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1 www.irf.com rd-0621 IRDC3622D user guide for dual output IRDC3622D evaluation board using irf6622 and irf6629 directfet mosfets table of contents page description 1 board features 1 connections & operating instructions 2 layout 5 schematic 10 bill of materials 11 waveforms 12 synchronization 21 voltage & tracking 22 mlpq package 24 downloaded from: http:///
2 www.irf.com rd-0621 user guide for dual output IRDC3622D evaluation board using irf6622 and irf6629 directfet mosfets description this user guide contains the schematic and bill of materials for the IRDC3622D evaluation board. the guide describes operation and use of the evaluation board itself. the ir3622 ic is a dual channel synchronous buck controller, providing a cost-effective, high performance and flexible solution. the two channels can be configured to either two independent outputs or current sharing single output. the current share configuration is ideal for high current applications. key features offered by the ir3622 include configurable dual output, output voltage tracking, power up/down sequencing, programmable soft- start ramp, pre-bias start-up, latched over-voltage protection, thermal protection, accurate reference voltage, on-board regulator, threshold sensitive enable input, programmable switching frequency up 600khz, and input under-voltage lockout for proper start-up. an output over-current protection function and a hiccup current limit are implemented by sensing the voltage developed across the on-resistance of the synchronous rectifier mosfet for optimum cost and performance. detailed application information for the ir3622 integrated circuit is available in the ir3622 data sheet. board features the board is designed for two output voltages 2.5v and 1.8v up to 20a for each output. v in = +12v, (13.2v max) v o1 = +2.5v 3% @ 20a, v o2 = +1.8v 3% @ 20a v o (ripple)= 50mv maximum for each output f s =350khz l1=990nh, l2=540nh c o1 =2x100uf (sp) + 2x10uf (ceramic 0805) for 2.5v output c o2 =2x220uf (sp) + 2x10uf (ceramic 0805) for 1.8v output the input voltage start threshold of the converter is set about 10v using enable pin and two external resistors (r16a1 and r16a2). the converter has the option to sequence with other supplies using seq and track pins (r6a1, r16a3 and r16a4). these pins are pulled high as default. downloaded from: http:///
3 www.irf.com rd-0621 connections and operating instructions input supplies connection: two supplies are required for this board, 3.3v and 12v. both supplies should be well regulated. the 3.3v supplies the pull-up resistor for power good. the track and seq pins are also pulled high using 3.3v. connect the 3.3v supply to tp1(+) and tp2(gnd). the12v supply is the bus voltage; it also biases ir3622 ic and should be able to source 10a current. connect this supply either to 8-pin connector (j1a) or solder other connectors, such as banana jacks, to the exposed pads. note: for correct start up the 3.3v supply needs to be powered first. output load connection: the load can be connected to the large screw-terminals or solder other connectors, such as banana jacks to the exposed pads. tb4a ground of v o2 (+1.8v) tb3a v o2 (+1.8v) tb2a ground of v o1 (+2.5v) tb1a v o1 (+2.5v) ground of v in j1a v in (+12v) tp2 ground of the 3.3v supply tp1 +3.3v supply connection signal name table i. connections downloaded from: http:///
4 www.irf.com rd-0621 connection diagram + - 20a load input supply (+3.3v) + - j1a 20a load 2.5v output 1.8v output input supply (+12v) fig. 1: connection diagram of the IRDC3622D evaluation board. downloaded from: http:///
