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datashee t product structure silicon monolithic integrated circuit this product has no designed protection against radioactive rays . 1/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 tsz22111 ? 14 ? 001 www.rohm.com 8 7 6 5 13 14 15 16 1 2 3 4 12 11 10 9 fb inv gnd vout vout lx 2 lx 2 pgnd rt stb vcc pvcc pgnd lx1 lx1 pvcc cfb 2200pf rfb 4.7k rrt 39 k on /off 2.8 5.5v 10uf (ceramic) murata grm 31 cb 11 a 106 ka 01 3.3v/1.0a 10uf (ceramic) murata grm 31 cb 11 a 106 ka 01 4.7 uh toko de 3518 c rinv1 56 k rinv2 10 k cc 120pf rc 4.7k cvcc 1 uf rvcc 0 1.8v to 5.5v, integrated 2.0a mosfet 1ch buck-boost converter BD8306MUV general description rohms highly-efficient buck-boost converter BD8306MUV produces buck-boost output voltage including 3.3 v from two-cell or three-cell alkaline battery, or one-cell lithium-ion battery with just one inductor. this ic adopts the original buck-boost drive system and creates a more efficient power supply than the conventional sepic-system or h-bridge system switching regulators. features ? highly-efficient buck-boost dc/dc converter constructed with just one inductor. ? maximum output current changes depending on the input and output voltages. input current for pvcc terminal should be less than 2.0a including the dc current and ripple current of the inductor. please refer to figure 25 and figure 34 for details about the maximum output current at 3.3v and 5.0v output. ? incorporates a soft-start function. ? incorporates a timer latch system with short protecti on function. application ? general portable equipment ? dsc ? dvc ? cellular phone ? pda ? led key specifications ? input voltage range: +1.8v to +5.5v ? output voltage range: +1.8v to +5.2v ? output current: (at 3.3v output, +2.8v to +5.5v input) 1.0a (at 5.0v output, +2.8v to +5.5v input) 0.7a ? pch fet on-resistance: 120m ? (typ) ? nch fet on-resistance: 100m ? (typ) ? standby current: 0 a ( typ) ? operating temperature range: - 40 c to +85c package w (typ) x d (typ) x h (max) typical application circuit 2.8v to 5.5v, output: 3.3v / 1.0 a, frequency 1mhz lx2 lx2 lx1 lx1 2.8v to 5.5v r rt 39k r vcc 0 10f (ceramic) murata 4.7h 10f (ceramic) murata c vcc 1f c fb 2200pf r fb 4.7k r inv1 56k r inv2 10 c c 120pf r c 4.7k vqfn016v3030 3.00mm x 3.00mm x 1.00mm downloaded from: http:///
2/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV pin configuration pin descriptions pin no. pin name function 1 fb output pin of error a mp 2 inv input pin of error a mp 3 gnd ground pin 4 to 5 vout output voltage pin 6 to 7 lx2 output side pin for inductor 8 to 9 pgnd ground pin for pow-mos 10 to 11 lx1 input side pin for inductor 12 to 13 pvcc voltage supply pin for dc/dc converter 14 vcc voltage supply pin for control block 15 stb on/off pin 16 rt pin for configuration of frequency block diagram 1 2 3 4 6 7 8 16 15 14 13 12 11 10 9 5 pvcc vcc stb rt fb inv gnd vout vout lx2 lx2 pgnd pvcc lx1 lx1 pgnd (top view) pgnd lx1 lx2 inv fb gnd pvcc vout stb rt vcc timing contol timing contol downloaded from: http:///
3/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV description of blocks 1. vref this block generates error amp reference voltage. the reference voltage is 0.5 v. 2. uvlo circuit for preventing malfunction at low voltage input. this circuit prevents malfunction of the internal circuit while star t up of the power supply voltage or while low power supply voltage input. the circuit monitors vcc pin voltage then turns off all output fets and dc/dc converter output when vcc voltage is lower than 1.6v, and reset the timer latch of the internal scp circuit and soft-start circuit . 3. scp short-circuit protection circuit based on timer latch system. when the inv pin voltage is lower than 0.5v, the internal scp circuit starts counting. scp circuit detects high vol tage output of error amp. since internal error amp has highly gain as high as 80db or more, the output voltage of error amp goes high and detects scp even 1mv drop than set voltage (0.5v typ) occurs on inv pin voltage. the internal counter is in synch with osc, the latch circuit activates after the counter counts about 16400 oscillations to turn off dc/dc converter output (about 16.4 msec when r rt =39k). to reset the latch circuit, turn off the stb pin once. then, turn it on again or turn on the power supply voltage again. 4. osc oscillation circuit to change frequency by external resistance of the rt pin (pin 16 ). when r rt = 39 k, operation frequency of dc/dc converter is set at 1 mhz. 5. error amp error amplifier for monitoring output voltage and output pwm control signals. the internal reference voltage for error amp is set at 0.5 v. 6. pwm comp voltage-pulse width converter for controlling output voltage corresponding to input voltage. comparing the internal slope waveform with the error amp output voltage, pwm comp controls the pulse width and outputs to the driver. max duty and min duty are set at the primary side (lx1) and the secondary side (lx2) of the inductor respectively, which are as follows: primary side (lx1) max duty : 100 %(lx1 high side pmos on duty) min duty : 0 %(lx1 high side pmos on duty) secondary side (lx2) max duty : 85 %(lx2 low side nmos on duty) min duty : 0 %(lx2 low side nmos on duty) 7. soft start circuit for preventing in-rush current at startup by bringing the output voltage of the dc/dc converter into a soft-start. soft-start time is in synch with the internal osc, and the output voltage of the dc/dc converter reaches the set voltag e after about 1000 oscillations (about 1 msec when r rt = 39 k). 