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bd9479fv product structure silicon monolithic integrated circuit this product is not designed protection against rad ioactive rays . 1/26 tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9 . aug .2012 rev. 001 tsz22111 ? 14 ? 001 www.rohm.com datasheet led drivers for lcd backlights white led driver for large lcd panels (dcdc converter type) bd9479fv general description bd9479fv is a high efficiency driver for white leds and designed for large lcds. this ic is built-in a boost dcdc converters that employ an array of leds as the light source. bd9479fv has some protect function against fault conditions, such as the over-voltage protection (ovp), the over current limit protection o f dcdc (ocp), the short circuit protection (scp), the open detection of led string. therefore bd9479fv is available for the fail-safe design over a wide rang e output voltage. key specification operating power supply voltage range: 9.0v to 35.0v oscillator frequency: 150khz (rt=100k ) operating current: 8.7ma (typ.) operating temperature range: -40 to +85 applications tv, computer display, notebook, lcd backlighting features 8ch led constant current driver (external pnp tr type) maximum led setting current 500ma (vref pin setting) build-in dc/dc converter analog dimming (linear) function individual channel pwm dimming function led protection function (open short protection) [pwm-independent type] output short protection (ovp) built-in timer latch function (cp) built-in under voltage lockout function (uvlo) ? over voltage protection (ovp) built-in fail indication function built-in ovp voltage feedback function built-in pwm-independent soft start circuit ssop-b40 package package w(typ.) d(typ.) h(max.) ssop-b40: 13.6mm x 7.80mm x 1.80mm pin pitch: 0.65mm typical application circuit pgnd reg50 1 2 3 4 5 6 7 8 40 39 38 37 36 35 34 33 n cs ovp cp lsp stb bsx pwmx vcc fail agnd uvlo rt ss fb vref clx stb pwmx vref fail figure 2. typical application circuit figure 1. ssop-b40
2/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 absolute maximum ratings (ta=25 ) parameter symbol ratings unit power supply voltage vcc 36 v bs1-8 terminal voltage bs1-8 40 v ovp, stb, pwm1-8,vref,uvlo terminal voltage ovp, stb, pwm1 -8,vref,uvlo 20 v reg50, n, cs, cp, lsp, cl1-8, fb, ss, rt terminal voltage reg50, n, cs, cp, lsp, cl1-8, fb, ss, rt 7 v power dissipation (ssop-b40)*1 pd 1125 *1 mw operating temperature range ta(opr) -40 to +85 storage temperature range tstg -55 to +150 junction temperature tjmax 150 *1 ssop-b40 package at ta = 25 c or higher, de - rating power rating by - 9.0mw/ c(70.0mm x 70.0mm x1.6mm with 1-layer board) operating ratings (ta = 25 ) parameter symbol limits unit vcc supply voltage vcc 9.0 to 35.0 v analog dimming setting (vref pin) range vref 0.6 to 3.0 v lsp setting voltage range vlsp 0.3 to 3.0 v dc/dc oscillation frequency fct 100 to 800 khz pwm pin input frequency range f_pwm 0.05 to 20 khz above operating condition are the constants of ic itself. please pay attention at the actual set. pin configuration marking diagram and physical dimension ssop-b40 figure 3. pin configuration figure 4. physical dimension lot no bd9479fv 1pin mark marking
3/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 electrical characteristics (unless otherwise noted, ta = 25 o c, vcc=24v) parameter symbol limit unit condition min. typ. max. [whole device] operation current icc 8.7 14.0 ma stb=3v, pwm1-8=0v standby current ist 12 24 ua stb=0v [uvlo block] operation voltage vcc vuvlo_vcc 6.5 7.5 8.5 v vcc=sweep up hysteresis voltage vcc vuhys_vcc 150 300 600 mv vcc=sweep down operation voltage uvlo vuvlo 2.91 3.00 3.09 v uvlo=sweep up hysteresis voltage uvlo vuhys 170 210 250 mv uvlo=sweep down [dc/dc block] error amp base voltage veamp 0.55 0.60 0.65 v bsx pin, vref =0.9v oscillation frequency fct 142.5 150.0 157.5 khz rt= 100k ? n pin max duty output nmax_dut y 90 95 99 % rt=100k ? n pin source on resistor rnso 0.5 1 2 ? n pin sink on resistor rnsi 0.5 1 2 ? rt pin voltage vrt 1.00 1.50 2.00 v rt=100k ? ss pin source current issso -2.4 -2.0 -1.6 ua soft start ended voltage vss_ed 3.6 4.0 4.4 v fb pin source current ifbso -110 -100 -90 ua fb pin sink current ifbsi 85 100 115 ua over current detect vlotage vcs 0.35 0.40 0.45 v [dc/dc protection block] cp pin source current icpso -2.4 -2.0 -1.6 ua cp pin detect voltage vcp 2.375 2.500 2.625 v ovp high detect voltage vovph 2.137 2.250 2.363 v ovp feedback voltage vovpfb 2.375 2.500 2.625 v ovp low detect voltage vovpl 0.14 0.20 0.30 v [led pnp driver block] cl pin current setting voltage vrcl 295.5 300.0 304. 5 mv vref=0.9v cl pin current setting voltage (analog max) vrclmax -3% 1.0 +3% v vref max=3.0v cl pin current setting voltage (analog min) vrclmin -3% 200.0 +3% mv vref min=0.6v pnp driver output sink resistor rbs 55 80 120 ? pwmx=high, vcl=low vref pin input current ivref -1.0 0.0 1.0 ua vref=1v
4/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 electrical characteristics (unless otherwise noted, ta = 25 o c, vcc=24v) parameter symbol limit unit condition min. typ. max. [led protection block] led open detect voltage vopen 0.05 0.10 0.15 v bsx=sweep dow n led short detect voltage vlsp 8.5 9.0 9.5 v bsx=sweep up, lsp=open cl pin detect voltage vcllvp 0.05 0.10 0.15 v lsp pin pull high resistor rulsp 1260 2100 3180 k ? lsp=0v lsp pin pull down resistor rdlsp 540 900 1620 k ? lsp=3v [reg50 block] reg50 output voltage reg50 4.95 5.00 5.05 v io=-5ma reg50 maximum output current |ireg50| 5 - - ma dcdc block consumption is neglected. [stb block] stb pin high voltage stbh 2.0 - vcc v stb=sweep up stb pin low voltage stbl -0.3 - 0.8 v stb=sweep down stb pin pull down resistor rstb 0.5 1.0 2.0 m ? stb=3.0v [pwm input block] pwmx pin high detect voltage pwm_h 2.0 - 18 v pwm=sw eep up pwmx pin low detect voltage pwm_l -0.3 - 0.8 v pwm=s weep down pwmx pin pull down resistor rpwm 0.5 1.0 2.0 m ? pwm=3.0v [fail block(open drain)] fail pin ron rfail 30 50 85 ? fail pin leakage current ilfail -1.0 0.0 1.0 ua fail=36v (this product is not designed to be radiation-proof .)
5/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 pin descriptions pin no pin name in/out function rating [v] 1 reg50 out 5v regulator output for n output pin -0. 3 ~ 7 2 n out dc/dc switching output pin -0.3 ~ 7 3 pgnd - power gnd - 4 cs in dcdc external nmos current monitor pin -0.3 ~ 7 5 ovp in overvoltage protection detection pin -0.3 ~ 20 6 cp out timer latch setting pin -0.3 ~ 7 7 lsp in led short voltage setting pin -0.3 ~ 7 8 stb in enable pin -0.3 ~ 20 9 bs1 in pnp tr base connecting pin -0.3 ~ 40 10 bs2 in pnp tr base connecting pin -0.3 ~ 40 11 bs3 in pnp tr base connecting pin -0.3 ~ 40 12 bs4 in pnp tr base connecting pin -0.3 ~ 40 13 bs5 in pnp tr base connecting pin -0.3 ~ 40 14 bs6 in pnp tr base connecting pin -0.3 ~ 40 15 bs7 in pnp tr base connecting pin -0.3 ~ 40 16 bs8 in pnp tr base connecting pin -0.3 ~ 40 17 pwm1 in dimming signal input pin -0.3 ~ 20 18 pwm2 in dimming signal input pin -0.3 ~ 20 19 pwm3 in dimming signal input pin -0.3 ~ 20 20 pwm4 in dimming signal input pin -0.3 ~ 20 21 pwm5 in dimming signal input pin -0.3 ~ 20 22 pwm6 in dimming signal input pin -0.3 ~ 20 23 pwm7 in dimming signal input pin -0.3 ~ 20 24 pwm8 in dimming signal input pin -0.3 ~ 20 25 cl8 out pnp tr collector ? current detection pin -0.3 ~ 7 26 cl7 out pnp tr collector ? current detection pin -0.3 ~ 7 27 cl6 out pnp tr collector ? current detection pin -0.3 ~ 7 28 cl5 out pnp tr collector ? current detection pin -0.3 ~ 7 29 cl4 out pnp tr collector ? current detection pin -0.3 ~ 7 30 cl3 out pnp tr collector ? current detection pin -0.3 ~ 7 31 cl2 out pnp tr collector ? current detection pin -0.3 ~ 7 32 cl1 out pnp tr collector ? current detection pin -0.3 ~ 7 33 vref in led voltage setting pin -0.3 ~ 20 34 fb in/out dcdc phase-compensation pin -0.3 ~ 7 35 ss out soft start pin -0.3 ~ 7 36 rt out dcdc frequency setting resistor connection pin -0.3 ~ 7 37 uvlo in under voltage lockout protection pin -0.3 ~ 20 38 agnd - analog gnd - 39 fail out error detection output pin -0.3 ~ 36 40 vcc - power supply pin -0.3 ~ 36
6/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 pin esd type reg50 / n / pgnd / cs ovp cp lsp stb bs (1-8) / cl (1-8) pwm (1-8) vref fb ss rt figure 5-1. pin esd type reg50 n pgnd cs 100k
7/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ? ? ? uvlo fail figure 5-2. pin esd type block diagram figure 6. block diagram
8/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 3 5 7 9 11 13 15 9 13 17 21 25 29 33 icc [ma] vcc [v] 2 3 4 5 6 7 9 13 17 21 25 29 33 reg50 [v] vcc [v] 0 0.4 0.8 1.2 1.6 2 0.6 1.1 1.6 2.1 2.6 vrcl1 [v] vref [v] 0.01 0.1 1 10 0.015 0.035 0.055 0.075 0.095 0.115 0.135 n freq [mhz] rrt [m ? ] 200 220 240 260 280 300 320 340 360 380 400 -40 -20 0 20 40 60 80 vrcl1 [v] temp [c] -160 -120 -80 -40 0 40 80 120 160 0 0.2 0.4 0.6 0.8 1 1.2 1.4 ifb [ua] vbs1 [v] typical performance curve figure 7. operating current (icc) [ma] vs. vcc[v] figure 8. reg50[v] vs. vcc[v] figure 9. cl1 voltage (vrcl1) [v] vs. vref [v] figure 10. n frequency [mhz] vs. r_rt [m ] figure 11. cl1 voltage (vrcl1) [v] vs. temp [ ] figure 12. fb current (ifb) [ua] vs. vbs1 [v]
9/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 pin function pin 1: reg50 the reg pin is used in the dc/dc converter driver bl ock to output 5v power. the maximum operating curre nt is 5ma. using the reg pin at a current higher than 5ma can a ffect the n pin output pulse, causing the ic to mal function and leading to heat generation of the ic itself. to avo id this problem, it is recommended to make load set ting to the minimum level. pin 2:n the n pin is used to output power to the external n mos gate driver for the dc/dc converter in the ampli tude range of approx. 0 to 5v. frequency setting can be made with a resistor connected to the rt pin. for details of frequency setting, refer to the description of the rt pin . pin 3: pgnd the pgnd pin is a power ground pin for the driver bl ock of the n output pin. pin 4: cs cs pin is current detect for dc/dc current mode indu ctor current control pin. current flowing through the inductor is converted i nto voltage by the current sensing resistor rcs conn ected to the cs pin and this voltage is compared with voltage set w ith the error amplifier to control the dc/dc output voltage. the cs pin also incorporates the overcurrent protect ion (ocp) function. if the cs pin voltage reaches 0.4 v (typ.) or more, switching operation will be forcedly stopped. in order to prevent the malfunction while ocp occur red in bd9479fv,it equipped with mask function.it ma