5 www.irf.com rd-0621 test points input, output, and control signals are accessible through test points as listed in table ii. table ii. test points output voltage and ground for the 1.8v output v o2 (1.8v) tp15, tp16 remote sensing at terminal block for the 1.8v output rem_sen1v8 tp30, tp31 remote sensing at terminal block for the 2.5v output rem_sen2v5 tp28, tp29 soft start for 1.8v output ss2 tp36 output voltage and ground for the 2.5v output v o1 (2.5v) tp9, tp13, tp21, tp22 enable input of the 3622 ic enable tp35 ground gnd tp17 power good output for the 1.8v output pgd_1v8 tp11 power good output for the 2.5v output pgd_2v5 tp7 enable input for sequence and tracking seq tp33 external synchronization signal sync tp32 soft start for 2.5v output ss1 tp37 description signal name test point downloaded from: http:///
6 www.irf.com rd-0621 layout the IRDC3622D is an eight-layer board. the top and bottom layers are 2 oz. copper and the internal layers are 1 oz. copper. the switching mosfets, inductors, 270uf input capacitors, output capacitors, and some smaller passive components are mounted on the top side of the board. the ir3622 ic and the rest of passive components are mounted on the bottom layer. the directfet technology is used for mosfets. fig. 2: parts placement, the top layer. fig. 3: parts placement, the bottom layer. downloaded from: http:///
7 www.irf.com rd-0621 fig. 4: board layout, top layer. fig. 5: board layout, mid layer 1. downloaded from: http:///
8 www.irf.com rd-0621 fig. 6: board layout, mid layer 2. fig. 7: board layout, mid layer 3. downloaded from: http:///
9 www.irf.com rd-0621 fig. 8: board layout, mid layer 4. fig. 9: board layout, mid layer 5. downloaded from: http:///
10 www.irf.com rd-0621 fig. 10: board layout, mid layer 6. fig. 11: board layout, bottom layer. downloaded from: http:///
11 www.irf.com rd-0621 p3v3_stby r18a5 11.5k r18a6 9.1k p3v3_stby c35a2 empty c36a2 empty vref c29a2 0.22uf r16a3 empty 1 2 r16a4 empty 1 2 l2a1 no stuff 1 2 vsen2 vref r18a1 0 tb3a 1 2 3 4 5 6 vsen2 r18a2 11.5k tb4a 1 2 3 4 5 6 r18a3 9.1k c10a 1uf p3v3_stby pgd_p1v8 pgood2 r30a1 4.99k c24a 5.6nf pgd_p1v8 tp11 r6a1 0 1 2 r24a 1m c28a 47pf c2a 10uf c34a 0.1uf r11a 26. r18a 5.1k ir3622 mlpq c25a 6.8nf c35a 10uf,6.3v r19a 5.1k c22a 22pf c16a 22pf remote sense at terminal block r10a open c17a open c6a 10uf p1v8 r16a5 0 1 2 c8a 0.47uf,25v c29a 0.22uf u1a ir3622 mlpq vsen1 22 ss2 5 vcc 30 vch 1 17 pgood1 29 trac k 32 ss1 19 hdrv 2 8 gnd 28 comp1 20 vch 2 7 fb1 21 vsen2 2 pgnd2 10 comp2 4 hdrv1 16 vp2 26 rt 1 vcl 12 vout3 31 ocset1 18 ldrv 1 13 pgnd1 14 fb2 3 ocset2 6 enable 9 ldrv 2 11 sync 23 vref 27 vp1 25 p g ood2 24 pad1 33 pad2 34 pad3 35 pad4 36 pad5 37 pad6 38 pad7 39 pad8 40 pad9 41 seq 15 signal gnd joins gnd at 1 point c36a 10uf,6.3v c24a1 1.2nf r18a4 0.887k r16a 10 1 2 l2a 540nh etqp6f0r6bfa 1 2 c30a1 open c9a 0.22u c27a 180pf c13a 220uf c7a 1uf r9a 3.92k r4a 3.92k d2a bat54ws a_sod323_b 1 2 rt = 26.7k, fs = 350khz c14a 1uf vout3 tp33 tp35 c19a 220uf pgood2 tp30 r16a1 10k 1 2 coa1 0.1uf c8a1 0.47uf,25v r16a2 1.4k 1 2 tp36 tp31 tp32 tp37 c14a1 1uf c35a1 empty c36a1 empty c13a1 empty c19a1 empty 1 2 c9a1 0.22uf q21a irf6622 sq 2 5 4 1 3 6 7 tp15 r24a1 1m c29a1 0.22uf q22a irf6629 mx 2 5 4 1 3 6 7 tp16 fig. 12: schematic of the IRDC3622D board. tp1 q12a irf6629 mx 2 5 4 1 3 6 7 p2v5 tp2 tp9 tp21 tb1a 1 2 3 4 5 6 + c80a 270uf 1 2 r15a1 0 l1a1 no stuf f 1 2 remote sense at ter minal bloc k tp22 c29a3 0.22uf tb2a 1 2 3 4 5 6 + c39a 270uf 1 2 l1a 990nh etqp6f1r1bfa 