8. pre driver cmos inverter circuit for driving the built-in pch/nch fet.dead time is provided for preventing feed through during switching. the dead time is set at about 15 nsec for each individual sws. 9. stby_io voltage applied on stb pin (pin 15) to control on/off of ic. turned on when a voltage of 1.5v or higher is applied and turned off when the terminal is open or 0v is applied. incorporates approximately 400 k pull -down resistance. 10. pch/nch fet sw built-in sw for switching the inductor curre nt of the dc/dc converter. pch fet is about 120m and nch is 100m. since the current rating of this fet is 2a, it should be used within 2a in total including the dc current and ripple current of the inductor. the peak current of the inductor can be calculated by equation (1), (2), (3). downloaded from: http:///
4/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV absolute maximum ratings parameter symbol rating unit maximum input supply voltage v cc , pv cc -0.3 to +7 v maximum input current i inmax 2.0 a maximum input voltage v l x1 7.0 v v lx2 7.0 v power dissipation (note 1) pd 0. 62 w storage temperature tstg -55 to +150 c junction temperature tjmax +150 c (note 1) when mounted on 74.2x74.2x1.6mm and operated over 25c pd reduces by 4.96mw/ c. caution : operating the ic over the absolute maximum ratings may damage the ic. the damage can either be a short circuit between pins or an open circuit between pins and the internal circuitry. therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the ic is operat ed over the absolute maximum ratings. recommended operating conditions (ta=25c) parameter symbol rating unit min typ max power supply voltage range v cc 1.8 - 5.5 v output voltage range v out 1.8 - 5.2 v operating temperature range topr - 40 - + 85 c downloaded from: http:///
5/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV electrical characteristics ( un less otherwise specified ta=25c , v cc =3v) parameter symbol limit unit conditions min typ max [under voltage lock out circuit] reset voltage v uv - 1.7 1.8 v vcc sweep up hysteresis width vuv hy 50 100 150 mv [oscillator] frequency f osc 0.9 1.0 1 .1 mhz r rt =39k [error amp] input threshold voltage v inv 0.495 0.500 0.505 v input bias current i inv - 50 0 +50 na v cc =7.0v , v inv =3.5v soft start time t ss 0.60 1.00 1.40 msec r rt =39k output source current i eo 10 20 30 a v inv =0.2v , v fb =1.5v output sink current i ei 0.6 1.2 2.4 ma v inv =0.8v , v fb =1.5v [pwm comparator] lx1 max duty d max1 - - 100 % high side on duty lx2 max duty d max2 77 85 93 % low side on duty [output] lx1 pmos on-resistance r on1p - 120 200 m v gs =3.0v lx1 nmos on-resistance r on1n - 100 160 m v gs =3.0v lx2 pmos on-resistance r on2p - 120 200 m v gs =3.0v lx2 nmos on-resistance r on2n - 100 160 m v gs =3.0v vout discharge switch r dvo - 100 160 v gs =3.0v, on at stb off lx1 ocp threshold i ocp 2.0 3.0 - a pv cc =3.0v lx1 leak c ur rent i leak1 -1 0 +1 a lx2 leak current i leak2 -1 0 +1 a [stb] stb p in control voltage enable v stbh 1.5 - 5.5 v disable v stbl -0.3 - +0.3 v stb p ull down resistance r stb 250 400 700 k [circuit current] stand-b y current vcc p in i stb1 - - 1 a pvcc p in i stb2 - - 1 a vcc circuit current i cc 1 - 500 750 a (note 2) v inv =0.8v, stop dc/dc pvcc circuit current i cc 2 - 10 20 a (note 2) v inv =0.8v, stop dc/dc vout circuit current i cc 3 - 10 20 a (note 2) v inv =0.8v, stop dc/dc (note 2) i cc1 , i cc 2 , i cc 3 are currents flow ing to vcc, pvcc, vout terminals. w hen the input voltage of inv pin is 0.8v, dc/dc converter operation stops. total input current on dc/dc converter operation would be greater than the limit mentioned above. please refer to f ig ure 26 and f ig ure 35 for details about the total input current under dc/dc converter operation at 3.3v and 5.0v output. downloaded from: http:///
6/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV typical performance curves (unless otherwise specified, ta = 25c , v cc = 3.7v) 0.490 0.495 0.500 0.505 0.510 - 50 0 50 100 150 inv threshold[v] temperature[ ] v cc =1.8v v cc =3.0v v cc =5.0v v cc =7.0v figure 1. inv threshold vs temperature inv threshold [v] temperature : ta [c] 0.490 0.495 0.500 0.505 0.510 0 2 4 6 8 inv threshold[v] vcc[v] figure 2. inv threshold vs power supply voltage inv threshold [v] power supply voltage : v cc [v] figure 4. oscillation frequency vs power supply voltage 0.800 0.900 1.000 1.100 1.200 0 2 4 6 8 frequency[mhz] vcc[v] power supply voltage : v cc [v] frequency [mhz] 0.800 0.900 1.000 1.100 1.200 - 50 0 50 100 150 freauency[mhz] temperature[ ] fi gure 3. oscillation frequency vs temperature temperature : ta [c] frequency [mhz] downloaded from: http:///
