA)

VOUT = +3.3V

VOUT = +2.85V

VOUT = +1.8V

MAXIMUM RECOMMENDED OUTPUT CURRENT

TA = +85°C

TA = +70°C

Figure 2. Power Operating Regions: Maximum Output Current

vs. Input Voltage

MAX8887/MAX8888

Low-Dropout, 300mA Linear Regulators in SOT23

8 _______________________________________________________________________________________

THIN SOT23.EPS

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.)

Low-Dropout, 300mA Linear Regulators in SOT23

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.

9_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

MAX8887/MAX8888

Package Information (continued)

(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.)

Revision History

Pages changed at Rev 3: 1, 8, 9