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ds04-27239-1e fujitsu semiconductor data sheet assp for power supply applications (general-purpose dc/dc converter) 3-ch dc/dc converter ic MB39A112 n description the MB39A112 is a 3-channel dc/dc converter ic using pulse width modulation (pwm) , and the MB39A112 is suitable for down-conversion. 3-channel is built in tssop-20p package. each channel can be controlled and soft-start. the MB39A112 contains a constant voltage bias circuit for output block, capable of implementing an efficient high-frequency dc/dc converter. it is ideal for built-in power supply such as adsl modems. n reatures ? supports for down-conversion (ch1 to ch3) ? power supply voltage range : 7 v to 25 v ? error amplifier threshold voltage : 1.00 v 1 % (ch1) : 1.23 v 1 % (ch2, ch3) ? oscillation frequency range : 250 khz to 2.6 mhz ? built-in soft-start circuit independent of loads ? built-in timer-latch short-circuit protection circuit ? built-in totem-pole type output for p-channel mos fet devices ? built-in constant voltage (vcco - 5 v) bias circuit for output block n pac k ag e 20-pin plastic tssop (fpt-20p-m06)
MB39A112 2 n pin assignment (top view) (fpt-20p-m06) cs1 : 1 - ine1 : 2 fb1 : 3 vcc : 4 rt : 5 ct : 6 gnd : 7 fb2 : 8 - ine2 : 9 cs2 : 10 20 : vcco 19 : out1 18 : out2 17 : out3 16 : vh 15 : gndo 14 : cscp 13 : fb3 12 : - ine3 11 : cs3
MB39A112 3 n pin description pin no. symbol i/o descriptions 1cs1 ? ch1 soft-start setting capacitor connection terminal. 2 - ine1 i ch1 error amplifer inverted input terminal. 3 fb1 o ch1 error amplifer output terminal. 4vcc ? control circuit power supply terminal. 5rt ? triangular-wave oscillation frequency setting resistor connection terminal. 6ct ? triangular-wave oscillation frequency setting capacitor connection terminal. 7gnd ? ground terminal. 8 fb2 o ch2 error amplifier output terminal. 9 - ine2 i ch2 error amplifier inverted input terminal. 10 cs2 ? ch2 soft-start setting capacitor connection terminal. 11 cs3 ? ch3 soft-start setting capacitor connection terminal. 12 - ine3 i ch3 error amplifier inverted input terminal. 13 fb3 o ch3 error amplifier output terminal. 14 cscp ? timer-latch short-circuit protection capacitor connection terminal. 15 gndo ? ground terminal. 16 vh o power supply terminal for driving output circuit. (vh = vcco - 5 v) . 17 out3 o ch3 external pch mos fet gate driving terminal. 18 out2 o ch2 external pch mos fet gate driving terminal. 19 out1 o ch1 external pch mos fet gate driving terminal. 20 vcco ? power supply terminal for driving output circuit. (connect to same potential as vcc terminal).
MB39A112 4 n block diagram - + + + - 2 1 3 19 - + + + - 9 10 8 18 - + + - + + + + - 12 11 13 14 5 6 7 17 16 15 4 20 - ine1 cs1 fb1 - ine2 cs2 fb2 - ine3 cs3 fb3 cscp rt ct gnd out1 out2 out3 vh gndo vcc vcco vref error amp1 1.0 v 10 m a vref error amp2 1.23 v 10 m a vref scp osc uvlo vref vr power on/off ctl bias voltage vh i o = 150 ma pch drive3 vcco - 5 v gnd bias 3.5 v error amp3 pwm comp.3 scp comp. 1.23 v 2.7 v 2.5 v 2.0 v 10 m a ch3 i o = 150 ma pch drive2 pwm comp.2 ch2 i o = 150 ma pch drive1 pwm comp.1 ch1 threshold voltage 1.0 v 1 % threshold voltage 1.23 v 1 % threshold voltage 1.23 v 1 % l priority l priority h priority h: at scp h: uvlo release error amp power supply scp comp. power supply erroramp reference 1.0 v/1.23 v l priority
MB39A112 5 n absolute maximum ratings * : the package is mounted on the dual-sided epoxy board (10 cm 10 cm) . warning: semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in excess of absolute maximum ratings. do not exceed these ratings. n recommended operating conditions warning: the recommended operating conditions are required in order to ensure the normal operation of the semiconductor device. all of the devices electrical characteristics are warranted when the device is operated within these ranges. always use semiconductor devices within their recommended operating condition ranges. operation outside these ranges may adversely affect reliability and could result in device failure. no warranty is made with respect to uses, operating conditions, or combinations not represented on the data sheet. users considering application outside the listed conditions are advised to contact their fujitsu representatives beforehand. parameter symbol conditions rating unit min max power supply voltage vcc vcc, vcco terminal ? 28 v output current io out1, out2, out3 terminal ? 