7/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV typical performance curves - continued ta=-25deg ta=25deg ta=85deg 0.0 0.2 0.4 0.6 0.8 1.0 1.5 1.6 1.7 1.8 erroramp buffer voltage[v] vcc[v] figure 5. erroramp buffer voltage vs power supply voltage (uvlo detect threshold) power supply voltage : v cc [v] erroramp buffer voltage [v] 0.0 0.2 0.4 0.6 0.8 1.0 1.5 1.6 1.7 1.8 erroramp buffer voltage[v] vcc[v] ta=-25deg ta=25deg ta=85de g figure 6. erroramp buffer voltage vs power supply voltage (uvlo reset threshold) power supply voltage : v cc [v] erroramp buffer voltage [v] 0.0 0.5 1.0 1.5 2.0 2.5 3.0 0.0 0.5 1.0 1.5 2.0 fb sink current[ma] vfb[v] figure 7. fb sink current vs v fb (v inv =0.8v, v fb =1.5v) v fb [v] fb sink current [ma] 0 5 10 15 20 25 30 35 40 0.0 0.5 1.0 1.5 2.0 fb source current[ua] vfb[v] figure 8. fb source current vs v fb (v inv =0.2v, v fb =1.5v) v fb [v] fb source current [a] t a= -25deg ta=25deg ta=85deg downloaded from: http:///
8/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV typical performance curves - continued 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.4 0.8 1.2 1.6 2.0 erroramp buffer voltage[v] stb[v] ta=150deg ta=25deg ta=-60deg figure 9. erroramp buffer voltage vs stb threshold voltage stb threshold voltage [v] erroramp buffer voltage [v] figure 10. on-resistance vs power supply voltage (lx1 pch fet) 0 50 100 150 200 250 300 0 2 4 6 8 on resistance[m ] vcc[v ta=25deg ta=-60deg ta=150deg power supply voltage : v cc [v] on - resistance [m] figure 12. on-resistance vs power supply voltage (lx2 pch fet) 0 50 100 150 200 250 300 0 2 4 6 8 on resistance[m ] vcc[v ta=-60deg ta=25deg ta=150deg power supply voltage : v cc [v] on - resistance [m] 0 50 100 150 200 250 300 0 2 4 6 8 on resistance[m ] vcc[v ta=-60deg ta=25deg ta=150deg figure 11. on-resistance vs power supply voltage (lx1 nch fet) power supply voltage : v cc [v] on - resistance [m] downloaded from: http:///
9/ 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV typical performance curves - continued 0 5 10 15 20 0 2 4 6 8 pvcc current[ua] vcc[v] figure 15. pvcc input current vs power supply voltage (v inv =0.8v, stop dc/dc) power supply voltage : v cc [v] pvcc current : i cc2 [a] 0 50 100 150 200 250 300 0 2 4 6 8 on resistance[m ] vcc[v ta=-60deg ta=25deg ta=150deg figure 13. on-resistance vs power supply voltage (lx2 nch fet) on - resistance [m] power supply voltage : v cc [v] 0 50 100 150 200 250 300 0 2 4 6 8 on resistance[ ] vcc[v] ta=-60deg ta=25deg ta=150deg figure 16. on-resistance vs power supply voltage (v stb =0v) power supply voltage : v cc [v] on - resistance [] 0 100 200 300 400 500 600 700 800 900 1,000 0 2 4 6 8 vcc current[ua] vcc[v] figure 14. vcc input current vs power supply voltage (v inv =0.8v, stop dc/dc) power supply voltage : v cc [v] vcc current : i cc1 [a] downloaded from: http:///
10 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV typical performance curves - continued 0.0 1.0 2.0 3.0 4.0 5.0 0 2 4 6 8 ocp detect current[a] vcc[v] ta=85deg ta=25deg ta=-25deg figure 17. ocp detect current vs power supply voltage power supply voltage : v cc [v] ocp detect current [a] downloaded from: http:///
11 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV application information 1. application circuit [1] input: 2.8v to 5.5v, output: 3.3v / 1.0a, frequency 1mhz 2. application circuit [2] input: 2.8v to 5.5v, output: 5.0v / 0.7a, frequency 1mhz figure 19. example of application circuit [2] figure 18. example of application circuit [1] r rt 8 7 6 5 13 14 15 16 1 2 3 4 12 11 10 9 fb inv gnd vout vout lx 2 lx 2 pgnd rt stb vcc pvcc pgnd lx1 lx1 pvcc cfb 2200pf rfb 4.7k rrt 39 k on /off 2.8 5.5v 10uf (ceramic) murata grm 31 cb 11 a 106 ka 01 3.3v/1.0a 10uf (ceramic) murata grm 31 cb 11 a 106 ka 01 4.7 uh toko de 3518 c rinv1 56 k rinv2 10 k cc 120pf rc 4.7k cvcc 1 uf rvcc 0 2.8v to 5.5v 4.7h 1f 10f (ceramic) 10f (ceramic) lx2 lx2 lx1 lx1 vout vout r vcc c vcc 1f c fb r fb 4.7k r inv1 r inv2 r rt 8 7 6 5 13 14 15 16 1 2 3 4 12 11 10 9 fb i n v gnd vout vout lx2 lx2 pgnd rt stb vcc pvcc pgnd lx1 lx1 pvcc cfb 2200pf rfb 4.7k rrt 39k on/off 2.8 5.5v 10uf(ceramic) murata grm31cb11a106ka01 3.3v/1.0a 10uf(ceramic) murata grm31cb11a106ka01 4.7uh toko de3518c rinv1 82k rinv2 9.1k cc 120pf rc 4.7k cvcc 1uf rvcc 0 4.7h 2.8v to 5.5v lx1 lx1 lx2 lx2 vout vout 10f (ceramic) 10f (ceramic) r inv1 r inv2 r fb c fb c vcc 1f r vcc r rt downloaded from: http:///
12 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV 3. sample board layout figure 20 . assembly layer figure 21. bottom layer downloaded from: http:///
