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1/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. single-chip type with built- in fet switching regulators high-efficiency step-up switching regulator with built-in power mosfet bd8311nuv description rohm?s high-efficiency step-up switching regulator built -in power mosfet bd8311nuv generates step-up output including 8 v or 10 v from 4 batteries, batteries such as li2cell etc. or a 5 v fixed power supply line. this ic allows easy production of small and a wide range of output current, and is equipped with an external coil/capacitor downsized by high frequency operation of 1.2 mhz, built-i n 2.5 a rated 80 m ? nch fet sw, and flexible phase compensation sy stem on board. features 1) incorporates nch fet capabl e of withstanding 2.5 a/14 v. 2) incorporates phase compensation device between input and output of error amp. 3) small coils and capacitors to be used by high frequency operation of 1.2 mhz 4) input voltage 3.5 v ? 11 v 5) output current 600 ma (3.5 v ? 10 v) at 10 v 800 ma (3.5 v ? 8 v) at 8 v 6) incorporates soft-start function. 7) incorporates timer latch system short protecting function. 8) as small as 3 mm 2 , son 10-pin package vson010v3030 application general portable equipment like dsc/dvc powered by 4 dry batteries or li2cell absolute maxi mum ratings parameter symbol ratings unit maximum applied power voltage vcc, lx 14 v maximum input voltage swout, inv 14 v maximum input current iinmax 2.5 a power dissipation pd 700 mw operating temperature range topr -25 to +85 c storage temperature range tstg -55 to +150 c junction temperature tjmax +150 c *1 when used at ta = 25c or more installed on a 74.2 74.2 1.6t mm board, the rating is reduced by 5.6 mw/c. * these specifications are subject to change without advance notice for modifications and other reasons. operating conditions (ta = 25c) parameter symbol ratings unit power supply voltage vcc 3.5 to 11 v output voltage vout 4.0 to 11 v no.10027ect03
bd8311nuv technical note 2/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. electrical characteristics parameter symbol limits unit conditions min. typ. max. [low voltage input malfunction preventing circuit] detection threshold voltage v uv - 2.9 3.2 v vreg monitor hysteresis range v uv hy 100 200 300 mv [oscillator] oscillation frequency fosc 1.1 1.2 1.3 mhz [regulator] output voltage vreg 4.65 5.0 5.35 v [error amp] inv threshold voltage vinv 0.99 1.00 1.01 v input bias current iinv -50 0 50 na vcc=11.0v , v inv =5.5v soft-start time tss 5.3 8.8 12.2 msec [pwm comparator] lx max duty dmax1 77 85 93 % [swout] on resistance r onswout - 50 100 ? [output] lx nmos on resistance r on - 80 150 m ? lx leak current ileak -1 0 1 a [stb] stb pin control voltage operation v stb h 2.5 - vcc v no-operation v stb l -0.3 - 0.3 v stb pin pull-down resistance r stb 250 400 700 k ? [circuit current] standby current vcc istb - - 1 a circuit current at operation vcc icc - 600 900 a v inv =1.2v ? not designed to be resistant to radiation
bd8311nuv technical note 3/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. stb + - + vref error_amp soft start scp osc16000 ount fb h stop stby_io vcc pwm control reference uvlo vref 5v reg pgnd lx pre driver vreg gnd inv 80m vreg vreg osc 1.2mhz swout stb 50 description of pins block diagram pin no. pin name function 1 gnd ground terminal 2 vcc control part power input terminal 3 vreg 5 v output terminal of regulator for internal circuit 4 5 lx coil connecting terminal 6 7 pgnd power transistor ground terminal 8 stb on/off terminal 9 inv error amp input terminal 10 swout stbsw for split resistance fig.1 pin layout lx gnd vreg vcc pgnd inv swout stb pgnd lx fig.2 block diagram
bd8311nuv technical note 4/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. description of blocks 1. vref this block generates error amp reference voltage. the reference voltage is 1.0 v. 2. uvlo circuit for preventing low voltage malfunction prevents malfunction of the internal circuit at activation of the power supply voltage or at low power supply voltage. monitors vcc pin voltage to turn off all output fet and dc/ dc converter output when vcc voltage is lower than 2.9 v, and reset the timer latch of the internal scp circuit and soft -start circuit. this threshold contains 200 mv hysteresis. 3. scp timer latch system short-circuit protection circuit when the inv pin is the set 1.0 v or lower volt age, the internal scp circuit starts counting. the internal counter is in synch with osc; the latch circui t activates after a lapse of 13.3 msec after the counter counts about 16000 oscillations and then, turn off dc/dc converter output. 