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product structure silicon monolithic integrated circuit this product ha s no designed protection against radioactive rays . 1/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 tsz22111 ? 14 ? 001 www.rohm.com 3.5v to 14v, 1.0a 1ch synchronous buck converter integrated mosfet bd8313h fn general description the bd8313hfn can produce stepped-down voltage from a power supply composed of 4 batteries, which can be li2cell, li3cell, etc., or from a 5v/12v fixed pow er supply line. output voltages include 1.2v, 1.8v, 3.3v, or 5.0v. this ic allows easy production of a compact power supply since its high operating frequency of 1.0mhz requires small-sized external inductor and capacitor and the phase compensation components are integrated in the chip. the built-in synchronous rectification switches are capable of withstanding 15v. features ? built-in pch/nch synchronous rectification sw capable of withstanding 1.2 a/15v. ? built-in phase compensation device between input and output of error amp. ? built-in soft-start function. ? built-in short-circuit protection with timer application for portable equipments like dsc/dvc powered by 4 dry batteries or li2cell and li3cell, or general consumer-equipment with 5v/12v lines key specifications ? input voltage range: +3.5v to + 14v ? output voltage range: +1.2v to + 12v ? output current: 1. 0a(max) ? switching frequency : 1.0mhz(typ) ? pch fet on-resistance : 450m ? (typ) ? nch fet on-resistance: 300m ? (typ) ? standby current: 0 a( t yp ) ? operating temperature range: - 25 c to +85c package w(typ) x d(typ) x h(ma x) typical application circuit vreg pgnd vcc gnd pvcc inv lx stb vt=.v 1 f grm188b11a105ka61 mraa 4.7 h 77mtoko 10 f grm31cb11a106ka01 mraa 51k 22k 200k 68k 10pf 3.3v/500ma on/off 1 f grm188b11a105ka61 mraa 10 f grm31cbe106ka75l mraa hson8 2.90mm x 3.00mm x 0.60mm lx figure 1. typical application circuit vbat=4.5v to 10v 10 f 1 f 1 f 4.7 h 10 f 22k 200k 51 k 68k datashee t downloaded from: http:///
bd8313hfn 2/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 pin configuration pin description pin no. pin name function 1 gnd ground pin 2 vcc control circuit power supply pin 3 vreg 5v output pin of regulator for internal circuit 4 pgnd power transistor ground pin 5 lx switching output pin (pin for external coil) 6 pvcc power transistor supply pin 7 stb on/off pin 8 inv error amp input pin block diagram figure 3. block diagram figure 2. pin configuration vcc inv vreg pgnd gnd stb pvcc lx (top view) lx downloaded from: http:///
bd8313hfn 3/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 description of blocks (1) reference this is the block that generates the 1v reference voltage for the erro r amp. (2) 5v reg this block produces a 5v regulated voltage supply for the interna l analog circuit. bd8313hfn is equipped with this regulator for the purpose of protecting the internal circuit from hi gh voltages. the output of this block decreases when vcc is less than 5v, increasing the pmos on resistance and decreasing t he dc/dc converters power efficiency and maximum output current (please see data in figures 15 , 1 6, 17, and 18 ). (3) uvlo this circuit prevents malfunction of the internal circuit w hen input voltage is not enough like, while the input suppl y is rising or when the power supply voltage is low. the uvlo circuit mo nitors v cc and turns off all output fets and dc/dc converter output when v cc is lower than 2.9v. it also resets the timer latch of the built- in scp and soft-start circuits. (4) scp the short-circuit protection circuit of this ic has a timer latc h system. when the dc/dc converter has a duty cycle of 100%, the built-in scp circuit starts counting. the inte rnal counter is synchronized with the frequency of osc. the latch circuit turns off the dc/dc converters output after a bout 4.0 milliseconds or when the counter has counted about 4000 clock pulses. to reset the latch circuit, turn the stb inp ut off and on once or turn the power supply off and then on. (5) osc this circuit generates a saw tooth wave with operating frequen cy fixed at 1.0mhz. (6) error amp the error amplifier monitors the output voltage of the dc/dc converter and it s output serves as a pwm control signal. the reference voltage for the error amp is 1.0v. primary phase compensation components, 200pf and 62k, are built -in and are placed between the inverting input and the output terminals of the error