njm2393 - 1 - ver.2009-09-28 step-down pwm dc/dc converter ic general description package outline features ? operating voltage 3.0v~40v ? wide oscillator frequency 1khz~150khz ? precision reference voltage v th =1.25v 1% ? internal high power transistor 1.5a max. ? maximum duty ratio 100% ? internal over current limit circuit ? pwm switching control ? bipolar technology ? package outline NJM2393D : dip8 njm2393m : dmp8 pin configuration block diagram the njm2393 is a step down pwm dc/dc converter ic. an internal 1.5a power transist or, a pulse-by-pulse current limit circuit and a 1% precision reference make the njm2393 suitable for a wide range of step down applications. the njm2393 features 100% maximum duty cycle for low voltage drop operation. NJM2393D njm2393m 1 1.5a 4 3 2 8 5 6 7 v + e s gnd vref 1.25v c d c t c s s i in- 300mv ipk sense pw m comp error amp 160 ? 1 8 2 7 3 6 4 5
njm2393 - 2 - ver.2009-09-28 absolute maximum ratings (ta=25 c) parameter symbol maximum ratings unit maximum supply voltage v + 40 v comparator input voltage v ir -0.3 ~ 40 (note) v output driver voltage v c (driver) 40 v output switch voltage v sw 40 v output driver current i c (driver) 100 ma output switch current i sw 1.5 a power dissipation p d dip8 dmp8 875 580 (*1) 750 (*2) mw operating temperature range topr -40 ~ +85 c storage temperature range tstg -50 ~ +150 c (note) when supply voltage is less than 40v, the abso lute maximum input voltage is equal to the supply voltage. (*1) at on pc board : 114.3mm 76.2mm 1.6mm(2 layer fr-4) : conform to eia/jedec (*2) at on pc board :114.3mm 76.2mm 1.6mm(4 layer fr-4) : conform to eia/jedec power dissipation vs. ambient temperature 0 200 400 600 800 1000 0255075100 ambient temperature ta ( o c) power dissipation p d (mw) power dissipation vs. ambient temperature (topr=-40~+85 o c, tj= ~150 o c) dip8 dmp8 at on 4 layer pc board at on 2 layer pc board
njm2393 - 3 - ver.2009-09-28 electrical characteristics dc characteristics (v + =5v, ta=25 c) parameter symbol test conditions min. typ. max. unit oscillator block oscillation frequency f osc in-=v th -5mv, c t =1nf 18 27 36 khz charge current i chg 11 18 27 a discharge current i dis 110 180 300 a voltage swing v osc c t =1nf - 0.5 - v p-p current limit peak current sense voltage v ipk 250 300 350 mv output switch saturation voltage 1 v sat1 darlington connection (c s =c d ), i sw =0.7a - 1.0 1.3 v saturation voltage 2 v sat2 i sw =0.7a, i c (driver)=50ma (forced ? 14) - 0.5 0.7 v saturation voltage 3 v sat3 i sw =3ma, i c (driver)=5ma - - 0.3 v output transistor bias resistance r bias - 160 - ? dc voltage gain h fe i sw =0.7a,v ce =5.0v 35 120 - - collector off-state current i c(off) v ce =40v - 0.01 1 a maximum duty ratio m ax d uty in-=0v 100 - - % error amplifier threshold voltage v th 1.2375 1.250 1.2625 v input bias current i ib in-=v th - 100 200 na general characteristics operating current i cc c t =1nf, s i =v + , in->v th , e s =gnd - 2.8 4.0 ma (note) output switch tests are performed under pul sed conditions to minimize power dissipation.
njm2393 - 4 - ver.2009-09-28 typical applications step-down converter 1 njm2393 43 2 c t 8 6 7 d1 r2 l1 5 r1 r sc c in c out v in v out c1 step-down converter (high current) 1 njm2393 43 2 c t f 8 6 7 5 r sc c in v in r be r bc d1 r2 l1 r1 c out v out c1 d1 use to schottky diode. timing chart oscillator waveform error amp output switch output off on osc block to ff, nor high low ipk sense output high low
njm2393 - 5 - ver.2009-09-28 typical characteristics 1 10 100 10 100 1000 10000 100000 oscillator frequency f osc (khz) oscillator frequency vs. timing capacitor (v + =5v, s i =v + , pin 5=gnd, ta=25 o c) timing capacitor c t (pf) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 saturation voltage 1 vs. collector current (v + =5v, c s =c d , ta=25 o c) collector current i c (a) saturation voltage 1 v sat1 (v) 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 saturation voltage 2 vs. collector current (v + =5v, ic(driver)=50ma, ? 14, ta=25 o c) collector current i c (a) saturation voltage2 v sat2 (v) 0 0.02 0.04 0.06 0.08 0.1 0 5 10 15 20 saturation voltage 3 vs. collector current (v + =5v, ic(driver)=5ma,ta=25 o c) collector current i c (ma) saturation voltage3 v sat3 (v) 0 100 200 300 400 500 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 input bias current vs. in- terminal voltage (v + =5v, ta=25 o c) in- terminal voltage (v) input bias current i ib (na) 0 1 2 3 4 010203040 operating current vs. operating voltage (c t =1nf, s i =v + , in->v th , es=gnd, ta=25 o c) operating voltage v + (v) operating current i cc (ma)
njm2393 - 6 - ver.2009-09-28 typical characteristics 1.2 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) threshold voltage v th (v) threshold voltage vs. temperature (v + =5v) 0.6 0.7 0.8 0.9 1 1.1 1.2 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) saturation voltage 1 v sat1 (v) saturation voltage 1 vs. temperature (v + =5v, c s =c d , i sw =0.7a) 0 0.2 0.4 0.6 0.8 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) saturation voltage 2 v sat2 (v) saturation voltage 2 vs. temperature (v + =5v, isw=0.7a, ic(driver)=50ma, ? 14) 0 2 4 6 8 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) saturation voltage 3 v sat3 (mv) saturation voltage 3 vs. temperature (v + =5v, isw=3ma, ic(driver)=5ma) 240 260 280 300 320 340 360 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) current limit sense voltage v ipk (mv) current limit sense voltage vs. temperature (v + =5v) 0 1 2 3 4 5 -50 -25 0 25 50 75 100 125 150 ambient temperature ta ( o c) operating current i cc (ma) operating current vs. temperature (v + =5v, c t =1nf, s i =v + , in->v th , es=gnd)
njm2393 - 7 - ver.2009-09-28 memo caution] the specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. the application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights.
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