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 circuit for oscillating sawtooth waves with an operation frequency fixed at 1.2 mhz 5. error amp error amplifier for detecting output si gnals and outputting pwm control signals the internal reference voltage is set at 1.0 v. a primary phase compensation device of 200 pf, 62 k ? is built in between the inverting input terminal and the output terminal of this error amp. 6. pwm comp voltage-pulse width converter for controlling output voltage corresponding to input voltage comparing the internal slope waveform with the error am p output voltage, pwm comp controls the pulse width to the output to the driver. max duty is set at 85%. 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 t he output voltage of the dc/dc conv erter reaches the set voltage after about 10000 oscillations . 8. pre driver cmos inverter circuit for driving the built-in nch fet. 9. stby_io voltage applied on stb pin (8 pin) to control on/off of ic turned on when a voltage of 2.5 v or higher is applied an d turned off when the terminal is open or 0 v is applied. incorporates approximately 400 k ? pull-down resistance. 10. nch fet sw built-in sw for switching the coil current of the dc/dc converter. incorporates an 80 m ? nchfet sw capable of withstanding 14 v. since the current rating of this fet is 2.5 a, it should be used within 2.5 a including the dc current and ripple current of the coil.
bd8311nuv technical note 5/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. reference data (unless otherwise specified, ta = 25c, vcc = 7.4 v) 0.00 0.05 0.10 0.15 0.20 0.25 120 1008550 25 0 -20-40 temparature [ ] ????R vhys [v] 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 uvlo threshold voltage [ ] 0 20 40 60 80 100 120 140 160 -40 0 40 80 120 temparature [] on resistance [ m ] 0.98 0.99 1.00 1.01 1.02 -40 -20 0 20 40 60 80 100 120 temperature [] inv threshold [v] 4.7 4.8 4.9 5.0 5.1 5.2 5.3 -40 0 40 80 120 temperature [] vreg voltage [v] 1.0 1.1 1.2 1.3 1.4 -40 0 40 80 120 temperature [] frequency [mhz] fig.3. inv threshold temperature property fig.7. fosc temperature property fig.5. vreg output te mperature property fig.10. nch fet on resistance temperature property fig.9. uvlo threshold temperature property hysteresis width uvlo detection uvlo release 0.98 0.99 1.00 1.01 1.02 0 2 4 6 8 10 12 14 vcc [v] inv threshold [v] fig.4. inv threshold power supply property 0 1 2 3 4 5 6 7 8 02468101214 vcc [v] vreg[v] fig.6. vreg output power supply property fig.8. fosc voltage property fig.11. nch fet on resistance power supply property id=500ma 1.0 1.1 1.2 1.3 1.4 3 6 9 12 15 vcc [v] frequency [ mhz ] 0 20 40 60 80 100 120 3691215 vcc [v] on resistance [ m] id=500ma hysteresis voltage vhys[v]
bd8311nuv technical note 6/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. fig.12. stb threshold temperature fig.13. swout on resistance temperature property fig.14. swout on resistance power supply property 0 20 40 60 80 100 36 91215 vcc [v] swout on resistance [ ] id=1ma 0 20 40 60 80 100 -40 0 40 80 120 temparature [] swout on resistance [ ] id=1ma 1.0 1.5 2.0 2.5 - 5 005 01 0 01 5 0 vcc [v] stb voltage [v] on off 0 200 400 600 800 1000 02468101214 vcc [v] icc [ua] fig.18. circuit current power supply property 1.0 1.5 2.0 2.5 -50 0 50 100 150 temparature [] stb voltage [v] fig.15. lx max duty temperature property fig.17. circuit current temperature property fig.16. lx max duty power supply property 75 80 85 90 95 -40 0 40 80 120 temparature [] lx max duty [%] 75 80 85 90 95 3 6 9 12 15 vcc [v] lx max duty [ % ]
bd8311nuv technical note 7/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. example of application input: 3.5 to 10 v, output: 10.1 v / 500 ma pgnd stb inv swout pgnd gnd vcc lx lx 1 3 4 5 2 10 8 7 6 9 on/off vreg 10v/500ma 10p 200k 10k 100k 22k 22f grm32eb31c226ke16( murata) rsx201l-30 (rohm) 4.7h de3518e( toko) vbat=2.5~ 4.5v 10f grm31cb31e106ka75l( murata ) 1f grm21bb11c105ka01( murata) 1f grm188b11a105ka61( murata) 3.3~ 5.0v reference application data 1 9.5 9.6 9.7 9.8 9.9 10.0 10.1 10.2 10.3 10.4 10.5 1 10 100 1000 10000 output current [ma] output voltage [v] fig.20 power conversion efficiency 1 fig.23 line regulation fig.24 load regulation 1 fig.19 reference application diagram fig.21 power conversion efficiency 2 fig.22 power conversion efficiency 3 0 20 40 60 80 100 1 10 100 1000 10000 output current [ma] efficiency [%] vcc=10v vcc=8.4v vcc=7.4v 0 20 40 60 80 100 1 10 100 1000 10000 output current [ma] efficiency [%] vcc=6.0v vcc=4.8v 0 20 40 60 80 100 1 10 100 1000 10000 output current [ma] efficiency [%] vcc=4.0v vcc=3.5v 5 6 7 8 9 10 11 12 13 14 15 024681012 input voltage [v] output voltage [v] io=100ma io=500ma fig.25 load regulation 2 9.5 9.6 9.7 9.8 9.9 10.0 10.1 10.2 10.3 10.4 10.5 1 10 100 1000 10000 output current [ma] output voltage [v] vcc=10v vcc=6.0v vcc=7.4v vcc=8.4v vcc=3.5v vcc=4.0v vcc=4.8v