sk ocp signal within 200ns interval after n driver is outputted. pin 5: ovp the ovp pin is an input pin for overvoltage protecti on and short circuit protection of dc/dc output vol tage.when voltage of it over 2.25v or higher,cp pin start to charge.wh en it over 2.5v(typ),it will control fb pin.when ovp p in voltage is near 2.5v,dcdc output feedback will controlled by o vp pin voltage. when ovp pin voltage<0.2v (typ.) or lower,short circu it protection (scp) function is activated, and output of gate driver will become low immediately. pin 6: cp cp pin which sets the time from detection of abnorma lity until shutdown (timer latch).it charges consta nt current of 2.0ua to capacitor externally connected with cp pi n and shuts down when it exceeds 2.5v(typ.). pin 7: lsp led short detect voltage setting pin.when lsp=open, lsp pin voltage is 0.9v( typ), the bsx pin of led short dete ct voltage is set to 9v. the 10 times of lsp pin voltage is the bsx pin led short protection detect voltage. please set lsp pin input voltage range from 0.3v 3.0v. pin 8 :stb on/off setting pin and allowed for use to reset the ic from shutdown. the ic state is switched (i.e., the ic is switched between on and off state) according to voltages inp ut in the stb pin. avoid using the stb pin between two states (0.8 to 2.0v). pin 9-16 :bs1-bs8 led driver output pin.please connect to base terminal of external pnp tr. pin 17-24 :pwm1 C pwm8 on/off terminal of led driver pin.it inputs pwm dimm ing signal directly to adjust output duty dimming. high/low level of pwm terminal is shown as follows: state pwm voltage led on state pwm= 2.0v~5.0v led off state pwm= 0.3v 0.8v pin 25-32 : cl8 C cl1
10/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 led current detect pin.by monitoring voltage of clx p in to detect led current.please connect resistor to collector pin of external pnp tr. pin 33 : vref led current setting pin.1/3(typ) of applied voltage to vref pin will be led current feedback voltage, 2/3(typ.) of its voltage will be dcdc feedback voltage the lowest bsx pin feedback voltage . basically, because hi accuracy of resistor divider i s inputted to vref pin externally, the ic internally will be open high impedance state.please use external power to design it.it cannot be used in open state. pin 34 : fb current mode control dc/dc converter error amplifie r output pin.by monitoring voltage of bs 1 8 pin, the highest vf of led column will set 2/3(typ.) of applied vref voltage to bs pin voltage to control inductor current. the phase compensation setting has described separa tely. in addition, pwm pin will become high impedance whe n all pwm signals are in low state, and will mainta in fb voltage. pin 35 : ss the ss pin is used to set the soft start time and dut y for soft start duration.ss pin normally sources 2.0 ua (typ.) of current.when stb pin become high, it wait for in any one pwmx signal from low to high.in start-up durati on, ss will not charge because all pwmx pin are in low state. the bd9479fv has a built-in soft start startup circu it independent of pwm light modulation , and thereby raises fb voltage as ss pin voltage rises independent of the d uty cycle range of pwm light modulation.please pay attention to overshoot problem will occur while low duty is inpu tted to ic in start-up duration. pin 36 : rt rt sets charge/discharge current determining freque ncy inside ic. only a resistor connected to rt determines saw-toot h wave frequency inside ic. when rt=100,frequency=150khz(typ.). for calculation example, please refer to section in 3.2.2 C dc/dc drive frequency setting. pin 37 : uvlo uvlo pin of the coil of step-up dc/dc converter and the power for external nmosfet. at 3.0 v (typ.) or higher, ic starts step-up operatio n and stops at 2.79v or lower (typ.). (it is not shu tdown of ic.) pin 38 : agnd gnd pin for analog system inside ic. pin 39 : fail fail signal indication output pin (open drain).in no rmal operation, fail pin is open when stb=low.when an abnormality is detected, cp starts to charge to ext ernal capacitance and then shutdown ic while it rea ch 2.5v or higher.nmos on is 50 ohm(typ. when ic is shutdown.when vcc voltage is insufficient or uvlo pin voltage is lower, fail pin is also in open state. state fail output normal, stb=low, under abnormality detection open abnormality (shutdown), uvlo is detected gnd level (50 ohm typ.) pin 40 : vcc power source pin of ic, which should be input in the range of 9 C 35 v. operation starts when vcc is 7.5v (typ.) or higher and shuts down when vcc is 7.2 v (typ.).
