small package pfm control step-up dc/dc converter LR8301 series introduction the LR8301 series is a cmos pfm-control step-up switching dc/dc converter that mainly consists of a reference voltage source, an oscillator, and a comparator. the pfm controller allows the duty ratio to be automatically switched according to the load (light load: 50%, high output current: 75%), enabling products with a low ripple over a wide range, high effici ency, and high output current. with the lr 8301 series, a step-up switching dc/dc converter can be configured by using an external coil, capacitor, and diode. the built-in mos fet is turned off by a protection circuit when the voltage at the lx pin exceeds the limit to prevent it from being da maged. this feature, along with the mini package and low current consumption, make s the LR8301 series ideal for applications such as the power suppl y unit of portable equipment. applications ? power supply for portable equipment such as digital cameras, electronic notebooks, and pdas ? power supply for audio equipment such as portable cd/md players ? constant voltage power supply for cameras, video equipment, and communications equipment ? power supply for microcomputers features ? low voltage operation: startup at 0.9 v min. (i out = 1 ma) guaranteed ? duty ratio: 66/78%, builtin auto switching type pfm controller ? external parts: coil, capacitor, diode ? output voltage: settable to between 1.8 to 6.5 v in 0.1 v steps ? accuracy of 2% ? high efficiency 85% typ. ? standard function (product type a) ? shutdown function (product type c d) ? external transistor type available (product type b d) ordering information leshan radio company, ltd. 1/9
pin assignment table 1 LR8301a series sot-23-3 pkg pin no. pin name functions 1 v out output voltage pin 2 v ss gnd pin 3 lx external inductor connection pin table 2 LR8301b series sot-23-3 pkg pin no. pin name functions 1 v out output voltage pin 2 v ss gnd pin 3 ext external transistor connection pin table 3 LR8301c series sot-23-5 pkg pin no. pin name functions 1 en shutdown pin ?h?: normal operation ?l?: step-up stopped 2 v out output voltage pin 3 nc (n.c.) 4 v ss gnd pin 5 lx external inductor connection pin table 4 LR8301d series sot-23-5 pkg pin no. pin name functions 1 en shutdown pin ?h?: normal operation ?l?: step-up stopped 2 v out output voltage pin 3 nc (n.c.) 4 v ss gnd pin 5 ext external transistor connection pin block diagrams leshan radio company, ltd. LR8301 series 2/9
table 5 LR8301a series sot-89-3 pkg pin no. pin name functions 1 v ss gnd pin 2 v out output voltage pin 3 lx external inductor connection pin table 6 LR8301b series sot-89-3 pkg pin no. pin name functions 1 v ss gnd pin 2 v out output voltage pin 3 ext external transistor connection pin table 7 LR8301c series sot-89-5 pkg pin no. pin name functions 1 nc (n.c.) 2 v out output voltage pin 3 en shutdown pin ?h?: normal operation ?l?: step-up stopped 4 lx external inductor connection pin 5 v ss gnd pin table 8 LR8301d series sot-89-5 pkg pin no. pin name functions 1 nc (n.c.) 2 v out output voltage pin 3 en shutdown pin ?h?: normal operation ?l?: step-up stopped 4 ext external transistor connection pin 5 v ss gnd pin absolute maximum ratings (unless otherwise specified, ta= ? 25 c) parameter symbol ratings unit v out pin voltage v out v ss 0.3 ~ v ss 10 v en pin voltage en v ss 0.3 ~ v ss 10 v lx pin voltage v lx v ss 0.3 ~ v ss 10 v lx pin current i lx 1000 ma sot-23-3 250 mw sot-23-5 250 mw power dissipation sot-89-3 pd 500 mw operating temperature topr 40 ~ 85 c storage temperature tstg 40 ~ 125 c leshan radio company, ltd. LR8301 series 3/9
