Datasheet

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19-1680; Rev 2; 11/12

MAX1725/MAX1726

12V, Ultra-Low I

, Low-Dropout

Linear Regulators

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

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

General Description

The MAX1725/MAX1726 are ultra-low supply current,

low-dropout linear regulators intended for low-power

applications that demand the longest possible battery

life. Unlike inferior PNP-based designs, the MAX1725/

MAX1726s’ PMOS pass elements maintain an ultra-low

2µA supply current throughout their entire operating

range and in dropout. Despite their ultra-low power

consumption, the MAX1725/MAX1726 have tight output

accuracy (1.5%) and require just 1µF output capacitance

to achieve good load-transient response.

These regulators have a wide input voltage range

(+2.5V to +12V), making them excellent choices for

systems powered from two lithium-ion (Li+) cells and 9V

batteries. Other features include reverse-battery protec-

tion, short-circuit protection, and thermal protection.

The MAX1725 provides an adjustable 1.5V to 5V output

using an external resistor-divider. The MAX1726 pro-

vides factory preset 1.8V, 2.5V, 3.3V, or 5V output volt-

ages (see the

Ordering Information

). Both devices are

available in a tiny 5-pin SOT23 package.

________________________Applications

Smoke Detectors

Remote Transmitters

Smart Battery Packs

Industrial Control Systems

Microcontroller Power

Real-Time Clock Backup Power

PDAs and Handy-Terminals

Battery-Powered Alarms

Features

o 2µA Supply Current

o Reverse-Battery Protection

o +2.5V to +12V Input Voltage Range

o Fixed 1.8V, 2.5V, 3.3V, and 5V Output Voltages

(MAX1726)

o Adjustable 1.5V to 5V Output Voltages (MAX1725)

o 20mA Guaranteed Output Current

o 1.5% Output Voltage Accuracy

o Small 1µF Output Capacitor

o Short-Circuit Protection

o Thermal Protection

o Tiny 5-Pin SOT23 Package

2.5V TO 12V

OUTPUT

1.5V TO 5V

MAX1726

OFF

IN OUT

SHDN

GND

PART

OUTPUT VOLTAGE

(V)

MAX1725EUK+T

Adj 1.5 to 5.0

MAX1726EUK18+T

Fixed 1.8

MAX1726EUK25+T

Fixed 2.5

MAX1726EUK25/V+T

Fixed 2.5

MAX1726EUK33+T

Fixed 3.3

MAX1726EUK50+T

Fixed 5.0

Typical Operating Circuit

Ordering Information

Selector Guide

Pin Configuration appears at end of data sheet.

PART

TEMP RANGE

PIN-

PACKAGE

TOP

MARK

MAX1725EUK+T

-40°C to +85°C 5 SOT23

ADNK

MAX1726EUK18+T

-40°C to +85°C 5 SOT23

ADNL

MAX1726EUK25+T

-40°C to +85°C 5 SOT23

ADNM

MAX1726EUK25/V+T

-40°C to +85°C 5 SOT23

AFMN

MAX1726EUK33+T

-40°C to +85°C 5 SOT23

ADNN

MAX1726EUK50+T

-40°C to +85°C 5 SOT23

ADNO

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

/V denotes an automotive-qualified part.

Note: See the Selector Guide for the output options as they relate

to the part number suffix.

Summary of content (8 pages)

PAGE 1
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators General Description Features The MAX1725/MAX1726 are ultra-low supply current, low-dropout linear regulators intended for low-power applications that demand the longest possible battery life. Unlike inferior PNP-based designs, the MAX1725/ MAX1726s’ PMOS pass elements maintain an ultra-low 2µA supply current throughout their entire operating range and in dropout.
PAGE 2
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators ABSOLUTE MAXIMUM RATINGS IN to GND ................................................................-14V to +14V SHDN to GND ..............................................-0.3V to (VIN + 0.3V) (-0.3V to + 0.3V when VIN < 0V) OUT, FB (MAX1725 only) to GND...................-0.3V to +6V when VIN >5.7V; -0.3V to (VIN + 0.3V) when 0V < VIN < 5.7V; -0.3V to +0.3V when VIN < 0V OUT Continuous Current...................................................
PAGE 3
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators ELECTRICAL CHARACTERISTICS (continued) (Circuit of Figure 1, VIN = VOUT + 1V, SHDN = IN, IOUT = 1mA, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS OUT Line-Transient Overshoot/Undershoot ∆VIN = ±0.
PAGE 4
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators Typical Operating Characteristics (continued) (VOUT = +3.3V, IOUT = 1mA, TA = +25°C, unless otherwise noted.) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY TA = +25°C 150 VIN = 5V VOUT = 3.3V RL = 3.3kΩ COUT = 1µF 70 60 PSRR (dB) VIN 200mV/div 50 40 30 100 VOUT 20mV/div 20 TA = -40°C 50 10 0 0 0 5 10 15 0.01 20 0.
PAGE 5
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators The error amplifier compares 1.245V to the selected feedback voltage and amplifies the difference. If the feedback voltage is lower than 1.245V, the pass-transistor gate is pulled lower, allowing more current to pass, and thus increasing the output voltage. If the feedback voltage is higher than 1.245V, the pass-tran- INPUT 2.5V TO 12V CIN 1µF OUTPUT 1.5V TO 5V IN OUT R1 MAX1725 ON OFF SHDN COUT 1µF FB GND R2 1.2MΩ Figure 1.
PAGE 6
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators Shutdown To enter shutdown, drive the SHDN pin below 0.5V. When the MAX1725/MAX1726 are shut down, the output pass transistor shuts off, the output falls to ground, and supply current drops from 2µA to 0.7µA. Connect SHDN to IN for normal operation. If reverse-battery protection is needed, drive SHDN through a 100kΩ resistor. Thermal-Overload Protection Thermal-overload protection limits total power dissipation in the MAX1725/MAX1726.
PAGE 7
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators Chip Information Package Information Pin Configuration 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.
PAGE 8
MAX1725/MAX1726 12V, Ultra-Low IQ, Low-Dropout Linear Regulators Revision History REVISION NUMBER REVISION DATE 2 11/12 DESCRIPTION Added MAX1726EUK26/V+ and “+” lead(Pb)-free designations to Ordering Information PAGES CHANGED 1 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.