amp. (7) pwm comp this block is a voltage- to -pulse width converter for controlling the output voltage correspo nding to an input voltage. the pwm comp controls the pulse width of the drivers output by com paring the internal slope wav e with the error amp output voltage. (8) soft start this circuit prevents inrush current during startup by making t he output voltage of the dc/dc converter increase gradually. the soft start time is synchronized with the internal o scillator. output voltage of the dc/dc converter reaches the set voltage after about 8000 clock pulses. (9) pre driver/timing control this block is the cmos inverter circuit for driving the bui lt-in synchronous rectifier switches. the dead time of the synchronous switches for preventing feed-through is about 25ns . (10) stby_io the voltage at stb (pin 7) determines whether the ic is on or off . the ic is on when stb is 2.5v or higher and off when stb pin is open or at 0v. stb pin is pulled down by an inte rnal resistor which is approximatel y 400k. (11) pch/nch fet sw the built- in synchronous rectification switches are for switching the coil current of the dc/dc converter. the 450m pch fet switch and the 300m nch fet switch are capable of withstandi ng 15v. since the current rating of the fets is 1.2a, the output current, including the ripple current of the coi l ic should not exceed this limit. downloaded from: http:///
bd8313hfn 4/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 absolute maximum ratings parameter symbol rating unit maximum applied power voltage v cc , p vcc 15 v maximum input current i inmax 1.2 a power dissipation pd 0.63 (note 1) w operating temperature range topr - 25 to +85 c storage temperature range tstg - 55 to +150 c junction temperature tjmax +150 c (note 1) when used at ta = 25c or more installed on a 70x 70 x1.6 t mm board, the rating is reduced by 5.04mw/c. (note) these specifications are subject to change without advance notice for m odifications and other reasons. 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 internal circuitry. therefore, it is important to conside r circuit protection measures, such as adding a fuse, in case the ic is o perated over the absolute maximum ratings. recommended operating conditions parameter sym bol rating unit power supply voltage v cc 3.5 to 14 v output voltage v out 1.2 to 12 v electrical characteristics (unless otherwise specified, ta = 25c, v cc = 7.4v) parameter symbol limit unit conditions min typ max [low input voltage malfunction prevention circuit] detection threshold voltage v uv - 2.9 3.2 v vreg monitor hysteresis range v uvhy 100 200 300 mv [oscillator] oscillation frequency f osc 0.9 1.0 1.1 mhz [regulator] output voltage v reg 4.65 5.0 5.35 v [error amp] inv threshold voltage v inv 0.99 1.00 1.01 v input bias current i inv - 50 0 +50 na v cc = 12.0v , v inv = 6.0v soft-start time t ss 4.8 8.0 11.1 msec [pwm comparator] lx max duty (note 2) d max - - 100 % [output] pmos on-resistance r onp - 450 600 m nmos on-resistance r onn - 300 420 m leak current i leak -1 0 +1 a [stb] stb pin control voltage operation v stbh 2.5 - 14 v no -operation v stbl -0.3 - +0.3 v stb p in p ull -down resistance r stb 250 400 700 k [circuit current] standby current vcc pin i stb1 - - 1 a pvcc pin i stb2 - - 1 a circuit current at operating vcc i cc1 - 600 900 a v inv = 1 .2v circuit current at operating p vc c i cc2 - 30 50 a v inv = 1.2v (note 2) 100% is max duty as behavior of a pwm comparator. for the condition where high side pmos is 100% on -state because the input voltage is less than or equal to the output voltage, the scp detector is activated and then the dc/dc converter operation stops . downloaded from: http:///
bd8313hfn 5/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 typical performance curves (unless otherwise specified, ta = 25c, v cc = 7.4v) figure 4. inv threshold vs temperature inv threshold [v] temperature [ c] 0.98 0.99 1.00 1.01 1.02 -40 -20 0 20 40 60 80 100 120 figure 5. inv threshold vs v cc inv threshold [v] v cc [v] 0.98 0.99 1.00 1.01 1.02 0 5 10 figure 6. vreg output vs temperature temperature [o c] v reg voltage [v] 4.7 4.8 4.9 5.0 5.1 5.2 5.3 -40 0 40 80 120 figure 7. vreg output vs v cc v reg [v] v cc [v] 0 1 2 3 4 5 6 7 8 0 2 4 6 8 10 12 14 downloaded from: http:///
