preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 1 of 7 synchronous boost dc/dc regulator general description the LP6206 is high efficiency synchronous, fixed frequency, current-mode step-up converter with output to input disconnect. a pwm step-up dc/dc converters optimized to provide a high efficiency solution to medium power system. when LP6206 is disabled, the internal conduction path from the battery. this output disconnect feature reduces the shutdown current to typically only 50na. the devices regulates the output voltage up to 6v from either a 2cell nimh/nicd or a single-cell li-ion battery with a 500khz fixed frequency switching. these features minimize overall solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. ordering information LP6206 - f: pb-free package type b5: tsot23-5 typical application circuit 4.7uh 22pf + 22uf r1 1.5m vin LP6206 3 5 4 1 2 out en sw fb gnd r2 500k vout + cout 22uf features up to 94% efficiency ? output to input disconnect at shutdown mode shut-down current:<1ua ? output voltage up to 5v internal synchronous rectifier internal soft-start internal compensation 500khz fixed frequency switching high switch on current:1.6a 50na shutdown current available in sct23-5 package ? applications battery products host products pin configurations marking information please see website.
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 2 of 7 functional pin description pin pin name description 1 fb regulation feedback input. connect to an external resistive voltage divider from the output to fb to set the output voltage. 2 gnd ground. 3 out supply input for the LP6206. connect to the output of the converter. 4 sw output switching node. sw is the drain of the internal low-side n-channel mosfet and high-side p-channel mosfet. connect the inductor to sw to complete the step-up converter. 5 en regulator on/off control input. a logic high input(ven>1.4v) turns on the regulator. a logic low input(ven<0.4v) puts the LP6206 into low current shutdown mode. function block diagram
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 3 of 7 absolute maximum ratings supply input voltage----------------------------------------------------------------------------------------------------------- ----6v power dissipation, pd @ ta = 25 c sot23-5--------------------------------------------------------------------------------------------------------600mw package thermal resistance sot23-5, ja ---------------------------------------------------------------------------------------------------------------250c/w lead temperature (soldering, 10 sec.) ----------------------------------------------------------------------------------260c storage temperature range --------------------------------------------------------------------------------- ? 65c to 150c recommended operating conditions supply input voltage-------------------------------------------------------------------------------------------------2.2v to 6v en input voltage -------------------------------------------------------------------------------------------------------0v to 5 .5v operation junction temperature range ------------------------------------------------------------------ ? 40c to 125c operation ambient temperaturerange---------------------------------------------------------------------- ? 40c to 85c electrical characteristics (vin=2.4v,vout=3.5v,cin=10uf,cout=10uf,l1=4.7uh,r1=178k,r2=100k,ta=-40 to 85 ,unless otherwise noted.typical values are at ta=25.) LP6206 parameter conditions min typ max units supply voltage 2.2 5 v output voltage range 2.5 6 v supply current(shutdown) ven=vout=0v,vsw=5v 0.05 1 ua supply current vfb=1.3v 0.39 ma feedback voltage 1.2 1.25 1.3 v feedback input current vfb=1.2v 50 na switching frequency 310 500 690 khz maximum duty cycle 80 85 90 % en input low voltage 0.4 v en input high voltage 1.4 v en pull down resistance 1 low-side on resistance vout=3.3v 450 low-side current limit 1.4 1.6 2 a high-side on resistance vout=3.3v 650
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 4 of 7 typical operating characteristics
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 5 of 7
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 6 of 7 operation information the LP6206 uses a 500khz fixed-frequency, current-mode regulation architecture to regulate the output voltage. the LP6206 measures the output voltage through an external resistive voltage divider and compares that to the internal 1.25v reference to generate the error voltage to the inductor current to regulate the output voltage.the use of current-mode regulation improves transient response and control loop stability. when the LP6206 is disable(en=low),both power switches are off. there is no current path from sw to out. there fore, the output voltage discharges to ground. when the LP6206 is enabled(en=high),a limited start-current charges the output voltage rising to sw, then th part operates in force pwm mode for regulating the output voltage to the target value. at the beginning of each cycle, the n-channel mosfet switch is turned on, forcing the inductor current to rise, the current at the source of the switch is internally measured and converted to a voltage by the current sense amplifier. that voltage is compared to the error voltage. when the inductor current rises sufficiently, the pwm comparator turns off the switch, forcin g the inductor current to the output capacitor through the internal p-channel mosfet rectifier, which forces the inductor current to decrease. the peak inductor current is controlled by the error voltage. thus the output voltage controls the inductor current to satisfy the lode. soft-start the LP6206 includes a soft-start timer that limits the voltage at the error amplifier output during startup to prevent excessive current at the input.this prevents premature termination of the source voltage at start-up due to inrush current.this also limits thd inductor current at startup,forcing the input current to rise slowly to the amount required to regulate the output voltage during soft-start. application information component selection setting the output voltage set the output voltage by selecting the resistive voltage divider ratio. the voltage divider drops the output voltage to the 1.25v feedback voltage. use a 100k resistor for r2 of the voltage divider. determine the high-side resistor r1 by the equation: vout=(r1/r2+1) x vfb LP6206 3 5 4 1 2 out en sw fb gnd 0.22uf + 22uf r1 1.5m 22pf 4.7uh 4.7uh LP6206 3 5 4 1 2 out en sw fb gnd vout 5v typical application with external diode(a) r1 1.5m vin 22pf + cout 22uf + cout 22uf r2 500k + 22uf r2 500k 5v typical application with external diode(b) vout pmos vin
preliminary datasheet LP6206 LP6206 ?00 ver. 1.0 datasheet dec.-2008 - - www.lowpowersemi.com - - page 7 of 7 packaging information
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