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1/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. single-chip built-in fet type switching regulator series output 1.5a or less high efficiency step-down switching regulators with built-in power mosfet BD9102FVM, bd9104fvm, bd9106fvm description rohm?s high efficiency step-down switching regulato r (BD9102FVM, bd9104fvm, bd9106fvm) is a power supply designed to produce a low voltage including 1.24 volts from 5 volts power supply line. offers high efficiency with our original pulse skip control technology and synchronous rectifie r. employs a current mode cont rol system to provide faster transient response to sudden change in load. features 1) offers fast transient response with current mode pwm control system. 2) offers highly efficiency for all load range with synchronous rectifier (nch/pch fet) and sllm tm (simple light load mode) 3) incorporates soft-start function. 4) incorporates thermal protection and ulvo functions. 5) incorporates short-current protec tion circuit with time delay function. 6) incorporates shutdown function 7) employs small surface mount package msop8 use power supply for hdd, power supply for portable electronic devices like pda, and power supply for lsi including cpu and asic lineup parameter BD9102FVM bd9104fvm bd9106fvm vcc voltage 4.0 5.5v 4.5 5.5v 4.0 5.5v output voltage 1.24v2% 3.30v2% adjustable (1.0 2.5v) output current 0.8a max. 0.9a max. 0.8a max. uvlo threshold voltage 2.7v typ. 4.1v typ. 3.4v typ. short-current protection with time delay function built-in built-in built-in soft start function built-in built-in built-in standby current 0 a typ. 0 a typ. 0 a typ. operating temperature range -25 +85 -25 +85 -25 +85 package msop8 msop8 msop8 absolute maximum rating (ta=25 ) parameter symbol limits unit vcc voltage v cc -0.3 +7 *1 v pvcc voltage pv cc -0.3 +7 *1 v en voltage en -0.3 +7 v sw,ith voltage sw,ith -0.3 +7 v power dissipation 1 pd1 387.5 *2 mw power dissipation 2 pd2 587.4 *3 mw operating temperature range topr -25 +85 storage temperature range tstg -55 +150 maximum junction temperature tjmax +150 *1 pd should not be exceeded. *2 derating in done 3.1mw/ for temperatures above ta=25 . *3 derating in done 4.7mw/ for temperatures above ta=25 ,mounted on 70mm70mm1.6mm glass epoxy pcb no.09027eat34
BD9102FVM, bd9104fvm, bd9106fvm technical note 2/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. recommended operating conditions (ta=25 ) parameter symbol BD9102FVM bd9104fvm bd9106fvm unit min. max. min. max. min. max. v cc voltage v cc 4.0 5.5 4.5 5.5 4.0 5.5 v pv cc voltage pv cc *4 4.0 5.5 4.5 5.5 4.0 5.5 v en voltage en 0 v cc 0 v cc 0 v cc v sw average output current isw *4 - 0.8 - 0.8 - 0.8 a *4 pd should not be exceeded. electrical characteristics BD9102FVM(ta=25 ,v cc =5v,en=v cc unless otherwise specified.) parameter symbol min. typ. max. unit conditions standby current i stb - 0 10 a en=gnd bias current i cc - 250 400 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 - 1 10 a ven=5v oscillation frequency f osc 0.8 1 1.2 mhz pch fet on resistance *5 r onp - 0.35 0.60 ? pv cc =5v nch fet on resistance *5 r onn - 0.25 0.50 ? pv cc =5v output voltage v out 1.215 1.24 1.265 v ith si nk current i thsi 10 20 - a v out =h ith s ource c urrent i thso 10 20 - a v out =l uvlo threshold voltage v uvloth 2.6 2.7 2.8 v v cc =h l uvlo hysteresis voltage v uvlohys 50 100 200 mv soft start time t ss 0.5 1 2 ms timer latch time t latch 0.5 1 2 ms *5 design guarantee outgoing inspection is not done on all products bd9104fvm(ta=25 ,v cc =5v,en=v cc unless otherwise specified.) parameter symbol min. typ. max. unit conditions standby current i stb - 0 10 a en=gnd bias current i cc - 250 400 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 - 1 10 a v en =5v oscillation frequency f osc 0.8 1 1.2 mhz pch fet on resistance *5 r onp - 0.35 0.60 ? pv cc =5v nch fet on resistance *5 r onn - 0.25 0.50 ? pv cc =5v output voltage v out 3.234 3.300 3.366 v ith si nk current i thsi 10 20 - a v out =h ith s ource c urrent i thso 10 20 - a v out =l uvlo threshold voltage v uvloth 3.9 4.1 4.3 v v cc =h l uvlo hysteresis voltage v uvlohys 50 100 200 mv soft start time t ss 0.5 1 2 ms timer latch time t latch 0.5 1 2 ms *5 design guarantee outgoing inspection is not done on all products