bd8313hfn 6/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 typical performance curves - continued (unless otherwise specified, ta = 25c, v cc = 7.4v) figure 8. frequency vs temperature temperature [o c] frequency [mhz] 0.8 0.9 1.0 1.1 1.2 -40 0 40 80 120 figure 9. frequency vs v cc frequency [mhz] v cc [v] 0.8 0.9 1.0 1.1 1.2 3 6 9 12 15 figure 10. uvlo threshold vs environmental temperature (uvlo threshold) uvlo threshold [ v ] environmental temperature ta [c] hysteresis voltage vhys [ v ] 2.50 2.70 2.90 3.10 3.30 3.50 -40 0 40 80 120 0.00 0.05 0.10 0.15 0.20 0.25 uvlo release voltage hysteresis width uvlo detection voltage 100 200 300 400 500 -40 0 40 80 120 i d =500ma figure11. nch fet on-resistance vs temperature nch on -resistance [ m? ] temperature [c] downloaded from: http:///
bd8313hfn 7/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 typical performance curves C continued (unless otherwise specified, ta = 25c, v cc = 7.4v) i d =500ma figure 13. pch fet on-resistance vs temperature temperature [o c] pch on -resistance [m ] 0 200 400 600 800 -40 0 40 80 120 i d =500ma 0 100 200 300 400 500 600 3 6 9 12 15 i d =500ma figure 12. nch fet on -resistance vs v cc nch on -resistance [ m ] v cc [v] 0 200 400 600 800 1000 3 6 9 12 15 i d =500ma figure 14. pch fet on-resistance vs v cc pch on -resistance [m ] v cc [v] figure 15. pch fet on-resistance vs i o (v cc =3.5v) pmos on-resistance [ ] i o [a] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 1.0 2.0 ta=25 oc ta=85 oc ta=- 25 oc downloaded from: http:///
bd8313hfn 8/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 typical performance curves C continued (unless otherwise specified, ta = 25c, v cc = 7.4v) figure 16. pch fet on resistance vs i o (v cc =4.0v) pmos on -resistance [ ] i o [a] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 1.0 2.0 ta=25 oc ta=85 oc ta=- 25 oc 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 1.0 2.0 figure 17. pch fet on-resistance vs i o (v cc =4.5v) pmos on -resistance [ ] i o [a] ta=- 25 oc ta=25 oc ta=85 oc figure 18. pch fet on-resistance vs i o (v cc =5.0v) pmos on -resistance [ ] i o [a] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 1.0 2.0 figure 19. stb threshold vs temperature stb voltage [v] ta [c] 1.0 1.5 2.0 2.5 -50 0 50 100 150 on off downloaded from: http:///
bd8313hfn 9/ 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 typical performance curves C continued (unless otherwise specified, ta = 25c, v cc = 7.4v) figure 20. circuit current i cc vs temperature temperature [o c] i cc [a] 0 200 400 600 800 1000 -40 0 40 80 120 figure 21. circuit current i cc vs v cc v cc [v] i cc [a] 0 200 400 600 800 1000 0 2 4 6 8 10 12 14 downloaded from: http:///
bd8313hfn 10 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 application information 1. example of application 1 input: 4.5v to 10v, output: 3.3v / 500ma 2. reference application data 1 (example of application 1) figure 22. reference application diagram 1 vreg pgnd vcc gnd pvcc inv lx stb vt=.v 1 f grm188b11a105ka61 mraa 4.7 h 77mtoko 10 f grm31cb11a106ka01 mraa 51k 22k 200k 68k 10pf 3.3v/500ma on/off 1 f grm188b11a105ka61 mraa 10 f grm31cbe106ka75l mraa vbat=4.5v to 10v lx figure 23. efficiency vs output current (v out = 3.3v) 0 20 40 60 80 100 1 10 100 1000 output current [ma] efficiency [%] efficiency [%] output current [ma] v cc =5.5v v cc =7.5v v cc =4.5v figure 24. output voltage vs output current (load regulation, v out = 3.3v) 3.00 3.05 3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50 1 10 100 1000 output current [ma] output voltage [v] output voltage [v] output current [ma] v cc =4.5v v cc =5.5v v cc =7.5v 10 f 1 f 1 f 4.7 h 10 f 22k 200k 51 k 68k downloaded from: http:///
bd8313hfn 11 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 3. reference application data 2 (example of application 1) ( input: 4.5v, 6.0v, 8.4v, 10v ; output: 3.3v ) figure 25. gain vs frequency 1 (v cc =4.5v, i o =250ma) phase gain gain [db] phase [deg] frequency [hz] figure 27. gain vs frequency 3 (v cc =8.4v, i o =250ma) phase gain gain [db] phase [deg] frequency [hz] figure 26 gain vs frequency 2 (v cc =6.0v, i o =250ma) phase [deg] gain phase frequency [hz] gain [db] figure 28. gain vs frequency 4 (v cc =10v, i o =250ma) gain [db] phase [deg] frequency [hz] gain phase downloaded from: http:///