11/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 3 ] [ ] [ ] [ = a i v v ohm r led vref cl led current setting (vref pin, clx pin) please decide vref pin input voltage first.when analog dimming is performed, please be noted that vref pin input voltage range is (0.6v 3.0v), and decide the input voltage in normal operation.basically, if vref p in voltage is high, it will cause power dissipation of external pnp tr become high, so it is preferred to set the vref pin voltage lower. later, vref 0.9v will be set as basic.for example if you create 0.9v from reg50, it is possible to use resistive divider by setting 82k ohm and 18kohm. in bd9479fv, the led current detection is performed b y clx pin.clx pin is controlled so that the voltage of 1/3v(typ.) of vref voltage.if vr ef=0.9v, clx=0.3v to control external pnp tr.therefore,if r cl is set as a resistance which between clx pin and gnd, and vref pin voltage is set as v vref , led current i led can be calculated as below. for current setting, set at each channel.for this r eason, in 1ch 4ch and 5ch 8ch, it is possible to change current by setting r cl value. dcdc operation frequency setting (rt pin) the operation frequency of dcdc output is set by re sistance which connected to rt pin. the relationship between operation and rt resistanc e (ideal) setting example ideal ] [ ] [ 15000 w = k khz f r sw rt above is an ideal equation which do not putted with correction terms for accurate frequency setting, please confirm on t he real system but, the frequency setting range is 100khz 800khz here, fsw dcdc converter oscillation frequency[khz]
12/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ] [0.4 ] [ 10 0.2 [sec] ] [ 6 v a t f c ss ss - = if dcdc frequency is set to be 200khz, rrt as below : maximum dcdc output voltage in bd9479fv, the voltage of bsx pin is depending on vr ef pin voltage.the maximum voltage of vref pin vref 3.0v , the voltage of bsx pin will become 2.0v 2/3 of vref voltage . the maximum voltage of dcdc output will have be var y with 1.6v while analog dimming is performed (2/3 of 3.0v - 0.6v). soft start time setting (ss pin) the start-up time of dcdc output is adjusted by con denser which connected to ss pin.its performs constan t current charge of 2.0ua to the external capacitor connected with ss pin, and the each protection and cp charge function will not activated before ss pin reaches to 4.0v. soft start time set here is mask time of cp charge, please pay attention to it is different from the t ime to stabilize dcdc output.the time to stabilize dcdc output is largely depending on step-up ratio and load condition. the soft start time t ss , and ss pin external condenser c ss can be calculated as below. ] [ 75 ] [ 200 15000 ] [ 15000 w = = = k khz khz f r sw rt
13/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 start-up and soft start (ss) capacitance setting the following describes the start-up sequence of th is ic. description of start-up sequence set stb from low to high system will be activated while pwm=h.ss start to charg e. at this time, a circuit in which ss pin voltage for sl ow start becomes equal to fb pin voltage operates t o equalize the fb pin and ss pin voltages regardless of whether the pwm pin is set to low or high l eve. since the fb pin and ss pin reach the lower limit of th e internal sawtooth wave of the ic, the dc/dc conve rter operates to start vout voltage rising. the vout voltage continues rising to reach a voltag e at which led current starts flowing. when the led current reaches the amount of current, isolate the fb circuit from the ss circuit. with thi s, the startup operation is completed. after that, normal operation is controlled by follow ing the feedback voltage of led pins. if the ss pin voltage reaches 4v or higher, the led pr otection function will be activated to forcedly end the ss and fb equalizing circuit. ss capacitance setting procedure as mentioned above, this ic stops dc/dc converter wh en the pwm pin is set to low level.conducts step-up operation only in the section in which the pwm pin is maintai ned at high level. consequently, setting the pwm du ty cycle to the minimum will extend the start-up time.in addition, start-up time also varies with application of outpu t capacitance selection, led current, output voltage, and others. start-up time at minimum duty cycle can be approxim ated according to the following method.first, measu re the start-up time of vout with a 100% duty and take this value as trise_100.the startup time trise_min for the rel evant application with the minimum duty cycle is given by the following equation. however, this calculation method is just for approx imation, use it only as a reference. please set a time t dcdcss during which the ss pin voltage reaches the fb pin vo ltage longer than this star-tup. assuming that the fb pin voltage is vfb, the time is gi ven by the following equation: as a result, it is recommended to make ss capacitance setting so that tdcdcss will be longer than trise_ min [sec] ] [ _ [sec] 100_ min_ ratio duty min t t rise rise = [sec] ] [2 ] [ ] [ a v vfb f c t ss dcdcss m = ss=fb circuit ss 5v led_driver driver comp n bsx vout iled pwm pwm=l:stop 2ua ss slope d q pwm clx
