SC431 Adjustable Shunt Regulator POWER MANAGEMENT Description Features The SC431 is a three terminal adjustable shunt Wide operating current range 130A to 150mA regulator with thermal stability guaranteed over Low dynamic output impedance 0.25 typ. temperature. The output voltage can be adjusted to any Trimmed bandgap design + 0.5% value from 2.5V (V ) to 30V with two external REF Alternate for TL1431, TL431, LM431 & AS431 resistors. The SC431 has a typical dynamic output Industrial temperature range impedance of 0.25 . Active output circuitry provides a Available in SOT-23-3 and SO-8 packages. very sharp turn on characteristic, making the SC431 an Also available in Lead-free, fully WEEE and RoHS excellent replacement for zener diodes. compliant. The SC431 shunt regulator is available with four Applications voltage tolerances (0.5%, 1.0% and 2.0% over T = -40C A to +85C and 0.5% over T = -40C to +125C) and two Linear Regulators A package options (SOT-23-3 and SO-8). This Adjustable Supplies allows the designer the opportunity to select the Switching Power Supplies optimum combination of cost and performance for their Battery Operated Computers application. Instrumentation Computer Disk Drives (1)(2) Typical Application Circuit Notes: 1) Set V according to the following equation: OUT R1 V = V 1+ +I R1 OUT REF REF R2 2) Choose the value for R as follows: The maximum limit for R should be such that the cathode current, I , is greater than the minimum Z operating current (130A) at V . IN(MIN) The minimum limit for R should be such that I does Z not exceed 150mA under all load conditions, and the instantaneous turn-on value for I does not exceed Z 200mA. Both of the following conditions must be met: V IN(max) R min (to limit instantaneous turn-on I ) 200mA Z V V IN(max) OUT R min (to limit I under normal Z I +150mA OUT(min) operating conditions) Revision: April 23, 2008 1 www.semtech.comSC431 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 SmymbolMsaximu Unit Cathode Voltage V 3V1 Z Continous Cathode Current I 1A50 m Z Reference Input Current I 1A0 m REF Power Dissipation at T = 25C A SOT-23-3 P 0.37 W D SO-8 0.78 Thermal Resistance SOT-23-3 336 C/W JA SO-8 163 Operating Ambient Temperature Range SC431Cx-.5, SC431Cx-1, SC431Cx-2 T -40 to +85 C A SC431CxQ -40 to +125 Operating Junction Temperature Range T -C40 to +150 J Storage Temperature Range T -C65 to +150 STG Lead Temperature (Soldering) 10 seconds T 3C00 LEAD ESD Rating (Human Body Model) V 2Vk ESD Electrical Characteristics Unless specified:T = 25C. Values in bold apply over full operating ambient temperature range. A SC431Cx-.5, SC431Cx-1 SC431CxQ PlarameterSnymboCnonditio Mpi Txy Mna Mpi Txy Msa Unit (1) RVeference Voltage V = V , I = 10mA 25.48227.4920.5025.4720.492V.52 REF Z REF Z (1) VTVemp Deviation V = V ,I = 10mA 8718 25 mV REF DEV Z REF Z RIatio of Change in = 10mA, V = 10V to V -70.5-52. -70. -V2. mV/ Z Z REF V REF V V to Change in V I = 10mA, V=030V to 10V -01.-02. -01. -2. Z REF Z Z Z Reference Input I R1 = 10k , R2 = , 04.5 04.5 A REF (2) Current I = 10mA Z I Temperature I R1 = 10k , R2 = , 02.414. 02. 1. A REF REF(DEV) (2) Deviation I =10mA Z (3) Off-State Cathode I V = 0V, V =30V 00.0404.5 00.0 0A.5 Z (OFF) REF Z Current Dynamic Output r f < 1kHz, V = V 00.2505.5 00.2 0.5 Z Z REF (1) Impedance I = 130A to 100mA Z (1) Minimum Operating I V = V 1030 1A3 Z (MIN) Z REF Current 2008 Semtech Corp. 2 www.semtech.com