IRDC3894-P0V95 SupIRBuck TM USER GUIDE FOR IR3894 EVALUATION BOARD 0.95Vout DESCRIPTION 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 and the current limit is thermally compensated. The IR3894 is a synchronous buck converter, providing a compact, high performance and flexible solution in a small 5mm X 6 mm Power QFN package. Key features offered by the IR3894 include internal Digital Soft Start/Soft Stop, precision 0.5Vreference 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, smart internal LDO and pre-bias start-up. This user guide contains the schematic and bill of materials for the IR3894 evaluation board. The guide describes operation and use of the evaluation board itself. Detailed application information for IR3894 is available in the IR3894 data sheet. BOARD FEATURES • Vin = +12V (+ 13.2V Max) • Vout = +0.95V @ 0- 9A • Fs=400kHz • L= 1uH • Cin= 2x22uF (ceramic 1206) + 1X330uF (electrolytic) • Cout=3x22uF (ceramic 0805) + 1X680uF (POSCAP) 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 1 IRDC3894-P0V95 CONNECTIONS AND OPERATING INSTRUCTIONS A well regulated +12V input supply should be connected to VIN+ and VIN-. A maximum of 9A load should be connected to VOUT+ and VOUT-. The input and output connections of the board are listed in Table I. IR3894 has only one input supply and internal LDO generates Vcc from Vin. If operation with external Vcc is required, then R15 can be removed and external Vcc can be applied between Vcc+ and Vcc- pins. Vin pin and Vcc/LDOout pins should be shorted together for external Vcc operation (use zero ohm resistor for R29). The output can track voltage at the Vp pin. For this purpose, Vref pin is to be connected to ground (use zero ohm resistor for R21). The value of R14 and R28 can be selected to provide the desired tracking ratio between output voltage and the tracking input. Table I. Connections Connection Signal Name VIN+ Vin (+12V) VIN- Ground of Vin Vout+ Vout(+0.95V) Vout- Ground for Vout Vcc+ Vcc/ LDO_out Pin Vcc- Ground for Vcc input Enable Enable PGood Power Good Signal Gnd Analog ground LAYOUT The PCB is a 4-layer board (2.23”x2”) using FR4 material. All layers use 2 Oz. copper. The PCB thickness is 0.062”. The IR3894 and other major power components are mounted on the top side of the board. Power supply decoupling capacitors, the bootstrap capacitor and feedback components are located close to IR3894. The feedback resistors are connected to the output at the point of regulation and are located close to the SupIRBuck IC. To improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path. 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 2 IRDC3894-P0V95 Vin Gnd Gnd Vout Enable Top View VDDQ Vref Sync PGood AGnd S_Ctrl Vsns Vcc+ Vcc- Bottom View Fig. 1: Connection Diagram of IR3894/94 Evaluation Boards 11/29/2012 3 IRDC3894-P0V95 Fig. 2: Board Layout-Top Layer Single point connection between Analog Gnd and PGnd Fig. 3: Board Layout-Bottom Layer 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 4 IRDC3894-P0V95 Fig. 4: Board Layout-Mid Layer 1 Fig. 5: Board Layout-Mid Layer 2 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 5 PGood VCC N/A C10 R17 49.9K Vcc+ Vcc- N/S R28 R14 0 VDDQ Agnd 1 17.8k R1 R9 C26 SY NC 2.2nF 80.4K 47pF C11 1 C12 0.1nF S_Ctrl 5 4 3 1 2.2uF C23 VCC S_Ctrl Vp Rt_Sy nc AGnd COMP 1 15 C32 1.0uF 49.9K IR3894 R7 0 (N/S) R3 11k SW VCC R2 2200pF C8 PGND 10k 11 12 C7 0.1uF 13 2.15k R4 PGnd SW PVin U1 N/S R29 R10 0 R15 0 A Vsns n/a 20 R6 C25 0.1uF C24 L1 B R11 10k 11k R12 1uH R50 0 C34 C33 C30 22uF 22uF 22uF C6 680uF N/S + C36 + C35 N/S C28 N/S 22uF C29 Fig. 6: Schematic of the IR3894 evaluation board 0 n/a C37 FB R13 6 16 7.5k R19 2 VREF 1 1 Boot 1 1 9 PGood 7 1 14 Vsns 8 R21 N/S 1 GND 17 Enable Vcc/LDO_OUT 10 Vin R18 1 VREF 1 1 1 11/29/2012 1 Enable C27 N/S C5 C20 N/S 22uF C19 N/S C4 N/S C18 N/S C3 N/S C17 N/S C16 N/S C2 N/S C15 N/S C1 + Vin+ Vin+ 1 1 1 1 1 1 Vout- Vout- Vout+ Vout+ Vin- Vin- 330uF/25V 1 1 C14 0.1uF Vout Vin IRDC3894-P0V95 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 6 IRDC3894-P0V95 Bill of Materials Item Qty Part Reference Value Description