A Product Line of Diodes Incorporated ZHT431 ADJUSTABLE PRECISION ZENER SHUNT REGULATOR Description Pin Assignments The ZHT431 is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 100mA. The device offers extended operating temperature range working from -55 to +125°C. 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. • • • • • VZ GND VREF (Top View) Features • • • • SOT23 Surface mount SOT23 package 0.5%, 1% and 2% tolerance Maximum temperature coefficient 67ppm/°C Temperature compensated for operation over the full temperature range Programmable output voltage 50μA to 100mA current sink capability Low output noise Available in “Green” Molding Compound (See page 7) Wide temperature range -55 to +125°C Applications • • • • Series and shunt regulator Voltage monitor Over voltage / under voltage protection Switch mode power supplies Typical Application Circuit ZHT431 Document number: DS32157 Rev. 11 - 2 1 of 8 www.diodes.com November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 Absolute Maximum Ratings (Voltages to GND Unless Otherwise Stated) Parameter Cathode Voltage (VZ) Cathode Current Operating Temperature Storage Temperature Power Dissipation (Tamb = 25°C, TJMAX = 150°C) Rating 20 150 -55 to 125 -55 to 150 Unit V mA °C °C 330 mW Recommended Operating Conditions Parameter Cathode Voltage VREF Cathode Current Electrical Characteristics Symbol VREF Min Max Units - 20 V 0.05 100 mA (Test conditions unless otherwise specified: Tamb = 25°C) Parameter Reference Voltage 2% 1% 0.5% VDEV Deviation of reference input voltage over temperature ΔVREF Ratio of the change in reference voltage to the change in cathode voltage ΔVZ Min. 2.45 2.475 2.4875 Values Typ. 2.50 2.50 2.50 Max. 2.55 2.525 2.5125 10 30 mV -1.85 -2.7 mV/V -1.0 -2. mV/V Units V Conditions IL=10mA (Fig.1), VZ=VREF IL=10mA, VZ=VREF Tamb=full range (Fig1) VZ from VREF to 10V IZ=10mA (Fig.2) VZ from 10V to 20V IZ=10mA (Fig.2) R1=10k, R2=O/C, lL=10mA (Fig.2) R1=10k, R2=O/C, IL=10mA Tamb=full range (Fig.2) IREF Reference input current 0.12 1.0 µA ΔIREF Deviation of reference input current over temperature 0.04 0.2 µA IZmin Minimum cathode current for regulation 35 50 µA VZ=VREF (Fig.1) IZoff Off-state current 0.1 µA VZ=20V, VREF=0V(Fig.3) RZ Dynamic output impedance 0.75 V VZ=VREF (Fig.1), f=0Hz, IC=1mA to 100mA 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: The dynamic output impedance, RZ, is defined as: 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: ZHT431 Document number: DS32157 Rev. 11 - 2 2 of 8 www.diodes.com November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 Typical Operating Conditions 170 0 Change in Reference Output Voltage (mV) IZ = 10mA Reference Current (nA) 160 150 140 130 120 110 100 90 -50 -25 -5 -10 -15 -20 -25 0 0 25 50 75 100 125 Temperature (°C) IR EF vs. Temperature 40 5 10 15 Cathode Voltage (V) Change in VREF vs. Cathode Voltage 20 100 V REF = V Z 1mA 36 Dynamic Impedance ( Ω) Minimum Cathode Current (µA) 38 34 32 30 28 10 10mA 1.0 26 24 -50 -25 0.1 100 0 25 50 75 100 125 Temperature (°C) IZ MIN vs. Temperature 2.502 1K 10K 100K Frequency (Hz) Dynamic Impedance vs. Frequency 1M 25 50 75 100 125 Ambient Temperature (°C) Power Dissipation Derating 150 0.5 2.500 0.4 Power Dissipation (W) Reference Voltage (V) 2.498 2.496 2.494 2.492 0.3 0.2 2.490 0.1 2.488 2.486 -50 -25 0 25 50 75 100 125 Temperature ( °C) V REF vs. Temperature ZHT431 Document number: DS32157 Rev. 11 - 2 0 3 of 8 www.diodes.com 0 November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 Typical Operating Conditions (Cont.) Open Loop Vol t age Gai n (dB) 60 VZ IZ 230 40 15k 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 Input Monitor 3.0 VZ Vol t ag e Sw i ng (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 Input Cat hod e Curr ent (m A) 50 80 150 VZ IZ STABLE STABLE 10k 60 40 20 0 10p 100p 1000p 0.01µ 0.1µ Load Capacitance (F) Stability Boundary Conditions ZHT431 Document number: DS32157 Rev. 11 - 2 1µ Vref < VZ < 20, IZ = 10mA, T A = 25°C Test Circuit for Stability Boundary Conditions 4 of 8 www.diodes.com November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 DC Test Circuits IL VZ Input IZ IL Iref R1 Vref R2 Fig 1 - Test circuit for V Z = V ref ZHT431 Document number: DS32157 Rev. 11 - 2 VZ Input IZ VZ Input IZOFF Iref Vref Fig 2 - Test circuit for V Z > V ref 5 of 8 www.diodes.com Fig 3 - Test circuit for Off state current† November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 Application Circuits V+Vout V+Vout R1 R1 Vref Vref R2 R2 Vout = 1+ R1 Vref Vout = R2 1+ R1 Vref R2 Shunt regulator Higher current shunt regulator V+ ZSR*** + Vout Out In 30Ω Common R1 0.01µF Vref R1 R2 Vref Vout R2 Vout M IN = Vref + Vreg Vout = 1+ R1 Vref R2 Vout = 1+ R1 Series regulator V+ V+ R1B R1A Output Input Vref R2 Output control of a three terminal fixed regulator V on 2V Vref Output Vref V off = V+ V TH = 2.5V R2A R2B Low limit = 1+ R1B Vref R2B Single supply comparator with temperature compensated threshold ZHT431 Document number: DS32157 Rev. 11 - 2 High limit = 1 + R1A Vref R2A Over voltage / under voltage protection circuit 6 of 8 www.diodes.com November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 Ordering Information Ordering Reference ZHT431F01TA 1 ZHT431F01-7 2 ZHT431FMTA 1 ZHT431F02TA 1 Notes: 1. 2. Tolerance (%) 1 1 0.5 2 Package Part Mark Status SOT23 SOT23 SOT23 SOT23 43C 43C 43P 43D Active Active Active Active Reel Size (inches) 7 7 7 7 Quantity per reel 3000 3000 3000 3000 Tape Width 8mm 8mm 8mm 8mm A ‘Green’ molding compound is used from date code 1010. For further details, refer to http://www.diodes.com/quality/lead_free.html All date codes of the ‘-7’ option use ‘Green’ molding compound. Package Outline Dimensions SOT23 ZHT431 Document number: DS32157 Rev. 11 - 2 7 of 8 www.diodes.com November 2010 © Diodes Incorporated A Product Line of Diodes Incorporated ZHT431 IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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