bd8313hfn 12 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 reference application data 2 (example of application 1) C continued ( input: 4.5v, 6.0v, 8.4v, 10v ; output: 3.3v ) figure 29. gain vs frequency 5 (v cc =4.5v, io=500ma) phase gain gain [db] phase [deg] frequency [hz] figure 32. gain vs frequency 8 (v cc =10v, io=500ma) phase gain frequency [hz] gain [db] phase [deg] figure 30. gain vs frequency 6 (v cc =6.0v, io=500ma) phase gain gain [db] phase [deg] frequency [hz] figure 31. gain vs frequency 7 (v cc =8.4v, io=500ma) phase frequency [hz] gain gain [db] phase [deg] downloaded from: http:///
bd8313hfn 13 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 4. example of a ppl ication2 input: 4 .5 v to 12v, output: 1.2v / 500ma 5. reference application data 1 (example of application 2) figure 33. reference application diagram 2 efficiency [%] lx vreg pgnd vcc gnd pvcc inv lx stb vbat =4.5 12 v 1 f grm 188 b 11 a 105 ka 61 murata 4.7 h 1 f grm 188 b 11 a 105 ka 61 murata 10 f 2para grm 31 cb 11 a 106 ka 01 murata 20 k 100 k 560 k 68 k 10pf 1.2v/ 500 ma on /off 10 f grm 31 cb 31 e 106 ka 75 l (murata) 100 nr 4012 -4r7m (taiyo yuden) 10 f 1 f 1 f 4.7 h 10 f 2para 100 560k 20k 68k vbat=4.5v to 12v 100 lx figure 35. output voltage vs output current (load regulation, v out = 1.2v) output voltage [v] output current [ma] v cc = 12v v cc =5.0v v cc =7.4v figure 34. efficiency vs output current (v out = 1.2v) output current [ma] v cc =7.4v v cc =5.0v v cc = 12v efficiency [%] downloaded from: http:///
bd8313hfn 14 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 6. reference application data 2 (example of application 2) (input: 5.0v, 7.4v, 10v; output: 1.2v) figure 38. gain vs frequency 3 (v cc =5.0v, i o =900ma) gain [db] phase [deg] gain phase frequency [hz] figure 39. gain vs frequency 4 (v cc =7.4v, i o =100ma) gain ph ase phase [deg] gain [db] frequency [hz] figure 36. gain vs frequency 1 (v cc =5.0v, i o =100ma) gain phase phase [deg] gain [db] frequency [hz] figure 37. gain vs frequency 2 (v cc =5.0v, i o =300ma) gain phase gain [db] frequency [hz] phase [deg] downloaded from: http:///
bd8313hfn 15 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 reference application data 2 (example of application 2) \ continued (input: 5.0v, 7.4v, 10v; output: 1.2v) phase [deg] figure 42. gain vs frequency 7 (v cc =10v, i o =100ma) frequency [hz] phase [deg] gain [db] gain phase figure 40. gain vs frequency 5 (v cc =7.4v, i o =300ma) gain [db] gain phase phase [deg] frequency [hz] figure 41. gain vs frequency 6 (v cc =7.4v, i o =900ma) gain gain [db] phase phase [deg] frequency [hz] figure 43. gain vs frequency 8 (v cc =10v, i o =300ma) gain [db] phase gain frequency [hz] phase [deg] downloaded from: http:///
bd8313hfn 16 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 reference application data 2 (example of application 2) \ continued (input: 5.0v, 7.4v, 10v; output: 1.2v) figure 44. gain vs frequency 9 (v cc =10v, i o =900ma) frequency [hz] phase [deg] gain [db] gain phase downloaded from: http:///
bd8313hfn 17 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 figure 49. output ripple 5 (v cc =12v, io=900ma) figure 48. output ripple 4 (v cc =12v, io=170ma) figure 47. output ripple 3 (v cc =12v, io=140ma) figure 45. output ripple 1 (v cc =12v, io=40ma) figure 46. output ripple 2 (v cc =12v, io=100ma) downloaded from: http:///
bd8313hfn 18 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 7. reference board pattern (1) the heat sink at the rear should be a low impedance trace at g nd potential and should be at the same potential with the pgnd trace. (2) it is recommended to install a gnd pin not direc tly connected to the pgnd pin, as shown in the pictu re above. (3) make the patterns for vbat, lx , and pgnd as wide as possible since these paths carry large current. vout vbat gnd lx lx downloaded from: http:///
bd8313hfn 19 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 8. selection of parts for application (1) inductor select a shielded inductor that satisfies the current rating (ipea k as shown in the equation below). low-dcr (direct resistance component) inductor is also recommended. inductor value s affect inductor ripple current, which will cause output ripple. ripple current can be reduced by increasing the c oil l value or increasing the switching frequency. (1) (2) where: is the efficiency. ? i l is the ou tput ripple current. f is the switching frequency. as a guide, inductor ripple current should be set at about 20% to 5 0% of the maximum input current. note: current flowing in the coil that is larger than the coil ratin g brings the coil into magnetic saturation, which may lead to lower efficiency or output oscillation. select