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product structure : silicon monolithic integrated circuit this product has no designed protection against radioactive rays . 1/ 21 tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 02.oct.2014 rev.002 tsz22111 ? 14 ? 001 www.rohm.com 4.5v to 5.5v, 2.0a 1ch synchronous buck converter with integrated fe t bd8961nv general description the bd8961nv is rohm's high efficiency step-down switching regulator designed to produce a voltage as low as 3.3v from a supply voltage of 5v. it offers h igh 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 mode control system ? h igh efficiency for all l oad ranges because of synchronous switches (nch/pch fet) ? soft-start function ? thermal shutdown and uvlo functions ? short circuit protection with time delay function ? shutdown function applications power supply for lsi including dsp, microcomputer and asic key specification ? input voltage range: 4.5v to 5.5v ? output voltage: 3.3v(typ) ? output current: 2.0a (max) ? switching frequency: 1.0mhz(typ) ? pch fet on-resistance: 200 m (typ) ? nch fet on-resistance: 150 m (typ) ? standby current: 0 a (typ) ? operating temperature range: - 25 c to + 10 5c package w(typ) x d(typ) x h(max) typical application circuit figure 1. typical application circuit son008v5060 5.00mm x 6.00mm x 1.00mm gnd,pgnd sw v cc ,pv cc en vout ith v cc v out c in r ith c ith l c o v out datashee t downloaded from: http:///
2/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 pin configuration pin description pin no. pin name p in function 1 vout output voltage pin 2 v cc v cc power supply input pin 3 ith gmamp output pin/connected phase compensation capacitor 4 gnd ground pin 5 pgnd nch fet source pin 6 sw pch/nch fet drain output pin 7 pv cc pch fet source pin 8 en enable pin (active high) block diagram top view en pv cc pgnd vout v cc ith gnd sw 1 8 7 8 6 5 3 4 2 figure 2. pin configuration figure 3 . block diagram vcc pvcc vcc downloaded from: http:///
3/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 absolute maximum ratings 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 en voltage v en -0.3 to +7 v sw,ith voltage v sw ,v ith -0.3 to +7 v po wer dissipation 1 pd1 0.90 (note 2) w power dissipation 2 pd2 3.90 (note 3) w operating temperature range topr - 25 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) mounted on 1 layer 70mm x 70mm x 1.6mm glass epoxy pcb (the density of copper: 3%). reduce by 7.2mw/c for ta over 25c. (note 3) mounted on jesd51-7. reduce by 31. 2mw/c for ta over 25 c. 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 prot ection measures, such as adding a fuse, in case the ic is operated over the absolute maximum ratings. recommended operating conditions (ta=25c) parameter symbol limit unit min typ max v cc voltage v cc (note 4) 4.5 5.0 5.5 v pv cc voltage pv cc (n ote 4) 4.5 5.0 5.5 v en voltage v en 0 - v cc v sw average output current i sw (note 4) - - 2.0 a (note 4) pd should not be exceeded. electrical characteristics (ta=25c , v cc =pv cc =3.3v, v en =v cc ) parameter symbol limit unit conditions min typ max standby current i stb - 0 10 a en =gnd bias current i cc - 250 450 a en low voltage v enl - gnd 0.8 v standby mode en high voltage v enh 2.0 v cc - v active m ode 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 r onp - 200 320 m pv cc =5v nch fet on-resistance r onn - 150 270 m pv cc =5v output voltage v out 3.250 3.300 3.350 v ith s i nk current i thsi 10 20 - a v out =3.6v ith source current i thso 10 20 - a v out =3.0v uvlo threshold voltage v uvlo1 3.6 3.8 4.0 v v cc =5 v to 0v uvlo release voltage v uvlo2 3.65 3.90 4.2 v v cc =0 v to 5v soft start time t ss 0.5 1 2 ms timer latch time t latch 1 2 3 ms scp/tsd operated output short circuit threshold voltage v scp - 1.65 2.31 v v out =3.3v to 0v downloaded from: http:///
4/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 typical performance curves figure 6. output voltage vs output current output current: i out [a] output voltage: v out [v] 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 figure 5. output voltage vs en voltage en voltage: v en [v] output voltage : v out [v] 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] ta=25c i o =2 a downloaded from: http:///