20 ma peak output current i op duty 5 % (t = 1/fosc duty) ? 400 ma power dissipation p d ta + 25 c ? 1280* mw storage temperature t stg ?- 55 + 125 c parameter symbol conditions value unit min typ max power supply voltage vcc vcc, vcco terminal 7 12 25 v input voltage v in - ine terminal 0 - ? vcc - 1.8 v output current i o out1, out2, out3 terminal - 15 ? 15 ma i vh vh terminal 0 ? 30 ma oscillation frequency fosc ? 250 1200 2600 khz timing capacitor c t ? 22 100 1000 pf timing resistor r t ? 4.7 10 22 k w vh terminal capacitor c vh vh terminal ? 0.1 1.0 m f soft-start capacitor c s cs1, cs2, cs3 terminal ? 0.1 1.0 m f short-circuit detection capacitor c scp cscp terminal ? 0.01 1.0 m f operating ambient temperature ta ?- 30 + 25 + 85 c
MB39A112 6 n electrical characteristics (vcc = vcco = 12 v, ta = + 25 c) * : standard design value (continued) parameter sym- bol pin no. conditions value unit min typ max undervoltage lockout protection circuit block [uvlo] threshold voltage v th 4vcc = 6.35 6.55 6.75 v hysteresis width v hys 4 ?? 0.15 ? v short-circuit protection circuit block [scp] threshold voltage v th 14 ? 0.67 0.72 0.77 v input source current i cscp 14 ?- 1.4 - 1.0 - 0.6 m a reset voltage v rst 4vcc = 6.2 6.4 6.6 v triangular wave oscillator block [osc] oscillation frequency fosc 17 to 19 ct = 100 pf, rt = 10 k w 1080 1200 1320 khz soft-start block [cs1, cs2, cs3] charge current i cs 1, 10, 11 ?- 14 - 10 - 6 m a error amp block (ch1) [error amp1] threshold voltage v th 2fb1 = 2.25 v 0.99 1.00 1.01 v input bias current i b 2 - ine1 = 0 v - 250 - 63 ? na voltage gain a v 3 dc 60 100 ? db frequency band width b w 3a v = 0db ? 1.5* ? mhz output voltage v oh 3 ? 3.2 3.4 ? v v ol 3 ?? 40 200 mv output source current i source 3fb1 = 2.25 v ?- 2 - 1ma output sink current i sink 3fb1 = 2.25 v 150 250 ?m a error amp block (ch2, ch3) [error amp2, error amp3] threshold voltage v th 9, 12 fb2 = fb3 = 2.25 v 1.218 1.230 1.242 v input bias current i b 9, 12 - ine2 = - ine3 = 0 v - 250 - 63 ? na voltage gain a v 8, 13 dc 60 100 ? db frequency band width b w 8, 13 a v = 0 db ? 1.5* ? mhz output voltage v oh 8, 13 ? 3.2 3.4 ? v v ol 8, 13 ?? 40 200 mv output source current i source 8, 13 fb2 = fb3 = 2.25 v ?- 2 - 1ma output sink current i sink 8, 13 fb2 = fb3 = 2.25 v 150 250 ?m a
MB39A112 7 (continued) (vcc = vcco = 12 v, ta = + 25 c) * : standard design value parameter sym- bol pin no. conditions value unit min typ max pwm comparator block [pwm comp.] threshold voltage v t0 17 to 19 duty cycle = 0 % 1.9 2.0 ? v v t100 17 to 19 duty cycle = 100 %? 2.5 2.6 v bias voltage block [vh] output voltage v h 16 ? v cco - 5.5 v cco - 5.0 v cco - 4.5 v output block [drive] output source current i sourc e 17 to 19 duty 5 % out1 = out2 = out3 = 7 v ?- 150* ? ma output sink current i sink 17 to 19 duty 5 % out1 = out2 = out3 = 12 v ? 150* ? ma output on resistor r oh 17 to 19 out1 = out2 = out3 = - 15 ma ? 13 19.5 w r ol 17 to 19 out1 = out2 = out3 = 15 ma ? 10 15 w general power supply current i cc 4 ?? 69ma
MB39A112 8 n typical charcteristics (continued) 10 8 6 4 2 0 0 5 10 15 20 25 ta = + 25 c rt = open rt = 22 k w rt = 10 k w rt = 4.7 k w ta = +25 c vcc = 12 v 10000 1000 100 10 10 100 1000 10000 ct = 1000 pf ct = 390 pf ct = 100 pf ct = 22 pf ta = +25 c vcc = 12 v 10000 1000 100 10 1 10 100 1000 power supply current i cc (ma) power supply voltage v cc (v) power supply current vs. power supply voltage 2.0 1.5 1.0 0.5 0.0 - 0.5 - 1.0 - 1.5 - 2.0 - 40 - 20 0 20 40 60 80 100 vcc = 12 v fb1 = 0 ma threshold voltage d v th (%) ambient temperature ta ( c) error amp (err1) threshold voltage vs. ambient temperature 2.0 1.5 1.0 0.5 0.0 - 0.5 - 1.0 - 1.5 - 2.0 - 40 - 20 0 20 40 60 80 100 vcc = 12 v fb2(3) = 0 ma threshold voltage d v th (%) ambient temperature ta ( c) error amp (err2, err3) threshold voltage vs. ambient temperature triangular wave oscillation frequency fosc (khz) timing resistor r t (k w ) triangular wave oscillation frequency vs. timing resistor triangular wave oscillation frequency fosc (khz) timing capacitor c t (pf) triangular wave oscillation frequency vs. timing capacitor
