utc BA9741A linear integrated circuit utc unisonic technologies co., ltd. 1 qw-r103-019,a two-channel switching regulator contorller description the utc BA9741A is a two-channel switching regulator controllers that use the pwm method. it can be used for dc to dc conversion for step-up, step-down, and inverting. the ic comes in a compact package, making it ideal for use in portable equipment. features *high-accuracy reference voltage circuit ( 1%). *time-latch, short-circuit protection circuit. *miss-operation prevention circuit for low-voltage input *reference voltage with output (2.5v) *rest period adjustment is possible over the entire duty * range. application *dc/dc converters for video cameras and notebook computers etc. dip-16 sop-16 tssop-16 pin configurations ct rt non1 inv1 fb1 dt1 out1 gnd vcc out2 dt2 inv2 scp vref non2 fb2 error amplifier 1 error amplifier 2 1 2 3 4 5 6 7 89 10 11 12 13 14 15 16
utc BA9741A linear integrated circuit utc unisonic technologies co., ltd. 2 qw-r103-019,a pin descriptions pin no. pin name functoin 1 ct external timing capacitor 2 rt external timing resistor 3 non1 positive input for error amplifier 1 4 inv1 negative input for error amplifier 1 5 fb1 error amplifier 1 output 6 dt1 output 1 dead time/soft start setting 7 out1 output 1 8 gnd ground 9 vcc power supply 10 out2 output 2 11 dt2 output 2 dead time / soft start setting 12 fb2 error amplifier 2 output 13 inv2 negative input for error amplifier 2 14 non2 positive input for error amplifier 2 15 scp time latch setting 16 vref reference voltage output (2.5v) block diagram vcc 2 1 9 reference voltage 3 4 5 6 8 7 triangle oscillator 16 14 13 12 15 11 10 vref vref + - + - + - + + - + + - + non 1 inv 1 fb 1 non 2 inv 2 fb 2 scp err amp 1 err amp 2 vref sr timer latch r uvlo scp comp vref vref dt1 dt2 gnd pwm comp2 pw m comp1 ct rt out1 out2
utc BA9741A linear integrated circuit utc unisonic technologies co., ltd. 3 qw-r103-019,a absolute maximum ratings ( ta=25 c ) parameter symbol value unit power supply voltage vcc 36 v power dissipation (note 1) sop-16 dip-16 pd 500 650 mw operating temperature topr -40 to 85 c storage temperature tstg -55 to 125 c output current io 120(note 2) ma output voltage vo 36 v note 1: when mounted on 70mm*70mm*1.6mm glass epoxy board. reduced by 5.0mw,for each increase in ta of 1 c over 25 c note 2: should not exceed pd and aso values. recommended operating conditions ( ta=25 c ) parameter symbol min typ. max unit power supply voltage vcc 3.6 6.0 35 v output current io 100 ma output voltage vo 35 v error amplifier input voltage v om 0.3 1.6 v timing capacitor c ct 100 15000 pf timing resistor r rt 5.1 50 k ? oscillator frequency f osc 10 800 khz electrical characteristics ( ta=25 c ,v cc =6v,unless otherwise noted.) parameter symbol test coniditions min typ. max unit reference voltage block output voltage vref iref =1ma 2.4 2.5 2.6 v input stability v dli vcc =3.6~35v 1 10 mv load stability v dlo iref =0~5ma 1 10 mv triangular wave oscillator oscillation frequency fosc r rt =10 k ? ,c ct =220pf 320 400 480 khz frequency deviation f dv vcc=3.6~35v 1 % protection circuit threshold voltage v it 1.48 1.64 1.80 v standby voltage v stb no pull up 50 100 mv latch voltage v lt no pull up 30 100 mv source current i scp 1.5 2.5 3.5 a comparator threshold voltage v ct 5pin,12pin 0.9 1.05 1.2 v rest period adjustment circuit v t0 duty cycle =0% 1.79 1.97 2.15 v input threshold voltage (fosc=10khz) v t100 duty cycle =100% 1.32 1.48 1.64 v
utc BA9741A linear integrated circuit utc unisonic technologies co., ltd. 4 qw-r103-019,a parameter symbol test coniditions min typ. max unit on duty cycle d on divide vref using 13 k ? and27 k ? 45 55 65 % input bias current i bdt dt1,dt2=2.0v 0.1 1 a latch mode source current i dt dt1,dt2=0v 200 560 a latch input voltage v dt i dt =40 a 2.28 2.48 v low-voltage input miss-operation prevention circuit threshold voltage v ut 2.53 v error amplifier input offset voltage v io 6 mv input offset current i io 30 na input bias current i ib 15 100 na open circuit gain av 70 85 db common-mode input voltage range vom vcc=3.6~35v 0.3 1.6 v common-mode rejection ratio cmrr 60 80 db maximum output voltage v oh 2.3 2.5 v minimum input voltage v ol 0.7 0.9 v output sink current i oi fb=1.25v 3 20 ma output source current i oo fb=1.25v 45 75 a pwm comparator v t0 duty cycle =0% 1.79 1.97 2.15 v input threshold voltage (fosc=10khz) v t100 duty cycle =100% 1.32 1.48 1.64 v output block saturation voltage v sat io=75ma 0.8 1.2 v leak current i reak vo=35v 0 5 a total device standby current iccs when output is off 1.3 1.8 ma average current consumption icc a r rt =10 k ? 1.6 2.3 ma timing chart 1.97v 1.05v 1.48v 1.64v 2.53v tdt > = vcc 3.6v triangular wave output(from oscillator) error amplifier output dead-time input voltage short protection comparator pwm comparator output output waveform scp waveform short protection comparator output power supply voltage lockout release figure. 1
utc BA9741A linear integrated circuit utc unisonic technologies co., ltd. 5 qw-r103-019,a electrical characteristic curves -40 -20 02040 2.0 -2.0 ambient temperature : ta ( ) figure 2. reference voltage vs.ambient temperature reference voltage variation: vref (%) -1.5 100 1k 10k 100k 1m -30 -50 -40 frequency :f (hz) gain :av (db) av 2.2 2.0 10k 100k 1m figure 3. swing voltage vs. frequency 1.2 swing voltage :vosc(v) figure 5. error amplifier ac gain characteristic (40db close) v cc =6v rt1=10k upper voltage lower voltage 60 80 100 -1.0 -0.5 0 0.5 1.0 1.5 v cc =6v iref = -1ma 1.8 1.6 1.4 0 20 40 60 80 0 output current :io (ma) figure4. output current vs.output saturation voltage output saturation voltage: vosat (v) 0.2 100 120 140 0.4 0.6 0.8 1.0 1.2 -20 -10 0 10 20 30 40 50 180 90 0 -90 -180 phase : (deg) oscillator frequency :fosc (hz)
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