TMC TA431 ADJUSTABLE PRECISION ZENER SHUNT REGULATOR TA 431 DESCRIPTION The TA431 is a three-terminal adjustable regulator with a guaranteed thermal stability over applicable temperature ranges. The output voltage may be set to any value between VREF (approximately 2.5V) and 36V with two external resistors. This device has typical dynamic output impedance of 0.2Ω. Active output circuitry provides a very sharp turn-on characteristic, making these devices excellent replacement for zener diodes in many applications. FEATURE Programmable output voltage to 36V Low dynamic output impedance 0.2Ωtypical Sink current capability of 1.0mA to 100mA Equivalent full-range temperature coefficient of 500ppm/℃ typical Temperature compensated for operation over full rated operating temperature range Low output noise voltage Fast turn on response EQUIVALENT CIRCUIT Vref Q7 C1 R6 12K R7 12K Q5 Q6 800 R4 R3 Q3 CATHODE (Vz) C2 Q4 Q2 Q1 2.5K R5 640 R2 1K R1 3.3K ANODE (GND) ABSOLUTE MAXIMUM RATINGS 1 TMC TA431 Operating temperature range applies unless otherwise specified.) Characteristic Symbol Value Unit Cathode Voltage Vka 37 V Cathode Current Range (continuous) Ika -10~+150 mA Reference Input Current Range IREF 10 mA Power Dissipation PD 770 mW Operating Temperature Range Topr 0~+70 ℃ Store temperature Range Tstg -65~+150 ℃ ELECTRICAL CHARACTERISTICS (Ta=25℃ unless otherwise specified) Parameter Reference Voltage Conditions Vz=VREF Deviation of Reference Input Current Over Temperature Minimum Cathode Current for Regulation Off-State Current Dynamic Output Impedance Min Typ Max Unit 2.485 2.5 2.51 V 1.0% 2.470 2.495 2.52 2.0% 2.440 2.495 2.55 0.5% Ii=10mA Deviation of Reference Input Voltage Over Temperature Ratio of the Change in Reference Voltage to the Change in Cathode Voltage Reference Input Current Symbol Vz=VREF, Ii=10mA VREF Vdev - 8.0 17 mV Vz=VREF~10V ΔVREF/ - -1.4 -2.7 mV/V Vz=10~36V ΔVz - -1.0 -2.0 IREF - 2.0 4.0 μA ΔIREF/ ΔT - 0.4 1.2 μA Vz=VREF Iz(min) - 0.4 1.0 mA Vz=36V,VREF=0V Iz(off) - 0.3 1.0 μA Vz=VREF, Iz=1 to 100mA,f<1.0kHz Rz - 0.15 0.5 Ω Iz=10mA R1=10kΩ,R2=∞ I1=10mA R1=10kΩ,R2=∞I1=10mA TEST CIRCUIT 2 TMC TA431 II IN IN II R1 IREF I REF Iz Iz V REF R2 Vz IN Iz OFF VREF Note: Vz=VREF(1+R1/R2)+IREF*R1 1.Test circuit for Vz=VREF 2.Test circuit for Vz>VREF 3.Test circuit for off-state current APPLICATION CIRCUIT V+ V+ Vo VREF 30 R1 0.01uF R1 R2 Vo R2 Vo = ( 1+R1/R2 ) V REF Vo = ( 1+R1/R2 ) R VEF 1. Shunt Regulator 2. Series Regulator V+ IN LM7805OUT Vo V+ COMMON R1 OUT IN R2 Vth=2.5V GND Vo = ( 1+R1/R2 )REF V VoM IN = VREF+ 5 V 3.Output Control of a Three Terminal Fixed Regulator Von=2V Voff=V+ 4.Single Supply Comparator with Temperature Compensated Threshold 5.Higher Current Shunt Regulator 6.Crow Bar 3 TMC V+ Vo Vo V+ R1 R1 R2 R2 Vo=(1+R1/R2)*VREF TA431 Vlimit=(1+R1/R2)*VREF CHARACTERISTIC CURVES Outline Drawing 4 TMC TA431 5