IRDC3038 1 rev. 1.2 06/05/02 www.irf.com specification data introduction iru3038 evaluation board user guide input/output connections the iru3038 controller ic is designed to provide a low cost synchronous buck regulator for voltage tracking applications such ddr memory and general purpose on-board dc to dc converter. modern micro processors combined with ddr memory, need high-speed bandwidth data bus which requires a particular bus termination volt- age. this voltage will be tightly regulated to track the half of chipset voltage for best performance. switcher: v in = 5v v out = 2.5v i out = 8a v out = 75mv fs = 200khz the following is the input/output connections: inputs: j1: input (+5v) j2: gnd outputs: j5: v out (+2.5v) j6: gnd other connections: j7: v ddq (for tracking system) j3: v ref (output for reference voltage) the connection points is shown in figure 1. connect the power supply cables according to this figure, minimize wire lengths to reduce losses in the wire. test point j8 and j9 provide easy connections for oscilloscope volt- age probe to monitor the output inductor point and the output voltages.
IRDC3038 2 rev. 1.2 06/05/02 www.irf.com figure 1 - connection diagram of evaluation-board for iru3038. connection diagram power supply gnd +5v 6a supply load 0 - 8a
IRDC3038 3 rev. 1.2 06/05/02 www.irf.com the top side (component) layer for iru3038 eval board is shown in figure 2. the input capacitors are all located close to the mosfets. all the decoupling capacitors, charge pump capacitor and feedback components are located close to ic. the feedback resistors are tied to the output voltage at the point of regulation. the pcb is 4-layers board, one layer is dedicated to power gnd and the analog gnd is kept separated from the pgnd and it is connected at a single point. layout figure 2 - top layer of evaluation-board for iru3038.
IRDC3038 4 rev. 1.2 06/05/02 www.irf.com schematic figure 3 - schematic of evaluation-board for iru3038. {doc} iru3038eval a 1 friday, may 24, 2002 title size document number date: sheet of input v o +5v gnd vref gnd vddq g n vc fb comp ss rt vo vrin +5v vgl vgh vp vref vd vds r3 0 ohm r5 0 ohm d1 bat54s 3 2 1 l1 1uh u1 iru3038 vc 10 vcc 4 vref 3 ss 13 vp 2 fb 1 comp 12 rt 11 hdrv 9 ldrv 6 pgnd 8 gnd 7 c5 0.1uf + c10 c3 1uf + c1 33uf, ecs-t1cd336r c17 open r10 open r8 1k r9 26.1k c15 1800pf c13 open c14 open c16 open r7 open r4 open c8 0.1uf r2 0 ohm r1 open c12 1uf c4 1uf l2 3.3uh, do5022p-332hc c9 470pf j1 1 j2 1 j5 1 j6 1 j4 1 + c11 2x150uf, 6tpc150m r13 open j7 1 r12 open c7 open r11 1.00k j3 1 + c2 47uf c6 1uf j9 tp1 4 3 2 1 j8 tp1 4 3 2 1 + c18 47uf, 16tpb47m q1 irf7460 8 7 5 6 1 2 3 4 q2 irf7460 8 7 5 6 1 2 3 4 r6 4.7ohm d2 not used 1 2
IRDC3038 5 rev. 1.2 06/05/02 www.irf.com bill of material ref desig description value qty part# manuf web site (www.) 2 1 1 1 1 1 2 2 2 1 1 1 3 1 1 2 3 6 5 1 q1, q2 u1 d1 l1 l2 c1 c2,c18 c10,c11 c5,c8 c4 c15 c9 c3,c6,c12 r9 r6 r8,r11 r2,r3,r5 r1,4,7, 10,12,13 c7,12,13, 14,16 d2 mosfet controller diode inductor inductor cap, tantalum cap, poscap cap, poscap cap, ceramic cap, ceramic cap, ceramic cap, ceramic cap, ceramic resistor resistor resistor resistor resistor capacitor diode irf7460 iru3038 bat54s d03316p-102hc d05022p-332hc ecs-t1cd336r 16tpb47m 6tpc150m ecj-2vf1e104z ecj-3yb1e105k ecj-2vb1h182k ecj-2vb2d471k ecj-2vf1c105z ir ir ir coilcraft coilcraft panasonic sanyo sanyo panasonic panasonic panasonic panasonic panasonic 20v, 10m , 12a synchronous pwm fast switching, schottky 1 h, 10a 3.3 h, 12a 33 f, 16v 47 f, 16v, 70m 150 f, 6.3v, 40m 0.1 f, y5v, 25v 1 f, x7r, 25v 1800pf, x7r, 50v 470pf, x7r 1 f, y5v, 16v 26.1k, 5% 4.7 , 5% 1k, 1% 0 not used not used not used irf.com coilcraft.com maco.panasonic.co.jp sanyo.com/industrial maco.panasonic.co.jp
IRDC3038 6 rev. 1.2 06/05/02 www.irf.com test data figure 16 - start-up time @ i out =5a. figure 17 - shutdoown the output by pulling down the soft-start. figure 18 - 3.3v output voltage ripple @ i out =5a. figure 19 - transient response @ i out =0 to 2a. figure 20 - transient response @ i out =0 to 4a. 0a 2a vss v out i out v in vss v out 4a 0a figure 15 - efficiency for iru3038 evaluation board. v in =5v, v out =2.5v 80 82 84 86 88 90 92 94 0123456789 output current (a) efficiency (%)
IRDC3038 7 rev. 1.2 06/05/02 www.irf.com ir world headquarters: 233 kansas st., el segundo, california 90245, usa tel: (310) 252-7105 tac fax: (310) 252-7903 visit us at www.irf.com for sales contact information data and specifications subject to change without notice. 7/25/2002
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