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product structure silicon monolithic integrated circuit this product ha s no designed protection against radioactive rays 1/ 22 tsz22111 ? 14 ? 001 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 2.7v to 5.5v, 3a 1ch synchronous buck converter with integrated fet bd8962muv general description the bd8962muv is rohm's high efficiency step-down switching regulator designed to produce a voltage as low as 0.8v from a supply voltage of 5.5v/3.3v. it offers high efficiency by using synchronous switches and provides fast transient response to sudden load changes by implementing current mode control. features ? fast transient response because of current m ode control system ? high efficiency for all lo ad ranges because of synchronous switches ? soft-start function ? thermal shutdown and uvlo functions ? short circuit protection with time delay function ? shutdown function key specifications ? input voltage range: 2.7v to 5.5v ? output voltage range: 0.8v to 2.5v ? averag e output current: 3.0a(max) ? switching frequency: 1mhz(typ) ? high side fet on-resistance: 82m ? (typ) ? low side fet on-resistance: 70m ? (typ) ? standby current: 0 a( typ) ? operating temperature range: - 40 c to +105c packages w(typ) x d(typ) x h(max) applications power supply for lsi including dsp, microcomputer and asic typical application circuit figure 1. typical application circuit vqfn020v4040 4.00mm x 4.00mm x 1.00mm en adj ith pvcc vcc sw gnd, pgnd c in v cc r ith c ith v out r 2 r 1 c o l c bst c 1 r f datashee t downloaded from: http:///
2/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 pin configuration (top view) pin description pin no. pin name function pin no. pin name function 1 sw power switch node 11 gnd ground pin 2 sw power switch node 12 adj output voltage detection pin 3 sw power switch node 13 ith gmamp output pin/connected to phase compensation capacitor 4 sw power switch node 14 n.c. no connection 5 sw power switch node 15 n.c. no connection 6 pvcc power switch supply pin 16 n.c. no connection 7 pvcc power switch supply pin 17 en enable pin(active high 8 pvcc power switch supply pin 18 pgnd power switch ground pin 9 bst bootstrapped voltage input pin 19 pgnd power switch ground pin 10 vcc power supply input pin 20 pgnd power switch ground pin bl ock diagram figure 2 . pin configuration 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 pvcc en pg nd gnd n.c. bst vcc adj ith n.c. sw figure 3. block diagram vcc pvcc vcc pv cc downloaded from: http:///
3/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 absolute maximum ratings(ta=25c) parameter symbol rating unit v cc voltage v cc -0.3 to +7 (note 1) v pv cc voltage pv cc -0.3 to +7 (note 1) v bst voltage v bst -0.3 to +13 v bst_sw voltage v bst - sw -0.3 to +7 v en voltage v en -0.3 to +7 v sw,ith voltage v sw , v ith -0.3 to +7 v power dissipation 1 pd1 0.34 (note 2) w power dissipation 2 pd2 0.70 (note 3) w power dissipation 3 pd3 1.21 (note 4) w power dissipation 4 pd4 3.56 (note 5) w operating temperature range topr -40 to +105 c storage temperature range tstg -55 to +150 c maximum junction temperature tjmax +150 c (note 1) pd should not be exceeded. (note 2) ic only (note 3) mounted on a 1-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied copper foil area : 10.29mm 2 (note 4) mounted on a 4-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied copper foil area: 10.29mm 2 in each layer (note 5) mounted on a 4-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied copper foil area : 5505mm 2 in each layer caution: operating the ic over the absolute maximum ratings may damage the ic. the damage can eit her be a short circuit between pins or an open circuit between pins and the internal circuitry. therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the ic is operat ed over the absolute maximum ratings. recommended operating conditions (ta=- 40 c to +105c) parameter symbol limit 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 - 5.5 v output voltage setting range v out 0.8 - 2.5 (note 6) v sw average output current i sw - - 3.0 (note 7) a (note 6) in case of setting the output voltage to 1.6v or more, v cc min = v out +1.2v. (note 7) pd should not be exceeded. electrical characteristics(ta=25c v cc = pv cc =3.3v, v en =v cc , r 1 =10k, r 2 =5k ,unless otherwise specified.) parameter symbol limit unit conditions min typ max standby current i stb - 0 10 a en=gnd active current i cc - 250 500 a vcc current en low voltage v enl - gnd 0.8 v standby mode en h igh voltage v enh 2.0 v cc - v active m ode en input current i en - 1 10 a v en =3.3v oscillation frequency f osc 0.8 1 1.2 mhz high side fet on-resistance r onh - 82 115 m ? pv cc =3.3v low side fet on-resistance r onl - 70 98 m ? pv cc =3.3v adj voltage v adj 0.788 0.800 0.812 v ith s i nk current i thsi 10 18 - a v adj =1v ith source current i thso 10 18 - a v adj =0.6v uvlo threshold voltage v uvlo1 2.400 2.500 2.600 v v cc =3.3v to 0v uvlo release voltage v uv lo2 2.425 2.550 2.700 v v cc =0v to 3.3v soft start time t ss 2.5 5 10 ms timer latch time t latch 0.5 1 2 ms output short circuit threshold voltage v scp - 0.40 0.56 v v adj =0.8v to 0v downloaded from: http:///
