Datasheet

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General Description

The MAX1832–MAX1835 are high-efficiency step-up

converters with complete reverse battery protection that

protects the device and the load when the battery is

reversed. They feature a built-in synchronous rectifier,

which allows for over 90% efficiency and reduces size

and cost by eliminating the need for an external

Schottky diode.

These step-up converters operate from a +1.5V to +5.5V

input voltage range and deliver up to 150mA of load cur-

rent. The MAX1833EUT/MAX1835EUT (SOT devices)

have a fixed 3.3V output voltage. The MAX1833ETT30

(TDFN device) has a fixed 3.0V output voltage. The

MAX1832/MAX1834 have adjustable outputs from +2V to

+5.5V. In shutdown, the MAX1832/MAX1833 connect the

battery input to the voltage output, allowing the input bat-

tery to be used as a backup or real-time clock supply

when the converter is off (see Selector Guide).

MAX183_EUT devices are available in a miniature 6-pin

SOT23 package. The MAX1833ETT30 is available in a

3mm ✕ 3mm thin DFN package. The MAX1832EVKIT is

available to speed designs.

________________________Applications

Medical Diagnostic Equipment

Pagers

Hand-Held Instruments

Remote Wireless Transmitters

Digital Cameras

Cordless Phones

Battery Backup

PC Cards

Local 3.3V or 5V Supply

Features

♦ Reverse Battery Protection for DC-DC Converter

and Load

♦ Up to 90% Efficiency

♦ No External Diode or FETs Needed

♦ Internal Synchronous Rectifier

♦ 4µA Quiescent Current

♦ <1µA Shutdown Supply Current

♦ +1.5V to +5.5V Input Voltage Range

♦ Accurate SHDN Threshold for Low-Battery Cutoff

♦ BATT Connected to OUT in Shutdown for Backup

Power (MAX1832/MAX1833)

♦ RST Output (MAX1833/MAX1835)

♦ Fixed 3.3V/3.0V Output Voltage

♦ Adjustable Output Voltage (MAX1832/MAX1834)

♦ Up to 150mA Output Current

♦ Tiny 6-Pin SOT23 Package

♦ Tiny 6-Pin Thin QFN Package (MAX1833ETT30)

MAX1832–MAX1835

High-Efficiency Step-Up Converters with

Reverse Battery Protection

________________________________________________________________ Maxim Integrated Products 1

BATT

LXGND

16FB (RST)

5 OUT

SHDN

MAX1832

MAX1834

(MAX1833EUT)

(MAX1835)

SOT23

TOP VIEW

RST

OUT

SHDN

BATT

GND

MAX1833ETT

TDFN

3mm ✕ 3mm

Pin Configurations

19-1802; Rev 2; 4/05

EVALUATION KIT

AVAILABLE

Ordering Information

PART T EM P R A N G E

PIN -

PA C K A G E

TOP

MARK

MAX1832EUT-T -40°C to +85°C 6 SOT23-6 AAOT

MAX1833EUT-T -40°C to +85°C 6 SOT23-6 AAOU

M A X1 8 3 3E TT30- T -40°C to +85°C

6 TDFN-6

(T633-1)

ABX

MAX1834EUT-T -40°C to +85°C 6 SOT23-6 AAOV

MAX1835EUT-T -40°C to +85°C 6 SOT23-6 AAOW

Selector Guide

PART

OUTPUT

VOLTAGE

OUTPUT VOLTAGE

IN SHUTDOWN

MAX1832EUT-T Adjustable V

BATT

MAX1833EUT-T Fixed 3.3V V

BATT

MAX1833ETT30-T Fixed 3.0V V

BATT

MAX1834EUT-T Adjustable V

BATT

- 0.7V

MAX1835EUT-T Fixed 3.3V V

BATT

- 0.7V

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.

Summary of content (12 pages)