BD9102FVM, bd9104fvm, bd9106fvm technical note 3/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. bd9106fvm(ta=25 ,v cc =5v,en=v cc ,r 1 =20k ? ,r 2 =10k ? unless otherwise specified.) parameter symbol min. typ. max. unit conditions standby current i stb - 0 10 a en=gnd bias current i cc - 250 400 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 - 1 10 a v en =5v oscillation frequency f osc 0.8 1 1.2 mhz pch fet on resistance *5 r onp - 0.35 0.60 ? pv cc =5v nch fet on resistance *5 r onn - 0.25 0.50 ? pv cc =5v adj reference voltage v adj 0.780 0.800 0.820 v output voltage v out - 1.200 - v ith si nk current i thsi 10 20 - a adj=h ith s ource c urrent i thso 10 20 - a adj=l uvlo threshold voltage v uvloth 3.2 3.4 3.6 v v cc =h l uvlo hysteresis voltage v uvlohys 50 100 200 mv soft start time t ss 1.5 3 6 ms timer latch time t latch 0.5 1 2 ms *5 design guarantee outgoing inspection is not done on all products
BD9102FVM, bd9104fvm, bd9106fvm technical note 4/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. characteristics data v cc -v out v en -v out i out -v out soft start 0 1 2 3 4 012345 input voltage:v cc [v] output voltage:v out [v] 0 0.5 1 1.5 2 0123 output current:i out [a] output voltage:v out [v] 0 0.5 1 1.5 2 0123 output current:i out [a] output voltage:v out [v] 0 0.5 1 1.5 2 012345 en voltage:ven[v] output voltage:v out [v] 0 1 2 3 4 012345 en voltage:ven[v] output voltage:v out [v] 0 0.5 1 1.5 2 012345 en voltage:ven[v] output voltage:v out [v] 0 0.5 1 1.5 2 012345 input voltage:v cc [v] output voltage:v out [v] 0 0.5 1 1.5 2 012345 input voltage:v cc [v] output voltage:v out [v] fig.2 vcc-vout fig.3 vcc-vout fi g .4 ven-vout fig.5 ven-vout fig.6 ven-vout fig.7 iout-vout fig.9 iout-vout fig.10 soft start waveform fig.11 soft start waveform fig.12 soft start waveform v out v cc =pv cc =en [BD9102FVM] v out v cc =pv cc =en [bd9104fvm] v out v cc =pv cc =en [bd9106fvm] ta =25 ta =25 ta =25 fig.1 vcc-vout [BD9102FVM] ta =25 [bd9104fvm] ta =25 [bd9106fvm] ta =25 [BD9102FVM] v cc =5v ta =25 [bd9104fvm] [bd9106fvm] [BD9102FVM] 0 1 2 3 4 0123 output current:i out [a] output voltage:v out [v] fig.8 iout-vout [bd9104fvm] [bd9106fvm] v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25
BD9102FVM, bd9104fvm, bd9106fvm technical note 5/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. sw waveform i o =10ma sw waveform i o =200ma transient response i o =100ma 600ma transient response i o =600ma 100ma fig.13 sw waveform io=10ma ( sllm tm control ) fig.16 sw waveform io=200ma(pwm control) fig.19 transient response io=100 600ma(10 s) v out i out [BD9102FVM] v out i out [BD9102FVM] sw v out [BD9102FVM] sw v out [BD9102FVM] sw v out [bd9104fvm] sw v out [bd9104fvm] sw v out [bd9106fvm] sw v out [bd9106fvm] v out i out [bd9104fvm] v out i out [bd9104fvm] v out i out [bd9106fvm] v out i out [bd9106fvm] v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 v cc =5v ta =25 fig.14 sw waveform io=10ma ( sllm tm control ) fig.15 sw waveform io=10ma ( sllm tm control fig.17 sw waveform io=200ma(pwm control) fig.18 sw waveform io=200ma(pwm control v out =1.8v) fig.20 transient response io=100 600ma(10 s) fig.21 transient response io=100 600ma(10 s) (v out =1.8v) fig.22 transient response io=600 100ma(10 s) fig.23 transient response io=600 100ma(10 s) fig.24 transient response io=600 100ma(10 s) (v out =1.8v)