an inductor with an adequate margin so that the peak current does not exceed the rated current of the coil. (2) output capacitor a ceramic capacitor with low esr (equivalent series resistance) is r ecommended for output in order to reduce output ripple. there must be an adequate margin between the max imum rating and output voltage of the capacitor, taking the dc bias property into consideration. output ripple vol tage is obtained through the following equation: (3) where: v pp is the output ripple voltage. c out is the output capacitance . r esr is the equivalent series resistance. setting must be performed so that output ripple is within the allo wable ripple voltage. (3) ou tput voltage setting the internal reference voltage of the error amp is 1.0v. output voltage i s acquired by equation (4). (4) i l figure 51 . setting of voltage feedback resistance figure 50. inductor current ? ? a f v v l v v i in out out in l 1 ? ? ? ? ? ? ? a i i i l out peak 2 ? ? ? ? ? v r i cout f i v esr l l pp ? ?? ? ? ? ?? ? 2 1 ? ? ? ? v r r r v o 0.1 2 2 1 ? ? ? vref 1.0v vout error amp r1 r2 inv v out r 1 r 2 v ref 1.0v downloaded from: http:///
bd8313hfn 20 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 (4) dc/dc converter frequency response adjustment system condition for stable application the condition for feedback system stability under negati ve feedback is that the phase delay is 135or less wh en gain is 1 (0db). since dc/dc converter application is sampled according to t he switching frequency, the bandwidth g bw of the whole system (frequency at which gain is 0 db) must be controlled to be equal to or lower than 1/10 of the switching frequency. in summary, the conditions necessary for the dc/dc converter are: - phase delay must be 135or lower when gain is 1 (0 db). - bandwidth g bw (frequency when gain is 0 db) must be equal to or lower than 1/10 o f the switching frequency. to satisfy those two conditions , r 1 , r 2 , r 3 , c s and r s in figure 53 should be set as follows. (a) setting r 1 , r 2 , r 3 bd 8313hfn incorporates phase compensation devices of r 4 =62k and c 2 =200pf. these c 2 and r 1 , r 2 , and r 3 values decide the primary pole that determines the bandwidt h of dc/dc converter primary pole point frequency. (5) dc/dc converter dc gain (6) where: a is the error amp gain (100db = 10 5 ). b is the oscillator amplification (typically 0.5v). v in is the input voltage. v out is the output voltage. using equations (5) and (6), the frequency f sw of point 0 db under limitation of the bandwidth of the dc gain at the primary pole point is as shown below. (7) it is recommended that f sw should be approximately10 khz. when load response is difficult, it may be set at app roximately 20 khz. in equation (7), r 1 and r 2 , which determine the voltage value, will be in the ord er of several hundred k. if an appropriate resistance value is not ava ilable since the resistance is so high and routing may cause noise, the use of r 3 enables easy setting. figure 52. example of phase compensation setting fb v out c 2 r 1 r 2 r s r 4 c s r 3 inside of ic ? ?? ? ? ?? ? ? ?? ? ? ?? ? ? ? ? ? ? ? 3 2 1 2 1 2 2 1 r r r r r c a f p ? ? ?? ? ? ?? ? ? ?? ? ?? ? ? ? o in v v b a dcgain 1 ? ?? ? ? ?? ? ? ?? ? ?? ? ? ?? ? ?? ? ? ? ? ? ? ? ? o in p sw v v b r r r r r c dcgain f f 1 2 1 3 2 1 2 1 2 ? downloaded from: http:///
bd8313hfn 21 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 (b) setting c s and r s for dc/dc converter, the second dimension pole point is caused by the coil and capacitor as expressed by the following equation. (8) this secondary pole causes a phase rotation of 180. to secure t he stability of the system, put a zero point in 2 places to perform compensation. zero point by built-in cr zero point by c s setting f z2 to be half to two times the frequency as large as f lc provides an appropriate phase margin. it is desirable to set r s at about 1/20 of (r 1 +r 3 ) to cancel any phase boosting at high frequencies. thos e pole points are summarized in the figure below. the actual frequency property is differen t from the ideal calculation because of part constants. if possible, check the phase margin with a frequency analyz er or network analyzer. otherwise, check for the presence or absence of ringing by load response waveform and also check for the presence or absence of oscillation under a load of an adequate margin. (9) ( 10 ) (8) (7) figure 53 . example of dc/dc converter frequency property (measured with fra5097 by nf corporation) lcout f lc ? 2 1 ? ???? ( 10 ) ? ? s z c r r f 3 1 2 2 1 ? ? ? ???? (9) khz cr f z 13 2 1 24 1 ? ? ? downloaded from: http:///