13 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV 4. reference application data (unless otherwise specified, ta = 25 c , v cc = 3.7 v) sample application 1 figure 22. total efficiency vs output current (power conversion efficiency) 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1,000 total efficiency[%] output current[ma] v cc =2.8v v cc =3.7v v cc =4.2v total efficiency [%] output current : i out [ma] 3.24 3.26 3.28 3.30 3.32 3.34 3.36 1.5 2.5 3.5 4.5 5.5 output voltage[v] vcc[v] figure 23. output voltage vs power supply voltage (output current = 500ma) power supply voltage : v cc [v] output voltage : v out [v] 3.24 3.26 3.28 3.30 3.32 3.34 3.36 1 10 100 1000 output voltage[v] output current[ma] figure 24. output voltage vs output current output current : i out [ma] output voltage : v out [v] 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 1.5 2.5 3.5 4.5 5.5 maximum output current[ma] vcc[v] figure 25. maximum output current vs power supply voltage power supply voltage : v cc [v] maximum output current [ma] downloaded from: http:///
14 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV v out [100mv/div] i out [500ma/div] figure 28. output current response (output current = 100ma ? 500ma 5msec/div) 50 55 60 65 70 75 80 85 90 95 100 1.50 2.50 3.50 4.50 5.50 high side on duty[%] vcc[v] lx1 lx2 figure 27. high side on duty vs power supply voltage (lx1, lx2) power supply voltage : v cc [v] high side on duty [%] stb [5.0v/div] v out [1.0v/div] figure 29. soft start waveform (stb: low to high 500sec/div ) 0 4 8 12 16 20 1.5 2.5 3.5 4.5 5.5 total input current[ma] vcc[v] figure 26. total input current vs power supply voltage (output current = 0ma) power supply voltage : v cc [v] total input current [ma] downloaded from: http:///
15 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV 5. reference application data (unless otherwise specified, ta = 25 c , v cc = 3.7v) sample application 2 figure 31. total efficiency vs output current (power conversion efficiency) 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1,000 total efficiency[%] output current[ma] v cc =4.2v v cc =3.7v v cc =2.8v total efficiency [%] output current [ma] figure 32. output voltage vs power supply voltage (output current = 500ma) 4.90 4.95 5.00 5.05 5.10 1.5 2.5 3.5 4.5 5.5 output voltage[v] vcc[v] power supply voltage : v cc [v] output voltage [v] figure 30. discharge waveform (stb: high to low 500sec/div ) v out [1.0v/div] stb [5.0v/div] downloaded from: http:///
16 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV figure 33. output voltage vs output current 4.90 4.95 5.00 5.05 5.10 1 10 100 1000 output voltage[v] output current[ma] output current [ma] output voltage [v] figure 34. maximum output current vs power supply voltage 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000 1.5 2.5 3.5 4.5 5.5 maximum output current[ma] vcc[v] power supply voltage : v cc [v] maximum output current [ma] figure 35. total input current vs power supply voltage (output current = 0ma) 0 4 8 12 16 20 1.5 2.5 3.5 4.5 5.5 total input current[ma] vcc[v] power supply voltage : v cc [v] total input current [ma] figure 36. high side on duty vs power supply voltage (lx1, lx2) 50 55 60 65 70 75 80 85 90 95 100 1.50 2.50 3.50 4.50 5.50 high side on duty[%] vcc[v] lx2 lx1 power supply voltage : v cc [v] high side on duty [%] downloaded from: http:///
17 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV 100 1,000 10,000 1 10 100 1,000 frequency[khz] rt[k ] 6. selection of parts for application (1) output inductor a shielded inductor that satisfies the current rating (current value, i peak as shown in the drawing below) and has a low dcr (direct current resistance component) is recommended. inductor values affect output ripple current greatly. ripple current can be reduced as the inductor l value becomes larger and the switching frequency becomes higher as shown in the equations below. ; (in step-down mode) (1) ; (in buck-boost mode) (2) ; (in step-up mode) (3) where: is the efficiency (<0.96) dc is the cross point duty ( 0.91) f is the switching frequency l is the inductance as a guide, output ripple current should be set at about 20% to 50% of the maximum output current. (note ) current flow that exceeds the coil rating 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 ex ceed the rated current of the coil. . (2) output capacitor a ceramic capacitor with a low esr is recommended at the output in order to reduce output ripple. there must be an adequate margin between the maximum rating and output voltage of the capacitor, taking the dc bias property into consideration. output ripple voltage when ceramic capacitor is used is obtained by the following equation. sett ing must be performed so that output ripple is within the allowable ripple voltage. ( 4) (3) setting of oscillation frequency oscillation frequency can be set using a resistance value connected to the rt pin (pin 16 ). the oscillation frequency is set at 1 [mhz] when r rt = 39 [k ], wherein frequency is inversely proportional to rt value. see figure 38 for the relationship between rt [k ] and frequency. soft-start time changes along with oscillation frequency. see figure 39 for the relationship between rt [k ] and soft-start time. frequency is calculated by the following equation. (5) note: that the above example of frequency setting is just a design target value, a nd may differ from the actual equipment. i l figure 37. ripple current figure 38. oscillation frequency vs rt pin resistance figure 39. soft-start time vs rt pin resistance 0 1 10 1 10 100 1,000 soft start time[msec] rt[k ] ? ? ? ? a f vl v v v i i in out out in out peak ? ? ? ? ? ? ? 