BD9102FVM, bd9104fvm, bd9106fvm technical note 6/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. ta-v out efficiency reference characteristics 1.75 1.76 1.77 1.78 1.79 1.8 1.81 1.82 1.83 1.84 1.85 -25 -15 -5 5 15 25 35 45 55 65 75 85 temperature:ta[ ] output voltage:v out [v] 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1000 output current:i out [ma] efficiency: [%] 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 -25-15-5 5 1525354555657585 temperature:ta[ ] pmos on resistance:r onp [ ] 3 3.05 3.1 3.15 3.2 3.25 3.3 3.35 3.4 3.45 3.5 -25-15-5 5 1525354555657585 temperature:ta[ ] output voltage:v out [v] fig.34 ta-v en fig.35 ta-i cc fig.36 vcc-fosc fig.25 ta-v out fig.26 ta-v out fig.27 ta-v out fig.28 efficiency (v cc =en=5v v out =1 24v) 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1000 output current:i out [ma] efficiency: [%] fig.29 efficiency (v cc =en=5v,v out =3.3v) [bd9104fvm] [BD9102FVM] 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1000 output current:i out [ma] efficiency: [%] fig.30 efficiency (v cc =en=5v,v out =1.8v) ta =25 [bd9106fvm] 1.2 1.21 1.22 1.23 1.24 1.25 1.26 1.27 1.28 -25-15-5 5 1525354555657585 temperature:ta[ ] output voltage:v out [v] [BD9102FVM] v cc =5v [bd9104fvm] [bd9106fvm] 0.8 0.85 0.9 0.95 1 1.05 1.1 1.15 1.2 -25-15-5 5 1525354555657585 temperature:ta[ ] frequency:f osc [mhz] BD9102FVM bd9104fvm bd9106fvm 0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 -25-15-5 5 1525354555657585 temperature:ta[ ] nmos on resistance:r onn [ ] BD9102FVM bd9104fvm bd9106fvm BD9102FVM bd9104fvm bd9106fvm fig.32 ta-r onn fig.33ta-r onp 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 -25-15-5 5 1525354555657585 temperature:ta[ ] en voltage:ven[v] BD9102FVM bd9104fvm bd9106fvm 0 50 100 150 200 250 300 350 -25-15-5 5 1525354555657585 temperature:ta[ ] circuit current:i cc [ a] v cc =5v BD9102FVM bd9104fvm bd9106fvm 0.8 0.9 1 1.1 1.2 44 . 555 . 5 input voltage:v cc [v] frequency:f osc [mhz] BD9102FVM bd9104fvm bd9106fvm ta =25 fig.31 ta-f osc v cc =5v v cc =5v ta =25 ta =25 v cc =5v v cc =5v v cc =5v v cc =5v
BD9102FVM, bd9104fvm, bd9106fvm technical note 7/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. block diagram, application circuit BD9102FVM,bd9104fvm fig.37 BD9102FVM bd9104fvm top view fig.38 BD9102FVM bd9104fvm block diagram fig.39 bd9106fvm top view fig.40 bd9106fvm block diagram pin no. & function table pin no. pin name pin function 1 v out /adj output voltage detect pin/ adj for bd9106fvm 2 ith gmamp output pin/connected phase compensation capacitor 3 en enable pin(active high) 4 gnd ground 5 pgnd nch fet source pin 6 sw pch/nch fet drain output pin 7 pv cc pch fet source pin 8 v cc vcc power supply input pin 8 7 6 5 v cc pv cc sw pgnd 1 2 3 4 v out ith en gnd top view 8 7 6 5 v cc pv cc sw pgnd 1 2 3 4 a dj ith en gnd top view bd9106fvm v ref osc uvlo tsd current sense/ protect driver logic + soft start 8 7 6 5 4 2 1 3 rq s en v cc pv cc 10 f 5v input 4.7 h sw 10 f output pgnd gnd ith v out v cc slope current comp. gm amp. v cc clk v ref osc uvlo tsd current sense/ protect driver logic + soft start 8 7 6 5 4 2 1 3 rq s en v cc pv cc 10 f 5v input 4.7 h sw 10 f output pgnd gnd ith a dj v cc slope current comp. gm amp. v cc clk
BD9102FVM, bd9104fvm, bd9106fvm technical note 8/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. information on advantages advantage 1 offers fast transient response with current mode control system. voltage drop due to sudden change in load was reduced by 50%. fig.41 comparison of transient response advantage 2 offers high efficiency for all load range. ? for lighter load: utilizes the current mode contro l mode called sllm for lighter load, which r educes various dissipation such as switching dissipation (p sw ), gate charge/discharge dissipation, esr dissipation of output capacitor (p esr ) and on-resistance dissipation (p ron ) that may otherwise cause degradation in efficiency for lighter load. achieves efficiency improvement for lighter load. ? for heavier load: utilizes the synchronous rectifyi ng mode and the low on-resistance mos fets incorporated as power transistor. on resistance of p-channel mos fet: 0.35 ? (typ.) on resistance of n-channel mos fet: 0.25 ? (typ.) achieves efficiency improvement for heavier load. offers high efficiency for all load range with the improvements mentioned above. advantage 3 ? supplied in smaller package like mosp8 due to small-sized power mos fet incorporated. ? allows reduction in size of application products reduces a mounting area required. fig.43 example application output capacitor co required for current mode control: 10 f ceramic capacitor inductance l required for the oper ating frequency of 1 mhz: 4.7 h inductor dc/dc convertor controller r ith l co v out c ith v cc cin 10mm 15mm r ith c ith c in c o l v out i out 228mv v out i out 110mv conventional product (vout of which is 3.3 volts) bd9104fvm (load response i o =100ma ? 