4/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 typical performance curves figure 6. output voltage vs output current output current: i out [a] output voltage: v out [v] [v out =1.2v] v cc =5v ta=25c figure 7. output voltage vs temperature temperature: ta [ c ] output voltage: v out [v] v cc =5v i o =0a [v out =1.2v] figure 5. output voltage vs en voltage en voltage : v en [v] output voltage : v out [v] [v out =1.2v] v cc =5v ta=25c i o =0a figure 4. output voltage vs input voltage input voltage: v cc [v] output voltage: v out [v] [v out =1.2v] ta=25c i o =3a downloaded from: http:///
5/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 typical performance curves - continued figure 11 . en voltage vs temperature temperature : ta [ c ] en voltage: v en [v] v cc =5v figure 9. frequency vs temperature temperature: ta [ c ] frequency: f osc [mhz] v cc =5v figure 8. efficiency vs output current output current : i out [ ma ] efficiency: [%] v cc =5v ta=25c [v out =1.2] figure 10 . on -resistance vs temperature temperature: ta [ c ] on -resistance: r on [] v cc =3.3v high side low side downloaded from: http:///
6/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 typical performance curves C continued figure 12. circuit current vs temperature circuit current: i cc [a] temperature: ta [ c ] v cc =5v figure 13 . frequency vs input voltage input voltage : v cc [v] frequency: f osc [mhz] ta=25c downloaded from: http:///
7/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 typical waveforms figure 14 . soft start waveform v cc =5v ta=25c i o =0a [v out =1.2v] v cc =pv cc =en v out figure 15. sw waveform (io=10ma) v cc =5v ta=25c v out [v out =1.2v] [pwm sw figure 16. transient response (io=1a to 3a , 10 s) v cc =5 v ta=25c [v out =1.2v] v out i out figure 17 . transient response (io=3a to 1a , 10 s) v cc =5v ta=25c [v out =1.2v] v out i out downloaded from: http:///
8/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 application information 1. operation bd8962muv is a synchronous step-down switching regulator that achieves fast transient response by emplo ying current mode pwm control system. (1) synchronous rectifier integrated synchronous rectification using two mosfets reduces power dissipation and increases efficiency whe n compared to converters using external diodes. internal shoot-through current limiting circuit further reduces power dissipation. (2) current mode pwm control pwm control signal of this ic depends on two feedback loops, the voltage feedback and the inductor current feedback. (a) pwm (pulse width modulation) control the clock signal coming from osc has a frequency of 1mhz. when osc sets the rs latch, the p-channel mosfet is turned on and the n-channel mosfet is turned off . the opposite happens when the current comparator (current comp) resets the rs latch i.e. the p-channel mosfet is turn ed off and the n-channel mosfet is turned on . current comp's output is a comparison of two signals, the current feedback control signal "sense" which is a voltage proportional to the current il, and the voltage feedback control signal, fb. figure 18. diagram of current mode pwm control figure 19. pwm switching timing chart current comp set reset sw v out pv cc gnd gnd gnd i l (ave) v out (ave) sense fb i l osc level shift driver logic r q s i l sw r ith current comp gm amp set reset fb load sense v out v out downloaded from: http:///
9/ 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 2. description of operations (1) soft-start function during start-up, the soft-start circuit gradually establishes the output voltage to limit the input current. this prevent s the overshoot in the output voltage and inrush current. (2) shutdown function when the en terminal is shifted to low, the device operates in standby mode, and all the function al blocks including the reference voltage circuit, internal oscillator and drivers are turned off . circuit current during standby is 0a (typ). (3) uvlo function the uvlo circuit detects whether the input voltage is sufficient to obtain the output voltage of this ic. a hysteresis width of 50 mv (typ) is provided to prevent the output from