2 ? ? ? ? ? ? a f v v l dc v v v v dc v v i i out in out out in in out in out peak ? ? ? ? ? ? ? ? ? ? ? ? ? ] [ 2 ? ? ? ? ? a f vl v v v v v i i out in in out in out out peak ? ?? ? ? ? ? ? ? 2 ? ? ? v r i c f i vpp esr l o l ? ?? ? ? ? ?? ? 2 1 ? ? khz rt f osc 1000 39 ? ? frequency [khz] soft start time [msec] downloaded from: http:///
18 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV (4) output voltage setting the internal reference voltage of the error amp is 0.5v. output voltage should be obtained by referring to equation (6) of figure 40. (6) (5) determination of phase compensation the condition for feedback system stability under negative feedback is as follows: (a) phase delay must be 135 or lower when gain is 1 (0 db) (phase margin is 45 or higher) . since dcdc converter application is sampled according to the switching frequency, the gain-bw of the whole system (frequency at which gain is 0db) must be set to be equal to or lower than 1/5 of the switching frequency. (b) phase delay must be 135 or lower when gain is 1 (0 db) (phase margin is 45 or higher). (c) the gain-bw at that time (frequency when gain is 0db) must be equal to or lower than 1/5 of the switching fr equency. for this reason, switching frequency must be increased to improve responsiveness. one of the points to secure stability by phase compensation is to cancel the second dimensional phase delay (-180) generated by lc resonance of the second dimensional phase lead (i.e. put two phase leads). since f gbw is determined by the phase compensation capacitor attached to the error amplifier, the capacitor should be made larger when it is necessary to reduce f gbw . (7 ) (8) v ref 0.5v v out error amp r 1 r 2 inv figure 40. setting of feedback resistance phase margin - 180 0 - 90 (a) gain [db] phase [degree] -20db/decade 0 figure 42. frequency property of integrator (b) figure 41. general integrator fb r c a ? ? ? ? v r r r v out 5.0 2 2 1 ? ? ? ? ? ? ? hz rca fp a po ? 2 1 int ? ? ? ? ? hz rc f b po gbw ? 2 1 int ? error amp is a low-pass filter because phase compensation by rc is performed as shown below. for dc/dc converter application, r is a parallel feedback resistance. downloaded from: http:///
19 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV phase compensation using an output capacitor with a low esr such as ceramic capacitor is as follows: when an output capacitor with a low esr (several tens of m) is used at the output, the secondary phase lead (two phase leads) must be put to cancel the secondary phase lead caused by lc. one example of phase compensati on methods is as follows: (9) (10) (11) for setting of phase-lead frequency (9) and (10), both of them should be put near the lc resonance frequency (12) or (13). when g bw frequency becomes too high due to the secondary phase lead, it may be stabilized by setting the primary phase delay (11) to a frequency slightly higher than the lc resonance frequency by r 3 to compensate it. the f gbw of the whole system (frequency at which gain is 0 db) which set responsiveness of the dc/dc converter c an be calculated by getting dc gain and the first dimension pole by equations below. the responsiveness can be set high by setting the f gbw to high frequency, but the whole system would be operated as bad oscillation if the f gbw is set too high since there are not enough phase margin. the f gbw must be equal to or lower than 1/5 of the switching frequency. dc gain of the dc/dc converter can be expressed as below. dc gain (in step-down mode) out in ref v v v b a gain dc ? ? ? (14) dc gain (in step-up mode) in out out ref v v v v b a gain dc ? ? ? ? (15) dc gain (in buck-boost mode) out out in ref v dc v v v b a gain dc ? ? ? ? ? 2 (16) the dc gain of the dc/dc converter declines by 20db/decade from the first dimension pole which is as shown below. the first dimension pole ? ? hz c r r rr a fp 2 2 1 21 2 1 ? ? ?? ? ? (17) where: a is the error amp gain=100db=10 5 b is the oscillator amplification=0.4v v ref is the reference voltage of error amp=0.5v the f gbw at 0 db under limitation of the band width of the dc gain at the first dimension pole point is as shown below. zero cross frequency ? ? hz fp gain dc f gbw ? ? (18) figure 43. example of setting of phase compensation lc resonance frequency (in step-down mode) (12) lc resonance frequency (in step-up mode) (13) ? ? hz cr fz lead phase 11 2 1 1 ? ? ? ? hz cr fz lead phase 24 2 1 2 ? ? ? ? hz cr fp delay phase 13 2 1 1 ? ? ? ? ? ? hz lc ? 2 1 ? ? ? ? ? hz lc d ? 2 1 ? ? out in out v v v on d ? : + fb v out c 2 r 1 r 2 r 3 r 4 c 1 - downloaded from: http:///