1 2 c32a 0.1uf c3a 10uf pgd_p2v5 c37a 10uf,6.3v c38a 10uf,6.3v coa 0.1uf tp28 7k r17a 3.01k p2v5 r15a 6.49k r21a 3.01k tp29 p2v5 p3v3_stby c30a open r7a open c5a 10uf c11a open r20a 0.499k r30a 4.99k m1a heatsink mount 1 c3v 3 10uf p12va j1a gnd1 1 gnd2 2 gnd3 3 gnd4 4 +12v4 8 +12v3 7 +12v2 6 +12v1 5 th 1 9 th 2 10 f c15a2 empty r14a 6.49k c26a 2.2nf d1a bat54ws a_sod323_b 1 2 c37a2 empty pgd_p2v5 input capacitors must support 9.6arms for 2.5vo at 20 a and 1.8vo at 20a tp13 c37a3 empty c15a3 empty c15a1 100uf c37a1 empty c38a1 empty tp7 d1a1 bat54ws a_sod323_b 1 2 tp17 2.5v and 1.8v / 20a, 350khz design d2a1 bat54ws a_sod323_b c15a 100uf q11a irf6622 sq 2 5 4 1 3 6 7 unless otherwise specified: capacitors are 0603, 10% max, 16v min, x5r min resistors are 0603, 1%, 100mw p3v3_stby downloaded from: http:///
12 www.irf.com rd-0621 bill of materials item qty reference value description pcb footprint manufacturer part number 14 coa1, c32a, c34a, coa 0.1uf 0.1uf-0603-25v-x7r-10% a_mc-0603 panasonic ecj1vb1e104 22 c30a, c30a1 open a_mc-0603 35 c2a, c3a, c5a, c6a, c3v3 10uf 10uf-1206-16v-x7r-20% a_mc-1206 murata grm31cr61c106kc31l 44 c7a, c10a, c14a, c14a1 1uf 1uf-0603-16v-x7r-10% a_mc-0603 murata grm188r71c105ka12d 52 c8a, c8a1 0.47uf 0.47uf-0603-25v-x7r-10% a_mc-0603 murata grm188r71e474ka12d 66 c9a,c29a, c9a1,c29a1, c29a2,c29a3 0.22uf 0.22uf-0603-16v-x7r-10% a_mc-0603 panasonic ecj1vb1c224 72 c11a, c17a open a_mc-0603 82 c13a, c19a 220uf 220uf-d4-2v-9mohm-sp a_mc-6mm panasonic eefsx0d221r 92 c15a, c15a1 100uf 100uf-d4-4v-9mohm-sp a_mc-6mm panasonic eefsx0g101r 10 2 c16a, c22a 22pf 22pf-0603-50v-x7r-10% a_mc-0603 panasonic ecj1vc1h220j 11 1 c24a 5.6nf 5600pf-0603-50v-x7r-10% a_mc-0603 panasonic ecj1vb1h562k 12 1 c25a 6.8nf 6800pf-0603-50v-x7r-10% a_mc-0603 panasonic ecj1vb1h682k 13 1 c26a 2.2nf 2200pf-0603-50v-x7r-10% a_mc-0603 panasonic ecj1vb1h222k 14 1 c27a 180pf 180pf-0603-50v-c0g-5% a_mc-0603 panasonic ecj1vc1h181j 15 1 c28a 47pf 47pf-0603-50v-c0g-5% a_mc-0603 avx 06035a470jat2a 16 4 c35a,c36a, c37a, c38a 10uf 10uf-0805-6.3v-x5r-10% a_mc-0805 avx 08056d106kat2a 17 2 c39a,c80a 270uf 270uf-8mm-16v a_mc138-336d sanyo 16sepc270m 18 4 c13a1, c15a2, c15a3, c19a1 open a_mc-6mm 19 1 c24a1 1.2nf 1200pf-0603-50v-x7r-10% a_mc-0603 20 8 c35a1, c35a2, c36a1, c36a2, c37a1, c37a2, c37a3, c38a1 open a_mc-0805 21 4 d1a, d2a, d1a1, d2a1 bat54ws schottky,sod323,30v,0.2a a_sod323_b international rectifier bat54ws 22 1 j1a atx8pins conn,8 pins,2 rows pwr2x4 molex 39299082 23 1 l1a 990nh a_induct-320 panasonic etqp6f1r1bfa 24 1 l2a 540nh a_induct-320 panasonic etqp6f0r6bfa 25 2 l1a1, l2a1 open ir_pa0513 26 2 q11a, q21a irf6622 sq irf6622 sq 25v ir_dirfet_sq international rectifier irf6622 27 2 q12a, q22a irf6629 mx irf6629 mx 25v ir_dirfet_mx international rectifier irf6629 28 2 r4a, r9a, 3.92k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx3922 29 2 r30a, r30a1 4.99k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx4991 30 2 r7a, r10a open a_cr-0805 31 1 r11a 26.7k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx4320 32 4 r6a1, r15a1, r16a5, r18a1 0 res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpj000 33 2 r14a, r15a 6.49k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx6491 34 1 r16a 10 res, 0603, 1%, 1/10w a_cr-0603 panasonic erj-3ekf10r0v 35 2 r17a, r21a 3.01k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx3011 36 2 r18a, r19a 5.1k res, 0603, 1%, 1/10w a_cr-0603 yageo 9c06031a5101fkhft 37 1 r20a 0.499k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx4990 38 2 r24a, r24a1 1m res, 0603, 1%, 1/10w a_cr-0603 