SC4431 Datasheet | SEMTECH

SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT PRELIMINARY - September 11, 2000 TEL:805-498-2111 FAX:805-498-3804 WEB:http://.semtech. DESCRIPTION The SC4431 is a four terminal device for regulating an isolated power supply with very low output voltage. It is intended to be used as a replacement for three terminal shunt regulators such as SC431L where the output voltage is too low for them to function in conjunction with an opto-isolator. It achieves this by having seperate supply and output pins, allowing the output to sink current at voltages as low as 0.2V, while the supply pin still has sufficient voltage for the device to function. In this way, allowing for a 1.6V drop through an opto-isolator diode, regulation down to 1.8V out can be achieved. The SC4431 shunt regulator is available with three initial reference voltage accuracies (0.5%, 1.0% and 2.0%) in the space saving 5-lead SOT-23 package. The three voltage tolerances allow the designer the opportunity to select the proper cost/tolerance for their application. Features - = Trimmed bandgap design - initial accuracies to - = - = - = - = + 0.5% 40m A drive capability Wide supply voltage range - 1.5V to 15V Low supply current - typically 110µA Full industrial temperature range APPLICATIONS - = Opto driver for very low output voltage isolated power supplies ORDERING INFORMATION Part Number (1)(2) Package SOT-23-5 SC4431CSK-X.TR Notes: (1) Where “-X” denotes initial reference voltage tolerance. Available options are ±0.5% (-.5), ±1% (-1) and ±2% (-2). (2) Only available in tape and reel packaging. A reel contains 3000 devices. TYPICAL APPLICATION CIRCUIT T1 VIN Primary Side Controller Secondary Side Rectification and Filtering R1 R2 C1 2V OUT U1 5.1k U2 5 OUT 1 VCC REF 33n F R3 6.34k SC4431 4 R4...