chattering. figure 20 . soft start, shutdown, uvlo timing chart (4) short circuit protection with time delay function to protect the ic from breakdown, the short circuit protection turns the output off when the internal circuit limiter is activated continuously for a fixed time (t latch ) or more. the output that is kept off may be turned on aga in by restarting en or by resetting uvlo. figure 21. short current protection circuit with time delay timing chart hysteresis 50mv t ss t ss t ss soft start standby m ode operating mode standby mode operating mode standby m ode operating mode standby m ode uvlo en uvlo uvlo v cc en v out 1/2v out 1msec output voltage off latch output current in non-control output current controlled by limit value (limit value changes in proportion to output voltage) en timer latch en standby m ode operated m ode standby m ode operated m ode en v out limit i l until output voltage goes up to half of vo or over, timer latch is not operated. (no timer latch, only limit to the output current) downloaded from: http:///
10 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 3. information on advantages advantage 1 offers fast transient response by using current mode control system voltage drop due to sudden change in load was reduced by about 50%. figure 22. comparison of transient response advantage 2 offers high efficiency for all load range because of its synchronous rectifier for heavier load: this ic utilizes the synchronous rectifying mode and uses low on -resistance mosfet power transistors. on-resistance of high side mosfet : 82m ? (typ) on -resistance of low s ide mosf et : 70m ? (typ) advantage 3 ? supplied in smaller package due to integration of small-sized power mosfets reduces the required mounting area figure 24 . example application figure 23. efficiency conventional product (load response i o =1a to 3a) bd8962muv (load response i o =1a to 3a) ? required output capacitor ,co, for current mode control: 22f ceramic capacitor ? required inductance ,l, for the operating frequency of 1 mhz: 2.2h inductor ? integrates fet + boot strap diode v out i out 145mv v out i out 62mv 0 10 20 30 40 50 60 70 80 90 100 10 100 1000 10000 output current:i out [ma] eff iciency: [ %] v cc =5v ta=25 c v out =1.2 output current :i out [ma] efficiency : [%] output pgnd gnd gm amp r s q osc uvlo tsd + v cc vcc clk slope en current comp soft start current sense/ protect + driver logic + vref ith adj r ith c ith r1 r2 pvcc sw pvcc bst vcc 3.3v input scp 15mm 20mm r 2 c ith c f co l r 1 r ith rf c bst c in downloaded from: http:///
11 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 4. switching regulator efficiency efficiency may be expressed by the equation shown below: efficiency may be improved by reducing the switching regulator power dissipation factors pd as follows: dissipation factors: (1) on -resistance dissipation of inductor and fet pd (i 2 r) where: r coil is the dc resistance of inductor r on is the on -resistance of fet i out is the output current (2) gate charge/discharge dissipation pd(gate) where: c gs is the gate capacitance of fet f is the switching frequency v is the gate driving voltage of fet (3) switching dissipation pd(sw) where: c rss is the reverse transfer capacitance of fet i drive is the peak current of gate (4) esr dissipation of capacitor pd(esr) where: i rms is the ripple current of capacitor esr is the equivalent series resistance (5) operating current dissipation of ic pd(ic) where: i cc is the circuit current ? ? ? ? on coil out r r i ri pd ? ? ? 2 2 ? ? drive out rss in i f i c v sw pd ? ? ? ? 2 ? ? esr i esr pd rms ? ? 2 ? ? cc in i v ic pd ? ? ? ? % pd p p p p i v i v out out in out in in out out 100 100 100 ? ? ? ? ? ? ? ? ? ? ? ? 2 v f c gate pd gs ? ? ? downloaded from: http:///
12 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 5. consideration on permissible dissipation and heat generation since this ic functions with 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, heavier load, and/or higher temperature, the permissible dissipation and/or heat generation must be carefully considered. for dissipation, only conduction losses due to the dc resistance of inductor and on-resistance of fet are considered because conduction losses are more significant than other means of dissipation mentioned above including gate charge/discharge dissipation and switching dissipation. if v cc =3.3v, v out =1.8v , r onh =82m ? , r onl =70m ? i out =3a, for example, d=v out /v cc =1.8/3.3=0.545 r on =0.545 x 0.082+(1-0.545) x 0.07 =0.0447+0.0319 =0.0766[ ? ] p=3 2 x 0.0766 0.6894[w] since r onh is greater than r onl in this ic, the dissipation increases as the on duty becomes greater. taking into consideration the dissipation as shown above, thermal design must be carried out with allowable sufficient margin. ? ? onl onh on on out r d r d r r i p ? ? ? ? ? ? 