SC4431CSK-X

Shunt Regulator With Open Collector Output POWER MANAGEMENT Description The SC4431 is a four terminal device for regulating an isolated power supply with output voltages down to 1.5V. 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 the device to function in conjunction with an opto-isolator. SC4431 achieves this by having seperate supply and output pins, allowing the output to sink current at voltages as low as 0.1V, while the supply pin still has sufficient voltage for the device to function. In this way, allowing for a 1.4V drop through an opto-isolator diode, regulation down to 1.5V 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. SC4431 Features Open Collector output drives Optoisolator with as little as 1.5V input voltage Trimmed bandgap design - initial accuracies to + 0.5% 40mA drive capability Regulates output as low as 50mV Wide supply voltage range - 1.5V to 15V Low supply current - typically 110µA Full industrial temperature range SOT-23 5 lead package Applications Telecom Power Supplies Opto driver for very low output voltage (1.5V) isolated power supplies Battery operated applications Point of use power supplies Typical Application Circuit 2V Output Isolated Power Supply T1 VIN Primary Side Controller Secondary Side Rectification and Filtering R1 R2 5.1k C1 2V OUT U1 C3 SC4431 1 VCC 33nF R3 6.34k 5 4N25 C2 22nF OUT 4 REF R4 10k 3 NC 2 GND Revision September 9 ,2003 1 www.semtech.com POWER MANAGEMENT Absolute Maximum Rating Parameter Input Supply Voltage Vcc pin current Output Voltage Reference Voltage (1) Continuous Output Current Reference Input Current Operating Ambient Temperature Range Operating Junction Temperature Range Storage Temperature Range Thermal Impedance Junction to Ambient Thermal Impedance Junction to Case Power Dissipation at TA = 25°C Lead Temperature (Soldering) 10 seconds ESD Rating (Human Body Model) Shunt Regulator With Open Collector Output Symbol V CC ICC VOUT VREF IOUT IREF TA TJ TSTG θJ A θJ C PD TLEAD ESD Maximum -0.5 to +16 8 -0.5 to VCC -0.5 to +4 40 5 -40 to +85 -40 to +150 -65 to +150 256 81 475 300 2 Units V mA V V mA mA °C °C °C °C/W °C/W mW °C kV SC4431 (1) If Vref will be forced above 1.224V, a resistor must be placed in series with the Vcc to limit the Icc current below 5mA. Electrical Characteristics Unless specified, TA = 25°C, VCC = 2V, IOUT = 2mA. Values in bold apply over full operating temperature range. Parameter VCC Input Supply Voltage Input Supply Current Off State Input Supply Current REF Reference Voltage Symbol VCC ICC ICC(OFF) Test Conditions MIN 1.5 T YP MAX 15 200 100 150 1.231 1.243 1.236 1.250 1.250 1.261 15 20 28 36 0.5 1.0 75 100 300 400 1 10 Units V µA µA VREF VREF = VOUT = 1.187V, VOUT = 2V 110 65 VREF SC4431-.5, VREF = VOUT SC4431-1, VREF = VOUT SC4431-2, VREF = VOUT 1.219 1.207 1.212 1.200 1.200 1.187 1.224 1.224 1.224 8 8 0.3 V V V mV mV µA Change in VREF due to change in Vcc Change in VREF due to change in IOUT Reference Input Current OUT Saturation Voltage dVREF/dVCC dVREF/dIOUT IREF VCC = 1.5V to 15V IOUT = 0.1mA to 40mA 0.1mA ≤ IOUT ≤ 10mA VOUT(SAT) IOUT = 5mA, ICC = 500µA VREF = 1.261V, IOUT = 40mA 50 275 0.50 mV mV µA Off State Output Current IOUT(OFF) VREF = 1.187V, VOUT = 2V  2003 Semtech Corp. 2 www.semtech.com Shunt Regulator With Open Collector Output POWER MANAGEMENT Pin Configurations (TOP VIEW) SC4431 Ordering Information Part Number(1)(2) SC4431CSK-X P ackag e SOT-23-5 Notes: (1) Only available in tape and reel packaging. (Suffix ‘.TR’ e.g. SC4431CSK-X.TR). (2) Where “-X” denotes initial reference voltage tolerance. Available options are ±0.5% (-.5), ±1% (-1) and ±2% (-2). (SOT-23-5 Lead ) Pin Descriptions Pin# 1 2 3 4 5 Pin Name VC C GND NC REF OUT Pin Function This is the input supply pin for the SC4431. A low ESR capacitor should be used to bypass this pin to GND right at the IC. Logic and power ground. No connection. This is connected to the non-inverting input of the error amplifier. This is the output pin