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 SOT23 extended operating temperature range working from -55 to +125C. VZ The output voltage may be set to any chosen voltage between 2.5 and 20 volts by selection of two external divider resistors. GND The devices can be used as a replacement for zener diodes in many applications requiring an improvement in zener performance. VREF (Top View) Features 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 50A to 100mA current sink capability Low output noise Available in Green Molding Compound (See page 7) Wide temperature range -55 to +125C Applications Series and shunt regulator Voltage monitor Over voltage / under voltage protection Switch mode power supplies Typical Application Circuit 1 of 8 November 2010 ZHT431 Diodes Incorporated www.diodes.com Document number: DS32157 Rev. 11 - 2 A Product Line of Diodes Incorporated ZHT431 Absolute Maximum Ratings (Voltages to GND Unless Otherwise Stated) Parameter Rating Unit 20 V Cathode Voltage (V ) Z Cathode Current 150 mA Operating Temperature -55 to 125 C Storage Temperature -55 to 150 C Power Dissipation 330 mW (T = 25C, T = 150C) amb JMAX Recommended Operating Conditions Parameter Min Max Units - 20 V Cathode Voltage V REF Cathode Current 0.05 100 mA Electrical Characteristics (Test conditions unless otherwise specified: T = 25C) amb Values Symbol Parameter Units Conditions Min. Typ. Max. Reference Voltage 2% 2.45 2.50 2.55 I =10mA (Fig.1), V L REF 1% 2.475 2.50 2.525 V V =V Z REF 0.5% 2.4875 2.50 2.5125 I =10mA, V =V L Z REF Deviation of reference input voltage V DEV 10 30 mV over temperature T =full range (Fig1) amb V from V to 10V Z REF Ratio of the change in reference voltage V REF -1.85 -2.7 mV/V to the change in cathode voltage I =10mA (Fig.2) Z V Z V from 10V to 20V Z -1.0 -2. mV/V I =10mA (Fig.2) Z R1=10k, R2=O/C, Reference input current I 0.12 1.0 A REF l =10mA (Fig.2) L R1=10k, R2=O/C, Deviation of reference input current I REF 0.04 0.2 A I =10mA T =full range over temperature L amb (Fig.2) 35 50 A Minimum cathode current for regulation V =V (Fig.1) Z REF I Zmin 0.1 A Off-state current V =20V, V =0V(Fig.3) Z REF I Zoff V =V (Fig.1), f=0Hz, Z REF Dynamic output impedance R Z 0.75 V I =1mA to 100mA C Deviation of reference input voltage, V , is defined as the maximum variation of the reference input voltage over the full DEV temperature range. The average temperature coefficient of the reference input voltage, V is defined as: REF The dynamic output impedance, R , is defined as: Z 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: 2 of 8 November 2010 ZHT431 Diodes Incorporated www.diodes.com Document number: DS32157 Rev. 11 - 2