1 2 where: d is the on duty (=v out /v cc ) r onh is the on -resistance of high s ide mosfet r onl is the on -resistance of low s ide mosfet i out is the output current figure 25 . thermal dissipation curve (vqfn020v4040) 4 layers (copper foil area : 5505mm 2 ) copper foil in each layer j-a=35.1c /w 4 layers (copper foil area : 10.29m 2 ) copper foil in each layer j-a=103.3c /w 1 layers (copper foil area : 10.29m 2 ) j-a=178.6c /w ic only. j-a=367.6c /w power dissipation: pd [w] ambient temperature: ta [c] 0 25 50 75 100 125 150 0 2.0 3.0 4.0 1.21w 3.56w 1.0 0.70w 0.34w 105 downloaded from: http:///
13 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 6. selection of externally connected components (1) selection of inductor (l) note: current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases efficiency. the inductor must be selected to allow a sufficient margin with which the peak current may not e xceed the inductors current rating. if v cc =5.0v, v out =2.5v, f=1mhz, i l =0.2a x 3a=0.6a, for example , ( bd8962muv) note: select an inductor with low resistance component (such as dcr and acr) to minimize dissipation in the induc tor for better efficiency. (2) selection of output capacitor (c o ) the inductance significantly depends on output ripple current. as shown in equation (1), the ripple current decreases as the inductor and/or switching frequency increases. appropriate ripple current at output should be +/-20% of the maximum output current. where: i l is the output ripple current, and f is the switching frequency figure 26 . output ripple current i l i l v out v cc i l l c o output capacitor should be selected with consideration on the stability region and the equivalent series resistance required in smoothing the ripple voltage. output ripple voltage is determined by equation (4) where: i l is the output ripple current , and esr is the equivalent series resistance of output capacitor note: rating of the capacitor should be determined to allow a sufficient margin against output voltage. a 22f to 100f ceramic capacitor is recommended. less esr allows reduction in output ripple voltage. figure 27 . output capacitor v cc l c o v out esr ? ? ? ? a f v l v v v i cc out out cc l ? ? ? ? ? ? ? ? ? ? ? ? h f v i v v v l a i i cc l out out cc outmax l ? ? ? ? ? ? ? ? ? 2.0 ? ? ? ? h m l ? ? 2.2 08 .2 1 5 6.0 5.2 5.2 5 ? ? ? ? ? ? ? ? ? v esr i v l out ? ?? ? ??? (1) ??? (3) ??? (2) ??? (4) downloaded from: http:///
14 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 (3) selection of input capacitor (c in ) when a low esr 22 f/10v ceramic capacitor is recommended to reduce esr dissipation of input capacitor for better efficiency. (4) calculating r ith , c ith for phase compensation since the current mode control is designed to limit the inductor current, a pole (phase lag) appears in low frequencies due to rc filter consisting of an output capacitor and load resistance, while a zero (phase lead) appears in high frequencies due to the output capacitor and its esr. therefore, 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. the input capacitor must be a low esr capacitor with a capacitance sufficient to cope with high ripple current. this is to prevent high transient voltage. the ripple curren t i rms is given by equation (5 ): < worst case > i rmsmax figure 28 . input capacitor v out v cc l c o c in if v cc =3.3v, v out =1.8v, and i outm ax = 3a, (bd8962muv) gain [db] phase [deg] figure 29 . open loop g ain characteristics a 0 0 - 90 a 0 0 - 90 f z (amp) figure 30 . error amp phase compensation characteristics pole at power amplifier when the output current decreases, the load resistance ro increases and the pole frequency decreases. zero at power amplifier fp(min) fp(max) f z (esr) i out min i out max gain [db] phase [deg] increasing the capacitance of the output capacitor lowers the pole frequency while the zero frequency does not change. (this is because when the capacitance is doubled, the capacitor esr is reduced to half.) ? ? ? ? a v v v v i i cc out cc out out rms ? ? ? 2 2 , out rms out cc i i v v ? ? ? ? ? ? ? rms rms a i 49 .1 3.3 8.1 3.38.1 3 ? ? ? ? o o c r fp ? ? ? ? 2 1 ? ? o z c esr esr f ? ? ? ? 2 1 ? ? ith ith z c r amp f ? ? ? ? 2 1 ??? (5) ? ? load lighter with hz c r fp o omax min ? ? ? ? ] [ 2 1 ? ? ? load heavier with hz c r fp o omin max ? ? ? ? ] [ 2 1 ? downloaded from: http:///
