april 2002 1/9 ? vb408 / VB408B high voltage linear regulator power i.c. n input voltage up to 400 v dc or 285 v rms rectified n output voltage adjustable from 1.25 to v in -30v n typical output current 40 ma n thermal shut-down protection n short circuit protection description the vb408, VB408B are fully protected positive adjustable voltage regulators made using a proprietary high voltage vipower ? technology. the device can be connected to a dc source (up to 400v) or in off-line application directly to the rectified main (110v/230v). it is particularly suitable to be used in the manufacture of dc/dc converters, ac/dc converters, start-up circuits, pneumatic valve drivers and current sources. the device is able to drive resistive or inductive loads with an output voltage from 1.25v to vin-30v providing an internally limited output current; it has built in short circuit and thermal shutdown protections. the device does not provide galvanic insulation from main. type d v in,out i lim v out vb408 VB408B 400 v 40 ma 1.25 to v in -30 v 1 to-220 block diagram 1 2 3 order codes: to-220 vb408 d 2 pak VB408B fc00410 v adj bias circuit current sense + _ + _ ref 1 + _ thermal protection control signal power stage current limitation ref 2 ref 3 v in out 1 3 d 2 pak
2/9 vb408 / VB408B absolute maximum rating thermal data (*) when mounted using the minimum recommended pad size on fr-4 board (1 inch 2 ) connection diagram symbol parameter value unit v in,out input to output voltage at 20 ma - 0.2 to 420 v i out output current internally limited ma v esd electrostatic discharge (r=1.5k w , c=100pf) 2000 v p tot power dissipation at t c =25 c 89 w t j junction operating temperature - 40 to 150 c t stg storage temperature - 55 to 150 c symbol parameter value unit to-220 d 2 pak r thj-case thermal resistance junction-case (max) 1.4 1.4 c/w r thj-amb thermal resistance junction-ambient (max) 60 35 (*) c/w d 1 electrical characteristics (v in =300vdc; -25c vb408 / VB408B 3/9 1 figure 1: typical application diagram operation description the vb408, VB408B are positive voltage regulators continuously adjustable from 1.25v to the input voltage minus a dropout of 30v by an external divider. in order to set the proper internal reference voltage, a typical 70 m a current has to be drawn from the adj pin. considering that, it results: v out = v ref (1+r 2 /r 1 ) + i adj r 2 to simplify this formula, neglecting i adj with respect to the term v ref /r 1 r1 must be chosen so to obtain a minimum 1.2ma current flowing through the divider. in such a way the v out value will be affected by an error <5%. the current set resistor r 1 should be tied directly to the output terminal of the regulator rather than near the load. this eliminates line drops from appearing in series with the reference and degrading regulation. the output voltage can also be set by a zener diode put between the adjustment pin and ground (figure 2). the biasing current of the zener is properly chosen by r1 resistor. the zener diode improves the ripple rejection and reduces the value of the worst case output voltage error. in this case the output voltage is given by v out = v ref +v z in order to reduce excessive output ringing, a minimum output capacitor c 2 of 0.1 m f is suggested. this capacitor will improve loop stability and output impedance. the vb408/VB408B can be connected both to a dc source or to a 285v r.m.s. line by a rectifier diode that prevents a negative voltage to be applied to the device. in the first case the input capacitor c 1 is not needed, whereas in the second case a high value of c 1 (>1 m f) must be chosen. in fact, in this kind of application, c 1 has to supply to the input pin the minimum allowed voltage during the negative half wave. obviously bigger c 1 value, more constant the input voltage is and consequently smaller the output voltage ripple. for the right choice of the input capacitor, you have also to remember that increasing its value you will obtain an increased power dissipation, and a heatsink could be required. the right heatsink is determined by the load current, input voltage and ambient temperature. in case of pulse or ac operation the junction temperature is limited by the thermal capacitances since the package and the heatsink masses are able to absorb heat. if the junction temperature reaches the thermal shutdown limit the output stage