bd8311nuv technical note 8/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. reference application data 2 (vcc = 3.5 v, 6.0 v, 8.4 v, vout = 10 v) reference board pattern the radiation plate on the rear should be a gnd flat surface of low impedance in common with the pgnd flat surface. it is recommended to install a gnd pin in another system as shown in the drawing wit hout connecting it directly to this pgnd -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.26 frequency response property 1 (vcc = 3.5 v, io = 200 ma) -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.30 frequency response property 5 (vcc = 6.0 v, io = 500 ma) -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.27 frequency response property 2 (vcc = 6.0 v, io = 200 ma) -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.28 frequency response property 3 (vcc = 8.4 v, io = 200 ma) -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.29 frequency response property 4 (vcc = 3.5 v, io = 500 ma) -60 -40 -20 0 20 40 60 100 1000 10000 100000 1000000 ? [hz] gain [db] -180 -120 -60 0 60 120 180 phase [deg] fig.31 frequency response property 6 (vcc = 8.4 v, io = 500 ma) phase gain phase gain phase gain phase gain phase gain phase gain 100 1k 10k 100k 1m 100 1k 10k 100k 1m 100 1k 10k 100k 1m 100 1k 10k 100k 1m 100 1k 10k 100k 1m 100 1k 10k 100k 1m 100 1k 10k 100k 1m vout gnd vbat lx frequency [hz] frequency [hz] frequency [hz] frequency [hz] frequency [hz] frequency [hz]
bd8311nuv technical note 9/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. selection of part for applications (1) inductor a shielded inductor that satisfies the current rating (current value, ipecac as shown in the drawing below) and has a low dcr (direct resistance component) is recommended. inductor values affect inductor ripple current, which will cause output ripple. ripple current can be reduced as the coil l value becomes larger and the switching frequency becomes higher. ipeak =iout (vout/vin) / + ? il/2 [a] (1) ( : efficiency, ? il: output ripple curren t, f: switching frequency) as a guide, inductor ripple current should be se t at about 20 to 50% of the maximum input current. * current over the coil rating flowing in the coil 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 is recommended for 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 is obtain ed by the following equation. setting must be performed so that output ripple is within the allowable ripple voltage. (3) output voltage setting the internal reference voltage of the erro r amp is 1.0 v. output voltage is obtai ned by equation (4) of fig. 33, but it should be designed taking about 50 ? , an error of nmos on resistance of swout into consideration. vo= 1.0 [v] ??? (4) r2 (r1+r2) vpp=iout + iout r esr [v] ? (3) fcovout vout-vin i l ? il= [a] (2) l vin vout vout -vin f 1 fig.32 inductor current fi g .33 settin g of volta g e feedback resistance vref 1.0v vout error amp r1 r2 inv stb swout
bd8311nuv technical note 10/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. (4) dc/dc converter frequency response adjustment system condition for stable application the condition for feedback system stability under negative feedback is that the phase delay is 135 or less when gain is 1 (0 d b). since dc/dc converter application is sampled according to the switching frequency, the bandwidth gbw 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 gbw (frequency when gain is 0 db) must be equ al to or lower than 1/10 of the switching frequency. to satisfy above two items, r 1 , r 2 , r 3 , d s and r s in fig. 34 should be set as follows. [1] r 1 , r 2 , r 3 bd8311nuv incorporates phase compensation devices of r4=62 k ? and c2=200pf. these c2 and r 1 , r 2 , and r 3 values decide the prim ary pole that determines the bandwidth of dc/dc converter. primary pole point frequency dc/dc converter dc gain by equations (1) and (2), the frequency f sw of point 0 db under limit ation of the bandwidth of the dc gain at the primary pole point is as shown below. f sw = fpdc gain = it is recommended that f sw should be approx.10 khz. when load response is difficult, it may be set at approx. 20 khz. by this setting, r 1 and r 2 , which determine the voltage value, will be in the order of several hundred k ? . therefore, if an appropriate resistance value is not availabl e and routing may cause noise, the use of r 3 enables easy setting. fig.34 example of phase compensation setting fb vout c2 r1 r2 rs r4 cs r3 inside of ic a: error amp gain about 100db = 10 5 b: oscillator amplification = 0.5 v in: input voltage v out : output voltage (2) 2 a ( +r 3 ) c 2 fp= 1 r 1 ? r 2 r 1 +r 2 dc gain =a v out -v in b 1 v out 2 c2 ( +r 3 ) (r 1+ r 2 ) (r 1 ? r 2 ) 1 v out -v in b 1 v out (1) (3)