electrical characteristics (unless otherwise specified, ta = ? 25 c) parameter symbol conditions min. typ. max. unit output voltage v out v out(s) 0.98 v out v out(s) 1.02 v input voltage v in 10 v operation start voltage v st1 i out = 1 ma 0.9 v oscillation start voltage v st2 no external parts, voltage applied to v out lx pulled up to v out via 300 resistor 0.8 v v out 3.0v 30 40 a current consumption 1 i ss1 v out =0.95 v out v out 5.0v 50 60 a current consumption 2 i ss2 v out =v out 0.5 v 6 10 a current consumption during shutdown i sss v en = 0 v 0.5 a switching current i sw v lx = 0.4 v 100 200 ma switching transistor leakage current i swq no external parts, v lx v out =10 v ,v en = 0 v 0.5 a line regulation ? v out1 v in = 0.4v out 0.6v out 20 50 mv load regulation ? v out2 i out = 10 a ~ 50ma 20 50 mv maximum oscillation frequency f osc v out = 0.95v out measure waveform at lx pin 100 khz duty ratio 1 duty1 v out = 0.95v out measure waveform at lx pin 70 78 85 % duty ratio 2 duty2 measure waveform at lx pin with light load 66 % efficiency effi 85 % v sh v out =0.95v out judge oscillation at lx pin 0.75 v shutdown pin input voltage v sl1 v out = 0.95v out judge stop at lx pin 0.3 v i sh v en 10v 0.1 0.1 a shutdown pin input current i sl v en 0v 0.1 0.1 a remark v in =v out(s) ? 0.6 applied, i out = ?v out(s) / 250 ? shutdown function built-in type: en pin is connected to v out v out(s) specified above is the set output voltage value, and v out is the typical value of the actual output voltage. leshan radio company, ltd. LR8301 series 4/9
standard circuits component: inductor 47uh(sumida) diode 1n5817 1n5819 capacitor 47uf/16v(tantalume type) transistor 2sd1628g 2sd3279 nmos xp151 xp161 base resistor(rb) 1k ? base capacitor(cb) 2200pf r fb set up so that r fb1 / b2 =vout-1(vout=set-up output voltage), please use with r fb1 +r fb2 2m ? c fb set up that fzfb=1/(2 c fb r fb1 ) is within the adjustments necessary in respect of l,c l . 1 LR8301a circuits 2 LR8301c circuits 3 LR8301b circuits 4 LR8301d circuits leshan radio company, ltd. LR8301 series 5/9
characteristics 1. LR8301a30p a v out vs. i out : b efficiency vs. i out : 2. LR8301a33p a v out vs. i out : b efficiency vs. i out : 3. LR8301a50p a v out vs. i out : b efficiency vs. i out : leshan radio company, ltd. LR8301 series 6/9
4. LR8301b33p a v out vs. i out : b efficiency vs. i out : 5. LR8301b36p a v out vs. i out : b efficiency vs. i out : 6. LR8301b50p a v out vs. i out : b efficiency vs. i out : leshan radio company, ltd. LR8301 series 7/9
sot-23 sot-89 dimensions in millimeters symbols min nom max a 1.40 1.50 1.60 b 0.36 0.42 0.48 b1 0.41 0.47 0.53 b2 1.40 1.60 1.75 c 0.38 0.40 0.43 d 4.40 4.50 4.60 e 4.25 e1 2.40 2.50 2.60 1.40 1.50 1.60 l 1.80 l1 0.40 inches millimeters dim min max min max a 0.1102 0.1197 2.80 3.04 b 0.0472 0.0551 1.20 1.40 c 0.0350 0.0440 0.89 1.11 d 0.0150 0.0200 0.37 0.50 g 0.0701 0.0807 1.78 2.04 h 0.0005 0.0040 0.013 0.100 j 0.0034 0.0070 0.085 0.177 k 0.0140 0.0285 0.35 0.69 l 0.0350 0.0401 0.89 1.02 s 0.0830 0.1039 2.10 2.64 v 0.0177 0.0236 0.45 0.60 d j k l a c b s h g v 12 3 leshan radio company, ltd. LR8301 series 8/9
sot- 23- 5 sot- 89- 5 leshan radio company, ltd. LR8301 series 9/9
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