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www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 1 / 20 02.mar.2012 rev.001 tsz22111 ? 14 ? 001 2.7v to 5.5v, 1.2a 1ch s ynchronous buck converter integrated fet BD9123MUV general description rohms high efficiency step - down switching regulator bd91 23muv is a power supply designed to produce a low voltage including 0. 85 to 1.2 volts from 5 .5/3.3 volts power supply line. offers high efficiency with our original pulse skip control technol ogy and synchronous rectifier. employs a current mode control system to provide faster transient response to sudden change in load. features offers fast transient response with current mode pwm control system. offers highly efficiency for all load range with synchronous rectifier (nch/ p ch fet) and sllm (simple light load mode) incorporates output voltage inside control function. (3 bit) incorporates pgood function. incorporates soft - start function. incorporates thermal protection and ulvo functions. incorporates short - current protection circuit with time delay function. incorporates shutdown function icc=0 a(typ.) key specification s ? i nput voltage range: 2.7 v to 5 .5v ? o utput voltage range: 0.85 v to 1.2 v ? o utput current: 1.2 a (max.) ? switching frequency: 1mhz (typ.) ? pch fet on resistance: 0.35 (typ.) ? nch fet on resistance: 0. 25 (typ.) ? s tandby current: 0a (typ.) ? operatin g temperature range : - 40 to + 9 5 package vqfn016v3030 : 3.0 0 mm x 3. 0 0mm x 1.0 0 mm applications p ower supply for lsi including dsp, micro computer and asic typical application circuit fig.1 typical application circuit gnd,pgnd sw vcc,pvcc en vout ith vcc vout cin rith cith l esr co ro vout pgood vcc rpg vid<2:0) vid<2:0> product structure silicon monolithic integrated circuit this product is not designed pr otection against radioactive rays. datasheet
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 2 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet pin configuration pin description pin no. pin name function 1 sw pch/nch fet drain output pin 2 3 4 pgnd nch fet source pin 5 6 gnd ground 7 pgood power good pin 8 ith gm amp output pin/connected phase compensation capacitor 9 v out output voltage pin 10 vid<2> output voltage control pin<2> 11 vid<1> output voltage control pin<1> 12 vid<0> output voltage control pin<0> 13 en enable pin(high active cc pch fet source pin 16 block diagram fig .2 pin configuration pv cc pgnd sw gnd output gm amp 4.7h v cc r s q osc uvlo tsd 22f vcc clk slope current comp 10f 14 2 4 6 soft start current sense/ protect + driver logic vref ith r ith c ith 8 selector 12 11 10 9 5 1 3 15 16 vid <0> vid<1> vid<2> v out pgood 7 pgood v cc en 13 v cc 100 0.1f input fig.3 block diagram (top view) (top view) 12 13 8 4 11 10 9 6 5 3 2 1 15 16 sw sw sw pgnd pgnd gnd vid<0 > > vid<1> vid<2> v out v cc pv cc pv cc 7 14 pgood ith en
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 3 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet absolute maximum ratings (ta=25 ) parameter symbol ratings unit vcc voltage vcc - 0.3 to +7 * 1 v pvcc voltage pvcc - 0.3 to +7 * 1 v en,sw,ith voltage en, sw, ith - 0.3 to +7 v logic i nput voltage vid<2:0> - 0.3 to +7 v power dissipation 1 pd1 0.27 * 2 w power dissipation 2 pd2 0.62 * 3 w power dissipation 3 pd3 1.77 * 4 w power dissipation 4 pd4 2.66 * 5 w operating temperature range topr - 40 to +95 storage temperature range tstg - 5 5 to +150 maximum junction temperature tj +150 *1 pd should not be exceeded . *2 ic only *3 1 - layer . mounted on a 74.2mm 74.2mm 1.6mm glass - epoxy board, occupied area by copper foil : 10.29mm 2 *4 4 - layer . mounted on a 74.2mm 74.2mm 1.6mm glass - epoxy b oard, 1 st and 4 th copper foil area : 10.29mm 2 , 2 nd and 3 rd copper foil area : 5505mm 2 *5 4 - layer . mounted on a 74.2mm 74.2mm 1.6mm glass - epoxy board, occupied area by copper foil : 5505mm 2 , i n each layers operating ratings (ta= - 40 to +95 ) parameter sym bol ratings unit min. typ. max. power supply voltage v cc 2.7 3.3 5.5 v pv cc 2.7 3.3 5.5 v en voltage v en 0 - vcc v logic input voltage vid<2:0> 0 - 5.5 v output voltage setting range v out 0.85 - 1.2 v sw average output current i sw - - 1.2 *6 a * 6 pd should not be exceeded . electrical characteristics (ta=25 v cc =pv cc =5v, en=v cc , vid<2>=vid<1>=vid<0>= 0v ), unless otherwise specified.) parameter symbol limits unit conditions min. typ. max. standby current