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product structure silicon monolithic integrated circuit this product has no designed protection against radioactive ra ys . 1/ 22 tsz02201-0j2j0a601100-1-2 ? 20 15 rohm co., ltd. all rights reserved. 02.nov.2015 rev.001 tsz22111 ? 14 ? 001 www.rohm.com 0.75v to v cc -1v, 3a 1ch ultra low dropout linear regulator BD3508MUV general description BD3508MUV is an ultra-low-dropout linear chipset regulator that can operate from a very low input supply voltage. the product offers ideal performance at low input voltage and low output voltage applications. a built -in n-channel mosfet is incorporated to minimize the input- to -output differential voltage across the on resistance (r on = 100m (max) ). th is lower dropout voltage ensur es high output current (i outmax =3.0a) and reduces conversion loss, and thereby eliminates the need for a switching regulator, its power transistor, choke coil, and rectifier diode. BD3508MUV is designed with si gnificant package profile downsizing and reducing cost. external resistors allow a wide range of output voltage configurations from 0.65 to 2.7v . nrcs (soft-start) function enables a controlled output voltage ramp- up , which can be programmed to any require d power supply sequence. features ? high-precision internal reference voltage circuit (0.65v1%) ? built-in vcc under voltage lock out circuit (v cc =3.80v) ? nrcs (soft-start) function for reduction of in-rush current ? internal n- ch annel mosfet driver offers low on resistance ? built-in current limit er circuit (3.0a min) ? built-in thermal shutdown (tsd) circuit ? tracking function key specifications ? in input voltage range: 0.75v to v cc -1v ? vcc input voltage range: 4.3v to 5.5v ? output voltage range: 0.65 v to 2.7v ? output current: 3 .0 a (max) ? on -resistance: 65 m (typ) ? standby current: 0 a (typ) ? operating temperature range: -10c to + 10 0c package w(typ) x d(typ) x h(max ) applications notebook computers, desktop computers, lcd-tv, dvd, digital appliances typical application circuit and block diagram vqfn020v4040 4.00mm x 4.00mm x 1.00mm out reference block thermal shutdown nrcs current limit cl uvlo tsd en vcc uvlo vcc cl en vcc vcc in1 in2 in3 out1 out2 out3 fb gate gnd nrcs in tsd 7 6 20 1 2 11 8 9 10 16 17 18 19 datashee t datashee t downloaded from: http:///
2/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 pin configuration pin descriptions pin no. pin name pin function 1 gnd1 ground pin 1 2 gnd2 ground pin 2 3 n.c. no connection (empty) pin (note) 4 n.c. no connection (empty) pin (note) 5 n.c. no connection (empty) pin (note) 6 vcc power supply pin 7 en enable input pin 8 in1 input pin 1 9 in2 input pin 2 10 in3 input pin 3 11 gate gate pin 12 n.c. no connection (empty) pin (note) 13 n.c. no connection (empty) pin (note) 14 n.c. no connection (empty) pin (note) 15 n.c. no connection (empty) pin (note) 16 out1 output voltage pin 1 17 out2 output voltage pin 2 18 out3 output voltage pin 3 19 fb reference voltage feedback pin 20 nrcs in -rush current protection (nrcs) capacitor connection p in reverse fin connected to heatsink and gnd (note) please short n.c to the gnd. description of blocks 1. amp this is an error amplifier that functions by comparing the reference voltage (0.65v) with the fb voltage to drive the output n- ch annel fet. the frequency characteristics are optimized su ch that polymer output capacitors can be used ad rapid transit response can be achieved . the amp output voltage ranges from gnd to vcc. when en is off, or when uvlo is active, the output goes low and the output n- ch annel fet switches off. 2. en en is a logic input pin which controls the regulator on or off . when the regulator is off, the circuit current is maintained at 0a, minimizing current consumption duri ng standby. when the fet is switched on , the discharge of nrcs and out is enabled , draining the excess charge and prevent ing the load ic from malfunctioning. since no electrical connection is required (such as between the v cc pin and the esd prevention diode), module operation is independent of the input sequence. 3. uvlo to prevent malfunction that can occur when there is a brief d ecrease in v cc supply voltage, the uvlo circuit switches the output off . like en, uvlo discharges the nrcs and out. once the uvlo threshold voltage (typ 3.80v) is exceeded, uvlo turns the output on. 4. current limit when the output is on and the output current exceeds the set c urrent limit threshold (0.6a or more), the output voltage is attenuated to protect the ic on the load side. when current decreas es, the output voltage is restored to the allowable value. 5. nrcs the soft-start function can be accomplished by connecti ng an external capacitor across the nrcs pin and the target ground. output ramp-up can be set to any period up to the time the nrcs pin reaches v fb (0.65v). during startup, the nrcs pin serves as a 20a ( ty p) constant current source and charges the external capacitor. 16 17 18 19 20 1 2 3 4 5 10 9 8 7 6 15 14 13 12 11 n.c n.c n.c n.c gate n.c n.c n.c gnd2 gnd1 in3 in2 in1 en vcc out1 out2 out3 fb nrcs fin top view downloaded from: http:///