14/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 uvlo setting procedure it is uvlo function for the dc/dc converter power su pply.if its voltage reaches 3.0v (typ.) or higher, t he ic will start step-up operation. if it reaches 2.79v (typ.) or les s, the ic will stop the step-up operation.the uvlo p in is the high impedance type and involves no pull-down resistor, resulting in unstable operation in the open-circuit ed state. avoid this problem, please make sure to input voltage by using resistor divider or otherwise. if the vin pin voltage to be detected is set by resi stor divider r1 and r2 as described below, resistan ce setting will be made by the following equation: uvlo detection setting equation assuming that a voltage vin decreasing, uvlo is vin det , r1 and r2 setting will be made by the following equation: uvlo release voltage setting equation when r1 and r2 setting is determined by the equatio n shown above, uvlo release voltage will be given by the following equation: setting example assuming that the vin input voltage is 24v, uvlo dete ction voltage is 17.36 v, and r2 resistance is 13k ? , r1 resistance setting is decided by the following equa tion: furthermore, vin can can be calculated as below equation when r1(68k ? ), r2(13k ? ) are decided above * for the selection of dc/dc components, please also consider the inaccuracy of each componentts . ] [ ] [ 79.2 ]) [ 79.2 ] [ ( ] [2 1 w - w = k v v v vin k r r det ] [ ] [2 ]) [2 ] [1 ( 0.3 v k r k r k r v vin can w w + w = ] [ 68 ] [ 79.2 ]) [ 79.2 ] [ 36.17( ] [13 ] [ 79.2 ]) [ 79.2 ] [ ( ] [2 1 w = - w = - w = k v v v k v v v vin k r r det ] [ 69. 18 ] [ ] [13 ] [ 68 ] [13 ] [0.3 ] [2 ]) [2 ] [1 ( ] [0.3 v v k k k v k r k r k r v vin can = w w + w = w w + w =
15/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ovp/scp setting procedure (ovp pin) there are two type of over voltage protection in bd9479fv.the one is ovp detection, another is ovp feedback. basically, the cp pin start to charge when ovp pin vo ltage higher than 2.25v.when ovp pin voltage is between 2. 25v with 2.5v, the operation of dcdc is continued and cp sta rt to charge only.when ovp pin voltage reaches 2.5v, unti l then the feedback voltage control will be switch from bs pin to ovp pin please refer to below figure .for this reason, its prevent the voltage of ovp pin become 2.5v or higher when led column has closed with impendence causing the ri sing of dcdc voltage. ovp pin is also used for feedback control, please no ted that not only the resistor divider of monitorin g normal voltage, but also the external cr of phase compensation is n eeded.basically, it is needed to aligned with the fe edback gain to led driver section.if r3 is same as r2 1k 10k ? , the breakdown voltage of c which connected to it should be confirmed first and in series of two or more if necessary , about 0.1uf is assumed and need to be decided in real system. the following section describes setting procedures to be followed if the vout pin voltage to be detecte d is setby the use of resistive dividers r1 and r2. ovp detection setting equation assuming that voltage of vout rising abnormally and d etecting ovp is vovp det , r1 and r2 setting will be made by the following equation. r2 will also affect phase compensation of feedback section, please set 1k 10k ? as basic. ovp feedback setting equation the ovp feedback vovp feed voltage is calculated as below when r1,r2 is decid ed above: scp detection setting the scp setting vscp det voltage is calculated as below when r1,r2 is decid ed above: ] [ ][25.2 ])[25.2 ][ ( ] [2 1 w - w = k v v v vovp k r r det ][ ] [2 ]) [2 ] [1( 5.2 v k r k r k r v vovp feed w w + w = ][ ] [2 ]) [2 ] [1( 2.0 v k r k r k r v vscp det w w + w = ovp vout r2 r1 2.25v +- + - 0.2v + - 2.5v fb r3 c1
16/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 10 ] [ ] [ v vled v v short lsp = led short voltage setting(bsx pin, lsp pin) the detection voltage of led short when bsx pin higher than 9v while lsp pin is in open state. it is possible to change the led short detection vol tage, please input (0.3v 3.0v) to lsp pin. the relationship between led short detection voltage vled short , and lsp pin voltage v lsp as below equation. in addition, because lsp pin has split 3v of terminal resistance inside ic. refer to upper right schematic , it will be combined resistance value of ics in ternal resistance and connecting to external resistor.for this reason, wh en configure the voltage of lsp in resistor divider , it is recommended to connect a resistor which has a little impact from internal resistance value. resistance is less susceptible to internal resistor, but care must be taken because power con sumption will become large. lsp setting procedure below equation shows how to calculate the detection voltage of vlsp by using r1,r2 resistor divide which connect to reg50 voltage. however, this equation is without considering ic re sistance. if internal resistance is taken into acco unt, the detection voltage vlsp will be given by the following equation : please set r1 and r2 resistance so that a difference between resistance values found by equations (1) an d (2) will come to approximately 2% or less as a reference. setting example assuming that lsp is approximated by equation (1) in o rder to set lsp detection voltage to 5v, r1 comes to 45k w and r2 comes to 5k w . when calculating lsp detection voltage taking into account internal ic resistance by equation (2), it w ill be given as: the difference is given as: as a result, this setting will be little affected by internal impedance. for the selection of dc/dc components, please also consider the inaccuracy of each componentts . )1( ][ 10 ] [2 ] [1( ] [2 ][50 l v k r k r k r v reg vlsp ? ?? ? ? ?? ? w + w w = ( ) ( ) ( ) )2( ][ 10 ] [3 ] [1 ] [4 ] [2 4 2 ] [3 ] [1( ] [1 ][ 3 ][50 ] [4 ] [2 k v k r k r k r k r r r k r k r k r v ref r v reg k r k r vlsp ? ?? ? ? ?? ? w + w w w + + w w w + w w = ( ) ( ) ( ) ][ 028.5 10 ] [ 2100 ] [45 ] [ 900 ] [5 900 5 ] [ 2100 ] [45( ] [45 ][3 2100 ][5 ] [ 900 ] [5 v v k k k k k k k v v k k vlsp = ? ?? ? ? ?? ? w + w w w + + w w w + w w = ( ) % 56.0 100 ] [5/] [5 ] [ 028 .5 = - v v v
17/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ] [5.2 ] [ 10 0.2 [sec] ] [ 6 v a t f c cp cp - = timer latch time (cp pin) the cp pin will source 2.0ua current when any abnor mal problem is detected.even is an error is detected , ic does not stop as long as cp pin is not to 2.5v.cp pin which sets the time from detection of abnormality until s hutdown (timer latch). cp charge time t cp is set by the following equation: fail signal fail pin will change to low when uvlo and latch occur red after cp charged.please make sure that there is no logic problem in module design.the breakdown voltage of t his pin is 36v. state fail output normal, stb=low, under abnormal detection open abnormality detected(shutdown), uvlo detected gnd level (50 ohm typ.)