i stb - 0 10 a en=gnd active current i cc - 300 500 a en low voltage v enl - gnd 0.8 v standby mode en high voltage v enh 2.0 v cc - v active mode en input current i en - 5 10 a v en =5v vid low voltage v vidl - gnd 0.8 v vid high voltage v vidh 2.0 v cc - v vid input current i vid - 5 10 a v vid =5v oscillation frequ ency f osc 0.8 1 1.2 mhz pch fet on resistance r onp - 0.35 0.60 cc =5v nch fet on resistance r onn - 0.25 0.50 cc =5v output voltage v out 0.98 1.0 1.02 v vid<2:0>=(0,0,0) ith si nk current i thsi 25 50 - a v out =1.2v ith s ource c urrent i thso 25 50 - a v out =0.8v uvlo threshold voltage v uvlo 1 2.4 2.5 2.6 v v cc =5v uvlo 2 2.425 2.55 2.7 v v cc =0v pgood 1 70 75 80 % v out pgood 2 85 90 95 % 0v out power good delay t pg 2.5 5 10 ms pgood on resistance r onpg - 140 280 ss 0 .4 0.8 1.6 ms timer latch time t latch 1 2 4 ms output short circuit t hreshold voltage v scp - v out out out
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 4 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet typical performance curves fig. 7 ta - v out fig. 4 vcc - vou t fig. 5 ven - vout fig. 6 i out - v out
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 5 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet fig. 10 ta - fosc fig. 8 efficiency fig. 9 power supply voltage - o perating frequency fig. 11 ta - r o nn ,r onp
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 6 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet fig. 1 2 ta - v en fig.1 4 soft start waveform fig.1 5 sw waveform io=0ma fig. 13 ta - icc
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 7 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet fig.1 6 sw waveform io=1.2a fig.1 7 transient response io=125ma
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 8 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet fig. 21 pgood delay fig. 20 bit chance response
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 9 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet application information o peration BD9123MUV is a synchronous rectifying step - down switching regulator that achieves faster transient response by employing curren t mode pwm c ontrol system. it utilizes switching operation in pwm (pulse width modulation) mode for heavier load, while it utilizes sllm (simple light load mode) operation for lighter load to improve efficiency. synchronous rectifier it does not requir e the power to be dissipated by a rectifier externally connected to a conventional dc/dc converter ic, and its p . n junction shoot - through protection circuit limits the shoot - through current during operation, by which the power dissipation of the set is red uced. current mode pwm control synthesizes a pwm control signal with a inductor current feedback loop added to the voltage feedback. ? pwm (pulse width modulation) control the oscillation frequency for pwm is 1 mhz. set signal form osc turns on a pch mos fet (w hile a nch mos fet is turned off), and a n inductor current i l increases. the current comparator (current comp) receives two signals, a current feedback control signal (sense: voltage converted from i l ) and a voltage feedback control signal (fb), and issue s a reset signal if both input signals are identical to each other, and turns off the highside mos fet (while a lowside mos fet is turned on) for the rest of the fixed period. the pwm control repeats this operation. ? sllm (simple light load mode) control when the control mode is shifted from pwm for heavier load to the one for lighter load or vise versa, the switching pulse is designed to turn off with the device held operated in normal pwm control loop, which allows linear operation without voltage drop or deterioration in transient response during the mode switching from light load to heavy load or vise versa. although the pwm control loop continues to operate with a set signal from osc and a reset signal from curren t comp, it is so designed that the reset signal is held issued if shifted to the light load mode, with which the switching is tuned off and the switching pulses are thinned out under control. activating the switching intermittently reduces the switching d issipation and improves the efficiency. fig. 22 diagram of current mode pwm control fig.2 3 pwm switching timing chart fig. 24 s llm tm switching timing chart current comp set reset sw v out pvcc gnd gnd gnd i l (ave) v out (ave) sense fb current comp set reset sw v out pvcc gnd gnd gnd 0a v out (ave) sense fb i l not switching i l osc level shift driver logic r q s i l sw ith current comp gm amp. set reset fb load sense v out v out