Manufacturer Part Number 1 1 C1 330uF SMD Electrolytic F size 25V 20% Panasonic EEV-FK1E331P 2 2 C5 C6 22uF 1206, 16V, X5R, 20% TDK C3216X5R1C226M 3 3 C7 C14 C24 0.1uF 0603, 25V, X7R, 10% Murata GRM188R71E104KA01B 4 1 C12 100pF 0603, 50V, 5% Murata GRM1885C1H101JA01D 5 1 C8 2200pF 0603,50V,X7R Murata GRM188R71H222KA01B 6 1 C11 47pF 0603, 50V, NP0, 5% Murata GRM1885C1H470JA01D 7 3 C15 C16 C17 22uF 0805, 6.3V, X5R, 20% TDK C2012X5R0J226M 8 1 C23 2.2uF 0603, 16V, X5R, 20% TDK C1608X5R1C225M 9 1 C35 680uF POSCAP, 2.5V, ESR 6mOhm SANYO 2R5TPF680M6L 10 1 C26 2200pF 0603, 50V, X7R Murata GRM188R71H222KA01B 11 1 C32 1.0uF 0603, 25V, X5R, 10% Murata GRM188R61E105KA12D 12 1 L1 1uH SMD 7.6x7.9x5mm, 5.8mΩ Coiltronics HCP0805-1R0-R 13 1 R1 17.8K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF1782V 14 2 R2 R11 10K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF1002V 15 2 R3 R12 11K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF1102V 16 1 R4 2.15k Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF2151V 17 1 R6 20 Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF20R0V 18 1 R9 60.4K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF6042V 19 5 R10 R13 R14 R15 R50 0 Panasonic ERJ-3GEY0R00V 20 2 R17 R18 49.9K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF4992V 21 1 R19 7.5K Thick Film, 0603,1/10W,1% Panasonic ERJ-3EKF7501V 22 1 U1 IR3894 PQFN 5x6mm IR IR3894MPBF 11/29/2012 Thick Film, 0603,1/10W Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 7 IRDC3894-P0V95 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=0.95V, Io=0-9A, Room Temperature, no airflow Fig. 8: Start up at 9A Load Ch1:Vout, Ch2:Vin, Ch3:PGood,Ch4:Vcc Fig. 7: Start up at 9A Load Ch1:Vout, Ch2:Vin, Ch3: PGood,Ch4:Enable Fig. 10: Output Voltage Ripple, 9A load Ch4: Vout , Fig. 9: Start up with 0.8V Pre Bias , 0A Load, Ch1:Vout, Ch3:PGood Fig. 12: Short circuit (Hiccup) Recovery Ch1:Vout , Ch3:PGood Fig. 11: : Inductor node at 9A load Ch2:LX 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 8 IRDC3894-P0V95 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=0.95V, Io=0-9A, Room Temperature, no air flow Fig. 13: Transient Response, 3A to 7A step Ch4:Vout Ch1:Iout 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 9 IRDC3894-P0V95 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=0.95V, Io=0-9A, Room Temperature Fig. 14: Bode Plot at 9A load bandwidth = 71.89kHz, phase margin = 52.08 deg, Gain Margin = 12.81dB 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 10 IRDC3894-P0V95 TYPICAL OPERATING WAVEFORMS Vin=12.0V, Vo=0.95V, Io=0-9A, Room Temperature, no air flow 88 86 Efficiency [%] 84 82 80 78 76 74 72 0 1 2 3 4 5 Io [A] 6 7 8 9 8 9 Fig.15: Efficiency versus load current 2.0 1.8 Power Loss [W] 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 1 2 3 4 5 Io [A] 6 7 Fig.16: Power loss versus load current 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 11 IRDC3894-P0V95 THERMAL IMAGES Vin=12.0V, Vo=0.95V, Io=0-9A, Room Temperature, No Air flow Fig. 17: Thermal Image of the board at 9A load Test point 1 is IR3894 Test point 2 is inductor 11/29/2012 12 IRDC3894-P0V95 PACKAGE INFORMATION DIM A A1 b b1 c D E e e1 e2 MILIMITERS MIN MAX 0.800 1.000 0.000 0.050 0.375 0.475 0.250 0.350 0.203 REF. 5.000 BASIC 6.000 BASIC 1.033 BASIC 0.650 BASIC 0.852 BASIC INCHES MIN MAX 0.0315 0.0394 0.0000 0.0020 0.1477 0.1871 0.0098 0.1379 0.008 REF. 1.969 BASIC 2.362 BASIC 0.0407 BASIC 0.0256 BASIC 0.0335 BASIC DIM L M N O P Q R S t1, t2, t3 t4 t5 MILIMITERS MIN MAX 0.350 0.450 2.441 2.541 0.703 0.803 2.079 2.179 3.242 3.342 1.265 1.365 2.644 2.744 1.500 1.600 0.401 BASIC 1.153 BASIC 0.727 BASIC INCHES MIN MAX 0.0138 0.0177 0.0961 0.1000 0.0277 0.0316 0.0819 0.0858 0.1276 0.1316 0.0498 0.0537 0.1041 0.1080 0.0591 0.0630 0.016 BACIS 0.045 BASIC 0.0286 BASIC Figure 20: Package Dimensions 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. 11/11 11/29/2012 Confidential This evaluation board is a preliminary version meant for the engineering evaluation of the IR3894. Based on the results of the continuing evaluation, this board can evolve and change without notice 13