tl431 programmable precision reference MB3800 switching regulator controller preliminary he MB3800 is a single - channel switching regulator control ic for low voltage applications incorporating a soft st art function and short circuit detection function. the device has a low minimum operating voltage of 1.8 v and is ideal for the power supply of battery-operated electronic equipment. ? wide supply voltage operat ing range: 1.8 to 15 v ? low current consumption: typically 5.5 ma in operation, 1 a or less in stand-by ? high speed operation is possib l e: maximum 1 mhz dip-8 ? the error amplifier gain is set inside the ic, so peripheral components are minimized. ? incorporates a soft start circuit. ? incorporates a timer-latch type short circuit detection circuit . ? totem-pole type output with adjustable on/off curr ent sop-8 (for npn transistors) ? incorporates a stand-by function. ? three types of packages (sop-8 or ssop-8) ssop-8 pin no symbol i/o description 1 -in i error amplifier inverting input pin 2 scp - soft start and scp setting capacitor connection pin 3 vcc - power supply pin 4 br/ctl i output current setting and control pin 5 out o totem-pole type output pin 6 gnd - gnd pin 7 osc - capacitor and resistor c onnection pin for setting the oscillation frequency 8 fb o error amplifier output pin t features
tl431 programmable precision reference MB3800 switching regulator controller preliminary absolute maximum ratings rated value parameter symbol condition min max unit power supply voltage v cc - 16 v output source current i o + - -50 ma output sink current i o - - - 50 ma dip-8, ta Q +25 sop-8,ta Q +25 allowable dissipation p d ssop-8, ta Q +25 - - - 570 430 580 mw operating temperature t op -30 +85 storage temperature t stg - -55 +125 * : when mounted on a 10 cm square double-sided epoxy board warning: semiconductor devices can be perm anently damaged by application of stress (voltage, current, temperature, etc.) in ex cess of absolute maximum ratings. do not exceed these ratings. recommended operating conditions values parameter symbol min typ max unit power supply voltage v cc 1.8 - 15 v error amp l ifier input voltage v i -0.2 - 1.0 v br/ctl pin input voltage v br -0.2 - v cc v output source current i o + -40 - - ma output sink current i o - - - 40 ma scp pin capacitance c pe - 0.1 - f phase compensation capacitance c p - 0.1 - f output current setting resistance r b 150 390 5000 timing resistance r t 1.0 3.0 10.0 k timing capacitance c t 100 270 10000 pf oscillation frequency f osc 10 500 1000 khz operating temperature t op -30 +25 +85 warning: recommended operating conditions are no rmal operating ranges for the semiconductor device. all the device's electrical characte ristics are warranted when operated within these ranges. always use semiconductor devices withi n the recommended operating conditions. operation outside these ranges may adversely affe ct reliability and could result in device failure.
tl431 programmable precision reference MB3800 switching regulator controller preliminary electrical characteristics value parameter symbol condition min typ max unit reset voltage v r - - 0.9 circuit to prevent malfunction at low input voltage (u.v.l.o.) threshold voltage v th - 1.1 1.3 1.5 v charging current i cs v scp =0v -1.5 -1.0 -0.7 a soft start voltage at soft start completion v ts - 0.7 0.8 0.9 v charging current i cpc v scp =0v -1.5 -1.0 -0.7 a short circuit detection (s.c.r) threshold voltage v tpc - 0.7 0.8 0.9 v oscillation frequency f osc r t =3.0k c t =270pf 400 500 600 khz frequency input stability f dv v cc =2v to 15v - 2 10 % sawtooth wave oscillator (osc) frequency variation with temperature f dt ta=-30 ~+85 - 5 - % input threshold voltage v t v fb =450mv v t input stability v tdv v cc =2v ~15v 480 500 520 mv v t variation with temperature v tdt ta=-30 ~+85 - 5 20 mv input bias current i b v in =0v - 1 - % voltage gain a v - 70 100 145 v/v frequency bandwidth bw a v =0db - 6 - mhz v om + 0.78 0.87 - v maximum output voltage range v om - - - 0.05 0.2 v output source current i om + - -40 -24 a error amplifier output sink current i om - v fb =0.45v 24 40 - a idle period adjustment section maximum duty cycle t duty r t =3.0k c t =270pf,v fb =0.8v 65 75 85 % v oh1 r b =390 ,i o =-15ma 1.0 1.2 - v v oh2 r b =750 , v cc =-15ma,i o =-10ma 0.8 1.0 - v v ol1 r b =390 ,i o =15ma - 0.1 0.2 v output voltage v ol2 r b =750 , v cc =-15ma,i o =10ma - 0.1 0.2 v output source current io + r b =390 ,v o =0.9v - -30 -20 ma output sink current io - r b =390 ,v o =0.3v 30 60 - ma output section pull down resistance r o - 20 30 40 k
tl431 programmable precision reference MB3800 switching regulator controller preliminary pin voltage v br r b =390 0.2 0.3 0.4 v input off condition i off -20 - 0 a input on condition i on - - -45 a output current setting section/ control section pin current range i br - -1.8 - -0.1 ma stand-by current i ccs br/ctl pin open or v cc - - 1 a entire device average supply current i cc r b =390 - 5.5 9.3 ma
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