3/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 6. tsd (thermal shut down) the thermal shutdown (tsd) circuit automatically switches o utput off when the chip temperature becomes too high, protecting the ic against thermal runaway and heat damage. si nce the tsd circuit shuts down the ic during extreme heat conditions, in order to avoid potential problems with the tsd, during thermal design, it is crucial that tj(max) parameter is not exceeded. 7. in the in line acts as the major current supply line, and is connected to the output n-channel fet drain. since there is no electrical connection with the vcc terminal, as in the case when an esd diode is connected, so its operation doe s not depend on the input sequence. however, because of the b ody diode of the output n-channel fet, there is electrical connection (diode connection) between in and out. con sequently, when the output is turned on and off by in, reverse current flows, in which case care must be taken. absolute maximum ratings (ta= 25 c ) parameter symbol rating unit input voltage 1 v cc 6.0 (note 1) v input voltage 2 v in 6.0 (note 1) v enable input voltage v en 6.0 v power dissipation 1 pd 1 0.34 (note 2) w power dissipation 2 pd 2 0.70 (note 3) w power dissipation 3 pd 3 2.21 (note 4) w power dissipation 4 pd 4 3.56 (note 5) w operating temperature range topr - 10 to + 100 c storage temperature range tstg - 55 to +1 25 c maximum junction temperature tjmax +150 c (note 1) should not exceed pd. (note 2) derating in done 2.7mv/ c for operating above ta 25 c no heat sink (note 3) derating in done 5.6mv/ c for operating above ta 25 c pcb size:74.2mm x 74.2mm x 1.6mm when mounted on a 1-layer glass ep oxy board(copper foil area : 10.29mm 2 ) (note 4) derating in done 17.7mv/ c for operating above ta 25 c pcb size:74.2mm x 74.2mm x 1.6mm when mounted on a 4-layer glass epoxy board(copper foil area : front and rever se 10.29mm 2 , 2nd and 3rd 5505mm 2 ) (note 5) derating in done 28.5mv/ c for operating above ta 25 c pcb size:74.2mm x 74.2mm x 1.6mm when mounted on a 4-layer glass ep oxy board(copper foil area : each 5505mm 2 ) caution : operating the ic over the absolute maximum ratings may damage the ic. the damage can either 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 operated over the absolute maximum ratings. recommended operating conditions (ta=25 c ) parameter symbol rating unit min max input voltage 1 v cc 4.3 5.5 v input voltage 2 v in 0.75 v cc - 1 (note 6) v output voltage setting range v out v fb 2.7 v enable input voltage v en -0.3 +5.5 v nrcs capacity c nrcs 0.001 1 f (note 6) vcc and in do not have to be implemented in the order listed. downloaded from: http:///
4/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 electrical characteristics (unless otherwise specified, ta=25 c v cc =5v v en =3v v in =1.8v r 1 =3.9k r 2 =3.3k ) parameter symbol limit unit conditions m in t yp m ax circuit current i cc - 0.7 1.4 ma vcc shutdown mode current i st - 0 10 a v en =0v output voltage v out - 1.200 - v maximum output current i out 3.0 - - a output short circuit current i ost - - 4.0 a v out =0v output voltage temperature coefficient tcvo - 0.01 - %/ c feedback voltage 1 v fb1 0.643 0.650 0.657 v feedback voltage 2 v fb2 0.630 0.650 0.670 v i out =0 a to 3a tj=- 10 c to +100 c (note 7) line regulation 1 reg.l1 - 0.1 0.5 %/v v cc =4.3v to 5.5v line regulation 2 reg.l2 - 0.1 0.5 %/v v in =1.2v to 3.3v load regulation reg.l - 0.5 10 mv i out =0 to 3a minimum input-output voltage differential dvo - 65 100 mv i out =1a,v in =1.2v tj=- 10 c to 100 c (note 7) standby discharge current i den 1 - - ma v en =0v, v out =1v [enable] enable pin input voltage hi gh v enhi 2 - - v enable pin input voltage low v enlow -0.2 - +0.8 v enable input bias current i en - 7 10 a v en =3v [feedback] feedback pin bias current i fb - 100 0 + 100 na [nrcs] nrcs charge current i nrcs 14 20 26 a v nrcs =0.5v nrcs standby voltage v stb - 0 50 mv v en =0v [uvlo] vcc under voltage lock out threshold voltage v cc uvlo 3.5 3.8 4.1 v vcc: sweep- up vcc under voltage lock out hysteresis voltage v cchys 100 160 220 mv vcc: sweep-down [amp] gate source current i gso 1.0 1.6 - ma v fb =0, v gate =2.5v gate sink current i gsi 3.0 4.7 - ma v fb =v cc , v gate =2.5v (note 7) not 100% tested downloaded from: http:///