bd8313hfn 22 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 i/o equivalent circuit stb inv vcc stb vreg vcc inv lx, pgnd, pv cc vreg vcc vreg vcc lx pgnd pvcc downloaded from: http:///
bd8313hfn 23 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 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 extern al diode between the power supply and the ic s power supply pin s. 2. power supply lines design the pcb layout pattern to provide low impedance sup ply lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the grou nd 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 trace s, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small- signal ground caused by large currents. also ensure that the groun d 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 ex ceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. in case of exceeding thi s absolute maximum rating, increase the board size and copper area to prevent exceeding the pd rating. 6. recommende d operating conditions these conditions represent a range within which the expe cted characteristics of the ic can be approximately obtained . the electrical characteristics are guaranteed under the condi tions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the ic has more than one powe r supply. therefore, give special consideration to power co upling 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 comple tely 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 mountin g 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 me tal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins du ring assembly to name a few. downloaded from: http:///
bd8313hfn 24 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 operational notes C continued 11. unused input pins input pins of an ic are often connected to the gate of a mos tran sistor. 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 sign ificant effect on the conduction through the transistor and cause unexpected operation of the ic. so unless otherwise spec ified, unused input pins should be connected to the power supply or ground line. 12. regarding the i np ut pin of the ic this monolithic ic contains p+ isolation and p substrate la yers 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 physic al 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 55. example of monolithic ic structure 13. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that prevent s heat damage to the ic. normal operation should always be within the ics power dissipation rating. if however the ratin g is exceeded for a continued 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 th e absolute maximum ratings and therefore, under no circumstances, should the tsd circuit be used in a set des ign or for any purpose other than protecting the ic from heat damage. 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:///
bd8313hfn 25 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 ordering information b d 8 3 1 3 h f n - t r part number package hfn: hson8 packaging and forming specification tr: embossed tape and reel marking diagram hson8 (top view) 313 part number marking lot number 1pin mark bd8 downloaded from: http:///
bd8313hfn 26 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 physical dimension, tape and reel information package name hson8 downloaded from: http:///
bd8313hfn 27 / 27 tsz02201-0q3q0nz00370-1-2 ? 2014 rohm co., ltd. all rights reserved. 17.feb.2015 rev.002 www.rohm.com tsz22111 ? 15 ? 001 revision history date revision changes 26 .nov.2014 001 new release 18.feb.2015 002 correction of the writing. downloaded from: http:///
datasheet d a t a s h e e t notice-ge rev.004 ? 2013 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 (pd) depending on ambient temper ature (ta). when used in seal ed area, confirm the actual ambient 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-ge rev.004 ? 2013 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 independent 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 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 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. 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. 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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