18/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ocp setting / dcdc component current tolerance sele ction guide the ocp detection function that is one of the funct ions of the cs pin will stop the dc/dc converter ope rating ifthe cs pin voltage becomes larger than 0.4v.consequently, it i s needed to calculate a peak current flowing throug h the coil l and then review the resistance of rcs.furthermore, a current tolerance for dc/dc components should be larger th an that for peak current flowing through the coil l.the following de scribes the peak coil current calculation procedure , cs pin connection resistor rcs selection procedure, and dc/dc componen t current tolerance selection procedure . peak coil current ipeak calculation ripple voltage generated at the cs pin is determine d by conditions for dc/dc application components first, assuming the conditions as below: output voltage=vout[v] led total current=iout[a] dcdc input voltage=vin[v] dcdc efficiency= [%] and then mean input current iin required for the who le system is given by the following equation. further, according to drive operation with the dc/d c converter switching frequency fsw [hz], inductor ripple current ? il [a] generated at the inductor l (or h) is given by the following equation. as a result, the peak current ipeak of il is given b y the following equation. cs pin connection resistor rcs selection procedure the current ipeak flows into rcs to generate voltage . see the timing chart shown to the right the voltage vcspeak is given by the following equation. if vcspeak voltage reaches 0.4v, dc/dc output will stop.consequently, to select rcs resistance, the fol lowing condition should be met. dc/dc component current tolerance selection procedu re iocp current needed for ocp detection voltage cs to reach 0.4v is given by the following equation: the relation among ipeak current (equation (1)), ioc p current (equation (2)), and maximum current tolera nce for component should meet the following equation. ][ [%] ][ ][ ][ a v v a i v v i in out out in h = ][ ] [ ][ ][ ][ ])[ ][ ( a hz f v v hl v v v v v v il sw out in in out - = )1( ][ 2 ][ ][ l a a il a i ipeak in d + = ][ v ipeak rcs vcs peak = < < ocp peak i i max current tolerance )2( ][ ][ ][4.0 l a rcs v i ocp w = ] [4.0 ] [ v v ipeak rcs < vin vout n cs pgnd rcs il l iout(total) fsw
19/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 dc/dc application components including fets, inducto rs, and diodes should be selected so that the equati on shown above will be met. in addition, it is recommended to use continuous mo de in dcdc application.and the lower limit value of coil ripples current imin so as to meet the following equation: a failure to meet this condition is referred to as discontinuous mode and this failure may result in a n inadequate rise in output voltage. setting example output=vout[v]=40v led 1ch current=120ma, total led current iout[a]=120ma 8ch=0.96a dcdc input voltage=vin [v] =24v dcdc efficiency= [%]=90% mean input current iin required for the whole syste m is given by the following equation: dcdc switching frequency=fsw[hz]=200khz inductor [h]=33 h the inductor ripple current ? il [a] is given by the following equation: as a result, the peak current ipeak of il is given b y the following equation. when rcs resistance is set to 0.1ohm, the vcs peak vol tage will be given by the following equation: consequently, the result meets the condition. furthermore, i ocp current at which ocp is detected is given by the f ollowing equation: so must select the component of about 5a in order to meet the above result. particularly, to select dc/dc components, give consi deration to ic variations as well as individual com ponent variations, and then conduct thorough verification on practical systems. . the lower limit value of coil ripple current imin i s given by the following equation, the component wi ll not be put into discontinuous mode. 0 ][ 2 ][ ][ min > d - = a a il a i i in ] [ 78.1 9.0 ] [ 24 ] [ 96.0 ] [ 40 [%] ] [ ] [ ] [ ] [ a v a v v v a i v v a i in out out in = = = h ] [ 45.1 ] [ 10 200 ] [40 ] [ 10 33 ] [24 ]) [24 ] [40( ] [ ] [ ] [ ] [ ]) [ ] [ ( 3 6 a hz v h v v v hz f v v h l v v v v v v il sw out in in out = - = - = - ] [ 51.2 2 ] [45.1 ] [78.1 ] [ 2 ] [ ] [ a a a a a il a i ipeak in = + = d + = 0 ] [05.1 ] [ 73.0 ] [ 78.1 ] [ 2 ] [ ] [ min > = - = d - = a a a a a il a i i in ] [4.0 ] [ 251.0 ] [51.2 ] [1.0 v v a ipeak rcs vcs peak < = w = = ] [ 0.4 ] [1.0 ] [4.0 a v i ocp = w = < < ocp peak i i ] [0.5 ] [0.4 ] [ 51.2 a a a < < =
20/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 selection of inductor l the value of inductor has significant influence on the input ripple current. as shown by equation (1), the larger the inductor and t he higher the switching frequency, the inductor ripple current ? il becomes increasingly lower. (1) ][ ) ( ????? a f v l v v v il sw out in in out - = expressing efficiency as shown by equation (2), peak input current is given as equation (3). (2) ????? in in out out i v i v = h (3) 2 2 ????? il v i v il i il in out out in max + = + = h here, l inductor value[h] v out dc/dc output voltage[v] v in input voltage[v] i out output total current[a] i in input current[a] f sw oscillation frequency[hz] basically, make setting of ? il to approximately 30% to 50% of the output load current. if a current in excess of the rated current of the inductor applies to the coil, the inductor will cau se magnetic saturation, resulting in efficiency degradation. select an inductor with an adequate margin so that p eak current will not exceed the rated current of th e inductor. to reduce power dissipation from and increase effic iency of inductor, select an inductor with low resi stance component (dcr or acr). selection of output capacitor c out select a capacitor on the output side taking into ac count the stability region of output voltage and equivalent series resistance necessary to smooth ripple voltage. note that higher output ripple volt age may result in a drop in led pin voltage, making it impossible to supply set led current. the output ripple voltage ? v out is given by equation (4). (4) ][ 1 1 ????? v f i c r ilmax v sw out out esr out + = h here, r esr = equivalent series resistance of c out . select capacitor ratings with an adequate margin for output voltage. to use an electrolytic capacitor, an adequate margi n should be provided for permissible current. partic ularly to apply pwm light modulation to led, note that a curre nt higher than the set led current transiently flows . i l v out v in c out r cs l i l v out v in c out r cs l r esr i l
21/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 selection of switching mosfet transistors there will be no problem for switching mosfet transis tors having absolute maximum rating higher than rat ed current of the inductor l and vf higher than c out breakdown voltage + rectifier diode. however, to achieve high-speed switching, select transistors with small gate capac ity (injected charge amount). note: rated current larger than overcurrent protect ion setting current is recommended. note: selecting transistors with low on resistance c an obtain high efficiency. selection of rectifier diodes select schottky barrier diodes having current capab ility higher than the rated current of the inductor l and inverse breakdown voltage higher that c out breakdown voltage, particularly having low forward voltage vf. selection of load switch mosfet and soft start functio n in usual dc/dc converter, because there is no switc hing to a path leading from v in to v out resulting in output voltage is also occur even if ic is in off state.please inse rt pmosfet between v in and inductor if you want voltage to 0v until the ic starts to operate.in addition, fail pin can be used for driving load switch after confirme d the logic theory, and the breakdown voltage of drain-source needed to be selected larger than v in . furthermore, if you would like to make soft start f unction to load switch, please insert a condenser b etween gate and source.
