Rainbow Electronics MAX1835 User Manual

For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

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 current. The MAX1833/MAX1835 have a fixed +3.3V output, and 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 battery to be used as a backup or real-time clock supply when the converter is off (see Selector Guide).

The MAX1832–MAX1835 are available in a miniature 6pin SOT23 package. The MAX1832EVKIT is available to shorten the design cycle.

________________________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 Output Voltage (MAX1833/MAX1835)

♦ Adjustable Output Voltage (MAX1832/MAX1834)

♦ Up to 150mA Output Current

♦ Tiny 6-Pin SOT23 Package

MAX1832–MAX1835

High-Efficiency Step-Up Converters with

Reverse Battery Protection in SOT23-6

________________________________________________________________ Maxim Integrated Products 1

Pin Configurations

19-1802; Rev 0; 10/00

EVALUATION KIT AVAILABLE

Ordering Information

Selector Guide

Note: Requires special solder temperature profile described in the Absolute Maximum Ratings.

PART T EM P. R A N G E

MAX1832EUT-T -40°C to +85°C 6 SOT23-6 AAOT MAX1833EUT-T -40°C to +85°C 6 SOT23-6 AAOU MAX1834EUT-T -40°C to +85°C 6 SOT23-6 AAOV MAX1835EUT-T -40°C to +85°C 6 SOT23-6 AAOW

PINPACKAGE

TOP

MARK

TOP VIEW

16FB

SHDN

BATT

MAX1832

MAX1834

SOT23-6

5 OUT

16RST

SHDN

BATT

LXGND

MAX1833

MAX1835

SOT23-6

5 OUT

LXGND

PART

MAX1832EUT-T Adjustable V

MAX1833EUT-T Fixed 3.3V V

MAX1834EUT-T Adjustable V

MAX1835EUT-T Fixed 3.3V V

OUTPUT

VOLTAGE

OUTPUT VOLTAGE

IN SHUTDOWN

BATT

- 0.7V

BATT

- 0.7V

BATT

MAX1832–MAX1835

High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

SHDN

= +1.5V, V

OUT

= +3.3V, V

BATT

= +2V, GND = 0, TA= -40°C to +85°C. Typical values are at TA= +25°C, unless otherwise

noted.) (Note 3)

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.

BATT, LX to GND.........................................................-6V to +6V

LX to OUT ....................................................................-6V to +1V

SHDN to GND..............................................-6V to (V

OUT

+ 0.3V)

OUT, FB, RST TO GND ............................................-0.3V to +6V

LX Current ................................................................................1A

Continuous Power Dissipation (T

= +70°C)

SOT23-6 (derate 9.1mW/°C above +70°C) (Note 1)....727mW

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

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

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

Lead Temperature (soldering, 10s) (Note 2) ...................+300°C

Note 1: Thermal properties are specified with product mounted on PC board with one square-inch of copper area and still air. Note 2: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device

can be exposed to during solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, IPC/JEDEC J-STD-020A, paragraph 7.6, Table 3 for the IR/VPR and Convection reflow. Preheating is required. Hand or wave soldering is not allowed.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Output Range V

Battery Input Range V

Startup Battery Input Voltage V

Output Voltage V

FB Trip Voltage V

FB Input Bias Current I

N-Channel On-Resistance R

P-Channel On-Resistance R

OUT

BATT

OUT

NCH

PCH

P-Channel Catch-Diode Voltage

N-Channel Switch Current Limit I

Switch Maximum On-Time t

MAX

Synchronous Rectifier ZeroCrossing Current

Quiescent Current into OUT (Note 4)

Shutdown Current into OUT V

MAX1832/MAX1834 2.0 5.5 V

= 2.6kΩ

LOAD

MAX1833/ MAX1835

MAX1832/ MAX1834

MAX1832/ MAX1834, V

= +1.3V

= +3.3V

OUT

= 100mA

= +3.3V

OUT

= 100mA

= 100mA, PCH off, V

= +1.3V

= +3.3V

OUT

= +3.3V

OUT

= +3.5V,

OUT

= +1.3V

= +3.5V, V

OUT

1.5 5.5 V

= +25°C 1.22 1.5

= -40°C to +85°C 1.24

= +25°C 3.225 3.290 3.355

= -40°C to +85°C 3.208 3.372

= +25°C 1.208 1.228 1.248

= -40°C to +85°C 1.204 1.252

= +25°C 3.5 20

= -40°C to +85°C 4.0

= +25°C 0.4 1.2

= -40°C to +85°C 1.5

= +25°C 0.5 1.3

= -40°C to +85°C 1.6

= +3.5V,

OUT

= +25°C 435 525 615

= -40°C to +85°C 400 650

0.73 V

3.5 5 6.5 µs

= +25°C 2 17 34

= -40°C to +85°C0 39

= +25°C 2.5 7.0

= -40°C to +85°C 8.0

= VFB = 0V 0.05 1 µA

SHDN

Ω

µA

MAX1832–MAX1835

High-Efficiency Step-Up Converters with

Reverse Battery Protection in SOT23-6

_______________________________________________________________________________________ 3

Note 3: All units are 100% production tested at TA=+25°C. Limits over the operating temperature range are guaranteed by design

and not production tested.

Note 4: Supply current into OUT. This current correlates directly to the actual battery-supply current, but is reduced in value accord-

ing to the step-up ratio and efficiency.

ELECTRICAL CHARACTERISTICS (continued)

SHDN

= +1.5V, V

OUT

= +3.3V, V

BATT

= +2V, GND = 0, TA= -40°C to +85°C. Typical values are at TA= +25°C, unless otherwise

noted.) (Note 3)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Reverse Battery Current into OUT

Quiescent Current into BATT

Shutdown Current into BATT V

Reverse Battery Current into BATT

SHDN Logic Low V

SHDN Threshold Rising edge

= 0, V

OUT

= +3.5V,

OUT

= +1.3V

= +3.5V, V

OUT

= 0, V

OUT

= +1.5V to +5.5V 0.3 V

BATT

= V

BATT

= V

= VLX = -3V 0 10 µA

SHDN

= +25°C 1.8 5.0

= -40°C to +85°C 6.0

= +2V, V

= VLX = -3V 0.002 10 µA

SHDN

= +25°C 1.185 1.228 1.271

= -40°C to +85°C 1.170 1.286

= 0 0.001 1 µA

SHDN

SHDN Threshold Hysteresis 0.02 V SHDN Input Bias Current V SHDN Reverse Battery Current V

RST Threshold

RST Voltage Low I

RST Leakage Current V

LX Leakage Current V

LX Reverse Battery Current V

Maximum Load Current I

LOAD

Efficiency V

= +5.5V, V

OUT

= 0, V

OUT

MAX1833/ MAX1835, falling edge

= 1mA, V

RST

= +5.5V

RST

= +5.5V

= 0, V

OUT

= +2V, V

BATT

= +2V, V

BATT

= +5.5V, T

SHDN

BATT

OUT

BATT

= V

OUT

= VLX = -3V 52 150 µA

SHDN

= +25°C 2.830 2.980 3.110

= -40°C to +85°C 2.800 3.140

= +2.5V 0.2 V

= +25°C 0.1 100

= -40°C to +85°C1

= +25°C 1 100

= -40°C to +85°C 100

= VLX = -3V 0.001 10 µA

SHDN

= +3.3V 150 mA

= +3.3V, I

= +25°C 13 100 nA

= 40mA 90 %

LOAD

µA

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