600ma) 0.001 0.01 0.1 1 0 50 100 pwm sllm tm inprovement by sllm system improvement by synchronous rectifier efficiency [%] output current io[a] fig.42 efficiency
BD9102FVM, bd9104fvm, bd9106fvm technical note 9/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. operation BD9102FVM, bd9104fvm, bd9106fvm are the synchronous rectifyi ng step-down switching regula tor that achieves faster transient response by employing current mode pwm control system. it utilizes switching operation in pwm (pulse width modulation) mode for heavier load, while it utilizes sllm tm (simple light load mode) operation for lighter load to improve efficiency. synchronous rectifier it does not require 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 reduced. 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 si gnal form osc turns on a p-channel mos fet (while a n-channel mos fet is turned off), and an inductor current i l increases. the current comparator (current comp) receives two signals, a current feedback contro l signal (sense: voltage converted from i l ) and a voltage feedback control signal (fb), and issues a reset signal if both input signals are identical to each other, and turns off the p-channel mos fet (while a n-channel mos fet is turned on ) for the rest of the fixe d period. the pwm control repeat this operation. ?sllm tm (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 norm al 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 contin ues to operate with a set signal from osc and a reset signal from current comp, it is so designed that the reset si gnal is held issued if shifted to the light load mode, with which the switching is tuned off and the switching pulses are th inned out under control. activating the switching intermittently reduces the switching dissipation and improves the efficiency. fig.44 diagram of current mode pwm control osc level shift driver logic rq s i l sw ith current comp gm amp. set reset fb load sense v out v out fig.45 pwm switching timing chart fig.46 sllm tm switching timing chart curren t comp set reset sw v out pvcc gnd gnd gnd i l (ave) v out (ave) sense fb curren t comp set reset sw v out pvcc gnd gnd gnd 0a v out (ave) sense fb i l not switching i l
BD9102FVM, bd9104fvm, bd9106fvm technical note 10/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. description of operations ? soft-start function en terminal shifted to ?high? activates a soft-starter to gradually establish the output voltage with the current limited durin g startup, by which it is possible to prevent an ov ershoot of output voltage and an inrush current. ? 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 f (typ.). ? uvlo function detects whether the input voltage sufficient to secure the output voltage of this ic is supplied. and the hysteresis width of 100 mv (typ.) is provided to prevent output chattering. ? BD9102FVM bd9104fvm t ss =1msec(typ.) ? bd9106fvm t ss =3msec(typ.) fig.47 soft start, shutdown, uvlo timing chart ? short-current protection circuit with time delay function turns off the output to protect the ic fr om breakdown when the incorporated current limiter is activated continuously for at least 1 ms. the output thus held tuned off may be recovered by restarting en or by re-unlocking uvlo. fig.48 short-current protection circuit with time delay timing chart hysteresis 100mv ts s ts s ts s soft start standby mode operating mode standby mode operating mode standby mode operating mode standby mode uvlo en uvlo uvlo v cc en v ou t 1msec output off latch en v out limi t i l standby mode operating mode standby mode operating mode en timer latch en