15 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 stable feedback loop may be achieved by canceling the pole fp (min) produced by the output capacitor and the load resistance with rc zero correction by the error amplifier. ? ? ? ? o omax ith ith z c r c r min fp amp f ? ? ? ? ? ? ? ? ? 2 1 2 1 (5) se tting the output voltage the output voltage v out is determined by equation (6): ??? ( 6) where: v adj is the voltage at adj terminal (0.8v typ) the required output voltage may be determined by adjusting r 1 and r 2 . output voltage range: 0.8v to 2.5v use 1 k? to 100 k? resistor for r 1 . when using a resistor with resistance higher than 100 k?, check the setup carefully for ripple voltage etc. v o =2.5v v o =2.0v v o =1.8v figure 33 . minimum input voltage in each output voltage the lower limit of input voltage depends on the output voltage. basically, it is recommended to use given condition: v v v out ccmin 2.1 ? ? figure 33. shows the necessary output current value at the lower limit of input voltage. (dcr of inductor: 20m ? ) th ese data show characteristic value of the ic. it doesn t guarantee the operat ing range. 2.7 2.9 3.1 3.3 3.5 3.7 0 1 2 3 input voltage : v cc [v] output current : i out [a] adj out v r r v ? ? ? )1 / ( 1 2 figure 31. typical application circuit en adj ith pvcc vcc sw gnd, pgnd c in v cc r ith c ith v out r 2 r 1 c o l c bst c 1 r f sw adj l co r 2 r 1 output figure 32. determination of output volt age downloaded from: http:///
16 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 7. bd8962muv cautions on pc board layout figure 34 . layout diagram (1) layout the input ceramic capacitor c in closer to the pins pv cc and pgnd, and the output capacitor co closer to the pin pgnd. (2) layout c ith and r ith between the pins ith and gnd as near as possible with the least necessary wiring. note: vqfn020v4040 (bd8962muv) has thermal pad on the reverse of the package. the package thermal performance may be enhanced by bonding the pad to gnd plane, which occupi es a large area of the pcb. 8. recommended components list for above application sy mbol part value manufacturer series l coil 2.0 h sumida cdr6d28mnp-2r0nc 2.2 h sumida cdr6d26np-2r2nc c in ceramic capacitor 22 f murata grm32eb11a226ke20 c o ceramic capacitor 22 f murata grm31cb30j226ke18 c ith ceramic capacitor v out =1.0v 1500pf mura ta crm18 series v out =1.2v 1000pf murata g rm 18 series v out =1.5v 1000pf murata g rm 18 series v out =1.8v 560pf murata g rm 18 series v out =2.5v 560pf murata g rm 18 series r ith resistance v out =1.0v 5.6k ? rohm mcr03 series v out =1.2v 6.8k ? rohm mcr03 series v out =1.5v 6.8k ? rohm mcr03 series v out =1.8v 8.2k ? rohm mcr03 series v out =2.5v 12k ? rohm mcr03 series cf ceramic capacitor 1000 pf murata g rm 18 series rf resistance 10 ? rohm mcr03 series c bst ceramic capacitor 0.1 f murata g rm 18 series note: the parts list presented above is an example of the recommended parts. although the parts are standard, actual circuit characteristics should be checked in your application carefully before use. be sure to allow sufficient margins to accommodate variations between external devices and this ic when employing the depicted circuit with oth er circuit constants modified. both static and transient characteristics should be considered in establishing these margins. when switching noise is significant and may affect the system, a low pass filter should be inserted between the v cc and pv cc pins, and a schottky barrier diode or snubber established between the sw and pgnd pins. downloaded from: http:///
17 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 i/o equivalent circuit figure 35 . i/o equivalent circuit en ? en pin ? sw pin pv cc sw pv cc pv cc ith ? ith pin v cc ? adj pin adj pv cc bst ? bst pin pv cc sw downloaded from: http:///
18 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 operational notes 1. reverse connection of power s upply connecting the power supply in reverse polarity can damage the ic. take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and th e ic s power supply pins. 2. power supply lines design the pcb layout pattern to provide low impedance supply lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the an alog block. furthermore, connect a capacitor to ground at all power supply pins . consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. ground voltage ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. ground wiring pattern when using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal ground caused by large currents. also ensure that the ground traces of external components do not cause variations on the ground voltage. the ground lines must be as short and thick as possible to reduce line impedance. 