MB39A112 9 (continued) ta = +25 c vcc = 12 v ct = 100 pf 2.8 2.6 2.4 2.2 2.0 1.8 0 500 1000 1500 2000 2500 3000 triangular wave upper/lower limit voltage v ct (v) triangular wave oscillation frequency fosc (khz) triangular wave upper/lower limit voltage vs. triangular wave oscillation frequency upper limit lower limit vcc = 12 v rt = 10 k w ct = 100 pf 2.8 2.6 2.4 2.2 2.0 1.8 - 40 - 20 0 20 40 60 80 100 triangular wave upper/lower limit voltage v ct (v) ambient temperature ta ( c) triangular wave upper/lower limit voltage vs. ambient temperature ta = +25 c rt = 10 k w ct = 100 pf 1400 1350 1300 1250 1200 1150 1100 1050 1000 0 5 10 15 20 25 30 triangular wave oscillation frequency fosc (khz) ambient temperature ta ( c) triangular wave oscillation frequency vs. ambient temperature vcc = 12 v rt = 10 k w ct = 100 pf 1400 1350 1300 1250 1200 1150 1100 1050 1000 - 40 - 20 0 20 40 60 80 100 triangular wave oscillation frequency fosc (khz) power supply voltage v cc (v) triangular wave oscillation frequency vs. power supply voltage upper limit lower limit
MB39A112 10 (conti n u ed ) 40 30 20 10 0 - 10 - 20 - 30 -4 0 180 90 0 - 90 - 180 out in 1.0 v 240 k w 2.4 k w 10 k w 10 k w 1 m f error amp1 100 1 k 10 k 100 k 1 m 10 m - + + + ta = + 25 c vcc = 12 v a v j 3.5 v 3 2 1 gain a v (db) frequency f (hz) error amp (ch1) gain, phase vs. frequency phase j (deg) 40 30 20 10 0 - 10 - 20 - 30 - 40 180 90 0 - 90 - 180 out in 1.23 v 240 k w 2.4 k (12) (13) (11) 10 k w 10 k w 1 m f error amp2 (error amp3) 100 1 k 10 k 100 k 1 m 10 m - + + + ta = + 25 c vcc = 12 v a v j 3.5 v 8 10 9 gain a v (db) frequency f (hz) error amp (ch2, ch3) gain, phase vs. frequency phase j (deg) 1400 1300 1280 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 - 40 - 20 20 40 60 80 1000 maximum power dissipation p d (mw) ambient temperature ta ( c) maximum power dissipation vs. ambient temperature
MB39A112 11 n function 1. dc/dc converter function (1) triangular wave oscillator block (osc) the triangular wave oscillator incorporates a timing capacitor and a timing resistor connected respectively to the ct terminl (pin 6) and rt terminl (pin 5) to generate triangular oscillation waveform amplitude of 2.0 v to 2.5 v. the triangular waveforms are input to the pwm comparator in the ic. (2) error amplifier block (error amp1, error amp2, error amp3) the error amplifier detects the dc/dc converter output voltage and outputs pwm control signals. in addition, an arbitrary loop gain can be set by connecting a feedback resistor and capacitor from the output terminal to inverted input terminal of the error amplifier, enabling stable phase compensation to the system. also, it is possible to prevent rush current at power supply start-up by connecting a soft-start capacitor with the cs1 terminl (pin 1) , cs2 terminl (pin10) and cs3 terminl (pin 11) which are the non-inverted input terminal for error amp. the use of error amp for soft-start detection makes it possible for a system to operate on a fixed soft-start time that is independent of the output load on the dc/dc converter. (3) pwm comparator block (pwm comp.) the pwm comparator is a voltage-to-pulse width modulator that controls the output duty depending on the input/ output voltage. the comparator keeps output transistor on while the error amplifier output voltage remain higher than the triangular wave voltage. (4) output block the output blobk is in the totem pole configulation, capable of driving an external p-channel mos fet. (5) bias voltage block (vh) this bias voltage circuit outputs v cc - 5 v (typ) as minimum potential of the output circuit. 2. protective function (1) timer latch short-circuit protection circuit (scp) each channel has a short-circuit detection comparator (scp comp.) which constantly compares the error amp. output level to the reference voltage. while dc/dc converter load conditions are stable on all channels, the short-circuit detection comparator output remains at l, and the cscp terminal is held at l level. if the load condition on a channel changes rapidly due to a short-circuit of the load, causing the output voltage to drop, the output of the short-circuit detection comparator on that channel goes to h level. this causes the external short-circuit protection capacitor c scp connected to the cscp terminal (pin 14) to be charged. when the capacitor c scp is charged to the threshold voltage (vth : = 0.72 v) , the latch is set and the external fet is turned off (dead time is set to 100 % ) . at this point, the latch input is closed and the cscp terminal is held at l level. the latch applied by the timer-latch short-circuit protection circuit can be reset by recycling the power supply (vcc) (see n setting time constant for timer-latch short-circuit protection circuit) .