5/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical waveforms figure 2. transient response (0 a to 3a) c out =150 f 64mv 3.0a v out 50mv/div i out 2a/div i out =0a to 3a/3sec t(5sec/div) figure 1. transient response (0 a to 3a) c out =150f x 2, c fb =0.01f 45mv 3.0a v out 50mv/div i out 2a/div i out =0a to 3a/3sec t(5sec/div) figure 3. transient response (0 a to 3a) c out =47f, c fb =0.01f 91mv 3a v out 100mv/div i out 2a/div i out =0a to 3a/3sec t(5sec/div) figure 4. transient response (3a to 0a) c out = 150 f x 2 v out 50mv/div i out 2a/div 55mv 3.0a i out =3a to 0a/3sec t(5sec/div) downloaded from: http:///
6/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical waveforms C continued figure 5. transient response (3a to 0a) c out =150f v out 50 mv/div i out 2a/div 79mv 3.0a i out =3a to 0a/3sec t(5sec/div) figure 6. transient response (3a to 0a) c out =47f v out 100mv/div i out 2a/div 87mv 3a i out =3a to 0a/3sec t(5sec/div) figure 7. wa veform at output start v en 2v/div v nrcs 2v/div v out 1v/div t(200sec/div) figure 8. waveform at output off v en 2v/div t(2msec/div) v nrcs 2v/div v out 1v/div downloaded from: http:///
7/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical waveforms C continued figure 9. input sequence v cc v en v in v out v cc to v in to v en figure 10 . input sequence v cc v en v in v out v in to v cc to v en figure 11 . input sequence v cc v en v in v out v en to v cc to v in figure 12. input sequence v cc v en v in v out v cc to v en to v in downloaded from: http:///
8/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical waveforms C continued v cc v en v in v out v in to v en to v cc figure 13. in put sequence figure 14. input sequence v cc v en v in v out v en to v in to v cc downloaded from: http:///
9/ 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical performance curves figure 17. i st vs temperature temperature : ta (c) i st (a) figure 18. i in vs temperature 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 -10 10 30 50 70 90 ta( ) iin(ma) 100 temperature : ta (c) i in (ma) figure 15. output voltage vs temperature (i out =0ma) 100 temperature : ta (c) output voltage : v out (v) figure 16. circuit current vs temperature 0.50 0.55 0.60 0.65 0.70 0.75 0.80 0.85 0.90 0.95 1.00 -10 10 30 50 70 90 ta( ) icc(ma) 100 temperature : ta (c) circuit current : i cc (ma) downloaded from: http:///
10 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical performance curves C continued figure 21. feedback pin bias current vs temperature -20 -15 -10 -5 0 5 10 15 20 -10 10 30 50 70 90 ta( ) if b(na) 100 temperature : ta (c) feedback pin bias current : i fb (na) figure 22. enable pin bias current vs temperature 0 1 2 3 4 5 6 7 8 9 10 -10 10 30 50 70 90 ta( ) ien(ua) 100 temperature : ta (c) enable input bias current : i en (a) figure 19. i instb vs temperature temperature : ta (c) i in stb (a) figure 20. nrcs charge current vs temperature 15 16 17 18 19 20 21 22 23 24 25 -10 10 30 50 70 90 ta( ) inrcs(ua) 100 temperature : ta (c) nrcs charge current : i nrcs (a) downloaded from: http:///
11 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 typical performance curves C continued figure 23. r on vs temperature (v cc =5v/v out =1.2v) 0 10 20 30 40 50 60 -10 10 30 50 70 90 ta( ) ron(m ) 100 temperature : ta (c) r on (m) figure 24. r on vs input voltage 2.5v 1.8v 1.2v r on (m) input voltage : v cc (v) downloaded from: http:///
12 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 timing chart en on/off vcc on/off in vcc en nrcs out start up 0.65v(typ) v out x 0.9v(typ) t 0.65v(typ) in v cc en nrcs out hysteresis uvlo start up 0.65v(typ) v out x 0.9v(typ) t downloaded from: http:///
13 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 application information 1. evaluation board evaluation board standard component list component rating manufacturer product name component rating manufacturer product name u1 - rohm BD3508MUV r7 0 - jumper c6 1 f murata grm188b11a105kd r18 3.9k rohm mcr03ezpf 5101 c8 10 f murata grm21bb10j106kd r19 2.2k rohm mcr03ezpf 3901 c16 22 f kyocera cm315w5r226k06at cfb 0.01 f murata grm188b11h103kd c20 0.01 f murata grm188b11h103kd - - - - evaluation board schematic out1 out2 out3 fb nrcs gnd1 gnd2 nc nc nc vcc en in1 in2 in3 nc nc nc nc gate 16 17 18 19 20 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 c8 c9 c10 c12 v in vin_s vcc sw1 en r7 vcc vcc c7 c6 c5 vdd pgood jp3 jp4a jp4b vcc vpgood r4 gnd_s gnd gnd c20 nrcs fb(s) r19 r18 cfb c17 c16 r15 c15 vo _s vo rld u2 mosfet rf1 rf2 jpf1 jpf2 vcc tp1 tp2 rf3 cf u3 bu4s584g2 jp14b jp14a jp13a r11 c11 gate jp13b u1 BD3508MUV downloaded from: http:///