5. thermal consideration should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. in case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the pd rating. 6. recommended operating conditions these conditions represent a range within which the expected characteristics of the ic can be approximately obtained . the electrical characteristics are guaranteed under the conditions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the ic has more than one power supply. therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. operation under strong electromagnetic field operating the ic in the presence of a strong electromagnetic field may cause the ic to malfunction. 9. testing on application boards when testing the ic on an application board, connecting a capacitor directly to a low-impedance output pin may subject the ic to stress. always discharge capacitors completely after each process or step. the ic s power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. to prevent damage from static discharge, ground the ic during assembly and use similar precautions during transport and storage. 10. inter-pin short and mounting errors ensure that the direction and position are correct when mounting the ic on the pcb. incorrect mounting may result in damaging the ic. avoid nearby pins being shorted to each other especially to ground, power supply and outp ut pin . inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environme nt) and unintentional solder bridge deposited in between pins during assembly to name a few. downloaded from: http:///
19 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 operational notes C continued 11. unused input pins input pins of an ic are often connected to the gate of a mos transistor. the gate has extremely high impedance and extremely low capacitance. if left unconnected, the electric field from the outside can easily charge i t. the small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the ic. so unless otherwise specified, unused input pins should be connected to the power supply or ground line. 12. regarding the input pin of the ic this monolithic ic contains p+ isolation and p substrate layers between adjacent elements in order t o keep them isolated. p-n junctions are formed at the intersection of the p layers with the n layers of other elements, creating a parasitic diode or transistor. for example (refer to figure below): when gnd > pin a and gnd > pin b, the p-n junction operates as a parasitic diode. when gnd > pin b, the p-n junction operates as a parasitic transistor. parasitic diodes inevitably occur in the structure of the ic. the operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the gnd voltage to an input pin (and thus to the p s ubstrate) should be avoided. figure 36. example of monolithic ic structure 13. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that prevents heat damage to the ic. normal operation should alway s be within the ic s power dissipation rating. if however the rating is exceeded for a continued period, the junction temperature (tj) will rise which will activate the tsd circuit that will turn off all output pins. when the tj falls below the tsd threshold, the circuits are automatically restored to normal operation. note that the tsd circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the tsd circuit be used in a set design or for any purpose other than protecting the ic from heat damage. 14. selection of inductor it is recommended to use an inductor with a series resistance element (dcr) 0.1 ? or less. especially, note that use of a high dcr inductor will cause an inductor loss, resulting in decreased output voltage. should this condi tion continue for a specified period (soft start time + timer latch time), output short circuit protection will be activated and output will be latched off. when using an inductor over 0.1 ? , be careful to ensure adequate margins for variation between external devices and this ic, including transient as well as static characteristics. furthermore, in any case, it is recommended to start up the output with en after supply voltage is within. n n p + p n n p + p substrate gnd n p + n n p + n p p substrate gnd gnd parasitic elements pin a pin a pin b pin b b c e parasitic elements gnd parasitic elements c be transistor (npn) resistor n region close-by parasitic elements downloaded from: http:///
20 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 ordering information b d 8 9 6 2 m u v e 2 part number type adjustable (0.8v to 2.5v) package muv: vqfn0 20 v4040 packaging and forming specification e2: embossed tape and reel marking diagram vqfn020v4040 (top view) d 8 9 6 2 part number marking lot number 1pin mark downloaded from: http:///
