www. b elling .com . cn 1 18 v (30v spike) 2.5 a synchronous pfm/ pwm buck converter b l8092 description the BL8092 is a high efficiency current - mode synchronous, 18v / 2.5 a buck converter. i ts input voltage range s from 3 .5 v to 18v and it provides an adjustable regulated output voltage from 0. 923 v to 15 v while delivering up to 2 a of output current. the internal synchronous switches increase efficiency and eliminate the need for an external schottky diode. the switching frequency is set to 340khz. and t he BL8092 will automatically switch between pfm and pwm mode based on the load current, thus to enhance the converter efficiency at light load . BL8092 consists of many protection block such as uvlo, input voltage over voltage protection to stand much higher input voltage spike, thermal protection and output short circuit protection. the BL8092 is available in the sop8 and esop8 (with exposed pad for heat dissipation) package . features ? adjustable output voltage, vfb=0. 923 v ? maximum output current is 2.5 a ? range of operation input voltage: max 18v ? uvlo: 3.4v (typ.) ? withstand input voltage spike > 30v ? standby current: 1 ma (typ.) ? operating current at zero load: 1.2ma (typ.) ? line regulation: 0. 1 %/v (typ.) ? load regulation: 10mv (typ.) ? high efficiency, up to 9 5 % ? environment temperature: - 2 0 ? c ~85 ? c applications ? set - top - box ? consumer electronic device for automobile ? lcd monitor and lcd tv ? portable dvd ? adsl modem , wlan router ? other 12v or double cell li - ion battery powered device typical application pin out sop8 and esop8 pfm at light load 0 1 2 3 4 5 6 7 0 5 10 15 20 iq(ma) vin(v) zero load operating current vs. vin lc2322 lc2322 bl8 09 2 bl8 09 2 l c 2 3 2 1 b s t v i n s w g n d s s e n c o m p f b 1 0 u h v i n 1 0 u f 1 0 n f 0 . 1 u f 1 0 0 k 3 . 3 n f 5 . 6 k v o u t 3 . 3 v / 2 a 2 2 u f x 2 2 6 . 1 k 1 0 k * c c o p t i o n a l * w h e n v i n i s a s l o w a s 5 v , c c i s r e c o m m e n d e d t o b e 1 0 0 p f , b u t n o t n e e d e d w h e n v i n l a r g e r t h a n 5 v . l c 2 3 2 1 b s t v i n s w g n d s s e n c o m p f b
www. b elling .com . cn 2 b l8092 mark and ordering information mark explanation ordering information hh: product code ll: lot no. u: fab code yw: date code sop8 2500pcs/reel BL8092 cd8tr esop8 2500pcs/reel BL8092 cs8tr pinout description pin # name description 1 bst high side power transistor gate drive boost input 2 vin power input, the input capacitor should be placed as close to vin and gnd pin as possible 3 sw power switching node to connect inductor 4 gnd ground. 5 fb feedback input with reference voltage set to 0.923 6 comp compensation node. a serial rc connected to this pin is required to maintain the buck converter control loop stable. 7 en enable input. setting it to high level or connecting to vin via a resistor may turn on the chip, while setting it to ground level will turn off the chip. 8 ss soft - start node. connecting a 0.1uf capacitor to ground make the buck converter output rise smoothly. block diagram + - 0 . 9 2 3 v r e f p w m l o g i c a n t i - s h o o t - t h r o u g h d r i v e r + - e a + - + - s l o p e c o m p o s c s w g n d u v l o & t h e r m a l s h u t d o w n v c o m p i s e n s e c o m p c o m p n e t w o r k f b e n v i n b s t 5 v s s
www. b elling .com . cn 3 b l8092 absolute maximum rating parameter value max input voltage 30 v max operating junction temperature(tj) 1 25 ? c ambient temperature(ta) - 2 0 ? c C 85 ? c package thermal resistance ( ? jc) sop - 8l 45 ? c / w esop - 8l 10 ? c / w storage temperature(ts) - 40 ? c - 150 ? c lead temperature & time 260 ? c , 10s esd (hbm) >2000v note: exceed these limits to damage to the device. exposure to absolute maximum rating conditions may affect device reliability. r ecommended work conditions parameter value input voltage range max . 18v operating junction t emperature(tj) - 2 0 ? c C 125 ? c electrical characteristics ( vin=12 v, t a =25 ? c ) symbol parameter conditions min typ max unit vdd input voltage range 3.5 18 v vref feedback voltage vin=12v, ven=5v 0. 900 0. 923 0. 946 v v uvlo uvlo voltage vin h -- >l , iout=0.5a 3.4 v ifb feedback leakage current 0.1 0.4 ua iq quiescent current active, vfb= 1v , no switching 1.1 1.5 m a shutdown , vin=8v 6 10 ua lnreg line regulation vin=5 v to 12 v 0.1 %/v ldreg load regulation iout= 0. 1 to 2 a 0.02 %/a fsoc switching frequency ven=2v, vin=12v 340 k hz rdsonp pmos rdson 1 3 0 mohm rdsonn nmos rdson 1 1 0 mohm ilimit peak current limit 3.8 a v en h en high threshold 1 1.5 2 v venl en low threshold 0.5 v vovp input over - voltage p rotection ven=2v 19 v tsd over temperature proection 160 ? c