20 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV i/o equivalent circuits fb inv vout, lx2, pgnd pvcc, lx1, pgnd stb rt vcc vcc fb vout lx2 pgnd vcc pvcc lx1 pgnd vcc vcc stb rt vcc vcc vcc vcc inv lx2 lx1 downloaded from: http:///
21 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV operational notes 1. reverse connection of power s upply connecting the power supply in reverse polarity can damage the ic. take precautions against reverse polarity whe n connecting the power supply, such as mounting an external diode between the power supply and th e ic s power supply pins. 2. power supply lines design the pcb layout pattern to provide low impedance supply lines. separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog block. furthermore, connect a capacitor to ground at all power supply pins . consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. ground voltage ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. ground wiring pattern when using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signa l ground caused by large currents. also ensure that the ground traces of external components do not cause variations on the ground voltage. the ground lines must be as short and thick as possible to reduce line impedance. 5. thermal consideration should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. in case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the pd rating. 6. recommended operating conditions these conditions represent a range within which the expected characteristics of the ic can be approximately obtained . the electrical characteristics are guaranteed under the conditions of each parameter. 7. inrush current when power is first supplied to the ic, it is possible that the internal logic may be unstable and inrush curre nt may flow instantaneously due to the internal powering sequence and delays, especially if the ic has more than one power supply. therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. operation under strong electromagnetic field op erating the ic in the presence of a strong electromagnetic field may cause the ic to malfunction. 9. testing on application boards when testing the ic on an application board, connecting a capacitor directly to a low-impedance output pin may subject the ic t o stress. always discharge capacitors completely after each process or step. the ics power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. to prevent damage from static discharge, ground the ic during assembly and use similar precautions during transport and storage. 10. inter-pin short and mounting errors ensure that the direction and position are correct when mounting the ic on the pcb. incorrect mounting may result in damaging the ic. avoid nearby pins being shorted to each other especially to ground, power supply and outp ut pin . inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environme nt) and unintentional solder bridge deposited in between pins during assembly to name a few. downloaded from: http:///
22 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV operational notes C continued 11. unused input pins input pins of an ic are often connected to the gate of a mos transistor. the gate has extremely high impedance and extremely low capacitance. if left unconnected, the electric field from the outside can easily charge it. the small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the ic. so unless otherwise specified, unused input pins should be connected to the power supply or ground line. 12. regarding the input pin of the ic this monolithic ic contains p+ isolation and p substrate layers between adjacent elements in order to keep them isolated. p-n junctions are formed at the intersection of the p layers with the n layers of other elements, creating a parasitic diode or transistor. for example (refer to figure below): when gnd > pin a and gnd > pin b, the p-n junction operates as a parasitic diode. when gnd > pin b, the p-n junction operates as a parasitic transistor. parasitic diodes inevitably occur in the structure of the ic. the operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. therefore, conditions that cause these diode s to operate, such as applying a voltage lower than the gnd voltage to an input pin (and thus to the p s ubstrate) should be avoided. figure 44. example of monolithic ic structure 13. thermal shutdown circuit(tsd) this ic has a built-in thermal shutdown circuit that prevents heat damage to the ic. normal operation should alwa ys be within the ics power dissipation rating. if however the rating is exceeded for a continued perio d, the junction temperature (tj) will rise which will activate the tsd circuit that will turn off all output pins. when the tj falls below the tsd threshold, the circuits are automatically restored to normal operation. note that the tsd circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the tsd circuit be used in a set design or for any purpose other than protecting the ic from heat damage. 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:///