22/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 phase compensation setting procedure dc/dc converter application for current mode contro l includes one each of pole f p (phase delay) by cr filer consisting of output capacitor and output resistor (i.e., led c urrent) and zero (phase lead) f z by the output capacitor and capacitor esr. furthermore, the step-up dc/dc converter includes r hp zero f zrhp as the second zero. since the rhp zero has phase delay ( - 90 ) characteristics like the pole, the crossover freq uency f c should be set to not more than rhp zero. i. find pole f p and rhp zero f zrhp of dc/dc converter. here, led total current[a], ii. find phase compensation to be inserted to error amplifier.(set f c is 1/5 to f zrhp ) here, iii. find zero used to compensate esr (r esr ) of c out (electrolytic capacitor). even if a ceramic capacitor (r esr of the order of milliohms) for c out , it is recommended to insert c fb2 for stable operation. to improve transient response, it is necessary to i ncrease r fb1 and reduce c fb1 . however, this improvement reduces a phase margin. to avoid this problem, conduct thor ough verification, including variations in external components, on practical systems. v out vin c out r cs l r esr ] [ 2 ) 1( 2 hz i l d v f led out zrhp - = p ] [ ) 1( 5 1 w - = d v gm f i r f r out p led cs rhzp fb ] [ 2 1 1 1 f f r c p fb fb = p ] [ 1 2 f r c r c fb out esr fb = ] [ 2 hz c v i f out out led p = p out in out v v v d - = ][ 10 0.4 4 s gm - = led i + - c fb1 fb r fb1 gm v out i led c fb2
23/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 timing chart
24/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 list of protect function (typ condition) protection name detection pin detect condition release condition protect type detection pin condition pwm ss led open bsx bsx < 0.1v h ss > 4v bsx > 0.1v latch clx clx < 0.1v h ss > 4v clx > 0.1v latch led short bsx bsx > 9v h ss > 4v bsx < 9v latch uvlo uvlo uvlo < 2.79v - - uvlo > 3v auto-restart reg50 reg50 < 4.2v - - reg50 > 4.5v auto-restart vcc vcc < 7.2v - - vcc > 7.5v auto-restart ovp feedback ovp ovp > 2.25v - ss > 4v ovp < 2.25v latch ovp ovp ovp > 2.5v h - ovp < 2.5v pulse-by-pulse scp ovp ovp < 0.2v - - ovp > 0.2v latch (pulse-by-pulse and gate is off) ocp cs cs > 0.4v - - cs < 0.4v n output stops (200ns mask from gate on) to release the latch function, stb should be set to l once, and then to h. (cp does not charged under soft start duration.) *when abnormality is detected under pwm=h, cp will continue to charge even if pwm=l. to release the latch function, stb should be set from l to h.(cp does not charged under soft start du ration.) protect function operation after protect function detects error dc/dc led driver soft start fail pin stb instantaneously stops instantaneously stops instantaneously discharged open led open stops operating after cp charged stops operating after cp charged discharge after cp discharged gnd after cp charged led short stops operating after cp charged stops operating after cp charged discharge after cp discharged gnd after cp charged uvlo instantaneously stops instantaneously stops instantaneously discharged gnd ovp stops operating after cp charged stops operating after cp charged discharge after cp discharged gnd after cp charged scp n output stops stops operating after cp charged discharge after cp discharged gnd after cp charged ocp n pin limits duty cycle normal operation normal operation open
25/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 operational notes 1) we pay utmost attention to the quality control o f this product. however, if it exceeds the absolute maximum ratings including applied voltage and operating temperature range, it may lead to its deterioration or breakdo wn. further, this makes it impossible to assume a breakdown state suc h as short or open circuit mode. if any special mod e to exceed the absolute maximum ratings is assumed, consider addin g physical safety measures such as fuses. 2) making a reverse connection of the power supply connector can cause the ic to break down. to protec t the ic form breakdown due to reverse connection, take preventiv e measures such as inserting a diode between the ex ternal power supply and the power supply pin of the ic. 3) since current regenerated by back electromotive f orce flows back, take preventive measures such as i nserting a capacitor between the power supply and the ground as a path o f the regenerative current and fully ensure that ca pacitance presents no problems with characteristics such as lack of ca pacitance of electrolytic capacitors causes at low temperatures, and then determine the power supply line. provide therma l design having an adequate margin in consideration of power dissipation (pd) in the practical operating conditio ns. 4) the potential of the gnd pin should be maintaine d at the minimum level in any operating state. 5) provide thermal design having an adequate margin in consideration of power dissipation (pd) in the pr actical operating conditions. 6) to mount the ic on a printed circuit board, pay utmost attention to the direction and displacement of the ic. furthermore, the ic may get damaged if it is mounted in an erron eous manner or if a short circuit is established du e to foreign matters entered between output pins or between output pin a nd power supply gnd pin. 7) note that using this ic in strong magnetic field may cause it to malfunction. 8) this ic has a built-in thermal-protection circui t (tsd circuit), which is designed to be activated i f the ic junction temperature reached 150 c to 200 c and deactivated with hysteresis of 10 c or more. the thermal-protection circuit (tsd circuit) is a circuit absolutely intended to protec t the ic from thermal runaway, not intended to prot ect or guarantee the ic. consequently, do not use the ic based on the activa tion of this tsd circuit for subsequent continuous u se and operation of the ic. 9) when testing the ic on a set board with a capaci tor connected to the pin, the ic can be subjected t o stress. in this case, be sure to discharge the capacitor for each process . in addition, to connect the ic to a jig up to the testing process, be sure to turn off the power supply prior to connection, a nd disconnect the jig only after turning off the po wer supply. 