14 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 evaluation board layout 2. recommended circuit example silk screen (bottom) bottom layer silk screen (top) middle layer_1 middle layer_2 top layer vo c 16 c 20 r 19 r 18 16 17 18 19 20 1 2 3 4 5 15 14 13 12 11 10 9 8 7 6 c 8 v in c 6 v cc v en c 18 downloaded from: http:///
15 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 component recommended value programming notes and precautions r 18 /r 19 3.6k / 3.9k ic output voltage can be set by feedback voltage(v fb ) and value of output voltage setting resistance(r 18 r 19 ). output voltage can be computed by v fb x (r 18 +r 19 )/r 19 but it is recommended to use at the resistance value(total:about 10k ) which is not suscepti ble to feedback pin bias current. c 16 22f to ensure output voltage stability, out1, out2 , out3 should be connected to each other . in additions, gnd pins should also be connected to each other. output capacitors play a role in loop gain phase compensation and mitig ation of output fluctuation during rapid changes in load level. insufficient capacitance ma y cause oscillation, while high equivalent series resistance (esr) will exacerbate output vol tage fluctuation under rapid load change conditions. while a 22 f ceramic capacitor is recommended, actual stability is highly dependent on temperature and load conditions. also, note that connecting different types of capacitors in series may result in insuf ficient total phase compensation, thus causing oscillation. confirm the operation a long a variety of temperature and load conditions. c 6 1f the input capacitor reduces the output impedence of the vol tage supply connected to the vcc. when the output impedence of this power supply increas es, the input voltage (v cc ) may become unstable. this may result to output oscillati on or lower ripple rejection. a low esr 1f capacitor with minimal susceptibility to temperature i s preferable, but stability depends on the power supply characteristics and the substr ate wiring pattern . confirm the operation across a variety of temperature and load condition s . c 8 10f input capacitors reduce the output impedance of the volta ge supply source connected to the in input pins. if the impedance of this power supply were to i ncrease , v in input voltage could become unstable, leading to oscillation or lowered ripple rejection function. while a low -esr 10f capacitor with minimal susceptibility to temperature is recommended, stability is highly dependent on the input power supply characteristics and the substrate wiring pattern. confirm the operation across a variety of temperature an d load conditions. c 20 0.01f during power supply start-up, the non-rush current on startu p (nrcs) function prevents rush current flow from in to out through the load, preventing impa ct on the output capacitors. constant current comes from the nrcs pin when en is high or the uvlo function is deactivated. the temporary reference voltage is proportional to time, due to the current charge of the nrcs pin capacitor, and output voltage start-up is proportionate to this reference voltage. capacitors with low susceptibility to temperature are recommended, in order to assure a stable soft-start time. c 18 0.01f this component is employed when the c 16 capacitor causes, or may cause, oscillation. this provides more precise internal phase correction. downloaded from: http:///
16 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 3. heat loss in thermal design, consider the temperature range wherein the ic is guaranteed to operate and apply appropriate margins . the temperature conditions that need to be considered are liste d below: (1) ambient temperature ta must not exceed 100 c . (2) chip junction temperature (tj) must not exceed 150 c . chip junction temperature can be determined as follows: calculation based on ambient temperature (ta) w aj ta tj ? ??? ? it is recommended to layout the heat radiation vias at the gnd pattern (at the back of the ic) when there is the gnd pattern in the inner layer (in using multiplayer substrat e). however, because this package is very small (size: 4 .0 mm x 4. 