23 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV ordering information b d 8 3 0 6 m u v - e 2 part number package muv: vqfn0 16 v3030 packaging and forming specification e2: embossed tape and reel marking diagram vqfn016v3030 (top view) 3 0 6 part number marking lot number 1pin mark b d 8 downloaded from: http:///
24 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV physical dimension, tape and reel information package name vqfn016v3030 downloaded from: http:///
25 / 25 tsz02201-0q3q0nz00340-1-2 ? 2014 rohm co., ltd. all rights reserved. 26.nov.2014 rev.001 www.rohm.com tsz22111 ? 15 ? 001 BD8306MUV revision history date revision changes 26.nov.2014 001 new release downloaded from: http:///
notice- ge rev.003 ? 2013 rohm co., ltd. all rights reserved. notice precaution on using rohm products 1. our products are designed and manufactured for application in ordinary electronic equipments (such as av equipment, oa equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). if you intend to use our products in devices requiring extremely h igh reliability (such as medical equipment (note 1) , transport equipment, traffic equipment, aircraft/spacecraft, nuclear powe r controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property ( specific applications ), please consult with the rohm sales representative in adv ance. unless otherwise agreed in writing by rohm in advance, rohm s hall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arisin g from the use of any rohm s products for specific applications. (note1) medical equipment classification of the specific app lications japan usa eu china class class class b class class | class 2. rohm designs and manufactures its products subject to s trict quality control system. however, semiconductor products can fail or malfunction at a certain rate. please be sure to implement, at your own responsibilities, adeq uate safety measures including but not limited to fail-safe desig n against the physical injury, damage to any property, whic h a failure or malfunction of our products may cause. the followi ng are examples of safety measures: [a] installation of protection circuits or other protective devic es to improve system safety [b] installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. our products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified be low. accordingly, rohm shall not be in any way responsible or liable for any damages, expenses or losses arisi ng from the use of any rohms products under any special or extraordinary environments or conditions. if you intend to use our products under any special or extraordinary environments or conditions (as exemplified belo w), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be n ecessary: [a] use of our products in any types of liquid, including water, oils, chemicals, and organi c solvents [b] use of our products outdoors or in places where the products are exposed to direct sunlight or dust [c] use of our products in places where the products are e xposed 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 t o static electricity or electromagnetic waves [e] use of our products in proximity to heat-producing component s, plastic cords, or other flammable items [f] sealing or coating our products with resin or other coating materials [g] use of our products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or washing our products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] use of the products in places subject to dew condensation 4. the products are not subject to radiation-proof design. 5. please verify and confirm characteristics of the final or mou nted products in using the products. 6. in particular, if a transient load (a large amount of load a pplied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mou nting is strongly recommended. avoid applying power exceeding normal rated power; exceeding the power rating u nder steady-state loading condition may negatively affec t product performance and reliability. 7. de -rate power dissipation (pd) depending on ambient temperature (ta). wh en used in sealed area, confirm the actual ambient temperature. 8. confirm that operation temperature is within the specified range described in the product specification. 9. rohm shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. precaution for mounting / circuit board design 1. when a highly active halogenous (chlorine, bromine, e tc.) flux is used, the residue of flux may negatively affect p roduct performance and reliability. 2. in principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method mu st be used on a through hole mount products. i f the flow soldering method is preferred on a surface-mount p roducts , please consult with the rohm representative in advance. for details, please refer to rohm mounting specification downloaded from: http:///