10) 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 intersections of the se p layers and the n layers of other elements, thu s making up different types of parasitic elements. for example, if a resistor and a transistor is conn ected with pins respectively as shown in fig. ? when gnd > (pin a) for the resistor, or when gnd > (pin b) for the transistor (npn), p-n junctions operat e as a parasitic diode. ? when gnd > (pin b) for the transistor (npn), the parasitic npn tra nsistor operates by the n layer of other element adjacent to the parasitic diode aforementioned. due to the structure of the ic, parasitic elements are inevitably formed depending on the relationship s of potential. the operation of parasitic diodes can result in interfe rences in circuit operation, leading to malfunction s and eventually breakdown of the ic. consequently, pay utmost atten tion not to use the ic for any applications by whic h the parasitic elements are operated, such as applying a voltage l ower than that of gnd (p substrate) to the input pi n. status of this document the japanese version of this document is formal spe cification. a customer may use this translation ver sion only for a reference to help reading the formal version. if there are any differences in translation version of this document formal version takes priority. figure 13. example of simple structure of monolithic ic b c e adjacent other elements parasitic (pin b) gnd parasitic element (pin a) parasitic element resistor p substrate n gnd p n p (pin a) p n transistor (npn) b parasitic element gnd e c gnd p p n n n p n p substrate (pin b)
26/26 datasheet bd9479fv tsz02201-0f1f0c100020-1- 2 ? 2012 rohm co., ltd. all rights reserved. 9.aug.2012 rev. 001 www.rohm.com tsz22111 ? 15 ? 001 ordering information b d 9 4 7 9 f v - xx part number package fv:ssop packaging and forming specification xx: please confirm the formal name to our sales. physical dimension tape and reel information (unit : mm) ssop-b40 0.08 m 0.1 s 0.22 0.1 0.65 0.15 0.1 0.5 0.2 7.8 0.3 5.4 0.2 1.8 0.1 0.1 1 40 20 21 13.6 0.2 (max 13.95 include burr) * order quantity needs to be multiple of the minimum quantity. embossed carrier tape tape quantity direction of feed the direction is the 1pin of product is at the upper left when you hold reel on the left hand and you pull out the tape on the right hand 2000pcs e2 ( ) direction of feed reel 1pin
datasheet d a t a s h e e t notice - rev.003 ? 2012 rohm co., ltd. all rights reserved. notice general precaution 1) before you use our products, you are requested to care fully read this document and fully understand its contents. rohm shall not be in any way responsible or liable for fa ilure, malfunction or accident arising from the use of any rohm?s products against warning, caution or note contained in this document. 2) all information contained in this document is current as of the issuing date and subjec t to change without any prior notice. before purchasing or using rohm?s products, please confirm the la test information with a rohm sales representative. precaution on using rohm products 1) our products are designed and manufactured for applicat ion in ordinary electronic 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 extremel y high reliability (such as medical equipment, 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, ro hm 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. 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 bel ow), 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 (pd) depending on ambient temper ature (ta). when used in seal ed area, confirm the actual ambient temperature. 8) confirm that operation temperature is within t he 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.
datasheet d a t a s h e e t notice - rev.003 ? 2012 rohm co., ltd. all rights reserved. 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; if flow soldering method is preferred, please consult with the rohm representative in advance. for details, please refer to rohm mounting specification 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 c onsidering 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 hum idity 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 our products might fall under cont rolled goods prescribed 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 application example contain ed 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. rohm shall not be in any way responsible or liable for infringement of any intellectual property rights or ot her damages arising from use of such information or data.: 2) 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 information contained in this document.
datasheet d a t a s h e e t notice - rev.003 ? 2012 rohm co., ltd. all rights reserved. other precaution 1) the information contained in this document is provi ded on an ?as is? basis and rohm does not warrant that all information contained in this document is accurate and/or error-free. rohm shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties resulting from inaccuracy or errors of or concerning such information. 2) this document may not be reprinted or reproduced, in whol e or in part, without prior written consent of rohm. 3) the products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of rohm. 4) in no event shall you use in any way whatsoever the pr oducts 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. 5) the proper names of companies or products described in this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties.

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