SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Description Features The SC4431 is a four terminal device for regulating an isolated power supply with output voltages down to 1.5V. Open Collector output drives Optoisolator with 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. Telecom Power Supplies Opto driver for very low output voltage (1.5V) 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 isolated power supplies Battery operated applications Point of use power supplies Typical Application Circuit 2V Output Isolated Power Supply 2V OUT T1 VIN Primary Side Controller Secondary Side Rectification and Filtering R1 R2 5.1k U1 C1 C3 33nF SC4431 5 1 VCC OUT 4N25 R3 6.34k 4 REF C2 22nF 3 NC R4 10k 2 GND Revision September 9 ,2003 1 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Absolute Maximum Rating Parameter Symbol Maximum Units V CC ICC VOUT VREF IOUT IREF -0.5 to +16 8 -0.5 to VCC -0.5 to +4 40 5 V mA V V mA mA Operating Ambient Temperature Range Operating Junction Temperature Range TA TJ -40 to +85 -40 to +150 °C °C Storage Temperature Range Thermal Impedance Junction to Ambient TSTG θJ A -65 to +150 256 °C °C/W Thermal Impedance Junction to Case θJ C 81 °C/W PD TLEAD ESD 475 300 2 mW °C kV Input Supply Voltage Vcc pin current Output Voltage Reference Voltage (1) Continuous Output Current Reference Input Current Power Dissipation at TA = 25°C Lead Temperature (Soldering) 10 seconds ESD Rating (Human Body Model) (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 Test Conditions VREF T YP MAX Units 110 65 15 200 100 150 V µA µA 1.231 1.243 1.236 1.250 1.250 1.261 15 20 28 36 V 1.5 VCC ICC ICC(OFF) MIN VREF VREF = VOUT = 1.187V, VOUT = 2V 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 V V Change in VREF due to change in Vcc dVREF/dVCC VCC = 1.5V to 15V 8 Change in VREF due to change in IOUT dVREF/dIOUT IOUT = 0.1mA to 40mA 8 IREF 0.1mA ≤ IOUT ≤ 10mA 0.3 0.5 1.0 µA VOUT(SAT) IOUT = 5mA, ICC = 500µA 50 mV VREF = 1.261V, IOUT = 40mA 275 VREF = 1.187V, VOUT = 2V 0.50 75 100 300 400 1 10 Reference Input Current OUT Saturation Voltage Off State Output Current 2003 Semtech Corp. IOUT(OFF) 2 mV mV mV µA www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Pin Configurations Ordering Information (TOP VIEW) Part Number(1)(2) P ackag e SC4431CSK-X 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# Pin Name Pin Function 1 VC C 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. 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. Note: A 22nF low ESR (ceramic) capacitor is required from this pin to GND for stable operation. Marking Information Block Diagram Top Mark 4431 Bottom Mark yyww yyww = Datecode (Example: 9908) 2003 Semtech Corp. 3 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Typical Characteristics V ref vs T a V cc = 2V V ref vs T a Io u t = 2m A 1 .2 2 8 1 .2 2 7 1 .2 3 6 V c c = 1 .5 V Io u t= 4 0 m a V cc= 2V V cc= 5V V cc= 15V Io u t= 2 m A 1 .2 3 4 1 .2 2 6 Io u t= 1 0 0 u A 1 .2 3 2 1 .2 2 5 V ref(V V ref(V 1 .2 2 4 1 .2 2 3 1 .2 2 2 1 .2 2 1 1 .2 3 0 1 .2 2 8 1 .2 2 6 1 .2 2 0 1 .2 2 4 1 .2 1 9 1 .2 1 8 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 1 .2 2 2 80 -4 0 -3 0 -2 0 -1 0 0 10 T a(D e g .C .) 