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 10 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet description of o perations ? soft - start function en terminal shifted to high activates a soft - starter to gradually establish the ou tput voltage with the current limited during startup, by which it is possible to prevent an overshoot of output voltage and an inrush current. the inclination of standing up is different and the soft start time is different because of constancy depending o n the value offset output voltage. when 1v settiing it, it is tss=1msec(typ.) fig.2 5 soft start action ? shutdown function with en terminal shifted to low, the device turns to standby mode, and all the function blocks including reference voltage circuit, internal oscillator and drivers are turned to off. circuit current during standby is 0 a (typ.). ? uvlo function detects whether the input voltage sufficient to secure the output voltage of this ic is supplied. and the hysteresis width of 50 mv (typ.) is provided to prevent output chattering. fig.2 6 soft start, shutdown, uvlo timing char t ? pgood function when the output voltage falls below 75% (typ.) of a set value, the pgood pin of open - drain is turned off. and the hysteresis width of 15% (typ.) is provided to prevent output chattering. fig. 27 pgood timing chart uvlo en uvlo uvlo hysteresi s 50mv tss tss tss soft start standby mode operating mode standby mode operating mode standby mode operating mode standby mode en vcc vout vcc,en tss tss 1.2v 0.85v [ms] vout 90% the hysteresis width v out 75% pgood t gp
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 11 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet about setting the output voltage output voltage shifts step by step as often as bit setting to control the overshoot/undershoot that happen when changing the setting value of output voltage. from the bit switching until output voltage reach to setting value, 8 steps ( m ax) delay will occur. , the original value is changeable optionally. table of output voltage setting vid<2> vid<1> vid<0> v out 0 0 0 1.0v 0 0 1 0.85v 0 1 0 0.9v 0 1 1 0.95v 1 0 0 1.05v 1 0 1 1.1v 1 1 0 1.15v 1 1 1 1.2v *after 10s(max) from the bit change, v out change starts. *requiring time for one step (50 mv shift) of v out is 5s(max). *from the bit switching until output voltage reach to settin g value, t vid ( max)=0.06ms delay will occur. vout vid<2:0> (0,0,1) (1,1,1) 1.2v 0.85v tvid (max)=0.06ms fig. 28 timing chart of setting the output voltage about 10s from bit switching vout count stop about 10s from switching the last bit vid<2> vid<1 > vid<0> about 10s from bit switching vid<2> vout count stop vid<1> vid<0> 5s(max)
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 12 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet ? short - current protection circuit with time delay function turns off the output to protect the ic from breakdown when the incorporated current limiter is activated continuously for the fixed time ( t latch ) or more . the output thus held tuned off may be reco vered by restarting en or by re - unlocking uvlo. fig. 29 short - current protection circuit with time delay timing chart information on advantages advantage 1 : offers fast transient response with current mode control system. fig. 30 comparison of transient response advantage 2 : offers high efficiency for all load range. ? for lighter load : utilizes the current mode control mode called sllm for lighter load, which reduces various dissipation such as switching dissipation (p sw ), gate charge/discharge dissipation, esr dissipation of output capacitor (p esr ) and on - resistance d issipation (p ron ) that may otherwise cause degradation in efficiency for lighter load. achieves efficiency improvement for lighter load. ? for heavier load : utilizes the synchronous rectifying mode and the low on - resistance mos fets incorporated as powe r transistor. o n resistance of pch side mos fet : 0.35m (typ.) on resistance of nch side mos fet : 0.25m (typ.) achieves efficiency improvement for heavier load. offers high efficiency for all load range with the improvements mentioned abov e. conventional product ( load response i o =0.1a o =0.6a 0.001 0.01 0.1 1 0 50 100 pwm sllm inprovement by sllm