Datasheet

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General Description

The MAX1818 low-dropout linear regulator operates

from a +2.5V to +5.5V supply and delivers a guaran-

teed 500mA load current with low 120mV dropout. The

high-accuracy (±1%) output voltage is preset at an

internally trimmed voltage (see

Selector Guide

) or can

be adjusted from 1.25V to 5.0V with an external resis-

tive divider.

An internal PMOS pass transistor allows the low 125µA

supply current to remain independent of load, making

this device ideal for portable battery-operated equip-

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

lar phones, cordless phones, base stations, and

notebook computers.

Other features include an active-low open-drain reset

output that indicates when the output is out of regula-

tion, a 0.1µA shutdown, short-circuit protection, and

thermal shutdown protection. The device is available in

a miniature 800mW 6-pin SOT23 package.

Applications

Notebook Computers

Cellular and Cordless Telephones

Personal Digital Assistants (PDAs)

Palmtop Computers

Base Stations

USB Hubs

Docking Stations

Features

♦ Guaranteed 500mA Output Current

♦ Low 120mV Dropout at 500mA

♦ ±1% Output Voltage Accuracy

Preset at 1.5V, 1.8V, 2.0V, 2.5V, 3.3V, 5V

Adjustable from 1.25V to 5.0V

♦ Power OK Output

♦ Low 125µA Ground Current

♦ 0.1µA Shutdown Current

♦ Thermal Overload Protection

♦ Output Current Limit

♦ Tiny 800mW 6-Pin SOT23 Package

MAX1818

500mA Low-Dropout

Linear Regulator in SOT23

________________________________________________________________

Maxim Integrated Products

19-1860; Rev 2; 6/08

Ordering Information

Insert the desired two-digit suffix (see Selector Guide) into the

blanks to complete the part number.

PART* TEMP RANGE PIN-PACKAGE

MAX1818EUT_ _-T -40°C to +85°C 6 SOT23

MAX1818EUT_ _#T -40°C to +85°C 6 SOT23

Typical Operating Circuit

MAX1818

OFF

1μF

SHDN

OUT

POK

GNDSET

OUT

3.3μF

OUT

μC

= 2.5V TO 5.5V

POK

100k

Pin Configuration

POK

GNDSHDN

16OUT

5 SET

MAX1818

SOT23

TOP VIEW

Note

The MAX1818 requires a special solder temperature

profile described in the Absolute Maximum Ratings section.

T = Tape and reel.

Denotes an RoHS-compliant package.

Selector Guide appears at end of data sheet.

Summary of content (9 pages)