yageo rc0603fr-071ml 39 1 r16a1 10k res, 0603, 1%, 1/10w a_cr-0603 yageo rc0603fr-0710kl 40 1 r16a2 1.4k res, 0603, 1%, 1/10w a_cr-0603 panasonic erj-s03f1401v 41 2 r16a3, r16a4 open a_cr-0603 42 2 r18a2, r18a5 11.5k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx1152 43 2 r18a3, r18a6 9.1k res, 0603, 1%, 1/10w a_cr-0603 yageo 9c06031a9101fkhft 44 1 r18a4 0.887k res, 0603, 1%, 1/10w a_cr-0603 rohm mcr03ezpfx8870 45 4 tb1a, tb2a, tb3a, tb4a t. block 1 pin terminal block tb_1_0 keystone 8197 46 20 tp37, tp36, tp32, tp33, tp7, tp11, tp17, tp35, tp9, tp13, tp21, tp22, tp15, tp16, tp28. tp29. tp30, tp31, tp1, tp2 tp testpoint v1054_nd vector k24a/m 47 1 u1a ir3622 mlpq controller a_mlpq32-0p5mm_ via_a international rectifier ir3622 48 1 m1a heat sink () (mm) thermaflo 7201598 49 2 tim1a, tim2a thermal interface material 7.65 x 20.51 (l x w) (mm) bergquist bg420754 50 1 scrw1a philips pan head screw stainless a-2(18-8), 2mm x .4 x 5mm bolt depot 6812 downloaded from: http:///
13 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig.13: start-up sequence into 20a load. ch 1 : v in , ch 2 : enable, ch 3 : v ss1 ,ch 4 : v ss2 fig.14: start-up sequence into 20a load. ch 1 : v in , ch 2 : enable, ch 3 :v o1 (2v5), ch 4 : v o2 (1v8) fig.16: start-up sequence into 20a load. ch 1 : enable, ch 2 :v ss2 , ch 3 :v o2 (1v8), ch 4 :pgood(1v8) fig.15: start-up sequence into 20a load. ch 1 : enable, ch 2 : v ss1 , ch 3 : v o1 (2v5), ch 4 :pgood(2v5) fig.17: inductor points. ch 1 : v l1 , ch 2 : v l2 fig.18: dead-time (rise) at 20a load. ch 1 : v l1 downloaded from: http:///
14 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig.19: dead-time (fall) at 20a load. ch 1 : v l1 fig.20: output voltage ripple at 20a load. ch 1 : v o1 (2v5) fig.22: load transient 0-10a. ch 1 : v o1 (2v5), ch 4 : i o1 fig.21: output voltage ripple at 20a load. ch 1 : v o2 (1v8), ch 4 : i o2 fig.24: load transient 0-10a. ch 1 : v o1 (2v5), ch 4 : i o1 fig.23: load transient 10-0a. ch 1 : v o1 (2v5), ch 4 : i o1 downloaded from: http:///
15 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig.26: load transient 0-10a. ch 1 : v o2 (1v8), ch 4 : i o2 fig.25: load transient 0-10a. ch 1 : v o2 (1v8), ch 4 : i o2 fig.28: hiccup operation ch 1 : v o2 (1v8), ch 3 : v ss2 fig.27: hiccup operation ch 1 : v o1 (2v5), ch 3 : v ss1 fig.29: inductor current at 15a load ch 1 : i o1 (2v5) fig. 30: inductor current at 15a ch 1 : i o2 (1v8) downloaded from: http:///
16 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow 2.4 2.42 2.44 2.46 2.48 2.5 2.52 2.54 2.56 2.58 2.6 0 2 4 6 8 1 01 21 41 61 82 0 io1 (a) vo1 (v) 2.5v+3% 2.5v-3% fig.31: v o1 versus its load current. 1.72 1.74 1.76 1.78 1.8 1.82 1.84 1.86 1.88 024681 01 21 41 61 82 0 io2(a) vo2(v) 1.8v+3% 1.8v-3% fig.32: v o2 versus its load current. downloaded from: http:///
17 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig .33: bode plot of 2.5v loop at 0a shows a bandwidth of 52khz and phase margin of 48 degree. fig. 34: bode plot of 2.5v loop at 20 a shows a bandwidth of 61khz and phase margin of 47 degree. downloaded from: http:///
18 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig. 35: bode plot of 1.8v loop at 0a shows a bandwidth of 39khz and phase margin of 61 degree. fig. 36: bode plot of 1.8v loop at 20a shows a bandwidth of 43khz and phase margin of 58 degree. downloaded from: http:///
19 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, room temperature, no air flow fig.37: thermal image, test points 1, 2, 3, and 4 are synchronous directfet for 2.5v output, synchronous directfet for 1.8v output, control directfet for 2.5v output, and control directfet for 1.8v output, respectively. downloaded from: http:///
