BU808DFI high voltage fast-switching npn power darlington transistor n stmicroelectronics preferred salestype n npn monolithic darlington with integrated free-wheeling diode n high voltage capability ( > 1400 v ) n high dc current gain ( typ. 150 ) n fully insulated package (u.l. compliant) for easy mounting n low base-drive requirements n dedicated application note an1184 applications n cost effective solution for horizontal deflection in low end tv up to 21 inches. description the BU808DFI is a npn transistor in monolithic darlington configuration. it is manufactured using multiepitaxial mesa technology for cost-effective high performance. ? internal schematic diagram april 2002 absolute maximum ratings symbol parameter value unit v cbo collector-base voltage (i e = 0) 1400 v v ceo collector-emitter voltage (i b = 0) 700 v v ebo emitter-base voltage (i c = 0) 5 v i c collector current 8 a i cm collector peak current (t p < 5 ms) 10 a i b base current 3 a i bm base peak current (t p < 5 ms) 6 a p tot total dissipation at t c = 25 o c52w v isol insulation withstand voltage (rms) from all three leads to exernal heatsink 2500 v t stg storage temperature -65 to 150 o c t j max. operating junction temperature 150 o c 1 2 3 isowatt218 1/7
thermal data r thj-case thermal resistance junction-case max 2.4 o c/w electrical characteristics (t case = 25 o c unless otherwise specified) symbol parameter test conditions min. typ. max. unit i ces collector cut-off current (v be = 0) v ce = 1400 v 400 m a i ebo emitter cut-off current (i c = 0) v eb = 5 v 100 ma v ce(sat) * collector-emitter saturation voltage i c = 5 a i b = 0.5 a 1.6 v v be(sat) * base-emitter saturation voltage i c = 5 a i b = 0.5 a 2.1 v h fe * dc current gain i c = 5 a v ce = 5 v i c = 5 a v ce = 5 v t j = 100 o c 60 20 230 t s t f inductive load storage time fall time v cc = 150 v i c = 5 a i b1 = 0.5 a v be(off) = -5 v 3 0.8 m s m s t s t f inductive load storage time fall time v cc = 150 v i c = 5 a i b1 = 0.5 a v be(off) = -5 v t j = 100 o c 2 0.8 m s m s v f diode forward voltage i f = 5 a 3 v * pulsed: pulse duration = 300 m s, duty cycle 1.5 % safe operating area thermal impedance BU808DFI 2/7
derating curve collector emitter saturation voltage power losses at 16 khz dc current gain base emitter saturation voltage switching time inductive load at 16khz BU808DFI 3/7
switching time inductive load at 16khz reverse biased soa base drive information in order to saturate the power switch and reduce conduction losses, adequate direct base current i b1 has to be provided for the lowest gain h fe at 100 o c (line scan phase). on the other hand, negative base current i b2 must be provided to turn off the power transistor (retrace phase). most of the dissipation, in the deflection application, occurs at switch-off. therefore it is essential to determine the value of i b2 which minimizes power losses, fall time t f and, consequently, t j . a new set of curves have been defined to give total power losses, t s and t f as a function of i b2 at both 16 khz scanning frequencies for choosing the optimum negative drive. the test circuit is illustrated in figure 1. inductance l 1 serves to control the slope of the negative base current i b2 to recombine the excess carrier in the collector when base current is still present, this would avoid any tailing phenomenon in the collector current. the values of l and c are calculated from the following equations: 1 2 l ( i c ) 2 = 1 2 c ( v cefly ) 2 w = 2 p f = 1 ? ``` ` l c where i c = operating collector current, v cefly = flyback voltage, f= frequency of oscillation during retrace. BU808DFI 4/7
figure 1: inductive load switching test circuits. figure 2: switching waveforms in a deflection circuit BU808DFI 5/7
dim. mm inch min. typ. max. min. typ. max. a 5.35 5.65 0.211 0.222 c 3.30 3.80 0.130 0.150 d 2.90 3.10 0.114 0.122 d1 1.88 2.08 0.074 0.082 e 0.75 0.95 0.030 0.037 f 1.05 1.25 0.041 0.049 f2 1.50 1.70 0.059 0.067 f3 1.90 2.10 0.075 0.083 g 10.80 11.20 0.425 0.441 h 15.80 16.20 0.622 0.638 l 9 0.354 l1 20.80 21.20 0.819 0.835 l2 19.10 19.90 0.752 0.783 l3 22.80 23.60 0.898 0.929 l4 40.50 42.50 1.594 1.673 l5 4.85 5.25 0.191 0.207 l6 20.25 20.75 0.797 0.817 n 2.1 2.3 0.083 0.091 r 4.6 0.181 dia 3.5 3.7 0.138 0.146 p025c/a isowatt218 mechanical data - weight : 4.9 g (typ.) - maximum torque (applied to mounting flange) recommended: 0.8 nm; maximum: 1 nm - the side of the dissipator must be flat within 80 m m BU808DFI 6/7
information furnished is believed to be accurate and reliable. however, stmicroelectronics assumes no responsib ility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of stmicroelectroni cs. specifi cation mentio ned in this publication are subject to change without notice. this publication supersedes and replaces all in formation previou sly supplied. stmicroe lectron ics products are not authorized for use as critical components in life support devices or systems without express written approval of stmicroelectron ics. the st logo is a trademark of stmicroelectronics ? 2002 stmicroelectronics C pr inted in italy C all rights reserved stmicroelectronics group of companies australia - brazil - canada - china - finland - france - germany - hong kong - india - israel - italy - japan - malaysia - malt a - morocco - singapore - spain - sweden - switzerland - united kingdom - united states. http://www.st.com BU808DFI 7/7
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