lpr30 low drop voltage regulator drive for external n-channel power mosfet ? may 2000 n very low dropout power mosfet driver n high precision vref = 2.5v ( 2%) n very low current drain (typ. 2ma) n reference output current up to 20ma n operating supply voltage from 5v to 30v n maximum input voltage on-gate pin (n. 8) up to 60v n internal current limit operational amplifier offset trimmed at 50mv 10mv n no capacitor is needed for stability of reference output n temperature range 0 o c to 70 o c application n ultra high current ultra low dropout voltage regulator n constant high current source block diagram dip-8 so-8 n low parts count 5v to 3.3v computer supply n low noise/low drop smps post regulator description the lpr30 is a very low dropout regulator controller in a single ic solution for very high current low dropout linear voltgage regulator. it uses an external n-channel power mosfet as the linear pass element. the lpr30 features a dropout voltage as low as the r ds(on) of the 1/10
external power mosfet multiplied by the output current. consequently the output current can be as high as the power mosfet can provide (also using an adeguate heatsink). the v cc of the lpr30 range from 5v to 30v. for very low drop voltage operation,the lpr30 requires an external gate drive supply to provide the control voltage needed to drive the gate of the external power mosfet. the regulator output is constant-current limited when the controller detects 50mv across an external sense resistor. it has an internal high precision ( 2%) voltage reference at 2.5v the output regulated voltage is possible to program to any voltage from 1v to more than 50v. flexible design is achieved by the availability of the voltage reference output through an external pin (n.4) that is able to supply more than 20ma as load current. the lpr30 is available in 8 pin plastic dip and in so-8 for smd. in both package versions it is able to operate from 0 o c to 70 o c. absolute maximum ratings symbol parameter value unit v cc dc input voltage 36 v i oref reference output current i nternally limited p tot power dissipation 1 w t op operating junction temperature range 0 to 70 o c t stg storage temperature range - 40 to 150 o c v gate maximum gate voltage (pin n8) 60 v i gate maximum gate current (pin n8) 200 ma absolute maximum ratings are those values beyond which damage to the device may occur. functional operation under these conditions is not implied. thermal data symbol parameter dip-8 so-8 unit r thj-amb thermal resistance junction-ambient (*) max 130 to 180 100 to 150 o c/w (*) this value depends from thermal design of pcb on which the device is mounted. connection diagram (top view) ordering numbers type dip-8 so-8 so-8 (tape & reel) lpr30 lpr30n lpr30d LPR30D-TR lpr30 2/10
electrical characteristics (refer to the test circuits, v cc = 10v, t j = 25 o c unless otherwise specified. general symbol parameter test conditions min. typ. max. unit v cc operating supply voltage 5 30 v i cc supply current i k = 0 m a v cc = 30 v t j = 0 to 70 o c err(-), lim(-) = 1v err(+), lim(+) = 0v 24ma v osat output saturation voltage v cc = 5 v i o = 100 ma t j = 0 to 70 o c err(-), lim(-) = 1v err(+), lim(+) = 0v 280 500 mv i olk output leakage current v cc = 5 v v o = 60 v err(-), lim(-) = 0v err(+), lim(+) = 1v 100 m a reference block symbol parameter test conditions min. typ. max. unit v ref reference output voltage 2.45 2.5 2.55 v i k reference output current 20 ma d v ref / d i k reference output voltage change i k = 1 to 20 ma c ref = 0 pf 3 mv svr supply voltage rejection v in < 10 v 1v f = 120 hz c ref = 0 pf 70 db en output noise b = 10 hz to 10 khz i k = 10 ma c ref = 0 pf 50 m v error amplifier block symbol parameter test conditions min. typ. max. unit i b input bias current 0.3 1 m a v os input offset voltage v cc = 5 to 30 v t j = 0 to 70 o c 5 mv i os input offset current 5 50 na g v open loop gain t j = 0 to 70 o c 80 db v cm input common mode voltage range t j = 0 to 70 o c 1 v cc -1 v cmr common mode rejection 70 db svr supply voltage rejection v in = 9 to 11v f = 120hz v in = 9 to 11v f = 10khz 70 60 db db current limiting block symbol parameter test conditions min. typ. max. unit i b input bias current 0.5 m a v os input offset voltage t j = 0 to 70 o c 40 60 v g v open loop gain t j = 0 to 70 o c 50 db v cm input common mode voltage range t j = 0 to 70 o c 0 v cc -3 v lpr30 3/10
test circuit reference output voltage vs temperature reference output voltage vs load current typical performance characteristics lpr30 4/10
reference output voltage vs load current current limit input offset voltage vs supply voltage reference supply voltage rejection vs output current error amplifier output saturation voltage vs temperature current limit input offset voltage vs supply voltage reference output noise vs output current lpr30 5/10
application information figure 1: lpr30 typical application figure 2: configuration for faster response figure 3: configuration for v in = 3.3v, v out = 2.9v, i out = 7a (*) this capacitor improves noise performance; can be omitted in most applications lpr30 6/10
application information (contiued) figure 4: application for very fast responce speed standard application demoboard (*) this capacitor improves noise performance; can be omitted in most applications note: this demoboard refers to the typical application shown in figure 1 lpr30 7/10
dim. mm inch min. typ. max. min. typ. max. a3.3 0.130 a1 0.7 0.028 b 1.39 1.65 0.055 0.065 b1 0.91 1.04 0.036 0.041 b0.5 0.020 b1 0.38 0.5 0.015 0.020 d9.80.386 e8.8 0.346 e2.54 0.100 e3 7.62 0.300 e4 7.62 0.300 f7.10.280 i4.80.189 l3.3 0.130 z 0.44 1.6 0.017 0.063 p001f plastic dip-8 mechanical data lpr30 8/10
dim. mm inch min. typ. max. min. typ. max. a1.750.068 a1 0.1 0.25 0.003 0.009 a2 1.65 0.064 a3 0.65 0.85 0.025 0.033 b 0.35 0.48 0.013 0.018 b1 0.19 0.25 0.007 0.010 c 0.25 0.5 0.010 0.019 c1 45 (typ.) d 4.8 5.0 0.188 0.196 e 5.8 6.2 0.228 0.244 e1.27 0.050 e3 3.81 0.150 f 3.8 4.0 0.14 0.157 l 0.4 1.27 0.015 0.050 m0.60.023 s 8 (max.) 0016023 so-8 mechanical data lpr30 9/10
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