BD9102FVM, bd9104fvm, bd9106fvm technical note 11/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. switching regulator efficiency efficiency ? may be expressed by the equation shown below: efficiency may be improved by reducing the swit ching regulator power dissipation factors 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 [ ? ] dc resistance of inductor, r on [ ? ] on resistance of fet i out [a] output current.) 2)pd(gate)=cgsfv (cgs[f] gate capacitance of fet,f[h] switching frequency,v[v] gate driving voltage of fet) 4)pd(esr)=i rms 2 esr (i rms [a] ripple current of capacitor,esr[ ? ] equivalent series resistance.) 5)pd(ic)=vini cc (i cc [a] circuit current.) consideration on permissible dissipation and heat generation as this ic functions with high efficien cy 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, heavier load, and/or higher temperature, the permissible di ssipation 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 conduction losses are considered to play the leading role among other dissipation mentioned above including gate charge/discharge dissipation and switching dissipation. p=i out 2 (r coil +r on ) r on =dr onp +(1-d)r onn d on duty (=v out /v cc ) r coil dc resistance of coil r onp on resistance of p-channel mos fet r onn on resistance of n-channel mos fet i out output current if v cc =5v, v out =3.3v, r coil =0.15 ? , r onp =0.35 ? , r onn =0.25 ? i out =0.8a, for example, d=v out /v cc =3.3/5=0.66 r on =0.660.35+(1-0.66)0.25 =0.231+0.085 =0.316[ ? ] p=0.8 2 (0.15+0.316) P 298[mv] as r onp is greater than r onn in this ic, the dissipation increases as the on duty becomes greater. with the consideration on the dissipation as above, the rmal design must be carried out with sufficient margin allowed. = v out i out viniin 100[%]= p out pin 100[%]= p out p out +p d 100[%] ambient temperature:ta [ h] fig.49 thermal derating curves 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.) 0 200 400 600 800 1000 387.5mw 587.4mw using an ic alone j-a=322.6 /w mounted on glass epoxy pcb j-a=212.8 /w power dissipation:pd [mw] 0 25 50 75 100 125 150 85
BD9102FVM, bd9104fvm, bd9106fvm technical note 12/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. selection of components externally connected 1. selection of inductor (l) * current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases efficien cy. the inductor must be selected allowing sufficient margin with which the peak current may not exceed its current rating. if v cc =5v, v out =3.3v, f=1mhz, i l =0.30.8a=0.24a, for example, *select the inductor of low resistance component (such as dcr and acr) to minimize dissipation in the inductor for better effic iency. 2. selection of output capacitor (c o ) as the output rise time must be designed to fall within the soft-start time, the capacitance of output capacitor should be determined with consideration on the requirements of equation (5): in case of bd9104fvm, for instance, and if v out =3.3v, i out =0.8a, and t ss =1ms, inappropriate capacitance may cause problem in startup. a 10 f to 100 f ceramic capacitor is recommended. 3. selection of input capacitor (cin) a low esr 10 f/10v ceramic capacitor is recommended to reduce esr di ssipation of input capacitor for better efficiency. the inductance significantly depe nds on output ripple current. a s seen in the equation (1), the ripple current decreases as the inductor and/or switching frequency increases. i l = (v cc -v out )v out l yv cc yf [ a ] ??? ( 1 ) a ppropriate ripple current at output should be 30% more or less of the maximum output current. i l =0.3i out max. [a] ???(2) l= (v cc -v out )v out i l v cc f [h] ??? ( 3 ) (?i l : output ripple current, and f: switching frequency) output capacitor should be selected with the consideration on the stability region and the equivalent series resistance re quired to smooth ripple voltage. output ripple voltage is determined by the equation (4) v out = i l esr [v] ???