system improvement by synchronous recti fier efficiency [%] fig. 31 efficiency output current io[a] v out 27mv v out 37mv i out i out output voltage off latch t2=t latch vcc v out output short circuit threshold voltage i l output voltage off operated mode operated mode uvlo timer latch uvlo output voltage off i l li mit t1 www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 13 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet advantage 3 : ? supplied in smaller package due to small - sized p ower mos fet incorporated. ? output capacitor co required for current mode control: 10 f ceramic capacitor ? inductance l required for the operating frequency of 1 mhz: 4.7 h inductor redu ces a mounting area required. fig. 32 example application switching r egulator efficiency efficiency ? may be expressed by the equation shown below: efficiency may be improved by reducing the switching regulator power dissipation factor s p d as follows: dissipation factors: 1) on resistance dissipation of inductor and fet : pd(i 2 r) 2) gate charge/discharge dissipation : pd(gate) 3) switching dissipation : pd ( sw) 4) esr dissipation of capacitor : pd ( esr) 5) operating current dissipation of ic : pd(ic) 1) pd(i 2 r)=i out 2 (r coil +r on ) (r coil [ ] : d c resistance of inductor , r on [ ] : on resistance of fet , i out [a] : output current. ) 2) pd(gate)=cgs f v (cgs[f] : gate capacitance of fet f[h] : switching frequency v[v] : gate driving voltage of fe t ) 4) pd(esr)=i rms 2 esr (i rms [a] : ripple current of capacitor , esr[ ] : equivalent series resistance. ) 5) pd(ic)=vin i cc (i cc [a] : circuit current. ) = v out i out vin iin 100[% ] = p out pin 100[% ] = p out p out +p d 1 00[% ] vin 2 c rss i out f i drive 3) pd(sw)= (c rss [f]: reverse transfer capacitance of fet , i drive [a]: peak current of gate. ) dc/dc convertor r ith l co v out c ith v cc cin v cc r pgood 15mm 20mm c ith co r ith c in l r pgood cf rf
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 14 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet consideration on permissible dissipation and heat generation as this ic functions wit h high efficiency without significant heat generation in most applications, no special consideration is needed on permissible dissipation or heat generation. in case of extreme conditions, however, including lower input voltage, higher output voltage, hea vier load, and/or higher temperature, the permissible dissipation and/or heat generation must be carefully considered. for dissipation, only conduction losses due to dc resistance of inductor and on resistance of fet are considered. because the conductio n losses are considered to play the leading role among other dissipation mentioned above including gate charge/discharge dissipation and switching dissipation. if v cc =3.3v, v out =1.2v, r onp =0.35m , r onn =0.25m i ou t =1.2a, for example, d=v out /v cc =1.2/5=0.24 r on =0.24 0.35+(1 - 0.24) 0.25 =0.084+0.19 =0.274[ ] p=1.2 2 0.247=0.394[w] as r on p is greater than r on n in this ic, the dissipation increases as the on duty becomes greater. with the consideration on the dissip ation as above, thermal design must be carried out with sufficient margin allowed. selection of components externally connected 1. selection of inductor (l) the inductance significantly depends on output ripple current. as seen in the equation (1), the ripple current decreases as the inductor and/or switching frequency increases. appropriate ripple current at output should be 20% more or less of the maximum output current. p=i out 2 on r on =d onp +(1 - d)r onn d out /v cc ) r onp onn out fig.3 3 thermal derating curve (vqfn016 v3030) ambient temperature:ta [ ] 0 25 50 75 100 125 150 0 2.0 3.0 4.0 1.77w 2.66w power dissipation:pd [w] 1.0 0. 62w 0.27w 4 layers (copper foil area : 5505mm 2 ) copper foil in each layers. j - a=47.0 /w 4 layers (1 st and 4 th copper foil area : 6.28m 2 ) (2 nd and 3 rd copper foil area: 5505m 2 ) (copper foil in each layers) j - a=70.62 /w 1 layer (copper foil ar ea : 6.28m 2 ) j - a=201.6 /w ic only. j - a=462.9 /w 105 l = (v cc - v out ) out l cc ??? l =0.3 out max. [a] ??? cc - v out ) out l cc ??? l : output ripple current, and f: switching frequency ) fig.3 4 output ripple current i l v cc il l co vout i l
