ZR2431G01TA

ADJUSTABLE PRECISION ZENER SHUNT REGULATOR ZR2431 ISSUE 3 DECEMBER 1997 DEVICE DESCRIPTION FEATURES The ZR2431 is a three terminal adjustable s hu n t r e g u l a t or o f f e r i n g e xc el l e nt temperature stability and output current handling capability up to 25mA. The output voltage may be set to any chosen voltage between 1.24 and 15 volts by selection of two external divider resistors. • • • • • The devices can be used as a replacement for zener diodes in many applications r e qu i r i n g a n i mpr o ve me nt i n z e ner performance. • • • The ZR2431 is particularly used in the feedback control loop of switch mode power supplies. In this application the device 1.24 volt reference enables the generation of low voltage supplies, typically 3.3 volts or 3 volts. Surface mount SOT23, SOT223, SOT89 and SO8 packages TO92 package 2.5% and 1% tolerance Maximum temperature coefficient 52 ppm/°C Temperature compensated for operation over the full temperature range Programmable output voltage 100µA to 25mA 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 Vref Gnd 4-154 ZR2431 ABSOLUTE MAXIMUM RATING Power Dissipation (Tamb=25°C, Tjmax=150°C) SOT23 330mW SOT223 2W SO8 780mW TO92 780mW SOT89 1.5W Cathode Voltage (VZ) 15V Cathode Current 50mA Operating Temperature -40 to 85°C Storage Temperature -55 to 125°C Recommended Operating Conditions Min Max Cathode Voltage VREF 15V Cathode Current 100µA 25mA ELECTRICAL CHARACTERISTICS TEST CONDITIONS (Unless otherwise stated):Tamb=25°C VALUE SYMBOL MIN TYP MAX UNITS CONDITIONS PARAMETER Reference Voltage 2.5% Vref 1.0% 1.209 1.24 1.271 V 1.228 1.24 1.252 IL=10mA (Fig1), VZ=Vref Deviation of Reference Input Vdev Voltage over Temperature 4.0 8.0 mV IL=10mA, VZ=Vref Ta=full range (Fig1) Ratio of the change in ∆Vref Reference Voltage to the ∆VZ Change in Cathode Voltage 0.5 2.0 mV/V VZ from Vref to 10V IZ=10mA (Fig2) 0.02 0.11 0.4 µA R1=10k, R2=O/C, lL=10mA (Fig2) Deviation of Reference Input ∆Iref Current over Temperature 0.02 0.2 µA R1=10k, R2=O/C, IL=10mA Ta=full range (Fig2) Minimum Cathode Current for Regulation IZmin 30 100 µA † Off-state Current IZoff 10 30 µA VZ=15V, Vref =0V (Fig3) Ω VZ=Vref (Fig1), f=0Hz, IL=10mA Reference Input Current Iref Dynamic Output Impedance RZ 0.25 2 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 Vdev x 1000000 Vref (ppm ⁄ °C)= Vref (T1−T2) The dynamic output impedance, Rz, is ∆VZ defined as: RZ = ∆IZ Vmin When the device is programmed with two external resistors, R1 and R2, (fig 2) , the dynamic output impedance of the overall Vdev = Vmax - Vmin circuit, R’, is defined as: R1 R’=Rz (1+ ) R2 † With a capacitance of greater than 100pF between cathode and anode, minimum cathode current must be 0.2mA. T1 Temperature T2 4-155 ZR2431 Change in Reference Output Voltage(mV) TYPICAL CHARACTERISTICS TYPICAL CHARACTERISTICS 140 Vref = Vz Iz=10mA Reference Current (nA) 130 120 110 100 90 80 -40 -20 0 20 40 60 80 Temperature (°C) 26 Iz = 10mA 1 0 -1 -2 -3 -4 -5 0 10 15 Change in Vref v Cathode Voltage 10 Vref = Vz 1mA 24 22 20 18 16 14 -40 -20 0 20 40 60 80 10mA 1 0.1 100 Temperature (°C) 10k 100k Dynamic Impedance v Frequency 2.0 1.244 1.242 Power Dissipation (W) Iz=10mA 1.240 1.238 1.236 1.234 1.232 -40 1k Frequency (Hz) Cathode Current v Temperature Reference Voltage (V) 5 Cathode Voltage (V) Vref = Vz Dynamic Impedance (Ω) Minimum Cathode Current(µA) Reference Current v Temperature 2 SOT 89 SOT 223 1.0 SO8/TO92 SOT23 0 -20 0 20 40 60 25 80 Temperature (°C) 50 75 85 Ambient Temprature (°C) Reference Voltage v Temperature Power Dissipation Derating 4-156 100 ZR2431 TYPICAL CHARACTERISTICS 60 VZ Open Loop Voltage Gain (dB) Iz = 10mA 50 40 240Ω 10µF 30 + 20 47k - 10 0 100 10k 1k 100k 1M Frequency (Hz) IZ = 10mA, TA = 25°C Test Circuit for Open Loop Voltage Gain Gain v Frequency 120Ω Input Monitor Single Pulse 2.0 Voltage Swing (V) IZ 47k VZ Vz 1.0 Repetitive Pulse Pulse Generator 0 5.0 50Ω 2.5 INPUT 0 TA = 25°C 0 200 100 300 400 500 Time (us) Test Circuit for Pulse Response Pulse Response Vref < VZ < 20, IZ = 10mA, TA = 25°C Cathode Current(mA) 30 Input 150Ω VZ 25 STABLE IZ 20 10k 15 STABLE UNSTABLE 10 100µF 5 0 10p 100p 1n 10n .1µ 1µ 10µ Load Capacitance(F) Stablity Boundary Conditions Test Circuit for Stability Boundary Conditions 4-157 ZR2431 DC TEST CIRCUITS IL Input VZ IL Input IZ R1 I ref VZ IZ 1µF R2 VZ I zoff I ref 1µF Vref Input 1µF Vref Fig 1 – Test Circuit for Vz=Vref Fig 2 – Test Circuit for Vz>Vref 4-158 Fig 3 – Test Circuit for Off State current ZR2431 APPLICATION CIRCUITS V+ Vout V+ Vout R1 R1 Vref Vref R2 Vout = R2 R1 1+ Vref Vout = R2 1+ 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 = High limit = SINGLE SUPPLY COMPARATOR WITH TEMPERATURE COMPENSATED THRESHOLD 1+ R1B Vref R2B 1+ R1A Vref R2A OVER VOLTAGE / UNDER VOLTAGE PROTECTION CIRCUIT 4-159 OUTPUT ZR2431 CONNECTION DIAGRAMS SO8 Package Suffix – N8 SOT223 Package Suffix – G Top View Top View – Pin 4 floating or connected to pin 2 SOT23 Package Suffix – F TO92 Package Suffix – C Top View Bottom View SOT89 Package Suffix – Z ORDERING INFORMATION Top View 4-160 Part Number Package Tol % Part Mark ZR2431N802 SO8 2.5 ZR243102 ZR2431N801 SO8 1 ZR243101 ZR2431G02 SOT223 2.5 ZR243102 ZR2431G01 SOT223 1 ZR243101 ZR2431F02 SOT23 2.5 24D ZR2431F01 SOT23 1 24E ZR2431Z02 SOT89 2.5 24D ZR2431Z01 SOT89 1 24E ZR2431C02 TO92 2.5 ZR243102 ZR2431C01 TO92 1 ZR243101