MB39A112 12 (2) undervoltage lockout protection circuit block (uvlo) the transient state or a momentary decrease in supply voltage, which occurs when the power supply is turned on, may cause the ic to malfunction, resulting in breakdown or degradation of the system. to prevent such malfunctions, under voltage lockout protection circuit detects a decrease in internal reference voltage with respect to the power supply voltage, turns off the output transistor, and sets the dead time to 100 % while holding the cscp terminal (pin 14) at the l level. the circuit restores the output transistor to normal when the supply voltage reaches the threshold voltage of the undervoltage lockout protection circuit. (3) protection circuit operating function table this table refers to output condition when each protection circuit is operating. the latch can be reset as follows after the short-circuit protection circuit is actuated. recycling vcc resets the latch whenever the short-circuit protection circuit has been actuated. operating circuit ch1 ch2 ch3 out1 out2 out3 short-circuit protection circuit h h h under-voltage lockout circuit h h h
MB39A112 13 n setting the output voltage n setting the triangular oscillation frequency the triangular oscillation frequency is determined by the timing capacitor (c t ) connected to the c t terminal (pin 6) and the timing resistor (r t ) connected to the r t terminal (pin 5) . triangular oscillation frequency : fosc fosc (khz) : = 1200000 c t (pf) r t (k w ) - + + 1 2 v o r1 r2 cs1 error amp 1.00 v v o (v) = (r1 + r2) 1.00 r2 - ine1 ch1 - + + 10 9 v o r1 r2 cs2 error amp 1.23 v v o (v) = (r1 + r2) 1.23 r2 - ine2 11 12 (cs3) ( - ine3) ch2, ch3
MB39A112 14 n setting the soft-start and discharge times to prevent rush currents when the ic is turned on, you can set a soft-start by connecting soft-start capacitors (c s1 , c s2 and c s3 ) to the cs1 terminal (pin 1) for channel 1, cs2 terminal (pin 10) for channel 2 and cs3 terminal (pin 11) for channel 3 respectively. setting each control terminal (ctlx ) from h to l starts charging the external soft-start capacitors (c s1 , c s2 and c s3 ) connected to the cs1, cs2 and cs3 terminal at about 10 m a. the dc/dc converter output voltage rises in proportion to the cs terminal voltage. also, soft-start time is obtained by the following formulas. soft-start time : ts (time to output 100 % ) ch1 : ts 1 [s] : = 0.100 c s1 [ m f] ch2 : ts 2 [s] : = 0.123 c s2 [ m f] ch3 : ts 3 [s] : = 0.123 c s3 [ m f] - + + - ine1 ( - ine2) ( - ine3) cs1 (cs2) (cs3) (l : on, h : off) fb1 (fb2) (fb3) error amp 1.23 v /1.0 v v o ctlx vref scp uvlo 10 m a l priority h : at scp h: uvlo release ch1 on/off signal soft-start circuit h t t l cs terminal voltage error amp. reference voltage soft-start time ts ctlx signal : = 1.23 v/ 1.00 v : = 0 v : = 3.4 v soft-start operation
MB39A112 15 n treatment without using cs terminal when not using the soft-start function, open the cs1 terminal (pin 1) , cs2 terminal (pin 10) and cs3 terminal (pin 11) . 1 10 11 cs1 cs2 cs3 open open open without setting soft-start tme
MB39A112 16 n setting time constant for timer-latch short-circuit protection circuit each channel uses the short-circuit detection comparator (scp comp.) to always compare the error amplifiers output level to the reference voltage. while dc/dc converter load conditions are stable on all channels, the short-circuit detection comparator output remains at l level, and the cscp terminal (pin 14) is held at l level. if the load condition on a channel changes rapidly due to a short-circuit of the load, causing the output voltage to drop, the output of the short-circuit detection comparator goes to h level. this causes the extemal short- circuit protection capacitor c scp connected to the cscp terminal to be charged at 1 m a. when the capacitor c scp is charged to the threshold voltage (v th : = 0.72 v) , the latch is set and the external fet is turned off (dead time is set to 100 % ) . at this time, the latch input is closed and the cscp terminal (pin 14) is held at l level. if any of ch1 to ch3 detects a short circuit, all the channels are stopped. short-circuit detection time : tcscp tcscp[s] : = 0.72 c scp [ m f] - + + - + + + - ine1 ( - ine2) ( - ine3) cs1 (cs2) (cs3) fb1 (fb2) (fb3) cscp latch uvlo vcc sr 14 error amp 1.23 v /1.0 v 2.7 v v o r1 r2 vref 10 m a 1 m a scp comp. [scp] h: at scp h: uvlo release timer-latch short-circuit protection circuit
MB39A112 17 n treatment without using cscp terminal when not using the timer-latch short-circuit protection circuit, connect the cscp terminal (pin 14) to gnd with the shortest distance. 14 7 cscp gnd treatment without using cscp terminal
