www.fairchildsemi.com LM431SA/LM431SB/LM431SC Programmable Shunt Regulator Features Description • • • • The LM431SA/LM431SB/LM431SC 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 0.2Ω Active output circuit provides a sharp turn-on characteristic, making these devices excellent replacement for Zener Diodes in many applications. Programmable Output Voltage to 36 Volts Low Dynamic Output Impedance 0.20 Typical Sink Current Capability of 1.0 to 100mA Equivalent Full-Range Temperature Coefficient of 50ppm/°C Typical • Temperature Compensated for Operation Over Full Rated Operating Temperature Range • Low Output Noise Voltage • Fast Turn-on Response SOT-89 1 1. Ref 2. Anode 3. Cathode SOT-23F 3 1 2 1. Cathode 2. Ref 3. Anode Internal Block Diagram Rev. 1.0.3 ©2002 Fairchild Semiconductor Corporation LM431SA/LM431SB/LM431SC Absolute Maximum Ratings (Operating temperature range applies unless otherwise specified.) Parameter Symbol Value Unit Cathode Voltage VKA 37 V Cathode current Range (Continuous) IKA -100 ~ +150 mA Reference Input Current Range IREF 0.05 ~ +10 mA Thermal Resistance Junction-Air (Note1,2) MF Suffix Package ML Suffix Package RθJA 350 220 °C/W Power Dissipation (Note3,4) MF Suffix Package ML Suffix Package PD 350 560 mW Junction Temperature TJ 150 °C Operating Temperature Range TOPR -25 ~ +85 °C Storage Temperature Range TSTG -65 ~ +150 °C Note: 1. Thermal resistance test board Size: 76.2mm * 114.3mm * 1.6mm (1S0P) JEDEC Standard: JESD51-3, JESD51-7 2. Assume no ambient airflow. 3. TJMAX = 150°C, Ratings apply to ambient temperature at 25°C 4. Power dissipation calculation: PD = (TJ - TA)/RθJA Recommended Operating Conditions Parameter 2 Symbol Min. Typ. Max. Unit Cathode Voltage VKA VREF - 36 V Cathode Current IKA 1.0 - 100 mA LM431SA/LM431SB/LM431SC Electrical Characteristics (TA = +25°C, unless otherwise specified) Parameter Symbol Reference Input Voltage VREF VKA=VREF, IKA=10mA ∆VREF/ ∆T VKA=VREF, IKA=10mA TMIN≤TA≤TMAX Deviation of Reference Input Voltage OverTemperature Ratio of Change in Reference Input Voltage to the Change in Cathode Voltage ∆VREF/ ∆VKA Conditions IKA =10mA ∆VKA=10VVREF LM431SA LM431SB LM431SC Min. Typ. Max. Min. Typ. Max. Min. Typ. Max. 2.450 2.500 2.550 2.470 2.495 2.520 2.482 2.495 2.508 - - 4.5 17 -1.0 -2.7 - - 4.5 17 -1.0 -2.7 - - 4.5 17 -1.0 -2.7 Unit V mV mV/V ∆VKA=36V10V - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0 IKA=10mA, R1=10KΩ,R2=∞ - 1.5 4 - 1.5 4 - 1.5 4 µA Deviation of Reference Input Current Over Full Temperature Range IKA=10mA, R1=10KΩ,R2=∞ ∆IREF/∆T TA =Full Range - 0.4 1.2 0.4 1.2 0.4 1.2 µA Minimum Cathode Current for Regulation IKA(MIN) VKA=VREF - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA Off -Stage Cathode Current IKA(OFF) VKA=36V, VREF=0 - 0.05 1.0 - 0.05 1.0 - 0.05 1.0 µA Dynamic Impedance ZKA VKA=VREF, IKA=1 to 100mA ,f ≥1.0kHz - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Ω Reference Input Current IREF - - Note1 TMIN = -25°C, TMAX = +85°C 3 LM431SA/LM431SB/LM431SC Test Circuits LM431S LM431S Figure 1. Test Circuit for VKA=VREF LM431S Figure 3. Test Circuit for lKA(OFF) 4 Figure 2. Test Circuit for VKA≥VREF LM431SA/LM431SB/LM431SC Typical Performance Characteristics 800 150 VKA = VREF o VKA = V REF TA = 25 C o T A = 25 C 600 IKA, CATHODE CURRENT (uA) IK, Cathode Current (mA) 100 50 0 400 I KA(MIN) 200 0 -50 -200 -100 -2 -1 0 1 2 -1 3 0 1 2 3 V KA, CATHODE VOLTAGE (V) VKA, Cathode Voltage (V) Figure 4. Cathode Current vs. Cathode Voltage Figure 5. Cathode Current vs. Cathode Voltage 3.5 0.100 Iref, Reference Input Current (uA) Ioff, Off-State Cathode Current (uA) 3.0 0.075 0.050 0.025 0.000 -50 -25 0 25 50 75 100 2.5 2.0 1.5 1.0 0.5 0.0 -50 125 -25 0 o 25 50 75 100 125 o TA, Ambient Temperature ( C) TA, Ambient Temperature ( C) Figure 6. OFF-State Cathode Current vs. Ambient Temperature Figure7. Reference Input Current vs. Ambient Temperature 6 60 o TA = 25 C IKA = 10mA 50 o TA=25 C 5 INPUT 4 Voltage Swing (V) Open Loop Voltage Gain (dB) 40 30 20 3 OUTPUT 2 10 1 0 0 -10 1k 10k 100k 1M 10M Frequency (Hz) Figure 8. Small Signal Voltage Amplification vs. Frequency 0 4 8 12 16 20 Time (us) Figure 9. Pulse Response 5 LM431SA/LM431SB/LM431SC Typical Performance Characteristics (Continued) 5 140 4 A V KA = Vref B V KA = 5.0 V @ IK = 10mA 120 o A 100 Current(mA) IK, CATHODE CURRENT(mA) T A = 25 C 80 60 1 B 0 100p 1n 10n 100n 1µ 10µ CL, LOAD CAPACITANCE 5 Current(mA) 4 3 2 1 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Anode-Ref. Voltage(V) Figure 10. Stability Boundary Conditions 1.6 1.8 2.0 Ref.-Cathode Voltage(V) Figure 12. Reference-Cathode Diode Curve 6 2 40 20 0 0.0 3 Figure 11. Anode-Reference Diode Curve LM431SA/LM431SB/LM431SC Typical Application R V O = V ref 1 + ------1- R2 R V O = 1 + ------1- V ref R 2 R V O = 1 + ------1- V ref R 2 LM7805/MC7805 LM431S LM431S Figure 13. Shunt Regulator - LM431S Figure 14. Output Control for Figure 15. High Current Shunt Regulator Three-Termianl Fixed Regulator LM431S Figure 16. Current Limit or Current Source LM431S Figure 17. Constant-Current Sink 7 LM431SA/LM431SB/LM431SC Mechanical Dimensions Package Dimensions in millimeters SOT-23F Marking 8 43A 43B 2% tolerance 1% tolerance 43C 0.5% tolerance LM431SA/LM431SB/LM431SC Mechanical Dimensions (Continued) Package Dimensions in millimeters SOT-89 1.50 ±0.20 4.50 ±0.20 (0.40) (1.10) 2.50 ±0.20 C0.2 4.10 ±0.20 (0.50) 1.65 ±0.10 0.50 ±0.10 0.40 ±0.10 0.40 +0.10 –0.05 1.50 TYP 1.50 TYP Marking 43A 2% tolerance 43B 43C 1% tolerance 0.5% tolerance 9 LM431SA/LM431SB/LM431SC Ordering Information Product Number LM431SCCML LM431SCCMF LM431SBCML LM431SBCMF LM431SACML LM431SACMF Output Voltage Tolerance 0.5% 1% 2% Package Operating Temperature SOT-89 SOT-23F SOT-89 SOT-23F -25 ~ +85°C SOT-89 SOT-23F 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. www.fairchildsemi.com 11/14/02 0.0m 001 Stock#DSxxxxxxxx 2002 Fairchild Semiconductor Corporation