21 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 physical dimension tape and reel information package name vqfn020v4040 downloaded from: http:///
22 / 22 bd8962muv datas heet tsz02201-0j3j0aj00030-1-2 02.oct.2014 rev.002 ? 2012 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 revision history date revision changes 02.mar.2012 001 new release 02.oct.2014 00 2 applied the rohm standard style and improved understandability. downloaded from: http:///
notice C ge rev.003 ? 2014 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. our products are designed and manufactured for application in ordinary electronic equipments (such as av equipment, oa equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). if you intend to use our products in devices requiring extremely h igh reliability (such as medical equipment (note 1) , transport equipment, traffic equipment, aircraft/spacecraft, nuclear power c ontrollers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (specific applications), please c onsult with the rohm sales representative in advance. unless otherwise agreed in writing by rohm in advance, rohm s hall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arisin g from the use of any rohms products for specific applications. (note1) medical equipment classification of the specific appli cations japan usa eu china class class class b class class | class 2. rohm designs and manufactures its products subject to s trict quality control system. however, semiconductor products can fail or malfunction at a certain rate. please be sure to implement, at your own responsibilities, adeq uate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our products may cause. the followi ng are examples of safety measures: [a] installation of protection circuits or other protective devic es to improve system safety [b] installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. our products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified be low. accordingly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any rohms products under any special or extraordinary environments or conditions. if you intend to use our products under any special or extraordinary environments or conditions (as exemplified belo w), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be n ecessary: [a] use of our products in any types of liquid, including water, oils, chemicals, and organi c solvents [b] use of our products outdoors or in places where the products are exposed to direct sunlight or dust [c] use of our products in places where the products are ex posed to sea wind or corrosive gases, including cl 2 , h 2 s, nh 3 , so 2 , and no 2 [d] use of our products in places where the products are exposed to static electricity or electromagnetic waves [e] use of our products in proximity to heat-producing components , plastic cords, or other flammable items [f] sealing or coating our products with resin or other coating materials [g] use of our products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or washing our products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] use of the products in places subject to dew condensation 4. the products are not subject to radiation-proof design. 5. please verify and confirm characteristics of the final or mou nted products in using the products. 6. in particular, if a transient load (a large amount of load a pplied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board moun ting is strongly recommended. avoid applying power exceeding normal rated power; exceeding the power rating u nder steady-state loading condition may negatively affect product performance and reliability. 7. de -rate power dissipation (pd) depending on ambient temperature (ta). whe n used in sealed area, confirm the actual ambient temperature. 8. confirm that operation temperature is within the specified range described in the product specification. 9. rohm shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. precaution for mounting / circuit board design 1. when a highly active halogenous (chlorine, bromine, e tc.) flux is used, the residue of flux may negatively affect p roduct performance and reliability. 2. in principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method mus t be used on a through hole mount products. i f the flow soldering method is preferred on a surface-mount p roducts , please consult with the rohm representative in advance. for details, please refer to rohm mounting specification downloaded from: http:///