MB39A112 18 n i/o equivalent circuit 4 14 vcc cscp 2 k w vref ( 3.5 v ) 7 2 gnd 5 vcc 1.2 v rt vref ( 3.5 v ) gnd - + 6 vcc vref ( 3.5 v ) gnd ct vcc vref ( 3.5 v ) gnd vcc cs1 fb1 1.00 v - ine1 vref ( 3.5 v ) gnd csx 3 vcc csx fbx vcc fbx ct gnd 1.23 v vref ( 3.5 v ) gnd 16 20 vcc vcco vcco gnd gndo outx vh vh 15 gndo <> esd protection element <> <> <> <> <> <> <> <> esd protection element x : each channel no. esd protection element
MB39A112 19 n application example a b c a b c r6 2.2 k w r7 18 k w r8 100 k w (l : on, h : off) (l : on, h : off) (l : on, h : off) r9 820 w c8 0.022 m f c7 0.1 m f ctl1 r11 4.7 k w r12 56 k w r13 36 k w r14 820 w c11 0.01 m f c12 0.1 m f ctl2 r15 680 w vin (12 v) r16 30 k w r17 10 k w r18 1 k w c14 0.01 m f c15 1000 pf r10 5.1 k w c10 100 pf c9 0.1 m f c16 0.1 m f c5 2.2 m f c6 4.7 m f v o 3 (5.0 v) i o 3 = 0.15 ~ 0.3 a q3 l3 10 m h d3 c3 2.2 m f c4 4.7 m f v o 2 (3.3 v) i o 2 = 0.15 ~ 1 a q2 l2 3.3 m h d2 c1 2.2 m f c17 0.1 m f c2 4.7 m f v o 1 (1.2 v) i o 1 = 0.8 ~ 1.5 a q1 l1 2 m h d1 c13 0.1 m f ctl3 - + + + - 2 1 3 19 - + + + - 9 10 8 18 - + + - + + + + - 12 11 13 14 5 6 7 17 16 15 4 20 - ine1 cs1 fb1 - ine2 cs2 fb2 - ine3 cs3 fb3 cscp rt ct gnd out1 out2 out3 vh gndo vcc vcco vref error amp1 1.0 v 10 m a vref error amp2 1.23 v 10 m a vref scp osc uvlo vref vr power on/off ctl bias voltage vh i o = 150 ma pch drive3 vcco - 5 v gnd bias 3.5 v error amp3 pwm comp.3 scp comp. 1.23 v 2.7 v 2.5 v 2.0 v 10 m a ch3 i o = 150 ma pch drive2 pwm comp.2 ch2 i o = 150 ma pch drive1 pwm comp.1 ch1 threshold voltage 1.23 v 1 % threshold voltage 1.0 v 1 % % % % charge current 1 m a error amp power supply scp comp. power supply l priority l priority l priority h priority h: at scp h: uvlo release step- down threshold voltage 1.23 v 1 % erroramp reference 1.0 v/1.23 v ch1 on/off signal ch2 on/off signal ch3 on/off signal step- down step- down
MB39A112 20 n parts list note : sanyo : sanyo electric co., ltd. toko : toko inc. tdk : tdk corporation ssm : susumu co., ltd. component item specification vendor parts no. q1, q2, q3 pch fet pch fet vds = - 30 v, id = - 2.0 a vds = - 30 v, id = - 1.0 a sanyo sanyo mch3312 mch3308 d1, d2 d3 diode diode vf = 0.55 v (max) , at if = 2 a vf = 0.4 v (max) , at if = 0.5 a sanyo sanyo sbe001 sbe005 l1 l2 l3 inductor inductor inductor 2 m h 3.3 m h 10 m h 3 a, 16 m w 2.57 a, 21.4 m w 1.49 a, 41.2 m w toko toko toko a916cy-2r0m a916cy-3r3m a916cy-100m c1, c3, c5 c2, c4, c6 c7, c9, c12 c8 c10 c11, c14 c13, c16, c17 c15 ceramics condenser ceramics condenser ceramics condenser ceramics condenser ceramics condenser ceramics condenser ceramics condenser ceramics condenser 2.2 m f 4.7 m f 0.1 m f 0.022 m f 100 pf 0.01 m f 0.1 m f 1000 pf 25 v 10 v 50 v 50 v 50 v 50 v 50 v 50 v tdk tdk tdk tdk tdk tdk tdk tdk c3216jb1e225k c3216jb1a475m c1608jb1h104k c1608jb1h223k c1608ch1h101j c1608jb1h103k c1608jb1h104k c1608jb1h102k r6 r7 r8 r9 r10 r11 r12 r13 r14 r15 r16 r17 r18 resistor resistor resistor resistor resistor resistor resistor resistor resistor resistor resistor resistor resistor 2.2 k w 18 k w 100 k w 820 w 5.1 k w 4.7 k w 56 k w 36 k w 820 w 680 w 30 k w 10 k w 1 k w 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % 0.5 % ssm ssm ssm ssm ssm ssm ssm ssm ssm ssm ssm ssm ssm rr0816p-222-d rr0816p-183-d rr0816p-104-d rr0816p-821-d rr0816p-512-d rr0816p-472-d rr0816p-563-d rr0816p-363-d rr0816p-821-d rr0816p-681-d rr0816p-303-d rr0816p-103-d rr0816p-102-d
MB39A112 21 n selection of components ?pch mos fet the pch mos fet for switching use should be rated for at least 20 % or more than the maximum input voltage. to minimize continuity loss, use a fet with low r ds (on) between the drain and source. for high input voltage and high frequency operation, on-cycle switching loss will be higher so that power dissipation must be considered. in this application, the sanyo mch3312 and mch3308 are used. continuity loss, on/off-cycle switching loss and total loss are determined by the following formulas. the selection must ensure that peak drain current does not exceed rated values. example : using the mch3312 ?ch1 input voltage v in = 12 v, output voltage v o = 1.2 v, drain current i d = 1.5 a, oscillation frequency f osc = 2350 khz, l = 2 m h, drain-source on resistance r ds(on) : = 180 m w , tr : = 2.9 ns, tf : = 8.7 ns. continuity loss : pc p c = i d 2 r ds (on) duty on-cycle switching loss : p s (on) p s (on) = v d (max) i d tr fosc 6 off-cycle switching loss : p s (off) p s (off) = v d (max) i d (max) tf fosc 6 total loss : p t p t = p c + p s (on) + p s (off) drain current (max) : i d (max) i d (max) = io + v in - vo t on 2l = 1.5 + 12 - 1.2 1 0.1 2 2.0 10 - 6 2350 10 3 : = 1.61 a drain current (min) : i d (min) i d (min) = io - v in - vo t on 2l = 1.5 - 12 - 1.2 1 0.1 2 2.0 10 - 6 2350 10 3 : =1.39 a