20 30 40 50 60 70 80 T a(D e g .C .) Typical Vref vs Ta Vcc = 2V Typical Vref vs Ta Io = 2mA Icc O ff vs T a V o u t = 2V Iref vs T a V o u t = 2V 7 0 E -6 1 3 E -9 Ic c _ O ff Ire f 1 2 E -9 1 1 E -9 6 5 E -6 Iref (A Icc O ff(A 1 0 E -9 6 0 E -6 9 E -9 8 E -9 7 E -9 5 5 E -6 6 E -9 5 E -9 5 0 E -6 4 E -9 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 80 -4 0 -3 0 -2 0 -1 0 0 10 T a(D e g .C .) 20 30 40 50 60 70 80 70 80 T a(D e g .C .) Typical Iout vs Ta Vo = 2V Typical Icc Off vs Ta Vo = 2V Iref vs T a V cc = 2V V sat vs T a V cc = 2V 4 5 E -9 Io u t= 1 0 0 u A 350 Io u t= 4 0 m a Io u t= 1 m A Io u t= 5 m A Io u t= 2 m A 300 4 0 E -9 Io u t= 5 m A Io u t= 1 0 m A 250 V s a t(m V Ire f(A ) Io u t= 1 5 m A 3 5 E -9 3 0 E -9 200 150 100 2 5 E -9 50 0 2 0 E -9 -4 0 -3 0 -2 0 -1 0 0 10 20 30 40 50 60 70 -4 0 -3 0 -2 0 -1 0 80 10 20 30 40 50 60 Typical Vsat vs Ta Vcc = 2V Typical Iref vs Ta Vcc = 2V 2003 Semtech Corp. 0 T a(D e g .C .) T a(D e g .C .) 4 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT 3.5000 3.5000 3.0000 3.0000 2.5000 2.5000 2.0000 2.0000 Icc(mA) Icc(mA) Typical Characteristics 1.5000 1.5000 1.0000 1.0000 0.5000 0.5000 0.0000 0.0000 -0.5000 -0.5000 1.2248 1.2703 1.3048 1.7030 1.2243 3.0182 1.2700 Vcc=2V,Io=1.3mA 1.3009 1.7073 3.0073 Vref(v) Vref(v) Vcc=5V,Io=1.3mA Vcc=15V,Io=1.3mA Vcc=2V,Io=2mA Typical Icc vs Vref, Io = 1.3mA, Ta = 25 Deg.C. Vcc=5V,Io=2mA Vcc=15V,Io=2mA Typical Icc vs Vref, Io = 2mA, Ta = 25 Deg.C. +VCC J1 +V adj C1 10uF 1 2 +Vref_Adjust R1 4k Io C3 1k J3 1 2 C4 10uF 1 Vref J2 3.9k U1 R4 R2 5 4 Vo C2 10uF 1 2 C5 22nF R5 1k Vref SC4431 2 Icc vs Vref Test Circuit 2003 Semtech Corp. 5 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Typical Gain Phase SC4431 Gain / Phase Vin = 2V, Iout = 2mA, Vout = 1.6V 200 70 60 150 Gain 50 Phase 100 50 30 20 0 Phase (deg) Gain (dB) 40 10 -50 0 -100 -10 -20 10 100 1000 10000 100000 -150 1000000 Freq (Hz) SC4431 Gain / Phase Vin = 4V, Iout = 2mA, Vout = 2V 80 200 Gain 70 150 60 50 100 Gain (dB) 30 50 Phase (deg) Phase 40 20 0 10 0 -50 -10 -20 10 100 1000 10000 100000 -100 1000000 Freq (Hz) R1 J1 A J2 R 1 2 3 4 5 1k for 2mA 1 2 3 4 5 U1 J3 1 1 2 4V IN 3 VCC OUT 5 2V OUT GND NC REF 4 R2 3.16k SC4431 C1 10u R3 C3 C2 0.1u C4 22u C5 22u C7 22n C6 22u 5.1k R4 4.99k 33n J4 1 GND J5 1 2 3 4 5 Signal In Gain Phase Test Circuit 2003 Semtech Corp. 6 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Typical Applications +V Monitor +Vcc C1 Power Good R2 R1 R4 R3 U1 1 5 Q1 4 C2 C4 C3 22nF R5 Vref SC4431 2 Power good Circuit +Vcc +Vout Secondary C1 R1 R2 +Vprimary 1 R3 R4 5 4 U2 C3 C2 22n U1 SC4431 PWM disable R5 C4 Vref 2 Isolated OVP Circuit +Vin +Vout Q1 C1 R1 1 R2 U1 R3 5 4 C2 R4 22nF C3 Vref 2 SC4431 Linear Regulator Circuit 2003 Semtech Corp. 7 www.semtech.com SC4431 Shunt Regulator With Open Collector Output POWER MANAGEMENT Outline Drawing SO T-23- 5L SOT ECN00 - 88 1 881 Land Pattern SO T- 23- 5L SOT ECN00 - 88 1 881 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