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 15 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases efficiency. t he inductor must be selected allowing sufficient margin with which the peak current may not exceed its current rating. if v cc =5.0v, v out =1.2v, f=1mhz, i l =0.3 1.2a=0.36a, for example, select the inductor of low resistance component (such as dcr and acr) to minimize dissipation in the inductor for better efficiency. 2. selection of output capacitor (c o ) output capacito r should be selected with the consideration on the stability region and the equivalent series resistance required to smooth ripple voltage. output ripple voltage is determined by the equation (4) : v out = i l esr [v] ??? (4) ( il: output ripple current , esr : equivalent series resistance of output capacitor ) rating of the capacitor should be determined allowing sufficient margin against output voltage. a 10 f to 100 f ceramic capacitor is recommended. less esr allows reduction in output ripple voltage. 3. selection of input capacitor (cin) input capacitor to select must be a low esr capacitor of the capacitance sufficient to cope with high ripple current to prevent high transient voltage. the ripple current i rms is given by the equation ( 5 ): a low esr 10 f/10v ceramic capacitor is recommended to reduce esr dissipation of input capacitor for better efficiency. (5 - 1.2) v cc l co v out esr i rms =i out out (v cc - v out ) v cc [a] ??? out , i rms = i rms = i out 2 < worst case > i rms(max.) if v cc =5v, v out =1.2v, and i outmax.= 1.2a, i rms =1.2 rms ] v cc l co v out cin
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 16 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet fig.3 9 typical application 4. determination of r ith , c ith that works as a phase compensator as the current mode control is designed to limit a inductor cu rrent, a pole (phase lag) appears in the low frequency area due to a cr filter consisting of a output capacitor and a load resistance, while a zero (phase lead) appears in the high frequency area due to the output capacitor and its esr. so, the phases are easily compensated by adding a zero to the power amplifier output with c and r as described below to cancel a pole at the power amplifier. stable feedback loop may be achieved by can celing the pole fp (min.) produced by the output capacitor and the load resistance with cr zero correction by the error amplifier. fig.3 7 open loop gain characteristics fig.3 8 error amp phase compensation characteristics fp= 2 o o 1 fz (esr) = 2 sr o 1 pole a t power amplifier when the output current decreases, the load resistance ro increases and the pole frequency lowers. fp (min.) = 2 omax. o 1 [hz] (max.) = 2 omin. o 1 [hz] (amp.) = 2 ith. ith 1 gain [db] phase [deg] a 0 0 - 90 a 0 0 - 90 fz(amp.) fp(min.) fp(max.) fz(esr) i out min. i out max. gain [db] phase [deg] fz (amp.) = fp (min.) 2 ith ith 1 = 2 omax. o 1 gnd,pgnd sw v cc ,pv cc en v out ith v cc v out cin r ith c ith l esr c o r o v out pgood v cc r pg vid<2:0) vid<2:0>
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 17 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet cautions on pc board layout fig. 40 layout diagram lay out the input ceramic capacitor c in c loser to the pins pv cc and pgnd, and the output capacitor c o closer to the pin pgnd. lay out cith and rith between the pins ith and gnd as neat as possible with least necessary wiring . vqfn016v3030 has thermal pad on the reverse of the package. the package thermal performance may be enhanced by bonding the pad to gnd plane which take a large area of pcb. recommended components lists on above application recommended components lists sy mbol part value manufacturer series l coil 4.7uh tdk vlf5014s - 4r7m1r7 c in ceramic capacitor 10uf kyocera cm 316x5r106m10a c o ceramic capacitor 22uf kyocera cm 316b226m06a c ith ceramic capacitor 1500pf murata grm 18 seri e s r ith resistance 9.1k the parts list presented above is an example of recommended parts. although the parts are sound, actual circuit characteristics should be checked on your appli cation carefully before use. be sure to allow sufficient margins to accommodate variations between external devices and this ic when employing the depicted circuit with other circuit constants modified. both static and transient characteristics should be c onsidered in establishing these margins. when switching noise is substantial and may impact the system, a low pass filter should be inserted between the vcc and pvcc pins, and a schottky barrier diode or snubber established between the sw and pgnd pins.
