LM431SA/LM431SB/LM431SC

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1 Programmable Shunt Regulator Features Programmable Output Voltage to 36 Volts Low Dynamic Output Impedance.2 Typical Sink Current Capability of 1. to 1mA Equivalent FullRange Temperature Coefficient of 5ppm/ C Typical Temperature Compensated for Operation Over Full Rated Operating Temperature Range Low Output Noise Voltage Fast Turnon Response Description The A/B/C are three terminal output adjustable regulators with thermal stability over operating temperature range. The output voltage can be set any value between VREF (approximately 2.5 volts) and 36 volts with two external resistors. These devices have a typical dynamic output impedance of.2ω Active output circuit provides a sharp turnon characteristic, making these devices excellent replacement for Zener Diodes in many applications. SOT Ref 2. Anode 3. Cathode SOT23F Cathode 2. Ref 3. Anode Internal Block Diagram Rev Fairchild Semiconductor Corporation

2 Absolute Maximum Ratings (Operating temperature range applies unless otherwise specified.) Parameter Symbol Value Unit Cathode Voltage VKA 37 V Cathode current Range (Continuous) IKA 1 ~ +15 ma Reference Input Current Range IREF.5 ~ +1 ma Thermal Resistance JunctionAir (Note1,2) MF Suffix Package ML Suffix Package Power Dissipation (Note3,4) MF Suffix Package ML Suffix Package Note: 1. Thermal resistance test board Size: 76.2mm * 114.3mm * 1.6mm (1SP) JEDEC Standard: JESD513, JESD Assume no ambient airflow. 3. TJMAX = 15 C, Ratings apply to ambient temperature at 25 C 4. Power dissipation calculation: PD = (TJ TA)/RθJA Recommended Operating Conditions RθJA PD Junction Temperature TJ 15 C Operating Temperature Range TOPR 25 ~ +85 C Storage Temperature Range TSTG 65 ~ +15 C Parameter Symbol Min. Typ. Max. Unit Cathode Voltage VKA VREF 36 V Cathode Current IKA 1. 1 ma C/W mw 2

3 Electrical Characteristics (TA = +25 C, unless otherwise specified) Parameter Symbol Conditions Reference Input Voltage Deviation of Reference Input Voltage Over Temperature Ratio of Change in Reference Input Voltage to the Change in Cathode Voltage Reference Input Current Deviation of Reference Input Current Over Full Temperature Range Minimum Cathode Current for Regulation Off Stage Cathode Current Dynamic Impedance A B C Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. VREF VKA=VREF, IKA=1mA V VREF/ T VREF/ VKA IREF IREF/ T VKA=VREF, IKA=1mA TMIN TA TMAX IKA =1mA IKA=1mA, R1=1KΩ,R2= IKA=1mA, R1=1KΩ,R2= TA =Full Range VKA=1V VREF VKA=36V 1V Unit mv mv/v µa µa IKA(MIN) VKA=VREF ma IKA(OFF) VKA=36V, VREF= µa ZKA VKA=VREF, IKA=1 to 1mA,f 1.kHz Ω Note1 TMIN = 25 C, TMAX = +85 C 3

4 Test Circuits Figure 1. Test Circuit for VKA=VREF Figure 2. Test Circuit for VKA VREF Figure 3. Test Circuit for lka(off) 4

5 Typical Performance Characteristics V KA = V REF T A = 25 o C 6 V KA = V REF T A = 25 o C I K, Cathode Current (ma) 5 I KA, CATHODE CURRENT (ua) 4 2 I KA(MIN) V KA, Cathode Voltage (V) V KA, CATHODE VOLTAGE (V) Figure 4. Cathode Current vs. Cathode Voltage Figure I off, OffState Cathode Current (ua) I ref, Reference Input Current (ua) T A, Ambient Temperature ( o C) T A, Ambient Temperature ( o C) T A = 25 o C I KA = 1mA 5 T A =25 o C INPUT Open Loop Voltage Gain (db) Voltage Swing (V) OUTPUT 1 1 1k 1k 1k 1M 1M Frequency (Hz) Time (us) 5

6 Typical Performance Characteristics (Continued) A V KA = Vref B V KA = 5. I K = 1 ma T A = 25 o C 4 I K, CATHODE CURRENT(mA) A Current(mA) B 1p 1n 1n 1n 1µ 1µ C L, LOAD CAPACITANCE AnodeRef. Voltage(V) Figure 1. Stability Boundary Conditions Figure 11. AnodeReference Diode Curve 5 4 Current(mA) Ref.Cathode Voltage(V) Figure 12. ReferenceCathode Diode Curve 6

7 Typical Application V O 1 R 1 = + Vref R 2 V O V ref 1 R 1 = + R 2 V O 1 R 1 = + Vref R 2 LM785/MC785 Figure 13. Shunt Regulator Figure 14. Output Control for ThreeTermianl Fixed Regulator Figure 15. High Current Shunt Regulator Figure 16. Current Limit or Current Source Figure 17. ConstantCurrent Sink 7

8 Mechanical Dimensions Package Dimensions in millimeters SOT23F Marking 43A 43B 43C 2% tolerance 1% tolerance.5% tolerance 8

9 Mechanical Dimensions (Continued) Package Dimensions in millimeters SOT ± ± ±.1 (.4) C.2 (1.1) 2.5 ±.2 (.5) 4.1 ±.2.5 ± TYP 1.5 TYP.4 ± Marking 43A 43B 43C 2% tolerance 1% tolerance.5% tolerance 9

10 Ordering Information Product Number Output Voltage Tolerance Package Operating Temperature CCML SOT89.5% CCMF SOT23F BCML SOT89 1% 25 ~ +85 C BCMF SOT23F ACML SOT89 2% ACMF SOT23F DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and (c) whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. 2. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 11/14/2.m 1 Stock#DSxxxxxxxx 22 Fairchild Semiconductor Corporation

KA431/KA431A/KA431L. Programmable Shunt Regulator. Features. Description. Internal Block Diagram.

KA431/KA431A/KA431L. Programmable Shunt Regulator. Features. Description. Internal Block Diagram. www.fairchildsemi.com KA431/KA431A/KA431L Programmable Shunt Regulator Features Programmable output voltage to 36 volts Low dynamic output impedance 0.20 typical Sink current capability of 1.0 to 100mA