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L6902D013TR

Up to 1 A switching regulator with adjustable current limit

STMicroelectronics 

L6902

Up to 1 A switching regulator with adjustable current limit

Features

■ Up to 1 A output current

■ Operating input voltage from 8 V to 36 V

■ Precise 3.3 V (±2%) reference voltage

■ 5 % output current accuracy

■ Output voltage adjustable from 1.235 V to 34 V

■ 250 kHz internally fixed frequency

■ Voltage feedforward

■ Zero load current operation

■ Adjustable current limit

■ Protection against feedback Disconnection

■ Thermal shutdown

Applications

■ Chargers for NiCd, NiMH batteries and

preregulator for lithium-ion batteries

■ Adjustable current generator

■ Simple step-down converters with adjustable

current limit

■ Battery equipped systems

■ Distributed power supply

■ Mobile PC and subnotebook

Description

The L6902D is a complete and simple step down

switching regulator with adjustable current limit.

Based on a voltage mode structure it integrates a

current error amplifier to have a constant voltage

and constant current control.

By means of an on board current sense resistor

and the availability of the current sense pins (both

compatible to Vcc and for Cs- compatible with

GND too) a current limit programming is very

simple and accurate (±5%). Moreover constant

SO-8

current control can be used to charge NiMH and

NiCd batteries.

The device can be used as a standard DC/DC

converter with adjustable current limit (set by

using the external sense resistor).

The internal robust P-channel DMOS transistor

with a typical of 250 mΩ assures high efficiency

and a minimum dropout even at high output

current level. The internal limiting current (latched

function) of typical value of 2.5 A protects the

device from accidental output short circuit

avoiding dangerous loads damage.

If the temperature of the chip goes higher than a

fixed internal threshold (150°C with 20°C

hysteresis), the power stage is turned off.

Other protections beside thermal shutdown

complete the device for a safe and reliable

application: overvoltage protection, frequency

folback overcurrent protection and protection vs.

feedback disconnection.

The internal fixed switching frequency of 250KHz,

and the SO-8 package pin allow to built an ultra

compact DC/ DC converter with a minimum board

space.

Table 1. Device summary

Order codes

Package

L6902D

L6902D013TR

SO-8

Packaging

Tube

Tape and reel

November 2010

Doc ID 7332 Rev 9

1/11

www.st.com

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