(4) ( i l : output ripple current, esr: equivalent se ries resistance of output capacitor) *rating of the capacitor should be determi ned allowing sufficient margin against output voltage. less esr allows reduction in output ripple voltage. 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 irms is given by the equation (6): i rms =i out v cc ( v cc -v out ) v cc [a] ??? ( 6 ) ? when vcc is twice the vout, i rms = i out 2 fig.51 output capacitor ( 5-3.3 ) 3.3 0.24y5 y 1m l= =4.675 4.7[ h] < worst case > i rms(max.) if v cc =5v, v out =3.3v, and i outmax.= 0.8a, i rms =0.8 5 ( 5-3.3 ) 5 =0.46 [ a rms ] ? coQ t ss (i limit -i out ) v out ??? ( 5 ) tss: soft-start time i limit : over current detection level, 2a(typ) fig.52 input capacitor ?i l fig.50 output ripple current i l v cc il l co vout v cc l co v out esr coQ 1m(2-0.8) 3.3 P364 [ f] v cc l co v out cin
BD9102FVM, bd9104fvm, bd9106fvm technical note 13/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. 4. determination of rith, cith that works as a phase compensator as the current mode control is designed to limit a inductor current, 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 bel ow to cancel a pole at the power amplifier. stable feedback loop may be achieved by canceling the pole fp (mi n.) produced by the output ca pacitor and the load resistance with cr zero correction by the error amplifier. 5. determination of output voltage (for bd9106fvm only) the output voltage v out is determined by the equation (7): v out =(r2/r1+1)v adj ??? (7) v adj : voltage at adj terminal (0.8v typ.) with r1 and r2 adjusted, the output voltage may be determined as required.(adjustable output voltage range 1.0v 2.5v) use 1 k ? 100 k ? resistor for r1. if a resistor of the resistance higher than100 k ? is used, check the assembled set carefully for ripple voltage etc. fig.56 determination of output voltage gain [db] phase [deg] fig.53 open loop gain characteristics a 0 0 -90 a 0 0 -90 fz(amp.) fig.54 error amp phase compensation characteristics fp= 2 r o c o 1 fz (esr) = 2 e sr c o 1 pole at power amplifie r when the output current decreases, the load resistance ro increases and the pole frequency lowers. fp (min.) = 2 r omax. c o 1 [hz] with lighter load fp (max.) = 2 r omin. c o 1 [hz] with heavier load zero at power amplifie r increasing capacitance of the out put capacitor lowers the pole frequency while the zero frequency does not change. (this is because when the capacitance is doubled, the capacitor esr reduces to half.) fz (amp.) = 2 r ith. c ith 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 fig.55 typical application fz (amp.) = fp (min.) 2 r ith c ith 1 = 2 r omax. c o 1 sw 6 1 a dj 4.7 h 10 f r2 r1 output fp(min.) fp(max.) fz(esr) i out min. i out max. gain [db] phase [deg]
BD9102FVM, bd9104fvm, bd9106fvm technical note 14/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. BD9102FVM, bd9104fvm, bd9106fvm cautions on pc board layout fig.57 layout diagram for the sections drawn with heavy line, use th ick conductor pattern as short as possible. lay out the input ceramic capacitor cin closer to the pins pvcc and pgnd, and the output capacitor co closer to the pin pgnd. lay out cith and rith between the pi ns ith and gnd as neat as possible with least necessary wiring. table1.recommended parts list of application [BD9102FVM] symbol part value manufacturer series l inductor 4.7 h sumida cmd6d11b c in ceramic capacitor 10 f kyocera cm316x5r106m10a c o ceramic capacitor 10 f kyocera cm316x5r106m10a c ith ceramic capacitor 330pf murata grm18series r ith resistor 30k ? rohm mcr10 3002 table2. recommended parts list of application [bd9104fvm] symbol part value manufacturer series l inductor 4.7 h sumida cmd6d11b c in ceramic capacitor 10 f kyocera cm316x5r106m10a c o ceramic capacitor 10 f kyocera cm316x5r106m10a c ith ceramic capacitor 330pf murata grm18series r ith resistor 51k ? rohm mcr10 5102 table3.recommended parts list of application [bd9106fvm] symbol part value manufacturer series l inductor 4.7 h sumida cmd6d11b c in ceramic capacitor 10 f kyocera cm316x5r106m10a c o ceramic capacitor 10 f kyocera cm316x5r106m10a c ith ceramic capacitor 750pf murata grm18series table4.bd9106fvm r ith recommended value vout[v] r ith 1.0 18k ? 