IRDC3448-P0V9 SupIRBuck TM USER GUIDE FOR IR3448 EVALUATION BOARD DESCRIPTION The IR3448 is a synchronous buck converter, providing a compact, high performance and flexible solution in a small 5mmx6mm QFN package. Key features offered by the IR3448 include internal Digital Soft Start, precision 0.6V reference voltage, Power Good, thermal protection, programmable switching frequency, Enable input, input under-voltage lockout for proper start-up, enhanced line/ load regulation with feed forward, external frequency synchronization with smooth clocking, internal LDO, true differential remote sensing and pre-bias start-up. A thermally compensated output over-current protection function is implemented by sensing the voltage developed across the on-resistance of the synchronous rectifier MOSFET for optimum cost and performance. This user guide contains the schematic and bill of materials for the IR3448 evaluation board. The guide describes operation and use of the evaluation board itself. Detailed application information for IR3448 is available in the IR3448 data sheet. BOARD FEATURES • Vin = +12V • Vout = +0.9V @ 0-16A • Fs = 1MHz • L = 0.16uH • Cin = 2x22uF (ceramic 1206) + 1x330uF* (electrolytic) • Cout = 6x47uF (ceramic 0805) * The 330uF input capacitor is placed for damping the parasitic inductance of bench power supply wires. It is not required for the POL applications where input is delivered with power planes. 9/18/2013 Confidential 1 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 CONNECTIONS and OPERATING INSTRUCTIONS A well regulated +12V input supply should be connected to VIN+ and VIN-. A maximum of 16A load should be connected to VOUT+ and VOUT-. The inputs and output connections of the board are listed in Table I. IR3448 needs only one input supply and internal LDO generates Vcc from Vin. The board is configured for remote sensing. External Enable signal can be applied to the board via exposed Enable pad and R18 should be removed for this purpose. Table I. Connections Connection Signal Name VIN+ Vin (+12V) VIN- Ground of Vin Vout+ Vout(+0.9V) Vout- Ground for Vout Vcc+ Vcc Pin Vcc- Ground for Vcc input Enable Enable PGood Power Good Signal AGnd Analog ground LAYOUT The PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passive components are mounted on the top side of the board. Power supply decoupling capacitors and feedback components are located close to IR3448. The feedback resistors are connected to the output of the remote sense amplifier of the IR3448 and are located close to the IR3448. To improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path. Separate power ground and analog ground are used and may be connected together using a single point connection. 9/18/2013 Confidential 2 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 CONNECTIONS and OPERATING INSTRUCTIONS LAYOUT The PCB is a 6-layer board. All of layers are 2 Oz. copper. The IR3448 and most of the passive components are mounted on the top side of the board. Power supply decoupling capacitors and feedback components are located close to IR3448. The feedback resistors are connected to the output of the remote sense amplifier of the IR3448 and are located close to the IR3448. To improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path. Vin Gnd Top View Vo Gnd 9/18/2013 Confidential 3 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL Fb 4.7nF C66 10uF 10k R17 C26 R1 1.8k 75pF 20 C11 R6 PGD 5 16 18 8 7 9 23.2k R9 49.9k IR3448 RS+ Vsns SW SW SW SW SW SW