nte7173 NTE7173SM integrated circuit 1.5a step?up/down inverting switching regulator description: the nte7173 and nte 7173sm are monolithic circuits containing the primary functions required for dc?to?dc converters. these devices consist of an internal temperature compensated reference, comparator, controlled duty cycle oscillator with an active current limit circuit, driver and high current output switch. this series was specifically designed to be incorporated in step?down and step?up and voltage?inverting applications with a minimum number of external components. features: operation from 3v to 40v input low standby current output switch current 1.5a output voltage adjustable frequency operation to 100khz precision 2% reference absolute maximum ratings: power supply voltage, v cc 40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . comparator input voltage range, v ir ?0.3 to +40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . switch collector voltage, v c(switch) 40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . switch emitter voltage (v pin1 ), v e 40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . switch collector?to?emitter voltage, v ce(switch) 40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . driver collector voltage, v c(driver) 40vdc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . driver collector current (note1), i c(driver) 100ma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . switch current, i sw 1.5a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . power dissipation (t a = +25 c), p d nte7173 1.25w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NTE7173SM 625mw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . thermal resistance, junction?to?ambient, r thja nte7173 +100 c/w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . NTE7173SM +160 c/w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . operating ambient temperature range, t a 0 to +70 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . storage temperature range, t stg ?65 to +150 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . note 1. maximum package power dissipation limits must be observed.
electrical characteristics: (v cc = 5v, t a = 0 c to +70 c, unless otherwise specified) parameter symbol test conditions min typ max unit oscillator frequency f osc v pin5 = 0v, c t = 1.0nf, t a = +25 c 24 33 42 khz charge current l chg v cc = 5v to 40v, t a = +25 c 24 35 42 a discharge current l dischg v cc = 5.0v to 40v, t a = +25 c 140 220 260 a discharge to charge current ratio l dischg /l chg pin7 to v cc , t a = +25 c 5.2 6.5 7.5 ? current limit sense voltage v ipk(sense) l chg = l dischg , t a = +25 c 250 300 350 mv output switch (note 2) saturation voltage, darlington connection v ce(sat) l sw = 1.0a pin1 and pin8 connected ? 1.0 1.3 v saturation voltage v ce(sat) l sw = 1.0a, r pin8 = 82 ? to v cc , forced ? 20, note 3 ? 0.45 0.7 v dc current gain h fe l sw = 1a, v ce = 5v, t a = +25 c 50 75 ? ? collector off?state current l c(off) v ce = 40v ? 0.01 100 a comparator threshold voltage v th t a = +25 c 1.225 1.25 1.275 v t a = 0 to +70 c 1.21 ? 1.29 v threshold voltage line regulation reg line v cc = 5v to 40v ? 1.4 5.0 mv input bias current l ib v in = 0v ? ?20 ?400 na total device supply current i cc v cc = 5v to 40v, c t = 1nf, pin7 = v cc , v pin5 > v th , pin2 = gnd, remaining pins open ? ? 4 ma note 2. low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible note 3. if the output switch is driven into hard saturation (non?darlington configuration) at low switch currents ( 300ma) and high driver currents ( 30ma), it may take up to 2 s for it to come out of saturation. thi condition will shorten the off time at frequencies 30khz, and is magni- fied at high temperatures. thi condition does not occur with a darlington configuration, since the output switch cannot saturate. if a non?darlington configuration is used, the following output condition is recommended: forced of output switch: 10 i c output i c driver ? 7ma * * the 100 ? resistor is the emitter of the driver device requires about 7ma before the * output switch conducts. v cc switch collector i pk sense driver collector gnd timing capacitor switch emitter 1 2 3 4 8 7 6 5 comparator inverting input pin connection diagram
.236 (5.99) .154 (3.91) .192 (4.9) 85 .256 (6.52) max .393 (10.0) max 14 .300 (7.62) .300 (7.62) .150 (3.81) .070 (1.77) min .100 (2.54) note: pin1 on beveled edge .061 (1.53) .006 (.152) 14 85 .050 (1.27) .016 (.406) .198 (5.03) nte7173 NTE7173SM
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