notice- ge rev.003 ? 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, please allow a sufficient margin considering variations of the characteristics of the products and external components, inc luding transient characteristics, as well as static characteristics. 2. you agree that application notes, reference designs, and associated data and information contained in this docu ment are presented only as guidance for products use. therefore, i n case you use such information, you are solel y responsible for it and you must exercise your own independ ent verification and judgment in the use of such information contained in this document. rohm shall not be in any way respon sible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such informat ion. precaution for electrostatic this product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. please take pr oper caution in your manufacturing process and storage so t hat voltage exceeding the products maximum rating will not be applied to products. please take special care under dry co ndition (e.g. grounding of human body / equipment / solder iro n, isolation from charged objects, setting of ionizer, friction prevention and temperature / humidity control). precaution for storage / transportation 1. product performance and soldered connections may deteriorate if the products are stored in the places where: [a] the products are exposed to sea winds or corrosive gases, in cluding cl2, h2s, nh3, so2, and no2 [b] the temperature or humidity exceeds those recommended by rohm [c] the products are exposed to direct sunshine or condensation [d] the products are exposed to high electrostatic 2. even under rohm recommended storage condition, solderab ility of products out of recommended storage time period may be degraded. it is strongly recommended to confirm so lderability before using products of which storage time is exceeding the recommended storage time period. 3. store / transport cartons in the correct direction, which is in dicated on a carton with a symbol. otherwise bent leads may occur due to excessive stress applied when dropping of a c arton. 4. use products within the specified time after opening a hum idity barrier bag. baking is required before using products of which storage time is exceeding the recommended storage tim e period. precaution for product label qr code printed on rohm products label is for rohm s internal use only. precaution for disposition when disposing products please dispose them properly usi ng an authorized industry waste company. precaution for foreign exchange and foreign trade act since our products might fall under controlled goods prescr ibed by the applicable foreign exchange and foreign trade act, please consult with rohm representative in case of export. precaution regarding intellectual property rights 1. all information and data including but not limited to ap plication example contained in this document is for referen ce only. rohm does not warrant that foregoing information or da ta will not infringe any intellectual property rights or any other rights of a ny third party regarding such information or data. rohm shall not be in any way responsible or liable for infringement of any intellectual property rights or other d amages arising from use of such information or data.: 2. no license, expressly or implied, is granted hereby under any i ntellectual property rights or other rights of rohm or any third parties with respect to the information contained in this d ocument. other precaution 1. this document may not be reprinted or reproduced, in whole or in part, without prior written consent of rohm. 2. the products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of rohm. 3. in no event shall you use in any way whatsoever the products and the related technical information contained in the products or this document for any military purposes, includi ng but not limited to, the development of mass-destruction weapons. 4. the proper names of companies or products described i n this document are trademarks or registered trademarks of rohm, its affiliated companies or third parties. downloaded from: http:///
datasheet datasheet notice ? we rev.001 ? 2014 rohm co., ltd. all rights reserved. general precaution 1. before you use our pro ducts, you are requested to care fully read this document and fully understand its contents. rohm shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny rohms products against warning, caution or note contained in this document. 2. all information contained in this docume nt is current as of the issuing date and subj ec t to change without any prior notice. before purchasing or using rohms products, please confirm the la test information with a rohm sale s representative. 3. the information contained in this doc ument is provi ded on an as is basis and rohm does not warrant that all information contained in this document is accurate an d/or error-free. rohm shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. downloaded from: http:///

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