1.2 22k ? 1.5 22k ? 1.8 27k ? 2.5 36k ? *bd9106fvm: as the resistance recommended for rith depends on the output voltage, check the output voltage for determination of resistance. 8 7 6 5 1 2 3 4 v out /adj ith en gnd v cc pv cc sw pgnd c o gnd v out v cc l en r ith c ith c in
BD9102FVM, bd9104fvm, bd9106fvm technical note 15/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. i/o equivalence circuit fig.58 i/o equivalence circuit v cc v out 10k ? 1pin(v out ) v cc a dj 10k ? bd9106fvm 1pin(adj) v cc ith 2pin(ith) v cc v cc en 10k ? 3pin(en) 2.8m ? 2.2k ? pv cc sw 6pin(sw) pv cc pv cc
BD9102FVM, bd9104fvm, bd9106fvm technical note 16/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. notes for use 1. absolute ma ximum ratings while utmost care is taken to quality control of this pr oduct, any application that may exceed some of the absolute maximum ratings including the voltage applied and the operatin g temperature range may result in breakage. if broken, short-mode or open-mode may not be identifi ed. so if it is expected to encounter with special mode that may exceed the absolute maximum ratings, it is requested to take necessary sa fety measures physically including insertion of fuses. 2. electrical potential at gnd gnd must be designed to have the lowest elec trical potential in any operating conditions. 3. short-circuiting between terminals, and mismounting when mounting to pc board, care must be taken to avoid mistak e in its orientation and alignment. failure to do so may result in ic breakdown. short-circuiting due to foreign matters entered between output te rminals, or between output and power supply or gnd may also cause breakdown. 4.operation in strong electromagnetic field be noted that using the ic in the strong electr omagnetic radiation can cause operation failures. 5. thermal shutdown protection circuit thermal shutdown protection circuit is the circuit designed to isolate the ic from thermal runaway, and not intended to protect and guarantee the ic. so, the ic the thermal shutdown protection circui t of which is once activated should not be used thereafter for any operation originally intended. 6. inspection with the ic set to a pc board if a capacitor must be connected to the pin of lower impedanc e during inspection with the ic set to a pc board, the capacitor must be discharged after each process to avoid stre ss to the ic. for electrostatic protection, provide proper grounding to assembling processes with special 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. 7. input to ic terminals this is a monolithic ic with p + isolation between p-substrate and each element as illustrated below. this p-layer and the n-layer of each element form a p-n junction, and various parasitic element are formed. if a resistor is joined to a transistor terminal as shown in fig 59: p-n junction works as a parasitic diode if the following rela tionship 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 ot her element adjacent to the above-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 breakdow n. it is therefore requested to take care not to use the device in such manner that the voltage lower than g nd (at p-substrate) may be applied to t he input terminal, which may result in activation of parasitic elements. fig.59 simplified structure of monorisic ic 8. ground wiring pattern if small-signal gnd and large-current gnd are provided, it will be recommended to separate the large-current gnd pattern from the small-signal gnd pattern and establish a si ngle ground at the reference poi nt of the set pcb so that resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluc tuations in voltages of the small-signal gnd. pay attention not to cause fluctuations in the gnd wiring pattern of external parts as well. (pin a) p+ p+ n n n p p substrate parasitic diode gnd gnd parasitic diode or transistor n p n c (pin b) b e gnd p+ p+ n n resistance transistor (npn) (pin b) c e b gnd (pin a) gnd p substrate parasitic diode parasitic diode or transistor
