www. belling .com . cn 1 24v/1.2a asynchronous buck converter in sot23 - 6 b l8095 description the BL8095 is a high efficiency current - mode a synchronous, 2 4 v/ 1 . 2 a buck converter. i ts input voltage range s from 4 v to 2 4 v and it provides an adjustable regulated output voltage from 0. 810 v to 5.5 v while delivering up to 1. 2 a of output current. the switching frequency is set to 1.4m hz , which works with a inductor as small as 4.7uh . and t he BL8095 will automatically switch between pfm and pwm mode based on the load current, thus to enhance the converter efficiency at light load . BL8095 consists of many protection block s such as uvlo, input voltage over voltage protection to stand much higher input voltage spike, thermal protection and output short circuit protection. the BL8095 is available in the tiny s ot23 - 6 package . features ? adjustable output voltage, vfb=0. 810 v ? o utput current is up to 1.2 a ? range of operation input voltage: 4 - 24 v ? input voltage uvlo: 3. 7 v ( voltage decreasing ) ? input overvoltage protection @2 6 v ? withstand input voltage spike >30v ? operating current at zero load: 0.8 ma (typ.) ? line regulation: 0. 1 %/v (typ.) ? load regulation: 10mv (typ.) ? high efficiency, up to 9 0 % ? environment temperature: - 2 0 ? c ~85 ? c applications ? security camera ? consumer electronic device for automobile ? portable dvd ? adsl modem , wlan router ? other 12v or double cell li - ion battery powered device typical application and pin out l ow current consumption yw : date code, year and week being assembled bl8 09 5 l c 2 3 2 5 g n d f b v i n s w v o u t 5 v / 1 . 2 a v i n 1 2 v 4 . 7 h 8 2 k 1 6 k e n 2 5 v 1 0 f 6 . 3 v 2 2 f 5 4 6 3 2 b s t 1 0 n f 1 s o t 2 3 - 6 s w f b e n g n d v i n h b y w b s t 2 3 6 5 4 1
www . b elling .com .cn 2 b l8095 mark and ordering information mark explanation ordering information hb : product code yw : date code product id BL8095 c b6 tr devices per reel 3000 pinout description pin # name description 1 bst high side power transistor gate drive boost input 2 gnd ground. 3 fb feedback input with reference voltage set to 0.810v 4 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. 5 vin power input, the input capacitor should be placed as close to vin and gnd pin as possible 6 sw power switching node to connect inductor block diagram r e g & r e f p w m l o g i c d r i v e r f b + + - s l o p e c o m p o s c v i n b s t s w g n d u v l o & t h e r m a l s h u t d o w n c u r r e n t s e n s e e a + - - e n c o m p n e t w o r k s o t 2 3 - 6 s w f b e n g n d v i n h b y w b s t 2 3 6 5 4 1
www . b elling .com .cn 3 b l8095 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 sot23 - 6 ( ? jc ) 110 ? c / w sot23 - 6 ( ? ja ) 220 ? 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 4v - 24 v output voltage range 0.81 C 5.5v 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 4 2 4 v vout output voltage range 0.81 5.5 v vref feedback voltage vin=12v, ven=5v 0. 790 0. 810 0. 830 v v uvlo uvlo voltage vin h -- >l , iout=0.5a 3. 7 v ifb feedback leakage current 0.1 0.4 ua iq quiescent current active, vfb= 1v , no switching 0.6 1.0 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 1.2 a 0.02 %/a fsoc switching frequency ven= 3 v, vin=12v 1.0 1.4 1.8 m hz rdson h high side switch rdson isw=200ma 25 0 350 mohm ilimit peak inductor current limit vin=12v, vout=5v 1.5 2 a v en h en high threshold 1 1.5 3 v venl en low threshold 0.5 v vovp input over - voltage p rotection ven= 3 v 26 v tsd over temperature proection hystersis=40 ? c 1 5 0 ? c
www . b elling .com .cn 4 b l8095 typical performance characteristics (v in=12v, vout= 5.0 v, l= 4.7 uh, cin=10uf, cout=22uf, t a =25 ? c , unless otherwise stated) switching waveform vin=1 2 v, iout=0 .5a (ch1=vin , ch2=vout , ch3=sw , ch4=isw) switching waveform vin=1 2 v, iout= 1 a (ch1=vin , ch2=vout , ch3=sw , ch4=isw)
www . b elling .com .cn 5 b l8095 switching waveform vin= 24 v, iout=0 . 5 a (ch1=vin , ch2=vout , ch3=sw , ch4=isw) switching waveform vin=24 v, iout= 1 a (ch1=vin , ch2=vout , ch3=sw , ch4=isw) load transient response vin=12v, iout=0. 12 - 1 a (ch1=vin , ch2=vout , ch4=isw) load transient response vin=24v, iout= 0.12 - 1a (ch1=vin , ch2=vout , ch4=isw) functional decriptions loop operation the BL8095 is a wide input range, high - efficiency, dc - to - dc step - down switching regulator, capable of delivering up to 1.2 a o f outpu t current, integrated with a 250 m ? mosfet, with external schottky 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. this operation generates a pwm signal that modulates the duty cy cle 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 1.5 a(typ). when the current flowing out of sw exceeds this limit, the high - side mosfet turns off and the external schottky diode rectifier turns on. unlike the traditional method of current limiting by limiting the voltage at the internal compensation node , which usually has large variation due to duty cycle variance, this type of peak current limiting sc heme 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 lo ad is small. when energy is shuffling back and forth through the power mosfets, power is lost due to the finite
www . b elling .com .cn 6 b l8095 rdsons of the mosfets and parasitic capacitances. at light load, this loss is prominent and efficiency is therefore very low. BL8095 employs a p roprietary 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. component selectrion when setting up the BL8095 for different output voltage, please use following recommended component value for the best performance. v out (v) c out ( ? ? thermal consideration BL8095 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/ 1. 2a, the output power is as high as 6 w, a heat dissipation path is strongly recommend ed to be routed on pcb. BL8095 is in sot23 - 6 package. t he heat is conducted out via pin 2 (gnd), so the heat dissipation route on pcb should be connected to the pin 2 of the chip. package out line package s ot23 - 6 devices per reel 30 00 unit mm package specification
|
