www. b elling .com . cn 1 4 a , 1 6 v high efficiency synchronous step - down converter bl80 34 description the BL8034 is a wide input range, high - efficiency, dc - to - dc step - down switching regulator, capable of delivering up to 4a of output current. current mode pwm control allows the use of small external components, such as ceramic input and output caps, as well as smal l inductors, while still providing low output ripples. on top of the integrated internal synchronous rectifier that eliminates external schottky diode, BL8034 also employs a proprietary control scheme that switches the device into a power save mode during light load, thereby extending the range of high efficiency operation. therefore, BL8034 is a much superior solution in comparison to other competitions in terms of efficiency and cost. overall, BL8034 is a highly efficient and robust solution for dc - dc ste p - down applications that requires wide input ranges. the BL8034 is available in esop8 package . features ? wide input operating range from 4. 2 v to 1 6 v ? high efficiency: up to 95% at light load ? capable of delivering 4 a ? no external schottky diode needed ? inductor short circuit protection ? current mode control ? 0.923v reference for low output voltages ? logic control shutdown ? thermal shutdown and uvlo ? available inesop8 package applications ? lcd tv s ? notebook computers ? fpga power supplies ? led drivers typical application mark and pin out esop8 ordering information mark explanation ordering information g p : product code ll : lot no. d : fab code yw : date code esop8 2500pcs/reel BL8034 cs8tr bl803 4 v i n e n b s t s w f b g n d v i n v o u t c 1 2 2 u f c 3 1 u f l 4 . 7 u h r 1 2 5 7 k r 2 1 0 0 k c 2 2 2 u f l c 2 3 3 4 3 . 3 v / 4 a r e n 1 0 0 k g p l l d y w b s t v i n s w g n d n c e n n c f b
www. b elling .com .cn 2 b l80 34 pinout description pin # name description 1 bst high side power transistor gate drive boost input . 2 vin power input . bypass with a 10uf~ 22uf ceramic capacitor to gnd. 3 sw power switching node to connect inductor . 4 gnd ground. 5 fb feedback input with reference voltage set to 0.923 v . 6 nc no connection 7 en enable input. set this pin to high level to enable the part, low level to disable . 8 nc no connection absolute maximum rating parameter value input voltage - 0.3v to 17 v sw.en voltage - 0.3v to vin +0.3v bst voltage - 0.3v to sw+6v fb voltage - 0.3v to 6v sw to ground current internally limited ambient temperature(ta) - 4 0 ? c - 85 ? c storage temperature(ts) - 55 ? c - 150 ? c note: exceed these limits to damage to the device. exposure to absolute maximum rating conditions may affect device reliability. electrical characteristics (v in = 12v, v out =5v, t a =25 ? c , unless otherwise stated ) parameter conditions min typ max unit input voltage range 4.2 1 6 v uvlo threshold 4.1 v supply current in operation v en = 2.0v, v fb = 1.1v 0. 5 m a supply current in shutdown v en = 0v or v en = gnd 5 1 0 ua regulated feedback voltage 4. 2 vv in bst - sw = 5v 120 m in = 5v 60 m en = 0v, v sw = 0v 0 10 ua upper switch current limit minimum duty cycle 6 a oscillation frequency 500 khz maximum duty cycle v fb = 0. 8 v 92 % minimum on time 100 ns en input voltage h input voltage l
www. b elling .com .cn 3 b l80 34 typical performance characteristics ( l= 4.7 uh, cin= 22 uf, cout=22uf, t a =25 ? c , unless otherwise stated) 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 1 2 3 4 efficiency(%) iout (a) efficiency vs. iout vout=1.2v vin=6v vin=12v vin=16v 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 1 2 3 4 efficiency(%) iout (a) efficiency vs. iout vout=3.3v vin=6v vin=12v vin=16v 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0 1 2 3 4 efficiency(%) iout (a) efficiency vs. iout vout=5.0v vin=6v vin=12v vin=16v 0.80 0.85 0.90 0.95 1.00 1.05 1.10 1.15 1.20 1.25 1.30 0 1 2 3 4 vout (v) iout (a) output voltage vs. iout vout=1.2v vin=6v vin=12v vin=16v 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 0 1 2 3 4 vout (v) iout (a) output voltage vs. iout vout=3.3v vin=6v vin=12v vin=16v 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 1 2 3 4 vout (v) iout (a) output voltage vs. iout vout=5.0v vin=6v vin=12v vin=16v
www. b elling .com .cn 4 b l80 34 functional decriptions loop operation the BL8034 is a wide input range, high - efficiency, dc - to - dc step - down switching regulator, capable of delivering up to 4 a of output current, integrated with a 120/60 m ? synchronous mosfet pair , eliminating the need for external diode. it uses a pwm current - mode contr ol 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 sign al 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 mosfet of 6 a(typ). when the current flowing out of sw 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, 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 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 parasitic capacitances. at light load, this loss is prominent and efficiency is therefore very low. BL8034 employs a proprietary co ntrol 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. pcb l ayout r ecommendation the devices performance and stability are dramatically affected by pcb layout. it is recommended to follow these general guidelines shown as below: 1. place the input capacitors and output capacitors as close to the device as possible. the traces which connect to these capacitors should be as shor t and wide as possible to minimize parasitic inductance and resistance. 2. place feedback resistors close to the fb pin. 3. keep the sensitive signal (fb) away from the switching signal ( sw ). 4. the exposed pad of the package should be soldered to an equi valent area of metal on the pcb. this area should connect to the gnd plane and have multiple via connections to the back of the pcb as well as connections to intermediate pcb layers. the gnd plane area connecting to the exposed pad should be maximized to i mprove thermal performance. 5. multi - layer pcb design is recommended. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4 8 12 16 vout (v) vin(v) vout vs. vin iout=0 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4 8 12 16 vout (v) vin(v) vout vs. vin iout=1a
www. b elling .com .cn 5 b l80 34 package out line package esop8 devices per reel 2500 unit mm package specification
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