PAGE 1
9-1860; Rev 2; 6/08 500mA Low-Dropout Linear Regulator in SOT23 Features ♦ Guaranteed 500mA Output Current ♦ Low 120mV Dropout at 500mA ♦ ±1% Output Voltage Accuracy Preset at 1.5V, 1.8V, 2.0V, 2.5V, 3.3V, 5V Adjustable from 1.25V to 5.0V ♦ Power OK Output ♦ Low 125µA Ground Current ♦ 0.
PAGE 2
MAX1818 500mA Low-Dropout Linear Regulator in SOT23 ABSOLUTE MAXIMUM RATINGS IN, SHDN, POK, SET to GND ...................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Output Short-Circuit Duration ...............................................1min Continuous Power Dissipation (TA = +70°C) (Note 1) 6-Pin SOT23 (derate 10mW/°C above +70°C)..............800mW Operating Temperature Range ...........................
PAGE 3
500mA Low-Dropout Linear Regulator in SOT23 (VIN = VOUT + 500mV or VIN = +2.5V, whichever is greater; SHDN = IN, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 3) PARAMETER SYMBOL ΔVLDR Load Regulation Output Voltage Noise TYP MAX UNITS IOUT = 1mA to 500mA CONDITIONS MIN 0.4 1.0 % 10Hz to 1MHz, COUT = 3.3µF (ESR < 0.1Ω) 115 0.1 µVRMS SHUTDOWN Shutdown Supply Current IOFF SHDN = GND, VIN = 5.5V SHDN Input Threshold VIH 2.5V < VIN < 5.5V VIL 2.
PAGE 4
Typical Operating Characteristics (continued) (VIN = (VOUT + 500mV) or +2.5V, whichever is greater; SHDN = IN, CIN = 1µF, COUT = 3.3µF, TA = +25°C, unless otherwise noted.) TA = +25°C 60 TA = -40°C 30 0 0 0.1 0.2 0.3 0.4 2.5V OUTPUT 1.8V OUTPUT 0.5 0 LOAD CURRENT (A) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY LINE TRANSIENT 70 COUT = 3.3μF 60 -15 ILOAD = 150mA 10 35 VOUT VOUT = 3.3V 85 LOAD-TRANSIENT RESPONSE MAX1818 toc09 VIN = 3.3V VOUT = 2.
PAGE 5
00mA Low-Dropout Linear Regulator in SOT23 SHORT-CIRCUIT CURRENT LIMIT vs. SUPPLY VOLTAGE SHUTDOWN WAVEFORM MAX1818 toc12 0 VOUT 0 2V/div 0 POK MAX1818 toc13 SHORT-CIRCUIT CURRENT LIMIT (A) SHUTDOWN VOLTAGE 1.11 VOUT(NOM) = +2V 1.10 1.09 1.08 1.07 1.06 1.05 1.04 1.03 1.02 1.01 1.00 200μs/div 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V) Pin Description PIN NAME FUNCTION 1 IN Regulator Input. Supply voltage can range from 2.5V to 5.5V.
PAGE 6
MAX1818 500mA Low-Dropout Linear Regulator in SOT23 VIN = 2.5V TO 5.5V IN CIN 1μF THERMAL SENSOR MOSFET DRIVER WITH I LIM OUT ON VOUT = 1.25V TO 5.0V SHDN OFF COUT 3.3μF SHUTDOWN LOGIC 5k VREF 1.25V ERROR AMPLIFIER LOGIC SUPPLY VOLTAGE (VOUT) RPOK 100k R1 MAX1818 POK TO μC SET R2 93% VREF 100mV GND Figure 1. Functional Diagram Additional blocks include an output current limiter, thermal sensor, and shutdown logic. Internal P-Channel Pass Transistor The MAX1818 features a 0.
PAGE 7
500mA Low-Dropout Linear Regulator in SOT23 CIN 1μF COUT 3.3μF MAX1818 R1 ON SHDN SET OFF R2 POK GND TA = +85°C TA = +70°C MAXIMUM RECOMMENDED OUTPUT CURRENT MAX1818 fig03 600 OUT MAXIMUM OUTPUT CURRENT (mA) IN -1 1.25V VOUT 400 VOUT = 1.8V 200 VOUT = 2.5V VOUT = 3.3V MAXIMUM INPUT VOLTAGE V IN = 2.5V TO 5.5V MAX1818 R1 = R2 MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE (POWER DISSIPATION LIMIT) VOUT 0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 INPUT VOLTAGE (V) Figure 2.
PAGE 8
MAX1818 500mA Low-Dropout Linear Regulator in SOT23 Applications Information Capacitor Selection and Regulator Stability Capacitors are required at the MAX1818’s input and output for stable operation over the full temperature range and with load currents up to 500mA. Connect a 1µF capacitor between IN and ground and a 3.3µF lowESR capacitor between OUT and ground. For output voltages less than 2V, use a 4.7µF low-ESR output capacitor.
PAGE 9
500mA Low-Dropout Linear Regulator in SOT23 REVISION NUMBER REVISION DATE 2 6/08 DESCRIPTION Updated Ordering Information and Selector Guide with RoHS-compliant package PAGES CHANGED 1, 8 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.