of the device, essentially an open collector. Note: A 22nF low ESR (ceramic) capacitor is required from this pin to GND for stable operation. Block Diagram Marking Information Top Mark 4431 Bottom Mark yyww yyww = Datecode (Example: 9908)  2003 Semtech Corp. 3 www.semtech.com POWER MANAGEMENT Typical Characteristics V ref vs T a I u t = 2m A o 1 .2 2 8 1 .2 2 7 1 .2 2 6 1 .2 2 5 1 .2 2 4 1 .2 3 2 1 .2 3 0 1 .2 3 6 V c c = 1 .5 V V cc= 2V V cc= 5V V cc= 15V Shunt Regulator With Open Collector Output SC4431 V ref vs T a V cc = 2V I u t= 4 0 m a o 1 .2 3 4 I u t= 2 m A o I u t= 1 0 0 u A o V ref(V 1 .2 2 3 1 .2 2 2 1 .2 2 1 1 .2 2 0 1 .2 1 9 1 .2 1 8 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 T a(D e g . . C) V ref(V 1 .2 2 8 1 .2 2 6 1 .2 2 4 1 .2 2 2 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 T a(D e g . . C) Typical Vref vs Ta Io = 2mA I O ff vs T a V o u t = 2V cc 7 0 E -6 I c_O f c f Typical Vref vs Ta Vcc = 2V I ref vs T a V o u t = 2V 1 3 E -9 If re 1 2 E -9 6 5 E -6 1 1 E -9 1 0 E -9 I O ff(A cc I ref (A -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 9 E -9 8 E -9 7 E -9 6 0 E -6 5 5 E -6 6 E -9 5 E -9 5 0 E -6 T a(D e g . . C) 4 E -9 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 T a(D e g . . C) Typical Icc Off vs Ta Vo = 2V I ref vs T a V cc = 2V 4 5 E -9 I u t= 1 0 0 u A o I u t= 1 m A o Typical Iout vs Ta Vo = 2V V sat vs T a V cc = 2V 350 I u t= 4 0 m a o I u t= 5 m A o I u t= 2 m A o 4 0 E -9 I u t= 5 m A o I u t= 1 0 m A o I u t= 1 5 m A o 300 250 I f(A ) re V s a t(m V 3 5 E -9 200 150 100 3 0 E -9 2 5 E -9 50 0 0 10 20 30 40 50 60 70 80 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 T a(D e g . . C) 2 0 E -9 -4 0 -3 0 -2 0 -1 0 T a(D e g . . C) Typical Iref vs Ta Vcc = 2V  2003 Semtech Corp. 4 Typical Vsat vs Ta Vcc = 2V www.semtech.com Shunt Regulator With Open Collector Output POWER MANAGEMENT Typical Characteristics 3.5000 3.5000 SC4431 3.0000 3.0000 2.5000 2.5000 2.0000 2.0000 Icc(mA) Icc(mA) 1.5000 1.5000 1.0000 1.0000 0.5000 0.5000 0.0000 0.0000 -0.5000 1.2248 1.2703 1.3048 1.7030 3.0182 -0.5000 1.2243 1.2700 1.3009 1.7073 3.0073 Vref(v) Vcc=2V,Io=1.3mA Vcc=5V,Io=1.3mA Vcc=15V,Io=1.3mA Vcc=2V,Io=2mA Vref(v) Vcc=5V,Io=2mA Vcc=15V,Io=2mA Typical Icc vs Vref, Io = 1.3mA, Ta = 25 Deg.C. Typical Icc vs Vref, Io = 2mA, Ta = 25 Deg.C. +VCC J1 +Vref_Adjust 1 2 C1 10uF R1 4k +V adj C3 U1 1 Io 5 R2 3.9k C2 10uF J2 1 2 R4 1k J3 1 2 C4 10uF Vref 4 Vo C5 22nF R5 1k Vref SC4431 2 Icc vs Vref Test Circuit  2003 Semtech Corp. 5 www.semtech.com POWER MANAGEMENT Typical Gain Phase SC4431 Gain / Phase Vin = 2V, Iout = 2mA, Vout = 1.6V 70 Shunt Regulator With Open Collector Output SC4431 200 60 50 Gain Phase 150 100 40 Phase (deg) Phase (deg) C3 33n Gain (dB) 30 50 20 0 10 -50 0 -100 -10 -20 10 100 1000 Freq (Hz) 10000 100000 -150 1000000 SC4431 Gain / Phase Vin = 4V, Iout = 2mA, Vout = 2V 80 70 60 50 100 40 Gain (dB) 30 20 0 10 0 -50 -10 -20 10 100 1000 Freq (Hz) 10000 100000 -100 1000000 200 Gain 150 Phase 50 R1 J1 A 12345 J2 R 12345 1k for 2mA U1 J3 1 4V IN 1 2 3 VCC GND NC SC4431 C1 10u C2 0.1u REF 4 OUT 5 2V OUT R2 3.16k R3 C4 22u C7 22n J4 1 GND J5 1 2 3 4 5 Signal In C5 22u C6 22u 5.1k R4 4.99k Gain Phase Test Circuit  2003 Semtech Corp. 6 www.semtech.com Shunt Regulator With Open Collector Output POWER MANAGEMENT Typical Applications +V Monitor +Vcc Power Good SC4431 C1 R4 R1 U1 5 R2 R3 1 Q1 C3 4 C4 C2 R5 Vref 22nF 2 SC4431 Power good Circuit P ower +Vcc +Vout Secondary C1 +Vprimary R2 R1 1 R3 U2 PWM disable Vref 5 4 C3 C2 22n U1 SC4431 R4 R5 C4 2 Isolated OVP Circuit Isolated +Vin +Vout Q1 C1 R1 U1 5 R2 R3 1 4 C2 22nF R4 C3 Vref 2 SC4431 Linear Regulator Circuit Linear  2003 Semtech Corp. 7 www.semtech.com POWER MANAGEMENT Outline Drawing Shunt Regulator With Open Collector Output SC4431 SOT SO T-23- 5L 881 ECN00 - 881 Land Pattern SOT SOT- 23- 5L 881 ECN00 - 881 Contact Information Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804  2003 Semtech Corp. 8 www.semtech.com