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L6902 Datasheet, PDF (1/11 Pages) STMicroelectronics – Zero load current operation | |||
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L6902
Up to 1 A switching regulator with adjustable current limit
Features
â Up to 1 A output current
â Operating input voltage from 8 V to 36 V
â Precise 3.3 V (±2%) reference voltage
â 5 % output current accuracy
â Output voltage adjustable from 1.235 V to 34 V
â 250 kHz internally fixed frequency
â Voltage feedforward
â Zero load current operation
â Adjustable current limit
â Protection against feedback Disconnection
â Thermal shutdown
Applications
â Chargers for NiCd, NiMH batteries and
preregulator for lithium-ion batteries
â Adjustable current generator
â Simple step-down converters with adjustable
current limit
â Battery equipped systems
â Distributed power supply
â 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
11
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