SC4431 SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT PRELIMINARY - September 11, 2000 TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com DESCRIPTION FEATURES •= Trimmed bandgap design - initial accuracies to 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. + 0.5% 40mA 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 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. ORDERING INFORMATION (1)(2) Part Number Package SC4431CSK-X.TR SOT-23-5 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 2V OUT T1 VIN Primary Side Controller Secondary Side Rectification and Filtering R1 U1 R2 C1 5.1k 33nF U2 1 R3 6.34k SC4431 VCC 5 OUT REF 4 4N25 C2 22nF NC 3 R4 10k GND 2 2V Output Isolated Power Supply 1 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SC4431 SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT PRELIMINARY - September 11, 2000 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Maximum Units Input Supply Voltage VCC -0.5 to +16 V Output Voltage VOUT -0.5 to VCC V Reference Voltage VREF -0.5 to +4 V Continuous Output Current IOUT 40 mA Reference Input Current IREF 5 mA Operating Ambient Temperature Range TA -40 to +85 °C Operating Junction Temperature Range TJ -40 to +150 °C TSTG -65 to +150 °C Thermal Impedance Junction to Ambient θJA 256 °C/W Thermal Impedance Junction to Case θJC 81 °C/W Power Dissipation at TA = 25°C PD 475 mW Lead Temperature (Soldering) 10 seconds TLEAD 300 °C ESD Rating (Human Body Model) ESD 2 kV Storage Temperature Range ELECTRICAL CHARACTERISTICS Unless specified, TA = 25°C, VCC = 2V, IOUT = 2mA. Values in bold apply over full operating temperature range. Parameter Symbol Test Conditions MIN TYP MAX Units 15 V VCC Input Supply Voltage VCC Input Supply Current ICC VREF = VOUT 110 200 µA ICC(OFF) VREF = 1.187V, VOUT = 2V 65 100 µA Off State Input Supply Current 1.5 150 REF Reference Voltage VREF SC4431-.5, VREF = VOUT 1.219 1.224 1.231 1.207 SC4431-1, VREF = VOUT 1.243 1.212 1.224 1.236 1.200 SC4431-2, VREF = VOUT in VCC Change in VREF due to change in IOUT dVREF dVCC VCC = 1.5V to 15V dVREF dIOUT IOUT = 0.1mA to 40mA V 1.250 1.200 1.224 1.250 1.187 Change in VREF due to change V V 1.261 8 15 mV 20 8 28 mV 36 2 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SC4431 SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT PRELIMINARY - September 11, 2000 ELECTRICAL CHARACTERISTICS (Cont.) Unless specified, TA = 25°C, VCC = 2V, IOUT = 2mA. Values in bold apply over full operating temperature range. Parameter Symbol Test Conditions IREF 0.1mA ≤ IOUT ≤ 10mA MIN TYP MAX Units 0.3 0.5 µA REF (Cont.) Reference Input Current 1.0 OUT Saturation Voltage VOUT(SAT) IOUT = 5mA, ICC = 500µA 50 75 mV 100 VREF = 1.261V, IOUT = 40mA 275 300 mV 400 Off State Output Current IOUT(OFF) VREF = 1.187V, VOUT = 2V 0.5 1 µA 10 3 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT SC4431 PRELIMINARY - September 11, 2000 BLOCK DIAGRAM PIN CONFIGURATION SOT-23 -5 Lead (Top View) PIN DESCRIPTION Pin Pin Name Pin Function 1 VCC This is the input supply pin for the IC. 2 GND Logic and power ground. 3 NC No connection. 4 REF This is connected to the non-inverting input of the error amplifier. 5 OUT This is the output pin of the device, essentially an open collector. 4 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320 SHUNT REGULATOR WITH OPEN COLLECTOR OR OUTPUT SC4431 PRELIMINARY - September 11, 2000 DEVICE OUTLINE - SOT-23-5 LAND PATTERN - SOT-23-5 ECN 00-1315 5 © 2000 SEMTECH CORP. 652 MITCHELL ROAD NEWBURY PARK CA 91320