ADJUSTABLE PRECISION ZENER SHUNT REGULATOR ISSUE 5 DECEMBER 22 DEVICE DESCRIPTION The ZR431 is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 1mA. The output voltage may be set to any chosen voltage between 2.5 and 2 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. SCHEMATIC DIAGRAM ZR431 FEATURES Surface mount SOT223 and SOT23 packages TO92 package 2%, 1 % and.5% tolerance Max. temperature coefficient 55 ppm/ C Temperature compensated for operation over the full temperature range Programmable output voltage 5µA to 1mA current sink capability Low output noise APPLICATIONS Shunt regulator Series regulator Voltage monitor Over voltage/ under voltage protection Switch mode power supplies V Z V ref G nd 4-189
ABSOLUTE MAXIMUM RATING Cathode Voltage (VZ) 2V Power Dissipation (Tamb=25 C,Tjmax=15 C) Cathode Current 15mA SOT23 33mW Operating Temperature -4 to 85 C TO92 mw Storage Temperature -55 to 125 C SOT223 2W Recommended Operating Conditions Min Max Cathode Voltage 2V Cathode Current 5µA 1mA ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated):t amb =25 C PARAMETER Reference Voltage 2% 1% (1).5% Deviation of Reference Input Voltage over Temperature Ratio of the change in Reference Voltage to the Change in Cathode Voltage VALUE SYMBOL MIN TYP MAX UNITS V ref 2.45 2.5 2.475 2.5 2.487 2.5 2.55 V 2.525 2.513 CONDITIONS I L =1mA (Fig1), V Z =V ref V dev 8. 17 mv I L =1mA, V Z =V ref T a =full range (Fig1) V ref V Z -1.85-2.7 mv/v V Z from V ref to 1V I Z =1mA (Fig2) -1. -2. mv/v V Z from 1V to 2V I Z =1mA (Fig2) Reference Input Current I ref.12 1. µa =1k, =O/C, l L =1mA (Fig2) Deviation of Reference Input Current over Temperature Minimum Cathode Current for Regulation I ref.4.2 µa =1k, =O/C, I L =1mA T a =full range (Fig2) I Zmin 35 5 µa V Z =V ref (Fig1) Off-state Current I Zoff.1 µa V Z =2V, V ref =V (Fig3) Dynamic Output Impedance R Z.75 Ω V Z =V ref (Fig1), f=hz (1).5% SOT23 only. For definitions of reference voltage temperature coefficient and dynamic output impedance see NOTES following DC TEST CIRCUITS 4-19
TYPICAL CHARACTERISTICS Reference Current (na) 16 15 14 13 12 11 1-4 -2 2 4 6 8 Temperature ( C) =VZ IZ=1mA Change in Reference Output Voltage (mv) -5-1 -15-2 -25 Cathode Voltage (V) IZ=1mA 5 1 15 2 Reference Current v Temperature Change in v Cathode Voltage Minimum Cathode Current ( A) 38 36 34 32 3 28 26 =VZ 24-4 -2 2 4 6 8 Dynamic Impedance ( ) 1 =VZ 1mA 1 1mA 1..1 1 1k 1k 1k 1M Temperature ( C) Frequency (Hz) Cathode Current v Temperature Dynamic Impedance v Frequency Reference Voltage (V) 2.56 2.54 2.52 2.5 2.498 2.496 2.494 2.492 IZ=1mA SOT223 TO92 SOT23 2.49-4 -2 2 4 6 8 Temperature ( C) Reference Voltage v Temperature 4-191 4-191
TYPICAL CHARACTERISTICS 6 VZ Open Loop Voltage Gain (db) 4 2 9µF 15k 8k25 IZ + - 23 1 1k 1k 1k 1M Frequency (Hz) Gain v Frequency IZ = 1mA, TA =25 C Test Circuit for Open Loop Voltage Gain 22 3. Repetitive pulse Input Monitor V Z Voltage Swing (V) 2. 1. 5. Single pulse VZ INPUT Pulse Generator 5.2.4.6.8 1. Time (µs) Pulse Response TA = 25 C Test Circuit for Pulse Response 1 Input 15 VZ Cathode Current (ma) 8 6 4 2 STABLE STABLE IZ 1k 1p 1p 1p.1µ.1µ 1µ Load Capacitance (F) Stability Boundary Conditions < VZ < 2, IZ = 1mA, TA = 25 C Test Circuit for Stability Boundary Conditions 4-192
APPLICATION CIRCUITS V+ Vout V+ Vout Vout = 1 + SHUNT REGULATOR Vout = 1 + HIGHER CURRENT SHUNT REGULATOR V+ ZSR*** V+ Vout In Out 3 Common Vout = + Vreg MIN Vout = 1 + OUTPUT CONTROL OF A THREE TERMINAL FIXED REGULATOR.1µF Vout = 1 + SERIES REGULATOR Vout V+ V+ INPUT OUTPUT A B OUTPUT V = 2.5V TH V on 2V V off = V+ A B Low limit = 1 + B B SINGLE SUPPLY COMPARATOR WITH TEMPERATURE COMPENSATED THRESHOLD High limit = 1 + A A OVER VOLTAGE / UNDER VOLTAGE 4-193
DC TEST CIRCUITS Input IL Input V Z I zoff Fig 1 Test Circuit for V z =V ref Fig 2 Test Circuit for V z >V ref Fig 3 Test Circuit for Off State current NOTES Deviation of reference input voltage, V dev, 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, V ref is defined as: Vmax Vmin Vdev = Vmax - Vmin V ref (ppm C)= V dev x 1 V ref (T1 T2) The dynamic output impedance, Rz, is defined as: R Z = V Z I Z When the device is programmed with two external resistors, and, (fig 2), the dynamic output impedance of the overall circuit, R, is defined as: R =R z (1+ ) 4-194
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 ZR431C1 TO92 1. ZR4311 ZR431C TO92 2. ZR431 ZR431G1 SOT223 1. ZR4311 ZR431G SOT223 2. ZR431 ZR431F5 SOT23.5 43R ZR431F1 SOT23 1. 43B ZR431F SOT23 2. 43A 4-195