adjustable precision zener shunt regulator issue 2 - february 1998 zh431 device description the zh431 is a three terminal adjustable shunt regulator offering excellent temperature stability and output current handling capability up to 30ma. the output voltage may be set to any chosen voltage between 2.5 and 36 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.they are also ideal for use in the feedback circuits of off line smpus as well as many general purpose regulator and reference applications where initial accuracy and low temperature coefficient are key requirements. note: zh431 is not recommended for new designs. refer to zr431 features surface mount so8, sot223,sot23 and sot89 packages to92 package 2% and 1% tolerance maximum temperature coefficient 55 ppm/c temperature compensated for operation over the full temperature range programmable output voltage 50 m a to 30ma current sink capability low output noise applications shunt regulator series regulator voltage monitor over voltage/ under voltage protection switch mode power supplies v z g nd v ref schematic diagram 4-15 not recommended for new design please use zr431
zh431 absolute maximum rating cathode voltage (v z ) 40v cathode current 50ma operating temperature -40 to 85c storage temperature -55 to 125c recommended operating conditions min max cathode voltage vref 36v cathode current 50 m a 30ma power dissipation (t amb =25c, t jmax =150c) sot23 330mw to92 780mw sot223 2w so8 780mw sot89 1.5w electrical characteristics test conditions (unless otherwise stated):t amb =25c parameter symbol value units conditions min typ max reference voltage 2% 1% v ref 2.45 2.475 2.50 2.50 2.55 2.525 vi l =10ma (fig1), v z =v ref deviation of reference input voltage over temperature v dev 8.0 17 mv i l =10ma, v z =v ref t a =full range (fig1) ratio of the change in reference voltage to the change in cathode voltage d v ref d v z -0.7 -2.7 mv/v v z from v ref to 10v i z =10ma (fig2) -0.6 -2.0 mv/v v z from 10v to 36v i z =10ma (fig2) reference input current i ref 0.15 1.0 m a r1=10k, r2=o/c, l l =10ma (fig2) deviation of reference input current over temperature d i ref 0.06 0.2 m a r1=10k, r2=o/c, i l =10ma t a =full range (fig2) minimum cathode current for regulation i zmin 21 50 m a v z =v ref (fig1) dynamic output impedance r z 0.75 w v z =v ref (fig1), f=0hz 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: v ref ( ppm c )= v dev x 1000000 v ref ( t 1 - t 2 ) the dynamic output impedance, rz, is defined as: r z = d v z d i 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: r = r z ( 1 + r 1 r 2 ) vmax vmin t1 t2 vdev = vmax - vmin temperature 4-16 not recommended for new design please use zr431
zh431 dynamic impedance v frequency frequency (hz) 10k 100k 1m 0.01 dynamic impedance (ohms) 0.1 100 10 1 100 1k power dissipation derating ambient temperature (c) 100 power dissipation (w) 1.0 0 25 75 2.0 50 sot223 s08/t092 sot23 cathode current v temperature temperature (c) 020 60 40 12 minimum cathode current (ua) 14 22 20 18 16 -40 -20 80 24 26 vref= vz reference current v temperature temperature (c) 020 60 40 100 reference current (na) 120 200 180 160 140 -40 -20 80 change in vref v cathode voltage cathode voltage (v) 10 15 2520 -25 change in reference voltage (mv) -20 0 -5 -10 -15 0 5 30 35 5 40 vref= vz iz= 10ma 1ma 10ma vref=vz typical characteristics sot89 reference voltage v temperature temperature (c) 020 60 40 2.47 reference voltage (v) 2.48 2.52 2.51 2.50 2.49 -40 -20 80 iz= 10ma 4-17 not recommended for new design please use zr431
zh431 gain v frequency frequency (hz) 100 10k open loop gain (db) 0 50 100k 1m 1k 40 30 20 10 70 60 pulse response time (s) 0.1 0.15 0.25 0.2 0 voltage swing (v) 5 3.0 2.0 1.0 0 00 . 0 5 input repetitive pulse single pulse stability boundary conditions load capacitance (f) 1000p 0.01 0.1 0 cathode current (ma) 5 20 15 10 10p 100p 1 unstable stable 25 30 typical characteristics stable i z 15k v z test circuit for open loop voltage gain 8k25 9 m f 230 w + - i z = 10ma, t a = 25c test circuit for pulse response input monitor v z 220 w 50 w pulse generator t a = 25c test circuit for stability boundary conditions input 150 10k v ref < v z < 40, i z = 10ma, t a = 25c v z i z 4-18 not recommended for new design please use zr431
i l input fig 1 C test circuit for v z =v ref dc test circuits fig 2 C test circuit for v z >v ref zh431 4-19 not recommended for new design please use zr431
application circuits r2 vout = 1 + r1 r2 vref series regulator v+ vout r1 30 0.01f vref vout = 1 + r1 r2 vref vout = vref + vreg min output control of a three terminal fixed regulator r2 r1 v + vout vref zsr*** in out common r2 r1 v+ vout vout = vref 1 + r1 r2 vref higher current shunt regulator v+ output input v = 2.5v th v 2v on v = v+ off single supply comparator with temperature compensated threshold r2a r1a v+ vref r2b r1b vref 1 + r1b r2b vref over voltage / under voltage protection circuit low limit = high limit = 1 + r1a r2a vref r2 r1 vout = vref 1 + r1 r2 vref shunt regulator v+ vout output zh431 4-20 not recommended for new design please use zr431
zh431 to92 package suffix C c bottom view connection diagrams so8 package suffix C n8 top view sot223 package suffix C g top view C pin 4 floating or connected to pin 2 sot23 package suffix C f top view sot89 package suffix C z top view C pin 4 floating or connected to pin 2 part number package tol. % part mark ZH431C01 to92 1.0 zh43101 zh431c02 to92 2.0 zh43102 zh431g01 sot223 1.0 zh43101 zh431g02 sot223 2.0 zh43102 zh431f01 sot23 1.0 43h zh431f02 sot23 2.0 43g zh431z01 sot89 1.0 43h zh431z02 sot89 2.0 43g zh431n801 so8 1.0 zh43101 zh431n802 so8 2.0 zh43102 ordering information 4-21 not recommended for new design please use zr431
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