BD9102FVM, bd9104fvm, bd9106fvm technical note 17/17 www.rohm.com 2009.05 - rev.a ? 2009 rohm co., ltd. all rights reserved. ordering part number b d 9 1 0 2 f v m - t r part no. part no. 9102,9104,9106 package fvm: msop8 packaging and forming specification tr: embossed tape and reel (msop8) (unit : mm) msop8 0.08 s s 4.00.2 8 3 2.80.1 1 6 2.90.1 0.475 4 57 (max 3.25 include burr) 2 1pin mark 0.9max 0.750.05 0.65 0.080.05 0.22 +0.05 ?0.04 0.60.2 0.290.15 0.145 +0.05 ?0.03 4 + 6 ?4 direction of feed reel ? order quantity needs to be multiple of the minimum quantity. embossed carrier tape tape quantity direction of feed the direction is the 1pin of product is at the upper right when you hold reel on the left hand and you pull out the tape on the right hand 3000pcs tr () 1pin
r0039 a www.rohm.com ? 2009 rohm co., ltd. all rights reserved. notice rohm customer support system http://www.rohm.com/contact/ thank you for your accessing to rohm product informations. more detail product informations and catalogs are available, please contact us. notes no copying or reproduction of this document, in part or in whole, is permitted without the consent of rohm co.,ltd. the content specied herein is subject to change for improvement without notice. the content specied herein is for the purpose of introducing rohm's products (hereinafter "products"). if you wish to use any such product, please be sure to refer to the specications, which can be obtained from rohm upon request. examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the products. the peripheral conditions must be taken into account when designing circuits for mass production. great care was taken in ensuring the accuracy of the information specied in this document. however, should you incur any damage arising from any inaccuracy or misprint of such information, rohm shall bear no responsibility for such damage. the technical information specied herein is intended only to show the typical functions of and examples of application circuits for the products. rohm does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by rohm and other parties. rohm shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. the products specied in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, ofce-automation equipment, commu- nication devices, electronic appliances and amusement devices). the products specied in this document are not designed to be radiation tolerant. while rohm always makes efforts to enhance the quality and reliability of its products, a product may fail or malfunction for a variety of reasons. please be sure to implement in your equipment using the products safety measures to guard against the possibility of physical injury, re or any other damage caused in the event of the failure of any product, such as derating, redundancy, re control and fail-safe designs. rohm shall bear no responsibility whatsoever for your use of any product outside of the prescribed scope or not in accordance with the instruction manual. the products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-controller or other safety device). rohm shall bear no responsibility in any way for use of any of the products for the above special purposes. if a product is intended to be used for any such special purpose, please contact a rohm sales representative before purchasing. if you intend to export or ship overseas any product or technology specied herein that may be controlled under the foreign exchange and the foreign trade law, you will be required to obtain a license or permit under the law.

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