bd8311nuv technical note 11/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. [2] cs and rs setting in the step-up dc/dc converter, the se condary pole point is caused by the coil and capacitor as expressed by the following equation. f lc = this secondary pole causes a phase rotation of 180. to secure the stability of the system, put zero points in 2 places to perform compensation. zero point by built-in cr f z1 = = 13khz zero point by cs f z1 = setting c s2 to be half to 2 times a frequency as large as f lc provides an appropriate phase margin. it is desirable to set rs at about 1/20 of (r 1 +r 3 ) to cancel any phase boosting at high frequencies. those pole points are summarized in the figure below. t he actual frequency property is different from the ideal calculation because of part constants. if possible, check the phase margin with a frequency analyzer or network analyzer, etc.. otherwise, check for the presence or absenc e of ringing by load response waveform and also check for the presence or absence of oscillation under a load of an adequate margin. 2 (lc) 1 d 2 r 4 c 2 1 2 (r 1+ r 3 )c s 1 (5) (6) (4) (3) fig. 35 example of dc/dc converter frequency property (measured with fra5097 by nf corporation) d: on duty = ( v out - v in ) / v out 1 (4) (6) (5)
bd8311nuv technical note 12/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. i/o equivalence circuit fb inv vreg swout stb lx, pgnd vreg vreg fb vcc stb vcc vreg vcc inv vcc vreg vcc swout vcc lx pgnd
bd8311nuv technical note 13/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. notes for use 1) absolute maximum rating we dedicate much attention to the qualit y control of these products, however the pos sibility of deterioration or destruction exists if the impressed voltag e, operating temperature range, etc., exceed the absolute ma ximum ratings. in addition, it is impossible to predict all destructive sit uations such as short-circuit modes, ope n circuit modes, etc. if a special mode exceeding the absolute maximum rating is expected, please re view matters and provide physical safety means such as fuses, etc. 2) gnd potential keep the potential of the gnd pin below th e minimum potential at all times. 3) thermal design work out the thermal design with sufficient margin taking power dissipation (pd) in the actual operation condition into account . 4) short circuit between pins and incorrect mounting attention to ic direction or displacement is required when inst alling the ic on a pcb. if the ic is installed in the wrong way, it may break. also, the threat of destruction from short-ci rcuits exists if foreign matter invades between outputs or the output and gnd of the power supply. 5) operation under strong electromagnetic field be careful of possible malfunctions un der strong electromagnetic fields. 6) common impedance when providing a power supply and gnd wirings, show su fficient consideration for lowering common impedance and reducing ripple (i.e., using thick short wiring, cutting ripple down by lc, etc.) as much as you can. 7) thermal protection circuit (tsd circuit) this ic contains a thermal protection circuit (tsd circuit). t he tsd circuit serves to shut off the ic from thermal runaway and does not aim to protect or assure operati on of the ic itself. therefore, do not us e the tsd circuit for continuous use or operation after the circuit has tripped. 8) rush current at the time of power activation be careful of the power supply coupling capacity and the width of the power supply and gnd pattern wiring and routing since rush current flows instantaneously at the time of power activation in the case of cmos ic or ics with multiple power supplies. 