of the regulator is turned- off so that only the biasing current of the device can flow into the input pin. thermal hysteresis is added just to prevent oscillations. the device is able to provide typical 40 ma for a time that is function of dissipated power and consequently of the used heatsink. in general the device is also suitable in electronically switched motor housekeeping supply, consumer equipments controls power supply or constant current source. application example the most common application for the device is in the dc/ dc converters with an input voltage up to 400 vdc. and a c 2 suggested value of 0,1 m f. using an external rectifier an ac/dc converter can be easily implemented, in this case the device can operate with an ac voltage up to 285vrms. in this case must be used a minimum 1 m f input capacitor to provide the load current during the negative half cycle of the main. another important circuit that can be implemented is the start up function for low voltage input pwm ics directly from a high voltage source (see figure 3). v out v in a dj vb408 r1 r2 c2 c1 fc00420 v in v out v ref
4/9 vb408 / VB408B figure 2: regulation with zener v out v in a dj vb408 r1 c2 c1 vv fc00430 z1 in out v out v in adj vb408 r1 r2 c2 c1 v v fc00470 pwm in out figure 3: start-up circuit
vb408 / VB408B 5/9 1 1 1 1 1 dim. mm. inch min. typ max. min. typ. max. a 4.40 4.60 0.173 0.181 c 1.23 1.32 0.048 0.051 d 2.40 2.72 0.094 0.107 e 0.49 0.70 0.019 0.027 f 0.61 0.88 0.024 0.034 f1 1.14 1.70 0.044 0.067 f2 1.14 1.70 0.044 0.067 g 4.95 5.15 0.194 0.203 g1 2.4 2.7 0.094 0.106 h2 10.0 10.40 0.393 0.409 l2 16.4 0.645 l4 13.0 14.0 0.511 0.551 l5 2.65 2.95 0.104 0.116 l6 15.25 15.75 0.600 0.620 l7 6.2 6.6 0.244 0.260 l9 3.5 3.93 0.137 0.154 m 2.6 0.102 dia. 3.75 3.85 0.147 0.151 to-220 mechanical data & k c * 8 ( ( ( ) ) * 8 . . . . . % . ' . # & /
6/9 vb408 / VB408B 1 dim. mm. inch min. typ max. min. typ. max. a 4.4 4.6 0.173 0.181 a1 2.49 2.69 0.098 0.106 a2 0.03 0.23 0.001 0.009 b 0.7 0.93 0.027 0.036 b1 0.8 1.3 0.031 0.051 b2 1.14 1.7 0.044 0.067 c 0.45 0.6 0.017 0.023 c2 1.23 1.36 0.048 0.053 d 8.95 9.35 0.352 0.368 d1 8 0.315 e 10 10.4 0.393 e1 8.5 0.334 g 4.88 5.28 0.192 0.208 l 15 15.85 0.590 0.625 l2 1.27 1.4 0.050 0.055 m 2.4 3.2 0.094 0.126 r 0.4 0.015 v2 0 o8o d 2 pak mechanical data 7106164
vb408 / VB408B 7/9 1 to-220 tube shipment (no suffix) all dimensions are in mm. base q.ty 50 bulk q.ty 1000 tube length ( 0.5) 532 a 5.5 b 31.4 c ( 0.1) 0.75 a b c
8/9 vb408 / VB408B 1 d 2 pak footprint tube shipment (no suffix) a c b all dimensions are in mm. base q.ty 50 bulk q.ty 500 tube length ( 0.5) 532 a 6 b 21.3 c ( 0.1) 0.6 tape and reel shipment (suffix 13tr) reel dimensions all dimensions are in mm. base q.ty 1000 bulk q.ty 1000 a (max) 330 b (min) 1.5 c ( 0.2) 13 f 20.2 g (+ 2 / -0) 24.4 n (min) 60 t (max) 30.4 tape dimensions according to electronic industries association (eia) standard 481 rev. a, feb 1986 all dimensions are in mm. tape width w 24 tape hole spacing p0 ( 0.1) 4 component spacing p 16 hole diameter d ( 0.1/-0) 1.5 hole diameter d1 (min) 1.5 hole position f ( 0.05) 11.5 compartment depth k (max) 6.5 hole spacing p1 ( 0.1) 2 top cover tape end start no components no components components 500mm min 500mm min empty components pockets saled with cover tape. user direction of feed 12.20 5.08 1.60 3.50 16.90 9.75 all dimensions are in millimeters
vb408 / VB408B 9/9 information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsibility for the co nsequences of use of such information nor for any infringement of patents or other rights of third parties which may results from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectronics. specifications mentioned in this p ublication are subject to change without notice. this publication supersedes and replaces all information previously supplied. stmicroelectron ics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicr oelectronics. the st logo is a trademark of stmicroelectronics ? 2002 stmicroelectronics - printed in italy- all rights reserved. stmicroelectronics group of companies australia - brazil - canada - china - finland - france - germany - hong kong - india - israel - italy - japan - malaysia - malta - morocco - singapore - spain - sweden - switzerland - united kingdom - u.s.a. http://www.st.com
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