________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 1/9 UM3433 600ma, 600khz step-up dc-dc converter UM3433 sot23-6 general description the UM3433 is synchronous rectified, fixed fre quency, step-up dc/dc converter series delivering high efficiency in a low profile sot23- 6 package. it is available both in 3.3v/3.0v fixed output and adjustable output. with an internal nmos switch and pmos synchronous rectifier and high switching frequency of 600khz , the UM3433 is capable of supplying 3.3v output at 100ma from a single aa cell input using low profile inductors and ceramic capacitors. current mode pwm control with internal compen sation cuts external parts count thereby saving bom cost and pcb real estate. at light loads, UM3433 enters automatically into power saving mode to keep high efficiency at light load. anti-ringing control circuitry inside reduces emi interferences by damping the i nductor in discontinuous mode. the device also features low shutdown current of under 1 a. with inrush current limiting and soft start built inside, it also limits the inrush of current during start up, minimizing surge currents seen by the input supply. applications features z mp3 players z digital cameras z lcd bias supplies z handheld instruments z wireless handsets z gps receivers z up to 92% efficiency z low voltage start-up: 0.9v z inrush current limiting and internal soft start z automatic power-saving mode operation with typical iq as 20 a z short circuit protection z 600khz switching frequency for low profile inductor/capacitor z anti-ringing control to minimizes emi z output range: 2.5v to 5v, with 3.3v/3.0v fixed output option pin configurations top view (*: only available for adjustable version) UM3433-3.3 (ucr) UM3433-3.0 (udr) UM3433-adj (ucs) sot23-6
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 2/9 UM3433 pin description pin number symbol description 1 sw switch pin for external inductance 2 gnd ground nc(UM3433-3.3/3.0) not connect 3 fb(UM3433-adj) feedback input pin 4 shdn ____________ logic controlled shutdown input shdn ____________ =high, normal operation mode shdn ____________ =low, shutdown mode 5 vout output voltage 6 vin input voltage ordering information part number packaging type marking code shipping qty UM3433-3.3 sot23-6 ucr 3000pcs/7inch tape & reel UM3433-3.0 sot23-6 udr 3000pcs/7inch tape & reel UM3433-adj sot23-6 ucs 3000pcs/7inch tape & reel absolute maximum ratings symbol parameter value unit v in v in supply voltage -0.3 to +6v v v sw sw voltage -0.3 to +6v v v fb fb voltage -0.3 to +6v v v shdn __________ shdn ____________ voltage -0.3 to +6v v v out output voltage -0.3 to +6v v t op operating temperature range -40 to +85 c t stg storage temperature range -65 to +150 c t l maximum lead temperature (soldering , 10s) +300 c maximum ratings are those values beyond which device damage can occur. maximum ratings applied to the device are individual stress limi t values (not normal ope rating conditions) and are not valid simultaneously. if these limits are exceed ed, device functional operation is not implied, damage may occur and reliability may be affected.
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 3/9 UM3433 electrical characteristics (v in = +1.2v, v out = +3.3v t a =+25c, unless otherwise noted.) parameter test conditions min typ max unit input voltage range 0.9 2.5 v UM3433-3.3, i load =100ma 3.22 3.3 3.38 fixed output voltage UM3433-3.0, i load =100ma 2.92 3.0 3.08 v output voltage adjustable range UM3433-adj 2.5 5 v feedback voltage 1.192 1.230 1.268 v quiescent current (power-saving mode) i load =0ma 20 a quiescent current (active) i load =100ma 380 550 a quiescent current (shutdown) shdn _____________ =0v 1 a nmos leakage v sw =3.3v 0.1 a pmos leakage 0.1 a nmos on-resistance 0.35 ? pmos on-resistance 0.45 ? nmos current limit 600 850 ma power-saving mode operation current threshold l=10h (note) 3 ma current limit delay to output 40 ns switching frequency i load =100ma, shdn _____________ =1v 600 khz shdn ____________ input high i load =100ma 1 v shdn ____________ input low i load =100ma 0.35 v shdn ____________ input current i load =100ma, shdn _____________ =1v 0.01 1 a note: design guaranteed.