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 18 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet i/o equivalence circuit BD9123MUV ? ? ? ? ? ? en pv cc sw pv cc pv cc ith v cc vout vid 2:0 pgood
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 19 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet operational notes 1. absolute maximum ratings while utmost care is taken to quality control of this product, a ny application that may exceed some of the absolute maximum ratings including the voltage applied and the operating temperature range may result in breakage. if broken, short - mode or open - mode may not be identified. so if it is expected to encounter with special mode that may exceed the absolute maximum ratings, it is requested to take necessary safety measures physically including insertion of fuses. 2. electrical potential at gnd gnd must be designed to have the lowest electrical potential in any opera ting conditions . 3. short - circuiting between terminals, and mismounting when mounting to pc board, care must be taken to avoid mistake in its orientation and alignment. failure to do so may result in ic breakdown. short - circuiting due to foreign matters entered between output terminals, or between output and power supply or gnd may also cause breakdown. 4. thermal shutdown protection circuit thermal shutdown protection circuit is the circuit designed to isolate the ic from thermal runaway, and not inten ded to protect and guarantee the ic. so, the ic the thermal shutdown protection circuit of which is once activated should not be used thereafter for any operation originally intended. 5. inspection with the ic set to a pc board if a capacitor must be con nected to the pin of lower impedance during inspection with the ic set to a pc board, the capacitor must be discharged after each process to avoid stress to the ic. for electrostatic protection, provide proper grounding to assembling processes with specia l care taken in handling and storage. when connecting to jigs in the inspection process, be sure to turn off the power supply before it is connected and removed. 6. input to ic terminals this is a monolithic ic with p + isolation between p - substrate and e ach element as illustrated below. this p - layer and the n - layer of each element form a p - n junction, and various parasitic element s are formed. if a resistor is joined to a transistor terminal as shown in fig 42 . p - n junction works as a parasitic diode if the following relationship is satisfied; gnd>terminal a (at resistor side), or gnd>terminal b (at transistor side); and if gnd>terminal b (at npn transistor side), a parasitic npn transistor is activated by n - layer of other element adjacent to the abo ve - mentioned parasitic diode. the structure of the ic inevitably forms parasitic elements, the activation of which may cause interference among circuits, and/or malfunctions contributing to breakdown. it is therefore requested to take care not to use the device in such manner that the voltage lower than gnd (at p - substrate) may be applied to the input terminal, which may result in activation of parasitic elements. 7. ground wiring pattern if small - signal gnd and large - current gnd are provid ed , it will be recommended to separate the large - current gnd pattern from the small - signal gnd pattern and establish a single ground at the reference point of the set pcb so that resistance to the wiring pattern and voltage fluctuations due to a large curr ent will cause no fluctuations in voltages of the small - signal gnd. pay attention not to cause fluctuations in the gnd wiring pattern of external parts as well. 8. selection of inductor it is recommended to use an inductor with a series resistance element (dcr) 50m or less. especially, in case output voltage is set 1.6v or more, note that use of a high dcr inductor will cause an inductor loss, resulting in decreased output voltage. should this condition continue for a specified period (soft start time + t imer latch time), output short circuit protection will be activated and output will be latched off. when using an inductor over 50m , be careful to ensure adequate margins for variation between external devices and this ic, including transient as well as s tatic characteristics. furthermore, in any case, it is recommended to start up the output with en after supply voltage is within operation range. status of this document the japanese version of this document is formal specification. a customer may use t his translation version only for a reference to help reading the formal version. if there are any differences in translation version of this document formal version takes priority. fig. 42 simplified structure of monorisic ic resistor transistor (npn) n n n p + p + p p substrate gnd parasitic element pin a n n p + p + p p substrate gnd parasitic element pin b c b e n gnd pin a parasitic element pin b other adjacent elements e b c gnd parasitic element
www.rohm.com tsz02201 - 0j3j0aj00120 - 1 - 2 ? roh m co., ltd. all rights reserved. 20 / 20 02.mar.2012 rev.001 tsz22111 ? 1 5 ? 001 BD9123MUV data s heet ordering information b d 9 1 2 3 m u v - e2 package mu v : vqfn016v3030 packaging and forming specification e2: embossed tape and reel physical dimension tape and reel information marking diagram vqfn016v3030 (top view) 23 part number marking lot number 1pin mark d 9 1