notice C ge rev.003 ? 2014 rohm co., ltd. all rights reserved. precautions regarding application examples and external circuits 1. if change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the products and external components, incl uding transient characteristics, as well as static characteristics. 2. you agree that application notes, reference designs, and associated data and information contained in this docu ment are presented only as guidance for products use. therefore, i n case you use such information, you are solel y responsible for it and you must exercise your own independ ent verification and judgment in the use of such information contained in this document. rohm shall not be in any way respon sible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such informat ion. precaution for electrostatic this product is electrostatic sensitive product, which may b e damaged due to electrostatic discharge. please take pro per caution in your manufacturing process and storage so t hat voltage exceeding the products maximum rating will not be applied to products. please take special care under dry con dition (e.g. grounding of human body / equipment / solder 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 places where: [a] the products are exposed to sea winds or corrosive gases, inc luding cl2, h2s, nh3, so2, and no2 [b] the temperature or humidity exceeds those recommended by rohm [c] the products are exposed to direct sunshine or condensation [d] the products are exposed to high electrostatic 2. even under rohm recommended storage condition, solderab ility of products out of recommended storage time period may be degraded. it is strongly recommended to confirm so lderability before using products of which storage time is exceeding the recommended storage time period. 3. store / transport cartons in the correct direction, which is in dicated on a carton with a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a c arton. 4. use products within the specified time after opening a hum idity barrier bag. baking is required before using products of which storage time is exceeding the recommended storage tim e period. precaution for product label qr code printed on rohm products label is for rohm s internal use only. precaution for disposition when disposing products please dispose them properly usin g an authorized industry waste company. precaution for foreign exchange and foreign trade act since our products might fall under controlled goods prescr ibed by the applicable foreign exchange and foreign trade act, please consult with rohm representative in case of export. precaution regarding intellectual property rights 1. all information and data including but not limited to ap plication example contained in this document is for referen ce only. rohm does not warrant that foregoing information or da ta will not infringe any intellectual property rights or any other rights of a ny third party regarding such information or data. rohm shall not be in any way responsible or liable for infringement of any intellectual property rights or other d amages arising from use of such information or data.: 2. no license, expressly or implied, is granted hereby under any i ntellectual property rights or other rights of rohm or any third parties with respect to the information contained in this d ocument. other precaution 1. this document may not be reprinted or reproduced, in whole or in part, without prior written consent of rohm. 2. the products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of rohm. 3. in no event shall you use in any way whatsoever the products and the related technical information contained in the products or this document for any military purposes, includi ng but not limited to, the development of mass-destruction weapons. 4. the proper names of companies or products described i n this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties. downloaded from: http:///
datasheet datasheet notice ? we rev.001 ? 2014 rohm co., ltd. all rights reserved. general precaution 1. before you use our pro ducts, you are requested to care fully read this document and fully understand its contents. rohm shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny rohms products against warning, caution or note contained in this document. 2. all information contained in this docume nt is current as of the issuing date and subj ec t to change without any prior notice. before purchasing or using rohms products, please confirm the la test information with a rohm sale s representative. 3. the information contained in this doc ument is provi ded on an as is basis and rohm does not warrant that all information contained in this document is accurate an d/or error-free. rohm shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. downloaded from: http:///

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