0mm) there is no available space to layout the via at the bottom of ic. spreading the pattern and increas ing the number of via like the figure below) can achieve superi or heat radiation characteristic. (see figure below. the via quantity and size number are designed suitable for the ac tual situation.) most of the heat loss that occurs in BD3508MUV is from the ou tput n-channel fet. power loss is determined by the total v in -v out voltage and output current. in the design, be sure to confi rm the system input , output voltage and the output current conditions in relation to the heat dissipatio n characteristics of the in and out. bear in mind that heat dissipation may vary substantially, depending on the su bstrate employed because due to the power package incorporated in BD3508MUV , consider conditions such as substrate size into thermal desig n. power consumption (w) = input voltage (v in ) - output voltage (v out ) x i out (ave) example) v in =1.5v, v out =1.25v, i out (ave) = 3 a ? ? ? ? ? ? ? ? ? ? ? ? w a v v w n consumptio power 75 .0 0.3 25 .1 5.1 ? ? ? ? ic only 1-layer board(copper foil area : 10.29mm 2 ) 4-layer board(copper foil area : front and reverse 10.29mm 2 , 2nd and 3rd 5505mm 2 ) 4-layer board(copper foil area : each 5505mm 2 ) substrate size: 74.2 x 74.2 x 1.6mm 3 (substrate with thermal via) j -a: vqfn020v4040 367.6 c /w 178.6 c /w 56.6 c /w 35.1 c /w downloaded from: http:///
17 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 power dissipation i /o equivalent circuits 4 layers (copper foil area : 5505mm 2 ) copper foil in each layers. j-a=35.1 c /w 4 layers (copper foil area front and reverse : 10.29mm 2 2nd and 3rd : 5505mm 2 ) j-a=56.6 c /w 1 layer (copper foil area : 10.29m 2 ) j-a=178.6 c /w ic only. j-a=367.6 c /w vcc out1 out2 50k 1k 1k out3 1k in1 in2 in3 vcc fb 1k 40 0k en nrcs vcc 1k 1k 1k 1k 1k vcc gate vcc vcc power dissipation:pd [w] ambient temperature:ta [ c ] 0 25 50 75 100 125 150 0 2.0 3.0 4.0 2.21w 3.56w 1.0 0.70w 0.34w 105 downloaded from: http:///
18 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 operational notes 1. reverse connection of power supply 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 externa l diode between the power supply and the ics power supply pins. 2. power supply lines design the pcb layout pattern to provide low impedance supp ly lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the groun d and supply lines of the digital block from affecting the analog block. furthermore, connect a capacitor to ground at all pow er supply pins. consider the effect of temperature and aging on the capacitance value when using electrolytic capa citors. 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-si gnal 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 exc eeded 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 expec ted characteristics of the ic can be approximately obtained. the electrical characteristics are guaranteed un der the conditions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that th e internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequen ce and delays, especially if the ic has more than one po wer supply. therefore, give special consideration to power cou pling 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 ma y 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 compl et ely 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 moun ting 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 output pin. inter-pin shorts could be due to many reasons such as m etal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins du ring assembly to name a few. 11. unused input pins input pins of an ic are often connected to the gate of a mos tra nsistor. the gate has extremely high impedance and extremely low capacitance. if left unconnected, the elec tric field from the outside can easily charge it. the smal l charge acquired in this way is enough to produce a signi ficant effect on the conduction through the transistor and cause unexpected operation of the ic. so unless otherwise spe cified, unused input pins should be connected to the power supply or ground line. downloaded from: http:///