5/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 typical performance curves - continued figure 8. efficiency vs output current figure 9. frequency vs temperature output current : i out [ma] temperature: ta [c] efficiency: [%] frequency :f osc [mhz] figure 11 . en voltage vs temperature temperature: ta [c] en voltage: v en [v] v cc =5v v cc =5v ta=25c v cc =5v figure 10 . on -resistance vs temperature temperature: ta [c] on -resistance: r on [ ] v cc =5v pmos nmos downloaded from: http:///
6/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 typical performance curves - continued figure 12 . circuit current vs temperature temperature: ta [c] circuit current: i cc [ a] v cc =5v figure 13 . frequency vs input voltage input voltage : v cc [v] frequency: f osc [mhz] ta=25c downloaded from: http:///
7/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 typical waveforms figure 14 . soft start waveform v cc =5v ta=25c i o =0a v out 1 msec v cc =pv cc =en figure 15 . sw waveform (i o =10ma) v cc =5v ta=25c sw v out figure 16. transient response (i o = 1a to 2 a, 10s) v cc =5v ta= 25 c v out i out 100mv figure 17. transient response (i o =2a to 1a, 10s) v cc =5v ta= 25 c v out i out 110mv downloaded from: http:///
8/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 application information 1. operation bd8961nv is a synchronous step-down switching regulator that achieves fast transient response by employing curr ent mode pwm control system. (1) synchronous rectifier integrated synchronous rectification using two mosfets reduces power dissipation and increases efficiency when 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 o ff . 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 i l , 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/ 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 2. description of functio ns (1) soft-start function during start-up, the soft-start circuit gradually establishes the output voltage to limit the input current. this prevents the overshoot in the output voltage and inrush current. (2) shutdown function when en terminal is l ow, the device operates in standby mode and all the functional blocks including reference voltage circuit, internal oscillator and drivers are turned off . circuit current during standby is 0 a (typ). (3) uvlo function the uvlo circuit detects whether the supplied input voltage is sufficient to obtain the output voltage of this ic. t he uvlo threshold, which has a hysteresis of 100mv (typ), prevents output bouncing. figure 20 . soft start, shutdown, uvlo timing chart (4) short circuit protection circuit with time delay function to protect the ic from breakdown, the short circuit protection circuit 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 again by restarting en or by resetting uvlo. figure 21 . short-current protection circuit with time delay timing chart hysteresis 100mv t ss tss t ss soft start standby m ode operating mode standby m ode operating mode standby m ode operating mode standby m ode uvlo en uvlo uvlo v cc en v out t2=t latch output off latch en v out output short circuit threshold voltage i l output o ff operating mode operating mode en timer latch en output off i l limit t1 10 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 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 because of its synchronous rectifier (a) for heavier load: this ic utilizes the synchronous rectifying mode and uses low on -resistance mosfet power transistors. on -resistance of p-c hannel mos fet : 200m(typ) on -resistance of n-channel mos fet : 15 0m(typ) advantage 3 supplied in smaller package due to small-sized power mosfets reduces a mounting area required. figure 24. example application figure 23. efficiency 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=25c conventional product (load response i o =0.1a to 0.6a) bd8961nv (load response i o =1a to 2a) v out i out v out i out 160mv 100mv ? output capacitor, co, required for current mode control: 22f ceramic capacitor ? inductance, l, required for the operating frequency of 1 mhz: 2.2 h inductor r ith l co v out c ith v cc c in 10mm 15mm r ith c ith c in c o l dc/dc convertor controller efficiency: [% ] output current :i out [ma] downloaded from: http:///