MB39A112 22 the above power dissipation figures for the mch3312 are satisfied with ample margin at 1.0 w (ta = + 25 c) . ?ch2 input voltage v in = 12 v, output voltage v o = 3.3 v, drain current i d = 1.0 a, oscillation frequency f osc = 2350 khz, l = 3.3 m h, drain-source on resistance r ds(on) : = 180 m w , tr : = 2.9 ns, tf : = 8.7 ns. p c = i d 2 r ds (on) duty = 1.5 2 0.18 0.1 : =0.04 w p s ( on ) = v d i d tr fosc 6 = 12 1.5 2.9 10 - 9 2350 10 3 6 : =0.02 w p s (off) = v d i d (max) tf fosc 6 = 12 1.61 8.7 10 - 9 2350 10 3 6 : = 0.066 w p t = p c + p s (on) + p s (of f ) : =0.04 + 0.02 + 0.066 : = 0.126 w drain current (max) : i d (max) i d (max) = io + v in - vo t on 2l = 1 + 12 - 3.3 1 0.275 2 3.3 10 - 6 2350 10 3 : =1.15 a drain current (min) : i d (min) i d (min) = io - v in - vo t on 2l = 1 - 12 - 3.3 1 0.275 2 3.3 10 -6 2350 10 3 : =0.85 a p c = i d 2 r ds (on) duty = 1 2 0.18 0.275 : = 0.0495 w
MB39A112 23 the above power dissipation figures for the mch3312 are satisfied with ample margin at 1.0 w (ta = + 25 c) . example : using the mch3308 ?ch3 input voltage v in = 12 v, output voltage vo = 5.0 v, drain current i d = 0.3 a, oscillation frequency fosc = 2350 khz, l = 10 m h, drain-source on resistance r ds (on) : = 600 m w , tr : = 4 ns, tf : = 4 ns. p s (on) = v d i d tr fosc 6 = 12 1 2.9 10 - 9 2350 10 3 6 : = 0.0136 w p s (off) = v d i d (max) tf fosc 6 = 12 1.15 8.7 10 - 9 2350 10 3 6 : =0.047 w p t = p c + p s (on) + p s (off) : = 0.0495 + 0.0136 + 0.047 : =0.11 w drain current (max) : i d (max) i d (max) = io + v in - vo t on 2l = 0.3 + 12 - 5 1 0.417 2 10 10 - 6 2350 10 3 : = 0.36 (a) drain current (min) : i d (min) i d (min) = io - v in - vo t on 2l = 0.3 - 12 - 5 1 0.417 2 10 10 - 6 2350 10 3 : = 0.24 (a) p c = i d 2 r ds (on) duty = 0.3 2 0.6 0.417 : = 0.023 w
MB39A112 24 the above power dissipation figures for the mch3308 are satisfied with ample margin at 0.8 w (ta = + 25 c) . ? inductors in selecting inductors, it is of course essential not to apply more current than the rated capacity of the inductor, but also to note that the lower limit for ripple current is a critical point that if reached will cause discontinuous operation and a considerable drop in efficiency. this can be prevented by choosing a higher inductance value, which will enable continuous operation under light loads. note that if the inductance value is too high, however, direct current resistance (dcr) is increased and this will also reduce efficiency. the inductance must be set at the point where efficiency is greatest. note also that the dc superimposition characteristics become worse as the load current value approaches the rated current value of the inductor, so that the inductance value is reduced and ripple current increases, causing loss of efficiency. the selection of rated current value and inductance value will vary depending on where the point of peak efficiency lies with respect to load current. inductance values are determined by the following formulas. the l value for all load current conditions is set so that the peak to peak value of the ripple current is 1/2 the load current or less. example ?ch1 p s (on) = v d i d tr fosc 6 = 12 0.3 4 10 - 9 2350 10 3 6 : = 0.0056 w p s (off) = v d i d (max) tf fosc 6 = 12 0.36 4 10 - 9 2350 10 3 6 : = 0.0068 w p t = p c + p s (on) + p s (of f ) : = 0.023 + 0.0056 + 0.0068 : = 0.0354 w inductance value : l l 3 2 (v in - vo) t on io l 3 2 (v in - vo1) t on io 3 2 (12 - 1.2) 1 0.1 1.5 2350 10 3 3 0.61 m h
MB39A112 25 ?ch2 ?ch3 inductance values derived from the above formulas are values that provide sufficient margin for continuous operation at maximum load current, but at which continuous operation is not possible at light loads. it is therefore necessary to determine the load level at which continuous operation becomes possible. in this application, the toko a916cy-2r0m, a916cy-3r3m and a916cy-100m are used. at 2 m h, 3.3 m h and 10 m h, the load current value under continuous operating conditions is determined by the following formula. example : using the a916cy-2r0m 2 m h (allowable tolerance 20 % ), rated current = 3 a ?ch1 example : using the a916cy-3r3m 3.3 m h (allowable tolerance 20 % ) , rated current = 2.57 a ?ch2 l 3 2 (v in - vo2) t on io 3 2 (12 - 3.3) 1 0.275 1 2350 10 3 3 2.04 m h l 3 2 (v in - vo3) t on io 3 2 (12 - 5) 1 0.417 0.3 2350 10 3 3 8.28 m h load current value under continuous operating conditions : io io 3 vo t off 2l io 3 vo1 t off 2l 3 1.2 1 (1 - 0.1) 2 2 10 - 6 2350 10 3 3 0.11 a io 3 vo2 t off 2l 3 3.3 1 (1 - 0.275) 2 3.3 10 - 6 2350 10 3 3 0.15 a