datasheet d a t a s h e e t notice - rev.001 notice precaution for circuit design 1) the products are designed and produced for applicatio n in ordinary electronic equipment (av equipment, oa equipment, telecommunication equipment, home appliances, amusement equipment, etc.). if the products are to be used in devices requiring extremel y high reliability (medical equipment, transport equipment, aircraft/spacecraft, nuclear power controllers, fuel contro llers, car equipment including car accessories, safety devices, etc.) and whose malfunction or operational error may endanger human life and sufficient fail-safe measures, please consult with the rohm sales staff in advance. if product malfunctions may re sult in serious damage, including that to human life, sufficient fail-safe measures must be taken, including the following: [a] installation of protection circuits or other protective devices to improve system safety [b] installation of redundant circuits in the case of single-circuit failure 2) the products are designed for use in a standard environment and not in any spec ial environments. a pplication of the products in a special environment can deteriorate product per formance. accordingly, verification and confirmation of product performance, prior to use, is recomm ended if used under the following conditions: [a] use in various types of liquid, includin g water, oils, chemicals, and organic solvents [b] use outdoors where the products are exposed to direct sunlight, or in dusty places [c] use in places where the products are exposed to sea winds or corrosive gases, including cl 2 , h 2 s, nh 3 , so 2 , and no 2 [d] use in places where the products are exposed to static electricity or electromagnetic waves [e] use in proximity to heat-producing componen ts, plastic cords, or other flammable items [f] use involving sealing or coating the prod ucts with resin or other coating materials [g] use involving unclean solder or use of water or water-soluble cleaning agents for cleaning after soldering [h] use of the products in places subject to dew condensation 3) the products are not radiation resistant. 4) verification and confirmation of performance characte ristics of products, after on- board mounting, is advised. 5) in particular, if a transient load (a large amount of load applied in a short per iod of time, such as pulse) is applied, confirmation of performance characteristics after on-boar d mounting is strongly recomm ended. avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading c ondition may negatively affect product performance and reliability. 6) de-rate power dissipation (pd) depending on ambient temperature (ta). when used in sealed area, confirm the actual ambient temperature. 7) confirm that operation temper ature is within the specified range described in product specification. 8) failure induced under deviant condition from what def ined in the product specific ation cannot be guaranteed. precaution for mounting / circuit board design 1) when a highly active halogenous (chlori ne, bromine, etc.) flux is used, the remainder of fl ux may negatively affect product performance and reliability. 2) in principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the company in advance. regarding precaution for mounting / circu it board design, please specially refe r to rohm mounting specification precautions regarding application examples and external circuits 1) if change is made to the constant of an external circuit, allow a sufficient margin due to variations of the characteristics of the products and external components, including transient characteristics, as well as static characteristics. 2) the application examples, their const ants, and other types of information cont ained herein are applicable only when the products are used in accordance with standard methods . therefore, if mass production is intended, sufficient consideration to external conditions must be made.
datasheet d a t a s h e e t notice - rev.001 precaution for electrostatic this product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. please take proper caution during manufacturing and st oring so that voltage exceeding product ma ximum rating won't be applied to products. please take special care under dry condition (e.g. grounding of human body / equipment / so lder iron, isolation from charged objects, setting of ionizer, friction prevention and temperature / humidity control). precaution for storage / transportation 1) product performance and soldered connections may deteriorate if the products are stored in the following places: [a] where the products are exposed to sea winds or corrosive gases, including cl2, h2s, nh3, so2, and no2 [b] where the temperature or humidity exceeds those recommended by the company [c] storage in direct sunshine or condensation [d] storage in high electrostatic 2) even under rohm recommended storage c ondition, solderability of products out of recommended storage time period may be degraded. it is strongly recommended to confirm sol derability before using products of which storage time is exceeding recommended storage time period . 3) store / transport cartons in the correct direction, whic h is indicated on a carton as a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4) use products within the specified time after opening a dry bag. precaution for product label qr code printed on rohm product label is only for internal us e, and please do not use at cust omer site. it might contain a internal part number that is inconsistent with an product part number. precaution for disposition when disposing products please dispose them properly with a industry waste company. precaution for foreign exchange and foreign trade act since concerned goods might be fallen under controlled goods prescribed by foreign exchange and foreign trade act, please consult with rohm in case of export. prohibitions regarding industrial property 1) information and data on products, including application exam ples, contained in these specifications are simply for reference; the company does not guarantee any industrial pr operty rights, intellectual property rights, or any other rights of a third party regarding this information or data. ac cordingly, the company does not bear any responsibility for: [a] infringement of the intellectual property rights of a third party [b] any problems incurred by the us e of the products listed herein. 2) the company prohibits the purchaser of its products to exercise or use the in tellectual property rights, industrial property rights, or any other rights that either belong to or are controlled by the company, other than the right to use, sell, or dispose of the products.

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