SW Boot PGnd 13 6 20 21 22 23 24 25 32 2 26 C39 1uF Vout 0.1uF C37 C25 0.1uF Vo_R_N Vo_R_P 22uF 22uF 160nH L1 C2 C3 + 47uF PIN11 C19 Vin- Vin+ 47uF 6 5 4 3 2 1 6 5 4 3 2 1 C20 330uF C1 PVin Fig. 1: Schematic of the IR3448 evaluation board Cby p NC0 NC1 NC2 NC3 NC4 100pF 19 28 30 31 33 Rt/Sy nc OCSelect PGD Vcc Comp FB RSo C10 U1 R19 7.5k Rt/Sy nc 4 BODE 2.67k 2200pF JUMPER 2 R2 R3 5.36k VCC 47.5 C8 15 NC5 3 Enable R4 LGnd 11 Cbyp 14 17 Vin 1 PVin PGnd PGnd PGnd 10 27 29 Confidential RS- 9/18/2013 12 R18 47uF C18 47uF C16 PIN10 47uF C17 47uF C15 6 5 4 3 2 1 0.1uF 6 5 4 3 2 1 14 Vout Vout- Vout+ IRDC3448-P0V9 4 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 Bill of Materials Item Qty Part Reference Value Description SMD Elecrolytic, Fsize, 25V, 20% Manufacturer Part Number Panasonic EEE-FK1E331P 1 1 C1 330uF 2 2 C2 C3 22uF 1206, 25V, X5R, 10% Murata GRM31CR61E226KE15L 3 4 5 6 1 3 1 1 100pF 0.1uF 2200pF 75pF 0402, 50V, NP0, 5% 0402, 50V, X7R, 10% 0402, 25V, NP0, 5% 0402, 50V, NP0, 5% Murata TDK Kemet Murata GRM1555C1H101JZ01D C1005X7R1H104K050BB C0402C222J3GACTU GRM1555C1H750JA01D 7 6 47uF 0805, 6.3V, X5R, 20% TDK C2012X5R0J476M 8 9 10 11 12 13 14 15 16 17 18 19 20 1 1 1 1 1 1 1 1 1 1 1 1 1 C10 C14 C25 C37 C8 C11 C15 C16 C17 C18 C19 C20 C26 C39 C66 L1 R1 R2 R3 R4 R6 R9 R17 R18 R19 4.7nF 1uF 10uF 0.16uH 1.8k 2.67k 5.36k 47.5 20 23.2k 10k 49.9k 7.5k 0402, 50V, X7R, 10% 0402, 25V, X5R,10% 0603, X5R, 10V, 20% 0.16uH, DCR=2.15mohm 0402,1/10W,1% 0402,1/10W,1% 0402,1/10W,1% 0402,1/10W,1% Murata TDK TDK Coilcraft Panasonic Panasonic Panasonic Panasonic GRM155R71H472KA01D C1005X5R1E105K050BC C1608X5R1A106M080AC XAL5030-161ME_ ERJ-2RKF1801X ERJ-2RKF2671X ERJ-2RKF5361X ERJ-2RKF47R5X 0402,1/10W,1% 0402,1/10W,1% 0402,1/10W,1% 0402,1/10W,1% 0402,1/10W,1% ERJ-2RKF20R0X ERJ-2RKF2322X ERJ-2RKF1002X ERJ-2RKF4992X ERJ-2RKF7501X 21 1 U1 IR3448 IR3448 5mm X6mm Panasonic Panasonic Panasonic Panasonic Panasonic International Rectifier 9/18/2013 Confidential IR3448MPBF 5 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow Fig. 2: Start up at 16A Load Ch1:Vin, Ch2:Vout, Ch3:PGood, Ch4:Enable Fig. 3: Start up at 16A Load Ch1:Vin, Ch2:Vout, Ch3:PGood,Ch4:Vcc Fig. 4: Start up with 0.81V Pre Bias , 0A Load Ch2:Vout , Ch3:PGood, Ch4:Enable Fig. 5: Output Voltage Ripple, 16A load Ch2: Vout Fig. 7: Short (Hiccup) Recovery Ch2:Vout, Ch3:PGood, Ch4:Iout Fig. 6: Inductor node at 16A load Ch1:SW Node 9/18/2013 Confidential 6 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vout=0.9V, Iout=8A-16A, Fs=1MHz, Room Temperature, No air flow Fig. 8: Transient Response, 8A to 16A step with Electronic load setting = 2.5A/us Ch2:Vout, Ch4:Iout 9/18/2013 Confidential 7 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow Fig. 9: Bode Plot at 16A load shows: Fc = 185.6kHz, Phase Margin = 52.3º 9/18/2013 Confidential 8 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow Fig.10: Efficiency versus load current Fig.11: Power loss versus load current 9/18/2013 Confidential 9 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL IRDC3448-P0V9 THERMAL IMAGES Vin=12.0V, Vout=0.9V, Iout=0A-16A, Fs=1MHz, Room Temperature, No air flow Fig. 12: Thermal Image of the board top at 16A load IR3448: 65.130C Fig. 13: Thermal Image of the board bottom at 16A load Inductor: 69.290C 9/18/2013 Confidential 10 This evaluation board is a preliminary version meant for the engineering evaluation of the IR3448. Based on the results of the continuing evaluation, this board can evolve and change without notice AL