ADJUSTABLE PRECISION ZENER SHUNT REGULATOR ZR431 ISSUE 5 – DECEMBER 2002 DEVICE DESCRIPTION FEATURES The ZR431 is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 100mA. The output voltage may be set to any chosen voltage between 2.5 and 20 volts by selection of two external divider resistors. • The devices can be used as a replacement for zener diodes in many applications requiring an improvement in zener performance. • • • • • • • Surface mount SOT223 and SOT23 packages TO92 package 2%, 1 % and 0.5% tolerance Max. temperature coefficient 55 ppm/°C Temperature compensated for operation over the full temperature range Programmable output voltage 50µA to 100mA current sink capability Low output noise APPLICATIONS • • • • • Shunt regulator Series regulator Voltage monitor Over voltage/ under voltage protection Switch mode power supplies SCHEMATIC DIAGRAM VZ V ref Gnd 4-189 78 ZR431 ABSOLUTE MAXIMUM RATING Cathode Voltage (VZ) 20V Cathode Current 150mA Operating Temperature -40 to 85°C Storage Temperature -55 to 125°C Recommended Operating Conditions Min Max Cathode Voltage Vref 20V Cathode Current 50µA 100mA Power Dissipation (Tamb=25°C,Tjmax=150°C) SOT23 330mW TO92 780mW SOT223 2W ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated):Tamb=25°C SYMBOL PARAMETER Reference Voltage 2% Vref 1% (1) 0.5% Deviation of Reference Input Vdev Voltage over Temperature VALUE MIN TYP MAX UNITS CONDITIONS 2.45 2.50 2.55 V 2.475 2.50 2.525 2.487 2.50 2.513 8.0 17 IL=10mA (Fig1), VZ=Vref mV IL=10mA, VZ=Vref Ta=full range (Fig1) -1.85 -2.7 mV/V VZ from Vref to 10V IZ=10mA (Fig2) -1.0 mV/V VZ from 10V to 20V IZ=10mA (Fig2) Ratio of the change in Reference Voltage to the Change in Cathode Voltage ∆Vref Reference Input Current Iref 0.12 1.0 µA R1=10k, R2=O/C, lL=10mA (Fig2) Deviation of Reference Input Current over Temperature ∆Iref 0.04 0.2 µA R1=10k, R2=O/C, IL=10mA Ta=full range (Fig2) Minimum Cathode Current for Regulation IZmin 35 50 µA VZ=Vref (Fig1) Off-state Current IZoff 0.1 µA VZ=20V, Vref =0V (Fig3) ∆VZ 0.75 Ω Dynamic Output Impedance RZ (1) -2.0 VZ=Vref (Fig1), f=0Hz 0.5% SOT23 only. For definitions of reference voltage temperature coefficient and dynamic output impedance see NOTES following DC TEST CIRCUITS 4-190 78 ZR431 Change in Reference Output Voltage (mV) TYPICAL CHARACTERISTICS Reference Current (nA) 160 Vref=VZ IZ=10mA 150 140 130 120 110 100 -40 -20 0 20 40 60 80 IZ=10mA -5 -10 -15 -20 -25 0 5 10 20 Cathode Voltage (V) Change in Vref v Cathode Voltage 38 100 Vref=VZ Vref=VZ 1mA 36 34 32 30 28 26 24 -40 -20 0 20 40 60 10 10mA 1.0 0.1 100 80 1k 10k 2.506 IZ=10mA 2.504 SOT223 2.502 2.500 2.498 TO92 2.496 2.494 SOT23 2.492 -20 0 20 40 1M Dynamic Impedance v Frequency Cathode Current v Temperature 2.490 -40 100k Frequency (Hz) Temperature (°C) Reference Voltage (V) 15 Reference Current v Temperature Dynamic Impedance ( ) Minimum Cathode Current ( A) Temperature (°C) 0 60 80 Temperature (°C) Reference Voltage v Temperature 4-191 78 4-191 78 ZR431 TYPICAL CHARACTERISTICS Open Loop Voltage Gain (dB) 60 VZ IZ 15k 40 230 9µF + 20 8k25 - 0 100 1k 10k 100k 1M IZ = 10mA, TA = 25°C Frequency (Hz) Gain v Frequency Test Circuit for Open Loop Voltage Gain 220 V Input Monitor 3.0 Z Voltage Swing (V) Repetitive pulse 2.0 Single pulse VZ 1.0 Pulse Generator 0 5.0 INPUT 0 0 0.2 0.4 0.6 0.8 1.0 Time (µs) TA = 25°C Test Circuit for Pulse Response Pulse Response 100 Cathode Current (mA) 50 Input 80 150 VZ IZ STABLE STABLE 10k 60 40 20 0 10p 100p 1000p 0.01µ 0.1µ 1µ Load Capacitance (F) Stability Boundary Conditions Vref < VZ < 20, IZ = 10mA, TA = 25°C Test Circuit for Stability Boundary Conditions 4-192 78 ZR431 APPLICATION CIRCUITS V+ Vout V+ Vout R1 R1 Vref Vref R2 R2 R1 Vout = 1 + Vref Vout = 1 + R2 R1 Vref R2 SHUNT REGULATOR HIGHER CURRENT SHUNT REGULATOR V+ ZSR*** V+ Vout Out In Common 30 R1 0.01µF Vref R1 R2 Vout Vref R2 Vout MIN = Vref + Vreg Vout = 1 + R1 Vref R2 Vout = 1 + R1 Vref R2 OUTPUT CONTROL OF A THREE TERMINAL FIXED REGULATOR SERIES REGULATOR V+ V+ R1A OUTPUT R1B Vref INPUT V on 2V Vref V off = V+ R2A V TH = 2.5V R2B Low limit = 1+ R1B Vref R2B High limit = 1 + SINGLE SUPPLY COMPARATOR WITH TEMPERATURE COMPENSATED THRESHOLD R1A Vref R2A OVER VOLTAGE / UNDER VOLTAGE 4-193 78 OUTPUT ZR431 DC TEST CIRCUITS IL Input Input VZ I zoff Fig 1 – Test Circuit for Vz=Vref Fig 2 – Test Circuit for Vz>Vref Fig 3 – Test Circuit for Off State current NOTES Deviation of reference input voltage, Vdev, is defined as the maximum variation of the reference input voltage over the full temperature range. The average temperature coefficient of the reference input voltage, Vref is defined as: Vmax Vref (ppm ⁄ °C)= Vdev x 1000000 Vref (T1−T2) The dynamic output impedance, Rz, is defined as: ∆VZ RZ = ∆IZ Vmin Vdev = Vmax - Vmin When the device is programmed with two external resistors, R1 and R2, (fig 2) , the dynamic output impedance of the overall circuit, R’, is defined as: R1 R’=Rz (1+ ) R2 4-194 78 ZR431 CONNECTION DIAGRAMS TO92 Package Suffix – C SOT223 Package Suffix – G Bottom View Top View – Pin 4 floating or connected to pin 2 SOT23 Package Suffix – F Top View ORDERING INFORMATION Part Number Package Tol. % Part Mark ZR431C01 TO92 1.0 ZR43101 ZR431C TO92 2.0 ZR431 ZR431G01 SOT223 1.0 ZR43101 ZR431G SOT223 2.0 ZR431 ZR431F005 SOT23 0.5 43R ZR431F01 SOT23 1.0 43B ZR431F SOT23 2.0 43A 4-195 78