SC431 Adjustable Shunt Regulator POWER MANAGEMENT Description Features The SC431 is a three terminal adjustable shunt regulator with thermal stability guaranteed over temperature. The output voltage can be adjusted to any value from 2.5V (V REF ) to 30V with two external resistors. The SC431 has a typical dynamic output impedance of 0.25. Active output circuitry provides a very sharp turn on characteristic, making the SC431 an excellent replacement for zener diodes. The SC431 shunt regulator is available with four voltage tolerances (0.5%, 1.0% and 2.0% over TA = -40C to +85C and 0.5% over TA = -40C to +125C) and three package options (SOT-23-3, SO-8 and TO-92). This allows the designer the opportunity to select the optimum combination of cost and performance for their application. Wide operating current range 130A to 150mA Low dynamic output impedance 0.25 typ. Trimmed bandgap design + 0.5% Alternate for TL1431, TL431, LM431 & AS431 Industrial temperature range Available in SOT-23-3, SO-8 and TO-92 packages Applications Typical Application Circuit(1)(2) Linear Regulators Adjustable Supplies Switching Power Supplies Battery Operated Computers Instrumentation Computer Disk Drives Notes: 1) Set VOUT according to the following equation: R1 VOUT = VREF 1 + + IREF R1 R 2 2) Choose the value for R as follows: * The maximum limit for R should be such that the cathode current, I Z , is greater than the minimum operating current (130A) at VIN(MIN). * The minimum limit for R should be such that IZ does not exceed 150mA under all load conditions, and the instantaneous turn-on value for I Z does not exceed 200mA. Both of the following conditions must be met: Rmin R min VIN(max) 200mA (to limit instantaneous turn-on IZ) VIN(max) - VOUT IOUT (min) + 150mA (to limit IZ under normal operating conditions) Revision 7, May 2003 1 www.semtech.com SC431 POWER MANAGEMENT Absolute Maximum Ratings Exceeding the specifications below may result in permanent damage to the device, or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Parameter Symbol Maximum Units Cathode Voltage VZ 31 V Continous Cathode Current IZ 150 mA Reference Input Current IREF 10 mA Power Dissipation at TA = 25C SOT-23-3 SO-8 TO-92 PD 0.37 0.78 0.95 W Thermal Resistance SOT-23-3 SO-8 TO-92 J A 336 163 132 C/W Operating Ambient Temperature Range SC431Cx-.5, SC431Cx-1, SC431Cx-2 SC431CxQ TA -40 to +85 -40 to +125 C Operating Junction Temperature Range TJ -40 to +150 C Storage Temperature Range TSTG -65 to +150 C Lead Temperature (Soldering) 10 seconds TLEAD 300 C ESD Rating (Human Body Model) V ESD 2 kV Electrical Characteristics Unless specified:TA = 25C. Values in bold apply over full operating ambient temperature range. SC431Cx-.5, S C 431C xQ Parameter SC431Cx-1 Symbol Condition Min Typ Max Min Typ Max Units Reference Voltage VREF VZ = VREF, IZ = 10mA(1) 2.482 2.495 2.507 2.470 2.495 2.520 V VREF Temp Deviation V D EV VZ = VREF, IZ = 10mA(1) 8 17 8 25 mV Ratio of Change in VREF VZ IZ = 10mA, VZ = 10V to VREF -0.5 -2.7 -0.5 -2.7 mV/V IZ = 10mA, VZ =30V to 10V -1.0 -2.0 -1.0 -2.0 Reference Input Current IREF R1 = 10k, R2 = , IZ = 10mA(2) 0.5 4 0.5 4 A IREF Temperature Deviation IREF(DEV) R1 = 10k, R2 = , IZ =10mA(2) 0.4 1.2 0.4 1.2 A IZ (OFF) VREF = 0V, VZ =30V(3) 0.04 0.50 0.04 0.50 A rZ f < 1kHz, VZ = VREF IZ = 130A to 100mA(1) 0.25 0.50 0.25 0.50 IZ (MIN) VZ = VREF(1) 130 A VREF to Change in VZ Off-State Cathode Current Dynamic Output Impedance Minimum Operating Current 2003 Semtech Corp. 130 2 www.semtech.com SC431 POWER MANAGEMENT Electrical Characteristics (Cont.) Unless specified:TA = 25C. Values in bold apply over full operating ambient temperature range. SC431Cx-2 Parameter Symbol Condition Min Typ Max Units Reference Voltage VREF VZ = VREF, IZ = 10mA(1) 2.445 2.495 2.545 V VREF Temp Deviation V D EV VZ = VREF, IZ = 10mA(1) 15 30 mV VREF VZ IZ = 10mA, VZ = 10V to VREF -0.5 -2.7 mV/V IZ = 10mA, VZ =30V to 10V -1.0 -2.0 IREF R1 = 10k, R2 = , IZ = 10mA(2) 0.5 4 A IREF Temperature Deviation IREF(DEV) R1 = 10k, R2 = , IZ =10mA(2) 0.4 1.2 A Off-State Cathode Current IZ (OFF) VREF = 0V, VZ =30V(3) 0.04 0.50 A Dynamic Output Impedance rZ f < 1kHz, VZ = VREF, IZ = 130A to 100mA(1) 0.25 0.50 Minimum Operating Current IZ (MIN) VZ = VREF(1) 130 A Ratio of Change in VREF to Change in VZ Reference Input Current Notes: (1) See Test Circuit 1 below. (2) See Test Circuit 2 below. (3) See Test Circuit 3 below. Test Circuits Test Circuit 2 VZ > VREF Test Circuit 1 VZ = VREF Test Circuit 3 Off-State Recommended Operating Conditions Cathode Voltage, VZ Cathode Current, IZ 2003 Semtech Corp. Min Max Symbol VREF 30 V 0.130 150 mA 3 www.semtech.com SC431 POWER MANAGEMENT Pin Configurations SOT-23-3 (Top View) SO-8 (Top View) Block Diagram TO-92 (Top View) Symbol Ordering Information Tolerance 0.5% 0.5% 1.0% 2.0% -40C to +85C -40C to +125C -40C to +85C -40C to +85C SC431CSK-.5 TR SC431CSKQTR SC431CSK-1.TR SC431CSK-2.TR SC431CSK-.5 TRT SC431CSKQTRT SC431CSK-1.TRT SC431CSK-2.TRT SO-8(2) SC431CS-.5 TR SC431CSQTR SC431CS-1.TR SC431CS-2.TR TO-92(3) SC431CZ-.5 TA SC431CZQTA SC431CZ-1.TA SC431CZ-2.TA Ambient Temperature Range SOT-23-3(1) SOT-23-3(1), (4) Notes: (1) Only available in tape and reel packaging. A reel contains 3000 devices. (2) Only available in tape and reel packaging. A reel contains 2500 devices. (3) Only available in an ammo pack. An ammo pack contains 2000 devices. (4) "T" at end of part number indicates "lead free". 2003 Semtech Corp. 4 www.semtech.com SC431 POWER MANAGEMENT Marking Information SOT-23-3 (Top View) 431 431 SO-8 (Top View) SC 431CS yyww TO-92 (Top View) SC 431 yyww SO-8 (Bottom View) yyww = Datecode (Example: 9815) xxxxx yyww = Datecode (Example: 0008) xxxxx = Semtech Lot # (Example: 00101) 2003 Semtech Corp. 5 www.semtech.com SC431 POWER MANAGEMENT Typical Characteristics 300 Cathode Current vs. Cathode Current vs. Cathode Voltage Cathode Voltage 150 VZ = VREF VZ = VREF o o TA = 25 C 200 50 IZ (mA) 100 IZ ( A) TA = 25 C 100 0 0 -100 -50 -200 -100 -300 -150 -2 -1 0 1 2 3 -2 -1 0 VZ (V) 2.515 2 Reference Voltage vs. Reference Input Current vs. Junction Temperature Junction Temperature 100 VZ = VREF IZ = 10mA 2.510 1 3 VZ (V) IZ = 10mA R1 = 10k R2 = 80 IREF (nA) VREF (V) 2.505 2.500 60 40 2.495 20 2.490 2.485 0 -50 -25 0 25 50 75 100 125 150 -50 -25 0 25 TJ (C) 50 75 100 Ratio of Delta Reference Voltage to Delta Cathode Off-State Cathode Current Voltage vs. Junction Temperature vs. Junction Temperature 150 100 IZ = 10mA VZ = 3V to 30V 0.4 10 0.3 1 125 150 VZ = 30V VREF = 0V IZ(off) VREF/ VZ (-mV/V) 0.5 125 TJ (C) 0.2 0.1 0.1 0.01 0.001 0 -50 -25 0 25 50 75 100 125 -50 150 2003 Semtech Corp. -25 0 25 50 75 100 TJ (C) TJ (C) 6 www.semtech.com SC431 POWER MANAGEMENT Typical Characteristics (Cont.) Test Circuit - Small-Signal Gain and Phase Small-Signal Gain and Phase Shift vs. Frequency IZ = 10mA TA = 25C AV (dB) 70 -180 -225 60 -270 50 -315 40 -360 30 -405 20 -450 10 -495 0 -540 -10 -585 -20 Phase Shift (deg) 80 -630 1.0E+02 1.0E+03 1.0E+04 1.0E+05 1.0E+06 f (Hz) Reference Impedance vs. Frequency 100 IZ = 10mA TA = 25C rZ ( ) 10 1 0.1 0.01 1.0E+03 1.0E+04 1.0E+05 1.0E+06 1.0E+07 f (Hz) Stability Boundary Condition For Shunt Regulation Test Circuit - Stability vs. Cathode Current and Load Capacitance 2003 Semtech Corp. 7 www.semtech.com SC431 POWER MANAGEMENT Outline Drawing - SOT-23-3 Land Pattern - SOT-23-3 Note: (1) Grid placement courtyard is 8 x 8 elements (4mm x 4mm) in accordance with the international grid detailed in IEC Publication 97. Outline Drawing - SO-8 2003 Semtech Corp. 8 www.semtech.com SC431 POWER MANAGEMENT Land Pattern - SO-8 Outline Drawing - TO-92 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. 9 www.semtech.com