9) ic terminal input this is a monolithic ic and has p+ isolation and a p substr ate for element isolation between each element. p-n junctions are formed and various parasitic elements are configured using these p layers and n layers of the individual elements. for example, if a resistor and transistor are connected to a terminal as shown on fig.36: the p-n junction operates as a parasitic diode when gnd > (terminal a) in the case of a resistor or when gnd > (pin b) in the case of a transistor (npn) also, a parasitic npn transistor operates using the n layer of another element adjacent to the previous diode in the case of a transistor (npn) when gnd > (pin b). the parasitic element consequently rises under the potential relationship because of the ic?s structure. the parasitic element pulls interference that could caus e malfunctions or destruction out of the ci rcuit. therefore, use caution to avoid the operation of parasitic elements caused by applying volta ge to an input terminal lower than the gnd (p board), etc. (pin a) gnd p substrate n p n p p (pin a) parasitic element resistor transistor ( npn ) gnd n p n p p (pin b) b n e c gnd n p substrate parasitic element parasitic element fig.36 example of simple structure of bipolar ic
bd8311nuv technical note 14/14 www.rohm.com 2010.11 - rev.c ? 2010 rohm co., ltd. all rights reserved. ordering part number b d 8 3 1 1 n u v - e 2 part no. part no. package nuv: vson010v3030 packaging and forming specification e2: embossed tape and reel (unit : mm) vson010v3030 s 3.00.1 3.00.1 1pin mark 1.0max (0.22) s 0.08 0.02 +0.03 - 0.02 610 51 0.40.1 0.5 0.5 2.00.1 1.20.1 0.25 +0.05 - 0.04 c0.25 ? 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 3000pcs e2 () direction of feed reel 1pin
r1010 a www.rohm.com ? 2010 rohm co., ltd. all rights reserved. notice rohm customer support system http://www.rohm.com/contact/ thank you for your accessing to rohm product informations. more detail product informations and catalogs are available, please contact us. notes no copying or reproduction of this document, in part or in whole, is permitted without the consent of rohm co.,ltd. the content specied herein is subject to change for improvement without notice. the content specied herein is for the purpose of introducing rohm's products (hereinafter "products"). if you wish to use any such product, please be sure to refer to the specications, which can be obtained from rohm upon request. examples of application circuits, circuit constants and any other information contained herein illustrate the standard usage and operations of the products. the peripheral conditions must be taken into account when designing circuits for mass production. great care was taken in ensuring the accuracy of the information specied in this document. however, should you incur any damage arising from any inaccuracy or misprint of such information, rohm shall bear no responsibility for such damage. the technical information specied herein is intended only to show the typical functions of and examples of application circuits for the products. rohm does not grant you, explicitly or implicitly, any license to use or exercise intellectual property or other rights held by rohm and other parties. rohm shall bear no responsibility whatsoever for any dispute arising from the use of such technical information. the products specied in this document are intended to be used with general-use electronic equipment or devices (such as audio visual equipment, ofce-automation equipment, commu- nication devices, electronic appliances and amusement devices). the products specied in this document are not designed to be radiation tolerant. while rohm always makes efforts to enhance the quality and reliability of its products, a product may fail or malfunction for a variety of reasons. please be sure to implement in your equipment using the products safety measures to guard against the possibility of physical injury, re or any other damage caused in the event of the failure of any product, such as derating, redunda ncy, re control and fail-safe designs. rohm shall bear no responsibility whatsoever for your use of any product outside of the prescribed scope or not in accordance with the instruction manual. the products are not designed or manufactured to be used with any equipment, device or system which requires an extremely high level of reliability the failure or malfunction of which may result in a direct threat to human life or create a risk of human injury (such as a medical instrument, transportation equipment, aerospac e machinery, nuclear-reactor controller, fuel- controller or other safety device). rohm shall bear no responsibility in any way for use of any of the products for the above special purposes. if a product is intended to be used for any such special purpose, please contact a rohm sales representative before purchasing. if you intend to export or ship overseas any product or technology specied herein that may be controlled under the foreign exchange and the foreign trade law, you will be required to obtain a license or permit under the law.

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