11 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 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 ? ? drive out rss in i f i c v sw pd ? ? ? ? 2 ? ? cc in i v ic pd ? ? esr i esr pd rms ? ? 2 ) ( ) ( ) ( 2 2 on coil out r r i ri pd ? ? ? ? ? % 100 100 100 ? ? ? ? ? ? ? ? ? ? ? pd p p p p i v i v out out in out in in out out ? ? 2 v f c gate pd gs ? ? ? downloaded from: http:///
12 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 5. considerations on permissible dissipation and heat generation since this ic functions with high efficiency without significant heat generation in most applications, no special cons ideration 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 generatio n must be carefully considered. for dissipation, only conduction losses due to dc resistance of inductor and on-resistance of fet are considered. this is because conduction losses are the most significant among other dissipation factors mentioned above, gate charge/discharge dissipation and switching dissipation. if v cc =5v, v out =3.3v, r onp =0.2, r onn =0.1? i out =2a, for example, d=v out /v cc =3.3/5.0=0.66 r on =0.66x0.20+(1-0.66)x0.16 =0.132+0.0544 =0.184[] p=2 2 x0.1864 0.7456[ w] since r onp is greater than r onn in this ic, the dissipation increases as the on duty becomes greater. taking into consideration the dissipation shown above, thermal design must be carried out with allowable sufficient margin. 0 25 50 75 100 125 150 0 2.0 3.0 4.0 0.90w 3.9w 105 1.0 0.64w figure 25. thermal derating curve (son008v5060) power dissipation:pd [w] ambient temperature:ta [ ] for son008v5060 jedec 4 layer board 76.2mmx114.3mmx1.6mm j -a=32.1c /w for son008v5060 rohm standard 1 layer board 70mmx70mmx1.6mm j -a=138.9c /w ic only j -a=195.3c /w power dissipation : pd [w] ambient temperature :ta[c] ? ? onn onp on on out r d r d r r i p ? ? ? ? ? ? 1 2 d is the on duty (=v out /v cc ) r coil is the dc resistance of coil r onp is the on -resistance of p-channel mos fet r onn is the on -resistance of n-channel mos fet i out is the output current downloaded from: http:///
13 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 6. selection of externally connected components (1) selection of inductor (l) note: current exceeding the current rating of the i nductor results in magnetic saturation of the induc tor, which decreases efficiency. the inductor must be selected allowing sufficient margin with which the peak current may not exceed its curre nt rating. if v cc =5v, v out =3.3v, f=1mhz, i l =0.3ax2a=0.6a, for example,(bd8961nv) note: select an 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 ) (3) selection of input capacitor (c in ) a low esr 22f/10v ceramic capacitor is recommended to reduce esr dissipation of input capacitor for better efficiency. the inductance significantly depends on output ripple current. as shown in the equation (1), the ripple current decreases as the inductor and/or switching frequency increases. appropriate ripple current at output should be 20% to 30% of the maximum output current. where: i l is the output ripple current, and f is the switching frequency i l v cc i l l c o v out fi gure 26 . output ripple current i l figure 27 . output capacitor v cc l c o v out esr figure 28 . input capacitor v cc l c o v out c in output capacitor should be selected with the consideration on the stability region and the equivalent series resistance required to minimize the ripple voltage. output ripple voltage is determined by the 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. the input capacitor must be a low esr capacitor with a capacitance sufficient to cope with high ripple current to prevent high transient voltage. the ripple current i rms is given by the equation (5 ): < worst case > i rmsmax if v cc =5.0v, v out =3.3v, and i outm ax = 2a, (bd8961nv) ? ? ? ? a f v l v v v i cc out out cc l ? ? ? ? ? ? ??? (1) ??? (2) ? ? a i i outmax l ? ? ? 3.0 ??? (3) ? ? ? ? h f v i v v v l cc l out out cc ? ? ? ? ? ? ? ? ? ? h m l ? ? 2.2 87 .1 0.10.56.0 3.3 3.3 0.5 ? ? ? ? ? ? ? ??? (4) ? ? v esr i v l out ? ?? ? ??? (5) ? ? ? ? a v v v v i i cc out cc out out rms ? ? ? ? ? ? ? rms rms a i 947 .0 0.5 3.3 0.53.3 2 ? ? ? ? when v cc is twice the v out , 2 i i out rms ? downloaded from: http:///
