L6902D 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 SO-8 250 kHz internally fixed frequency current control can be used to charge NiMH and Voltage feedforward NiCd batteries. Zero load current operation The device can be used as a standard DC/DC Adjustable current limit converter with adjustable current limit (set by Protection against feedback Disconnection using the external sense resistor). Thermal shutdown The internal robust P-channel DMOS transistor with a typical of 250 m assures high efficiency and a minimum dropout even at high output Applications current level. The internal limiting current (latched Chargers for NiCd, NiMH batteries and function) of typical value of 2.5 A protects the preregulator for lithium-ion batteries device from accidental output short circuit avoiding dangerous loads damage. Adjustable current generator If the temperature of the chip goes higher than a Simple step-down converters with adjustable fixed internal threshold (150C with 20C current limit hysteresis), the power stage is turned off. Battery equipped systems Other protections beside thermal shutdown Distributed power supply complete the device for a safe and reliable Mobile PC and subnotebook application: overvoltage protection, frequency folback overcurrent protection and protection vs. Description feedback disconnection. The internal fixed switching frequency of 250KHz, The L6902D is a complete and simple step down and the SO-8 package pin allow to built an ultra switching regulator with adjustable current limit. compact DC/ DC converter with a minimum board Based on a voltage mode structure it integrates a space. current error amplifier to have a constant voltage and constant current control. Table 1. Device summary By means of an on board current sense resistor Order codes Package Packaging and the availability of the current sense pins (both compatible to Vcc and for Cs- compatible with L6902D Tube SO-8 GND too) a current limit programming is very L6902D013TR Tape and reel simple and accurate (5%). Moreover constant November 2010 Doc ID 7332 Rev 9 1/11 www.st.com 11Content L6902 Content 1 Test and application circuit . 3 2 Pin connection 3 3 Maximum ratings 4 4 Internal block diagram . 5 5 Electrical characteristics . 6 6 Package mechanical data . 8 7 Revision history . 10 2/11 Doc ID 7332 Rev 9