PAGE 1
9-1802; Rev 2; 4/05 KIT ATION EVALU E L B A AVAIL High-Efficiency Step-Up Converters with Reverse Battery Protection The MAX1832–MAX1835 are high-efficiency step-up converters with complete reverse battery protection that protects the device and the load when the battery is reversed. They feature a built-in synchronous rectifier, which allows for over 90% efficiency and reduces size and cost by eliminating the need for an external Schottky diode. These step-up converters operate from a +1.5V to +5.
PAGE 2
MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection ABSOLUTE MAXIMUM RATINGS BATT, LX to GND.........................................................-6V to +6V LX to OUT ....................................................................-6V to +1V SHDN to GND..............................................-6V to (VOUT + 0.3V) OUT, FB, RST TO GND ............................................-0.3V to +6V LX Current .................................................................
PAGE 3
High-Efficiency Step-Up Converters with Reverse Battery Protection (V SHDN = +1.5V, VOUT = +3.3V, VBATT = +2V, GND = 0, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0 10 µA 1.8 5.0 Reverse Battery Current into OUT VOUT = 0, VBATT = V SHDN = VLX = -3V Quiescent Current into BATT VOUT = +3.5V, VFB = +1.3V Shutdown Current into BATT VOUT = +3.5V, VBATT = +2V, V SHDN = 0 0.
PAGE 4
Typical Operating Characteristics (VOUT = +3.3V, VBATT = +2V, unless otherwise noted.) (Figure 1) EFFICIENCY vs. LOAD CURRENT (VOUT = 3.3V) VBATT = +2.7V 75 VSHDN = VBATT R1 = 309Ω R2 = 100kΩ MAX1834 VBATT = +1.5V 85 1 10 100 VBATT = +1.5V VSHDN = VBATT R1 = 100kΩ R2 = 100kΩ CIN = 20µF COUT = 20µF MAX1834 75 VSHDN = VBATT MAX1835 75 0.1 80 80 65 70 1000 0.1 1 10 100 1000 0.1 1 10 10 100 ILOAD (mA) ILOAD (mA) ILOAD (mA) MAXIMUM OUTPUT CURRENT vs.
PAGE 5
High-Efficiency Step-Up Converters with Reverse Battery Protection in a SOT23-6 ON/OFF RESPONSE LOAD TRANSIENT MAX1832/35 toc10 MAX1832/35 toc11 VBATT 1V/div VOUT 100mV/div VOUT 1V/div ILOAD 100mA/div 0 2ms/div VSHDN = VBATT = 2.0V, RLOAD = 22Ω, VOUT = 3.3V 40µs/div RLOAD = 22Ω TO 200Ω, VOUT = +3.3V, VBATT = +2.0V SHUTDOWN RESPONSE LINE TRANSIENT MAX1832/35 toc13 MAX1832/35 toc12 VSHDN 1V/div VBATT 500mV/div 0 VOUT 1V/div VOUT 50mV/div 0 MAX1833 40µs/div RLOAD = 22Ω, VBATT = 3.3V, VBATT = 2.
PAGE 6
High-Efficiency Step-Up Converters with Reverse Battery Protection MAX1832–MAX1835 Pin Description PIN MAX1832 MAX1834 NAME MAX1833 MAX1835 FUNCTION 1 1 SHDN Shutdown. A high logic level turns on the device. When SHDN is low the part is off, and the current into BATT is typically 0.1µA. For the MAX1832/MAX1833, the battery is connected to OUT through an internal PFET and the external inductor when SHDN is low. SHDN can be used for low-battery cutoff (1.228V threshold). See Low-Battery Cutoff.
PAGE 7
High-Efficiency Step-Up Converters with Reverse Battery Protection The MAX1832–MAX1835 compact, high-efficiency step-up converters feature 4µA quiescent supply current to ensure the highest possible efficiency over a wide load range. With a minimum +1.5V input voltage, these devices are well suited for applications with two alkaline cells, two nickel-metal-hydride (NiMH) cells, or one lithium ion (Li+) cell.
PAGE 8
MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection OUT STARTUP CIRCUITRY ZEROCROSSING DETECTOR MAX1832 MAX1834 P SHDN CONTROL LOGIC LX DRIVER FB N ERROR COMPARATOR BATT REVERSE BATTERY N PROTECTION MOSFET CURRENT LIMIT 1.228V GND Figure 2. MAX1832/MAX1834 Simplified Functional Diagram OUT MAX1833 MAX1835 STARTUP CIRCUITRY ZEROCROSSING DETECTOR P CONTROL LOGIC N 1.
PAGE 9
High-Efficiency Step-Up Converters with Reverse Battery Protection Table 1. Suggested Inductors and Suppliers MANUFACTURER INDUCTOR PHONE Coilcraft DS1608C-103 DO1606T-103 847-639-6400 Sumida CDRH4D18-100 CR43-100 847-956-0666 Murata LQH4N100K 814-237-1431 Power-On Reset The MAX1833/MAX1835 provide a power-on reset output (RST). A 100kΩ to 1MΩ pullup resistor from RST to OUT provides a logic control signal. This open-drain output pulls low when the output is 10% below its regulation point.
PAGE 10
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.) 6LSOT.
PAGE 11
High-Efficiency Step-Up Converters with Reverse Battery Protection 6, 8, &10L, DFN THIN.EPS D2 D A2 PIN 1 ID N 0.35x0.35 b PIN 1 INDEX AREA E [(N/2)-1] x e REF. E2 DETAIL A e k A1 CL CL A L L e e PACKAGE OUTLINE, 6,8,10 & 14L, TDFN, EXPOSED PAD, 3x3x0.
PAGE 12
MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection 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.) COMMON DIMENSIONS MIN. MAX. D 0.70 2.90 0.80 3.10 E A1 2.90 0.00 3.10 0.05 L k 0.20 0.40 0.25 MIN. A2 0.20 REF. SYMBOL A PACKAGE VARIATIONS PKG.