MB39A112 26 example : using the a916cy-100m 10.0 m h (allowable tolerance 20 % ) , rated current = 1.49 a ?ch3 to determine whether the current through the inductor is within rated values, it is necessary to determine the peak value of the ripple current as well as the peak-to-peak values of the ripple current that affect the output ripple voltage. the peak value and peak-to-peak value of the ripple current can be determined by the following formulas. example : using the a916cy-2r0m 2.0 m h (allowable tolerance 20 % ) , rated current = 3.0 a ?ch1 peak value peak-to-peak value io 3 vo3 t off 2l 3 5 1 (1 - 0.417) 2 10 10 - 6 2350 10 3 3 62.0 ma peak value : i l i l 3 io + v in - vo t on 2l peak-to-peak value : d i l d i l = v in - vo t on l i l 3 io + v in - vo1 t on 2l 3 1.5 + 12 - 1.2 1 0.1 2 2.0 10 - 6 2350 10 3 3 1.61 a d i l = v in - vo1 t on l = 12 - 1.2 1 0.1 2.0 10 - 6 2350 10 3 : =0.23 a
MB39A112 27 example : using the a916cy-3r3m 3.3 m h (allowable tolerance 20 % ) , rated current = 2.57 a ?ch2 peak value peak-to-peak value example : using the a916cy-100m 10.0 m h (allowable tolerance 20 % ) , rated current = 1.49 a ?ch3 peak value peak-to-peak value i l 3 io + v in - vo2 t on 2l 3 1.0 + 12 - 3.3 1 0.275 2 3.3 10 - 6 2350 10 3 3 1.15 a d i l = v in - vo2 t on l = 12 - 3.3 1 0.275 3.3 10 - 6 2350 10 3 : = 0.309 a i l 3 io + v in - vo3 t on 2l 3 0.3 + 12 - 5 1 0.417 2 10 10 - 6 2350 10 3 3 0.36 a d i l = v in - vo3 t on l = 12 - 5 1 0.417 10 10 - 6 2350 10 3 : = 0.124 a
MB39A112 28 ? flyback diode the flyback diode is generally used as a shottky barrier diode (sbd) when the reverse voltage to the diode is less than 40 v. the sbd has the characteristics of higher speed in terms of faster reverse recovery time, and lower forward voltage, and is ideal for archiving high efficiency. as long as the dc reverse voltage is sufficiently higher than the input voltage, the average current flowing through the diode is within the average output current level, and peak current is within peak surge current limits, there is no problem. in this application the sanyo sbe001, sbs005 are used. the diode average current and diode peak current can be calculated by the following formulas. example : using the sbe001 vr (dc reverse voltage) = 30 v, average output current = 2.0 a, peak surge current = 20 a, vf (forward voltage) = 0.55 v, at if = 2.0 a ?ch1 diode mean current diode peak current ?ch2 diode mean current diode mean current : i di i di 3 io (1 - vo ) v in diode peak current : i dip i dip 3 (io + vo t off ) 2l i di 3 io (1 - vo1 ) v in 3 1.5 (1 - 0.1) 3 1.35 a i dip 3 (io + vo1 t off ) 2l 3 1.61 a i di 3 io (1 - vo2 ) v in 3 1.0 (1 - 0.275) 3 0.725 a
MB39A112 29 diode peak current example : using the sbs005 vr (dc reverse voltage) = 30 v, average output current = 1.0 a, peak surge current = 10 a, vf (forward voltage) = 0.4 v, at if = 0.5 a ?ch3 diode mean current diode peak current i dip 3 (io + vo2 t off ) 2l 3 1.15 a i di 3 io (1 - vo3 ) v in 3 0.3 (1 - 0.417) 3 0.175 a i dip 3 (io + vo3 t off ) 2l 3 0.36 a
MB39A112 30 n reference data (continued) 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch1) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 1.2 v output ctl1 = l ctl2 = h ctl3 = h rt = 5.1 k w ct = 100 pf 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch2) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 3.3 v output ctl1 = h ctl2 = l ctl3 = h rt = 5.1 k w ct = 100 pf 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch3) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 5.0 v output ctl1 = h ctl2 = h ctl3 = l rt = 5.1 k w ct = 100 pf
MB39A112 31 (continued) 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch1) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 1.2 v output ctl1 = l ctl2 = h ctl3 = h rt = 10 k w ct = 100 pf 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch2) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 3.3 v output ctl1 = h ctl2 = l ctl3 = h rt = 10 k w ct = 100 pf 100 90 80 70 60 50 40 30 10m 100m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch3) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 5.0 v output ctl1 = h ctl2 = h ctl3 = l rt = 10 k w ct = 100 pf
MB39A112 32 (continued) 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch1) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 1.2 v output ctl1 = l ctl2 = h ctl3 = h rt = 24 k w ct = 100 pf 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v conversion efficiency vs. load current characteristics (ch2) conversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 3.3 v output ctl1 = h ctl2 = l ctl3 = h rt = 24 k w ct = 100 pf 100 90 80 70 60 50 40 30 10 m 100 m 1 10 v in = 7 v v in = 10 v v in = 12 v cconversion efficiency vs. load current characteristics (ch3) cconversion efficiency h h h h ( % ) load current il (a) ta = + 25 c 5.0 v output ctl1 = h ctl2 = h ctl3 = l rt = 24 k w ct = 100 pf