20 www.irf.com rd-0621 fig. 38: efficiency of 2.5v channel versus load current with 200lfm air flow and heat sink at 45 c. typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, 45 c, 200lfm air flow fig.39: power loss of 2.5v channel versus load current with 200lfm air flow and heat sink at 45 c. 88.0 88.2 88.4 88.6 88.8 89.0 89.2 89.4 89.6 89.8 90.0 90.2 90.4 90.6 90.8 91.0 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 output current (amps) efficiency % 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 output current (amps) watts downloaded from: http:///
21 www.irf.com rd-0621 typical operating waveforms v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a fs=350 khz, 45 c, 200lfm air flow fig.40: efficiency of 1.8v channel versus load current with heat sink and 200lfm air flow at 45 c. 85.0 85.2 85.4 85.6 85.8 86.0 86.2 86.4 86.6 86.8 87.0 87.2 87.4 87.6 5 6 7 8 9 1011121314151617181920 output current (amps) efficiency % fig.41: power loss of 1.8v channel versus load current with heat sink and 200lfm air flow at 45 c. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 01234567891011121314151617181920 output current (amps) watts downloaded from: http:///
22 www.irf.com rd-0621 frequency synchronization v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a, room temperature, no air flow the switching frequency of channels can be synchr onized by applying a digital input signal to the sync pin of the ir3622. this fr equency of input is twice as the switching frequency of the channels. fig.42: frequency synchronization. ch 1 : v l1 (2v5) ch 2 : sync pin ch 3 : v l2 (1v8) downloaded from: http:///
23 www.irf.com rd-0621 output voltage tracking and sequencing v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a, room temperature, no air flow in order to run the ir3622 in the ratio-metr ic mode, the following steps should be taken: - remove c29a1, r24a1, r6 a1, r16a5 from the board. -set the value of r16a3 and r16a4 as r15a (6.49k) and r17a (3 .01k), respectively. -connect tp33 to the seq input signal. fig.43: ratio-metric tracking at the voltage rise to a 20a load. ch 1 : seq ch 2 : v ss1 ch 3 : v o1 (2v5) ch 4 :v o2 (1v8) fig.44: ratio-metric tracking at the voltage fall with a 20a load. ch 1 : seq ch 2 : v ss1 ch 3 : v o1 (2v5) ch 4 :v o2 (1v8) downloaded from: http:///
24 www.irf.com rd-0621 output voltage tracking and sequencing v in =12v, v o1 =2.5v, v o2 =1.8v, i o1 =0-20a, i o2 =0-20a, room temperature, no air flow in order to run the ir3622 in the simultaneously mode, the following steps should be taken: - remove c29a1, r24a1, r6 a1, r16a5 from the board. -set the value of r16a3 and r16a4 as r18a 2 (11.5k) and r18a3 (9 .1k), respectively. -connect tp33 to the controlling input signal. fig.45: simultaneously tracking at the voltage rise to a 20a load ch 1 : seq ch 2 : v ss1 ch 3 : v o1 (2v5) ch 4 :v o2 (1v8) fig.46: simultaneously seq. at the voltage fall with a 20a load ch 1 : seq ch 2 : v ss1 ch 3 : v o1 (2v5) ch 4 :v o2 (1v8) downloaded from: http:///
25 www.irf.com rd-0621 tape & reel orientation ir world headquarters: 233 kansas st., el segundo, california 90245, usa tel: (310) 252-7105 tac fax: (310) 252-7903 this product has been designed and qualified for the industrial market. visit us at www.irf.com for sales contact information data and specifications subject to change without notice. 01/23/2007 downloaded from: http:///

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