19 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 operational notes C continued 12. regarding the input pin of the ic this monolithic ic contains p+ isolation and p substrate l ayers between adjacent elements in order to keep them isolated. p-n junctions are formed at the intersection of t he 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 paras itic 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 physica l damage. therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the gnd vo ltage to an input pin (and thus to the p substrate) should be avoided. figure 25. example of monolithic ic structure 13. area of safe operation (aso) operate the ic such that the output voltage, output current, and power dissipation are all within the area of safe operation (aso). 14. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that preven ts heat damage to the ic. normal operation should always be within the ics power dissipa tion rating. if however the rating is exceeded for a contin ued period, the junction temperature (tj) will rise which will activate the tsd circuit t hat 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 desi gn or for any purpose other than protecting the ic from heat damage. 15. output pin in the event that load containing a large inductance compone nt is connected to the output terminal, and generation of back-emf at the sta rt -up and when output is turned off is assumed, it is requested to ins ert a protection diode. tsd on temperature [c] (typ) hysteresis temperature [c] (typ) BD3508MUV 175 15 output pin (example) 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 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 ordering information b d 3 5 0 8 m u v - e 2 part number package muv : vqfn020v4040 packaging and forming specification e2 : embossed tape and reel marking diagram vqfn020v4040 (top view) d 3 5 0 8 part number marking lot number 1pin mark downloaded from: http:///
21 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 physical dimension, tape and reel information package name vqfn020v4040 downloaded from: http:///
22 / 22 BD3508MUV ? 20 15 rohm co., ltd. all rights reserved. www.rohm.com tsz22111 ? 15 ? 001 tsz02201-0j2j0a601100-1-2 02.nov.2015 rev.001 revision history date revision changes 02.nov.2015 001 new release downloaded from: http:///
datasheet d a t a s h e e t notice-pga-e rev.00 2 ? 2015 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. our products are designed and manufac tured for application in ordinary elec tronic equipments (such as av equipment, oa equipment, telecommunication equipment, home electroni c appliances, amusement equipment, etc.). if you intend to use our products in devices requiring ex tremely high reliability (such as medical equipment (note 1) , transport equipment, traffic equipment, aircraft/spacecra ft, nuclear power controllers, fuel c ontrollers, 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 consult with the rohm sale s representative in advance. unless otherwise agreed in writing by rohm in advance, rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ro hm?s products for specific applications. (note1) medical equipment classification of the specific applications japan usa eu china class class class b class class ? class 2. rohm designs and manufactures its products subject to strict quality control system. however, semiconductor products can fail or malfunction at a certain rate. please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe desi gn against the physical injury, damage to any property, which a failure or malfunction of our products may cause. the following are examples of safety measures: [a] installation of protection circuits or other protective devices 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 conditio ns, as exemplified below. accordin gly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of an y rohm?s 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 below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] use of our products in any types of liquid, incl uding water, oils, chemicals, and organic 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 ar e exposed 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 (ev en 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 subjec t to radiation-proof design. 5. please verify and confirm characteristics of the final or mounted products in using the products. 6. in particular, if a transient load (a large amount of load applied in a short per iod of time, such as pulse. is applied, confirmation of performance characteristics after on-boar d mounting is strongly recomm ended. avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading c ondition may negatively affect product performance and reliability. 7. de-rate power dissipation depending on ambient temperature. when used in sealed area, c onfirm that it is the use in the range that does not exceed t he maximum junction temperature. 8. confirm that operation temperat ure is within the specified range described in the product specification. 9. rohm shall not be in any way responsible or liable for fa ilure induced under deviant condi tion from what is defined in this document. precaution for mounting / circuit board design 1. when a highly active halogenous (chlori ne, bromine, etc.) flux is used, the resi due of flux may negatively affect product performance and reliability. 2. in principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. if the flow sol dering method is preferred on a surface-mount products, please consult with the rohm representative in advance. for details, please refer to rohm mounting specification downloaded from: http:///