www. b elling .com . cn 4 b l8092 typical performance characteristics (v in=12v, vout=3.3v, l=10uh, cin=10uf, cout=22uf, t a =25 ? c , unless otherwise stated) switching waveform vin=18v, iout=0 (ch1=vin , ch2=vout , ch3=sw , ch4=isw) switching waveform vin=18v, iout=2a (ch1=vin , ch2=vout , ch3=sw , ch4=isw) 0 20 40 60 80 100 0.001 0.01 0.1 1 10 efficiency(%) iout (a) efficiency(vout=3.3v) vin=5v vin=3.6v vin=12v 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 vout(v) iout(a) vout vs. iout vin=5v vin=3.6v vin=12v 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 2 4 6 8 10 12 14 16 18 20 vout(v) vin(v) vout vs. iout iout=300ma 0 1 2 3 4 5 6 7 0 5 10 15 20 iq(ma) vin(v) zero load operating current vs. vin
www. b elling .com . cn 5 b l8092 switching waveform vin=5v, iout=0 (ch1=vin , ch2=vout , ch3=sw , ch4=isw) switching waveform vin=5v, iout=2a (ch1=vin , ch2=vout , ch3=sw , ch4=isw) functional decriptions loop operation the BL8092 is a wide input range, high - efficiency, dc - to - dc step - down switching regulator, capable of delivering up to 2.5 a o f output current, integrated with a 110m ? synchronous mosfet, eliminating the need for external diode. it uses a pwm current - mode control scheme. an error amplifier integrates error between the fb signal and the internal reference voltage. the output of the integrator is then compared to the sum of a current - sense signal and the slope compensation ramp. thi s operation generates a pwm signal that modulates the duty cycle of the power mosfets to achieve regulation for output voltage. current limit there is a cycle - by - cycle current limit on the high - side mos fet of 3 .8 a (typ). when the current flowing out of s w exceeds this limit, the high - side mosfet turns off and the synchronous rectifier turns on. unlike the traditional method of current limiting by limiting the voltage at the compensation pin, which usually has large variation due to duty cycle variance, th is type of peak current limiting scheme provides a relatively more accurate limit for output current, thereby lowering the requirements for system design. light load operation traditionally, a fixed current mode constant frequency pwm dc - dc regulator always switches even when the output load is small. when energy is shuffling back and forth through the power mosfets, power is lost due to the finite rdsons of the mosfets and para sitic capacitances. at light load, this loss is prominent and efficiency is therefore very low. BL8092 employs a proprietary control scheme that improves efficiency in this situation by enabling the device into a power save mode during light load, thereby extending the range of high efficiency operation. faster transient response normally, people use 3.3nf and 5.6kohm rc for compensation to keep the loop stable. however, if one needs to have faster load transient response, 3.3nf and 8.5kohm is recommended .
www. b elling .com . cn 6 b l8092 component selectrion when setting up the BL8092 for different output voltage, please use following recommended component value for the best performance. v out (v) c out ( ? ? thermal consideration BL8092 is high efficiency buck converter, which means it consumes very few power when converting the high voltage to low voltage. however, when output power is very large, like 5v/2a, the output power is as high as 10w, a heat dissipation path is strongly recommende d to be routed on pcb. BL8092 has two different sop8 package. for the normal sop8, the heat is conducted out via pin 4 (gnd), so the heat dissipation route on pcb should be connected to the pin 4 of the chip. if esop8 is selected, the heat dissipation copp er area should be exposed and connected to the exposed pad underneath the chip body. when output power is larger than 10w, the esop8 package is recommended.
www. b elling .com . cn 7 b l8092 package out line package sop8 devices per reel 2500 unit mm package specification package esop8 devices per reel 2500 unit mm package specification
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