MB39A112 33 n usage precaution ? printed circuit board ground lines should be set up with consideration for common impedance. ? take appropriate static electricity measures. containers for semiconductor materials should have anti-static protection or be made of conductive material. after mounting, printed circuit boards should be stored and shipped in conductive bags or containers. work platforms, tools and instruments should be properly grounded. working personnel should be grounded with resistance of 250 k w to 1 m w between body and ground. ? do not apply negative voltages. the use of negative voltages below - 0.3 v may create parasitic transistors on lsi lines, which can cause abnormal operation. n ordering information part number package remarks MB39A112pft 20-pin plastic tssop (fpt-20p-m06)
MB39A112 34 n package dimension 20-pin plastic tssop (fpt-20p-m06) note 1) *1 : resin protrusion. (each side : + 0.15 (.006) max) . note 2) *2 : these dimensions do not include resin protrusion. note 3) pins width and pins thickness include plating thickness. note 4) pins width do not include tie bar cutting remainder. dimensions in mm (inches) . note : the values in parentheses are reference values. c 2003 fujitsu limited f20026s-c-3-3 6.500.10(.256.004) 4.400.10 6.400.20 (.252.008) (.173.004) 0.10(.004) 0.65(.026) 0.240.08 (.009.003) 1 10 20 11 "a" 0.170.05 (.007.002) m 0.13(.005) details of "a" part 0~8 ? (.024.006) 0.600.15 (0.50(.020)) 0.25(.010) (.041.002) 1.050.05 (mounting height) 0.07 +0.03 C0.07 +.001 C.003 .003 (stand off) lead no. index * 1 * 2
MB39A112 fujitsu limited all rights reserved. the contents of this document are subject to change without notice. customers are advised to consult with fujitsu sales representatives before ordering. the information, such as descriptions of function and application circuit examples, in this document are presented solely for the purpose of reference to show examples of operations and uses of fujitsu semiconductor device; fujitsu does not warrant proper operation of the device with respect to use based on such information. when you develop equipment incorporating the device based on such information, you must assume any responsibility arising out of such use of the information. fujitsu assumes no liability for any damages whatsoever arising out of the use of the information. any information in this document, including descriptions of function and schematic diagrams, shall not be construed as license of the use or exercise of any intellectual property right, such as patent right or copyright, or any other right of fujitsu or any third party or does fujitsu warrant non-infringement of any third-partys intellectual property right or other right by using such information. fujitsu assumes no liability for any infringement of the intellectual property rights or other rights of third parties which would result from the use of information contained herein. the products described in this document are designed, developed and manufactured as contemplated for general use, including without limitation, ordinary industrial use, general office use, personal use, and household use, but are not designed, developed and manufactured as contemplated (1) for use accompanying fatal risks or dangers that, unless extremely high safety is secured, could have a serious effect to the public, and could lead directly to death, personal injury, severe physical damage or other loss (i.e., nuclear reaction control in nuclear facility, aircraft flight control, air traffic control, mass transport control, medical life support system, missile launch control in weapon system), or (2) for use requiring extremely high reliability (i.e., submersible repeater and artificial satellite). please note that fujitsu will not be liable against you and/or any third party for any claims or damages arising in connection with above-mentioned uses of the products. any semiconductor devices have an inherent chance of failure. you must protect against injury, damage or loss from such failures by incorporating safety design measures into your facility and equipment such as redundancy, fire protection, and prevention of over-current levels and other abnormal operating conditions. if any products described in this document represent goods or technologies subject to certain restrictions on export under the foreign exchange and foreign trade law of japan, the prior authorization by japanese government will be required for export of those products from japan. f0311 ? fujitsu limited printed in japan

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