NJM2340 ver 2. 0 - 1 - high precision dc/dc converter control ic general description package outline features pwm switching control operating voltage (3.6 to 32v) wide oscillator range (20khz to 500 khz) duty cycle (0% to 100%) current sensing amplifier high precision reference voltage voltage detect: 1v1.5% current detect: 150mv4% bipolar technology package outline dmp8, tvsp8 pin configuration NJM2340 is a high precision dc/dc converter control ic with current sense amplifier. it uses a low side current sensing which reduces external components and improves accuracy. it is applicable for a wide range of application since it features high operating voltage and small outline packages. pin function 1.in1 2.in2 3.f.b 4.gnd 5.out 6.ct 7.v ref 8.v + NJM2340m NJM2340rb1 1 4 3 2 5 6 7 8 NJM2340m NJM2340rb1
NJM2340 - 2 - block diagram 1 current sense amp v ref error amp pwm osc 4 3 2 0.15v 8 5 6 7 v ref v + ct out in1 in2 f.b gnd 1v absolute maximum ratings (ta=25c ) parameter symbol ratings unit maximum supply voltage v + 36 v output sink current i sink 15 ma power dissipation p d (dmp8) 300 (tvsp8) 320 mw operating temperature range topr -40 +85 c storage temperature range ts t g -50 +150 c recommended operating conditions (ta=25c) parameter symbol min. max. unit supply voltage v + 3.6 32 v oscillation frequency fosc 20 500 khz oscillator timing resistance r t 20 100 k ?
NJM2340 - 3 - electrical characteristics (v + =12v,ta=25c) reference voltage block parameter symbol test condition min. typ. max. unit output voltage v ref i or =1ma 1.98 2.00 2.02 v line regulation l ine v + =3.6 32v, i or =1ma ? 4.0 20 mv load regulation l oad i or =0.1 5.0ma ? 6.0 40 mv oscillator block parameter symbol test condition min. typ. max. unit oscillation frequency f osc r t =27k ? , c t =220pf 315 350 385 khz current sense amplifier block parameter symbol test condition min. typ. max. unit reference voltage1 v b 1 144 150 156 mv input bias voltage1 i b 1 ? 20 100 na v om+ 1 r nf =100k ? ? v ref -0.15 ? v maximum output voltage1 (f.b pin ) v om- 1 r nf =100k ? 0.6 0.75 0.9 v maximum source current1 (f.b pin ) i om 1 v om 1=0.5v 40 85 200 a error amplifier block parameter symbol test condition min. typ. max. unit reference voltage2 v b 2 0.985 1.000 1.015 v input bias voltage2 i b 2 ? 20 100 na v om+ 2 r nf =100k ? ? v ref -0.15 ? v maximum output voltage2 (f.b pin ) v om- 2 r nf =100k ? 0.6 0.75 0.9 v maximum source current2 (f.b pin ) i om 2 v om 2=0.5v 40 85 200 a pwm comparate block parameter symbol test condition min. typ. max. unit input threshold voltage (f.b pin) v th0 dutycycle=0% (note) v om - 1.0 1.1 v input threshold voltage (f.b pin) v th100 dutycycle=100% (note) ? 1.4 ? v output block parameter symbol test condition min. typ. max. unit l output voltage (out pin) v ol i sink =10ma ? 0.5 0.7 v general characteristics parameter symbol test condition min. typ. max. unit average quiescent current i ccav r l = , dutycycle=50% ? 1.5 2.0 ma (note) dutycycle is defined as follows: dutycycle=0%: ic output transistor is off. dutycycle=100%: ic output transistor is on.
NJM2340 - 4 - typical application 1 current sense amp v ref error amp osc 4 3 2 0.15v 8 5 6 7 v ref v + ct out in1 in2 f.b gnd v in gnd in v out gnd out r t 27k ? c t 220pf pwm 1v c in r be c out r sc q1 l d1 r1 r2 r nf 1 r nf 2 c nf 1 c nf 2 r cin r bc
NJM2340 - 5 - tipical characteristics l output voltage vs. source current (v + =12v,ta=25c) 0 0.2 0.4 0.6 0.8 03691215 source current i source (ma) l output voltage v ol (v) oscillator fr equency vs. timing resistor (v + =12v,ta=25c) 10 100 1000 10 100 timing resistor r t (k ? ) osillator frequency f osc (khz) c t =100pf c t =4700pf c t =220pf c t =1000pf oscillator fr equency vs. timing capacitor (v + =12v,ta=25c) 10 100 1000 10 100 1000 10000 timing capacitor c t (pf) oscillator frequency f osc (khz) r t =20k ? r t =100k ? r t =47k ? reference voltage vs. output current (v + =12v,ta=25c) 0 0.5 1 1.5 2 2.5 0 5 10 15 20 25 30 output current i or (ma) reference voltage v ref (v) average quiescent current (r l = ,dutycycle=50%,ta=25c) 0 0.5 1 1.5 2 2.5 3 0 10203040 ??R v + (v) average quiescent current i cc (ma)
NJM2340 - 6 - tipical characteristics [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. l level output voltage vs. temperaure (v + =12v,i sink =10ma) 0 0.1 0.2 0.3 0.4 0.5 -50 -25 0 25 50 75 100 125 150 ambient temperature ta (c) l output voltage v ol (v) oscillation fr equency vs. temperature (v + =12v,r t =27k ? ,c t =220pf) 300 320 340 360 380 400 -50 -25 0 25 50 75 100 125 150 ambient temperature ta (c) oscillation frequency f osc (khz) input threshold voltage vs. temperature (v + =12v) 0 0.4 0.8 1.2 1.6 2 -50 -25 0 25 50 75 100 125 150 ambient temperature ta (c) input threshold voltage (v) v th100 v th0 reference voltage 1 ,2 vs. temperaure (v + =12v) 147 148 149 150 151 152 153 -50 -25 0 25 50 75 100 125 150 ambient temperature ta (c) reference voltage1 v b 1 (mv) 0.97 0.98 0.99 1 1.01 1.02 1.03 reference voltage2 v b 2 (v) v b 1 v b 2 average quisent current vs. temperature (v + =12v,r l = ,dutycycle=50%) 0 0.5 1 1.5 2 2.5 3 -50 -25 0 25 50 75 100 125 150 ambient temperature ta (c) average quisent current i ccav (ma)
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