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 4/9 UM3433 typical operating characteristics efficiency vs output current efficiency vs input voltage output voltage vs temperature pow er-saving mode quiescent current vs temperature v out =3.3v i out =40ma 0.5 1.0 1.5 2.0 2.5 40 50 60 70 80 90 100 input voltage (v) efficiency (%) 0 20 40 60 100 80 82 86 90 100 output current (ma) efficiency (%) 80 v in =1.3v 84 88 92 96 94 98 v in =1.5v v in =1.5v i out =30ma -60 -20 20 60 100 3.20 3.24 3.28 3.32 3.36 3.40 3.44 temperature ( ) v out (v) -4004080 -60 -20 20 60 100 10 15 20 25 30 35 40 temperature ( ) quiescent current (ua) -40 0 40 80 v out =3.3v
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 5/9 UM3433 typical operating characteristics fixed frequency discontinuous mode operation fixed frequency continuous mode operation power-saving mode operation
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 6/9 UM3433 pin functions sw (pin 1) : switch pin. connect inductor between sw and v in . keep these pcb trace lengths as short and wide as possible to reduce emi and voltage overshoot. gnd (pin 2) : signal and power ground. provide a short direct pcb path between gnd and the (?) side of the output capacitor(s). nc (pin 3): not connect. fb (pin 3): feedback input. connect resistor divider tap to this pin. the output voltage can be adjusted from 2.5v to 5v by: v out =v fb (1+r1/r2) shdn ____________ (pin 4) : logic controlled shutdown input. shdn ____________ =high: normal free running operation, 600khz typical operating frequency. shdn ____________ =low: shutdown, quiescent current <1 a.output capacitor can be completely discharged through the load. vout (pin 5) : output voltage sense input and drain of the internal synchronous rectifier mosfet. bias is derived from v out . pcb trace length from v out to the output filter capacitor(s) should be as short and wide as possible. vin (pin 6) : battery input voltage. the device gets its start-up bias from v in . once v out exceeds v in , bias comes from v out . thus, once started, operation is completely independent from vin. operation is only limited by the output po wer level and the battery?s internal series resistance. typical application circuits figure 1 fixed output application circuit figure 2 adjustable output application circuit 10uf vou t r1 vin + shdn UM3433-adj vin - gnd 4.7uh sw on 4.7uf fb r2 off vou t ad j 4.7uh UM3433-3.3/3.0 gnd vin vou t sw shdn 4.7uf - + 3.3v/3.0v vou t 10uf on vin off
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 7/9 UM3433 applications information inductor selection the UM3433 can utilize small surface mount and ch ip inductors due to its 600khz switching frequency. typically, a 4.7 h inductor is recommended for most applications. larger values of inductance will allow greater output current capab ility by reducing the inductor ripple current. increasing the inductance above 10 h will increase size while providing little improvement in output current capability. the approximate output current capability of th e UM3433 versus inductance value is given in the equation below. where: = estimated efficiency i p = peak current limit value (0.6a) v in = input (battery) voltage d = steady-state duty ratio = (v out ? v in )/v out f = switching frequency (600khz typical) l = inductance value the inductor current ripple is typically set for 20% to 40% of the maximum inductor current (i p ). high frequency ferrite core inductor material s reduce frequency dependent power losses compared to cheaper powdered iron types, improving efficiency. the inductor should have low esr (series resistance of the windings) to reduce the i 2 r power losses, and must be able to handle the peak inductor current without saturating. mo lded chokes and some chip inductors usually do not have enough core to support the peak inductor currents of 850ma seen on the UM3433. to minimize radiated noise, use a toroid, po t core or shielded bobbin inductor. output and input capacitor selection low esr (equivalent series resistance) capacitors should be used to minimize the output voltage ripple. multilayer ceramic capacitors are an exce llent choice as they have extremely low esr and are available in small footprints. a4.7 f to 15 f output capacitor is sufficient for most applications. larger values up to 22 f may be used to obtain extremely low output voltage ripple and improve transient response. an additional ph ase lead capacitor may be required with output capacitors larger than 10 f to maintain acceptable phase ma rgin. x5r and x7r dielectric materials are preferred for their ability to mainta in capacitance over wide voltage and temperature ranges. low esr input capacitors reduce input switching noise and reduce the peak current drawn from the battery. it follows that ceramic capacitors are also a good choice for input decoupling and should be located as close as possible to the device. a 10 f input capacitor is sufficient for virtually any application. larger values may be used without limitations.
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 8/9 UM3433 package information UM3433: sot23-6 outline drawing dimensions millimeters inches symbol min max min max a 1.050 1.250 0.041 0.049 a1 0.000 0.100 0.000 0.004 a2 1.050 1.150 0.041 0.045 b 0.300 0.500 0.012 0.020 c 0.100 0.200 0.004 0.008 d 2.820 3.020 0.111 0.119 e 1.500 1.700 0.059 0.067 e1 2.650 2.950 0.104 0.116 e 0.950ref 0.037ref e1 1.800 2.000 0.071 0.079 l 0.600ref 0.023ref l1 0.300 0.600 0.012 0.024 0 8 0 8 land pattern notes: 1. compound dimension: 2.921.60 2. unit: mm; 3. general tolerance 0.05mm unless otherwise specified; 4. the layout is just for reference. tape and reel orientation
________________________________________________________________________ http://www.union-ic.com rev.05 dec.2009 9/9 UM3433 important notice the information in this document has been ca refully reviewed and is believed to be accurate. nonetheless, this document is subjec t to change without notice. union assumes no responsibility for any inaccuracies that may be contained in this document, and makes no commitment to update or to keep current the contained information, or to notify a person or organization of any update. union rese rves the right to make changes, at any time, in order to improve reliability, function or design and to attempt to supply the best product possible. union semiconductor, inc add: 7f, no. 5, bibo road, shanghai 201203 tel: 021-51097928 fax: 021-51026018 website: www.union-ic.com
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