LM431

www.fairchildsemi.com LM431SA/LM431SB/LM431SC 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 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 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. 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 Cathode Voltage Cathode current Range (Continuous) Reference Input Current Range Thermal Resistance Junction-Air (Note1,2) MF Suffix Package ML Suffix Package Power Dissipation (Note3,4) MF Suffix Package ML Suffix Package Junction Temperature Operating Temperature Range Storage Temperature Range Note: 1. Thermal resistance test board Symbol VKA IKA IREF RθJA Value 37 -100 ~ +150 0.05 ~ +10 350 220 350 560 150 -25 ~ +85 -65 ~ +150 Unit V mA mA °C/W PD TJ TOPR TSTG mW °C °C °C 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 Cathode Voltage Cathode Current Symbol VKA IKA Min. VREF 1.0 Typ. Max. 36 100 Unit V mA 2 LM431SA/LM431SB/LM431SC Electrical Characteristics (TA = +25°C, unless otherwise specified) Parameter Reference Input Voltage Deviation of Reference Input Voltage OverTemperature 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 Symbol VREF Conditions VKA=VREF, IKA=10mA 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 Unit V ∆VREF/ ∆T VKA=VREF, IKA=10mA TMIN≤TA≤TMAX - 4.5 17 - 4.5 17 - 4.5 17 mV ∆VREF/ ∆VKA IKA =10mA ∆VKA=10VVREF - -1.0 -2.7 - -1.0 -2.7 - -1.0 -2.7 mV/V ∆VKA=36V10V IREF IKA=10mA, R1=10KΩ,R2=∞ - -0.5 -2.0 - -0.5 -2.0 - -0.5 -2.0 - 1.5 4 - 1.5 4 - 1.5 4 µA IKA=10mA, R1=10KΩ,R2=∞ ∆IREF/∆T TA =Full Range - 0.4 1.2 - 0.4 1.2 - 0.4 1.2 µA IKA(MIN) VKA=VREF - 0.45 1.0 - 0.45 1.0 - 0.45 1.0 mA IKA(OFF) VKA=36V, VREF=0 VKA=VREF, IKA=1 to 100mA ,f ≥1.0kHz - 0.05 1.0 - 0.05 1.0 - 0.05 1.0 µA Ω ZKA - 0.15 0.5 - 0.15 0.5 - 0.15 0.5 Note1 TMIN = -25°C, TMAX = +85°C 3 LM431SA/LM431SB/LM431SC Test Circuits LM431S LM431S Figure 1. Test Circuit for VKA=VREF Figure 2. Test Circuit for VKA≥VREF LM431S Figure 3. Test Circuit for lKA(OFF) 4 LM431SA/LM431SB/LM431SC Typical Performance Characteristics 800 150 VKA = V REF TA = 2 5 C o VKA = VREF TA = 2 5 C o 600 100 IKA, CATHODE CURRENT (uA) IK, Cathode Current (mA) 400 50 I KA(MIN) 0 200 -50 0 -100 -2 -1 0 1 2 3 VKA, Cathode Voltage (V) -200 -1 0 1 V KA, CATHODE VOLTAGE (V) 2 3 Figure 4. Cathode Current vs. Cathode Voltage Figure 5. Cathode Current vs. Cathode Voltage 0.100 3.5 3.0 Ioff, Off-State Cathode Current (uA) 0.075 Iref, Reference Input Current (uA) -25 0 25 50 75 o 2.5 2.0 0.050 1.5 0.025 1.0 0.5 0.000 -50 100 125 0.0 -50 -25 0 25 50 75 o 100 125 TA, Ambient Temperature ( C) TA, Ambient Temperature ( C) Figure 6. OFF-State Cathode Current vs. Ambient Temperature Figure7. Reference Input Current vs. Ambient Temperature 60 T A = 25 C IKA = 10mA o 6 TA=25 C o 50 5 INPUT 40 Open Loop Voltage Gain (dB) 4 30 Voltage Swing (V) 3 OUTPUT 20 2 10 1 0 -10 1k 10k 100k Frequency (Hz) 0 1M 10M 0 4 8 Time (us) 12 16 20 Figure 8. Small Signal Voltage Amplification vs. Frequency Figure 9. Pulse Response 5 LM431SA/LM431SB/LM431SC Typical Performance Characteristics (Continued) 5 140 A V KA = Vref B V KA = 5.0 V @ IK = 10mA T A = 25 C o 4 120 IK, CATHODE CURRENT(mA) 100 A 80 Current(mA) B 1n 10n 100n 1µ 10µ 3 60 2 40 1 20 0 100p 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 CL, LOAD CAPACITANCE Anode-Ref. Voltage(V) Figure 10. Stability Boundary Conditions 5 Figure 11. Anode-Reference Diode Curve 4 Current(mA) 3 2 1 0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Ref.-Cathode Voltage(V) Figure 12. Reference-Cathode Diode Curve 6 LM431SA/LM431SB/LM431SC Typical Application R1 V O =  1 + ------  V ref  R 2 R1 V O = V ref  1 + ------  R 2 R1 V O =  1 + ------ V ref  R 2 LM7805/MC7805 LM431S LM431S LM431S Figure 13. Shunt Regulator - Figure 14. Output Control for Figure 15. High Current Shunt Regulator Three-Termianl Fixed Regulator LM431S LM431S Figure 16. Current Limit or Current Source Figure 17. Constant-Current Sink 7 LM431SA/LM431SB/LM431SC Mechanical Dimensions Package Dimensions in millimeters SOT-23F Marking 43A 43B 43C 2% tolerance 1% tolerance 0.5% tolerance 8 LM431SA/LM431SB/LM431SC Mechanical Dimensions (Continued) Package Dimensions in millimeters SOT-89 4.50 ±0.20 1.65 ±0.10 C0.2 (0.50) 1.50 ±0.20 (0.40) 2.50 ±0.20 0.50 ±0.10 1.50 TYP 1.50 TYP 0.40 ±0.10 0.40 +0.10 –0.05 Marking 43A (1.10) 43B 4.10 ±0.20 43C 2% tolerance 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 SOT-89 SOT-23F SOT-89 SOT-23F SOT-89 SOT-23F -25 ~ +85°C Operating Temperature 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. www.fairchildsemi.com 11/14/02 0.0m 001 Stock#DSxxxxxxxx  2002 Fairchild Semiconductor Corporation 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.