datasheet d a t a s h e e t notice-pga-e rev.00 2 ? 2015 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, pl ease allow a sufficient margin considering variations of the characteristics of the products and external components, including transient characteri stics, as well as static characteristics. 2. you agree that application notes, re ference designs, and associated data and in formation contained in this document are presented only as guidance for products use. theref ore, in case you use such information, you are solely responsible for it and you must exercise your own indepen dent verification and judgment in the use of such information contained in this document. rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. precaution for electrostatic this product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. please take proper caution in your manufacturing process and storage so that voltage exceeding t he products maximum rating will not be applied to products. please take special care under dry condit ion (e.g. grounding of human body / equipment / solder iron, isolation from charged objects, se tting of ionizer, friction prevention and temperature / humidity control). precaution for storage / transportation 1. product performance and soldered connections may deteriora te if the products are stor ed in the places where: [a] the products are exposed to sea winds or corros ive gases, including cl2, h2s, nh3, so2, and no2 [b] the temperature or humidity exceeds those recommended by rohm [c] the products are exposed to di rect sunshine or condensation [d] the products are exposed to high electrostatic 2. even under rohm recommended storage c ondition, solderability of products out of recommended storage time period may be degraded. it is strongly recommended to confirm sol derability before using products of which storage time is exceeding the recommended storage time period. 3. store / transport cartons in the co rrect direction, which is indicated on a carton with a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. use products within the specified time after opening a humidity barrier bag. baking is required before using products of which storage time is exceeding the recommended storage time 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 proper ly using an authorized industry waste company. precaution for foreign exchange and foreign trade act since concerned goods might be fallen under listed items of export control prescribed by foreign exchange and foreign trade act, please consult with rohm in case of export. precaution regarding intellectual property rights 1. all information and data including but not limited to application example contained in this document is for reference only. rohm does not warrant that foregoi ng information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. rohm shall not have any obligations where the claims, actions or demands arising from the co mbination of the products with other articles such as components, circuits, systems or external equipment (including software). 3. no license, expressly or implied, is granted hereby under any intellectual property rights or other rights of rohm or any third parties with respect to the products or the informati on contained in this document. pr ovided, however, that rohm will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the produc ts, subject to the terms and conditions herein. other precaution 1. this document may not be reprinted or reproduced, in whol e 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 wa y whatsoever the products and the related technical information contained in the products or this document for any military purposes, incl uding but not limited to, the development of mass-destruction weapons. 4. the proper names of companies or products described in this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties. downloaded from: http:///
datasheet datasheet notice ? we rev.001 ? 201 5 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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