14 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 (4) calculating r ith , c ith for phase compensat ion as the current mode control is designed to limit the inductor current, a pole (phase lag) appears in the low frequency area due to a cr filter consisting of an 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 canceling the pole fp (min) produced by the output cap acitor and the load resistance with cr zero correction by the error amplifier. pole at power amplifier when the output current decreases, the load resistance ro increases and the pole frequency decreases. zero at power amplifier figure 31. typical application circuit 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 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.) o o c r fp ? ? ? ? 2 1 ? ? o esr z c esr f ? ? ? ? 2 1 with lighter load ? ? ? ? hz co r fp omax min ? ? ? ? 2 1 with heavier load ? ? ? ? hz co r fp omin max ? ? ? ? 2 1 ? ? ith ith amp z c r f ? ? ? ? 2 1 ? ? ? ? co r c r f f omax ith ith min p amp z ? ? ? ? ? ? ? ? ? 2 1 2 1 gnd,pgnd sw v cc ,pv cc en vout ith v cc v out c in r ith c ith l c o v out downloaded from: http:///
15 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 7. bd8961nv cautions on pc board layout figure 32 . layout diagram for the sections drawn with heavy line, use thick conductor pattern as short as possible. lay out the input ceramic capacitor c in closer to the pins pv cc and pgnd, and the output capacitor co closer to pin pgnd. lay out c ith and r ith between the pins ith and gnd as near as possible with least necessary wiring. note: son008v5060 (bd8961nv) has thermal fin on the reverse of the package. the package thermal performance may be enhanced by bonding the fin to gnd plane which take a large area of pcb. 8. recommended components list for above application symbol part value manufacturer series l coil 2.2 h tdk ltf5022-2r2n3r2 c in ceramic capacitor 22 f kyocera cm32x5r226m10a c o ceramic capacitor 22 f kyocera cm316b226m06a c ith ceramic capacitor 680pf murata grm18 seri es r ith resistance 12k rohm mc r 03 seri es note: the parts list presented above is an example of recommended parts. although the parts are standard, actual circuit characteristics should be checked on your application carefully before use. be sure to allow sufficient margins to acc ommodate variations between external devices and this ic wh en employing the depicted circuit with other circuit constants modified. both stat ic and transient characteristics should be considered in establishing these margins. when switching noise is substantial and may impact the system, a low pass filter should be inserted between the v cc and pv cc pins, and a schottky barrier diode established between the sw and pgnd pins. vout v cc ith gnd en pv cc sw pgnd v cc r ith gnd c o c in v out en l c ith 1 2 3 4 8 7 6 5 downloaded from: http:///
16 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 i/o equivalent circuit figure 33 . i/o equivalent circuit en ? en pin ? sw pin pv cc sw pv cc pv cc it h ? ith pin v cc v cc vout 10k ? ? vout pin downloaded from: http:///
17 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 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 ics 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 ou tput pin . inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. downloaded from: http:///
18 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 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 to 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 34. 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 alwa ys be within the ics power dissipation rating. if however the rating is exceeded for a continued perio d, 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 con dition 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:///
19 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 ordering information b d 8 9 6 1 n v - e 2 part number package nv :son008v5060 packaging and forming specification e2: embossed tape and reel marking diagram son008v5060 (top view) d 8 9 6 1 part number marking lot number 1pin mark downloaded from: http:///
20 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. tsz22111 ? 15 ? 001 physical dimension, tape and reel information package name son008v5060 downloaded from: http:///
21 / 21 bd8961nv datas heet 02.oct.2014 rev.002 www.rohm.com tsz02201-0j3j0aj00020-1-2 ? 2012 rohm co., ltd. all rights reserved. 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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