REFERENCE DESIGN IRDCiP1206-A International Rectifier * 233 Kansas Street, El Segundo, CA 90245 USA IRDCiP1206-A: 300 kHz, 30A, Synchronous Buck Converter using iP1206 Overview This reference design is capable of delivering a continuous current of 30A (at an ambient temperature of 25C and no airflow. Figures 1-16 provide performance graphs, thermal images, and waveforms. Figures 17-27, and Table 1 are provided to engineers as design references for implementing an iP1206 solution. The components installed on this demoboard were selected based on operation at an input voltage of 12V and at a switching frequency of 300 kHz. Changes from these set points may require optimizing the control loop and/or adjusting the values of input/output filters in order to meet the user's specific application requirements. Refer to the iP1206 datasheet User Design Guidelines section for more information. Note: The 16-pin connector (CON1) is used only for production test purposes and should not be used for evaluation of this demoboard. Demoboard Quick Start Guide Initial Settings: VOUT is set to 1.2V, but can be adjusted from 0.8V to 5.5V by changing the values of R5 and R6 according to the following formula: R5 = R6 = (10.0k * 0.8) / (VOUT - 0.8) The switching frequency is set to 300kHz, but can be adjusted by changing the value of RT. The graph in Figure 18 shows the relationship between RT and the switching frequency. Power Up Procedure: 1. Apply input voltage across VIN and PGND. 2. Apply load across VOUT pads and PGND pads. 3. Adjust load to desired level. See recommendations below. IRDCiP1206-A Recommended Operating Conditions (Refer to the iP1206 datasheet for maximum operating conditions) Input voltage: 7.5V - 14.5V Output voltage: 0.8 - 5.5V Switching Freq: 300kHz Output current: This reference design is capable of delivering a continuous current of 30A (without heatsink) at an ambient temperature of 45C with 200LFM of airflow. IRDCiP1206-A_______ _____ 10 1.2V 9 1.5V 1.8V 2.5V 3.3V 8 Power Loss (W) 7 6 5 Fig. 1: Power Loss vs. Output Current 4 3 2 1 0 0A 5A 10A 15A 20A 25A 30A Conditions: Vin = 12V Vout = 1.2V to 3.3V Fsw= 300KHz Ta = 25O C No heat sink No Airflow Output Current (A) 100.00% 90.00% 80.00% Efficiency (%) 70.00% 60.00% 50.00% 40.00% 1.2V 1.5V 1.8V 2.5V Fig. 2: Efficiency vs. Output Current 3.3V 30.00% 20.00% 10.00% 0.00% 0A 5A 10A 15A 20A Output Current (A) www.irf.com 2 25A 30A _____________ __IRDCiP1206-A The Voltage Regulation is better than 0.35% Fig. 3: Output Voltage Regulation vs. Current PM =70 o Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300KHz No Airflow Fc = 50 KHz GM = 13dB Fig. 4: Bode Plot 3 www.irf.com IRDCiP1206-A_______ _____ Conditions: Vin = 12V Vout = 1.2V Iout = 30A Fsw = 300kHz Ambient Temp. = 45C Airflow = 200LFM Stabilizing Time = 15 min Fig. 5: Thermograph (No Heatsink) Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 6: Power Up Sequence www.irf.com 4 _____________ __IRDCiP1206-A Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 7: Power Down Sequence (Turning off a 30A Load) Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 8: Close-up of Power Down when Enable is pulled low 5 www.irf.com IRDCiP1206-A_______ _____ Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 9: Current Share Mode (Switch Node Waveforms) Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Peak to Peak Output Ripple = 13mV Fig. 10: Output Voltage Ripple www.irf.com 6 _____________ __IRDCiP1206-A Short Circuit Current = 62A Tested at Room Temperature ROCSET = 10K Fig. 11: Short Circuit Protection Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 12: Over-voltage Protection 7 www.irf.com IRDCiP1206-A_______ _____ 60 mV 60 mV Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 13: Iout Transient Step-Up 50% - 75% Fig. 14: Iout Transient Step-Down 75% - 50% 105 mV 110 mV Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Vin = 12V Vo = 1.2V Iout = 30A Fsw = 300kHz No Airflow Fig. 15: Iout Transient Step-Up 50% - 100% Fig. 16: Iout Transient Step-Down 100% - 50% www.irf.com 8 _____________ __IRDCiP1206-A Adjusting the Over-Current Limit ROCx is the resistor used to adjust the over-current trip point. The trip point corresponds to the peak inductor current indicated on the x-axis of Fig. 21. (Note: The trip point will be higher than expected if the reference board is cool and is being used for short circuit testing.) 13 12 11 9 8 7 6 5 4 3 2 1 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Peak Inductor Current (A) Fig. 17: ROCSET vs. Over-Current Trip Point Switching Frequency Vs. Rt 700 600 500 F sw (kH z ) Current Limit Resistor (kOhms) 10 400 300 200 100 0 0 10 20 30 40 50 60 70 Rt (Kohm) Fig. 18: RT vs. Frequency 9 www.irf.com IRDCiP1206-A_______ Fig. 19: Component Placement Top Layer Fig. 20: Component Placement Bottom Layer Fig. 22: 1st Mid Copper Layer Fig. 21: Top Copper Layer www.irf.com _____ 10 _____________ __IRDCiP1206-A Fig. 23: 2nd Mid Copper Layer Fig. 24: 3rd Mid Copper Layer Fig. 25: 4th Mid Copper Layer Fig. 26: Bottom Copper Layer 11 www.irf.com TP6 1.2V_EN 1.43K R20 0 10K 1uF C19 R18 R19 SYNC TP5 SS1 TP7 100pF C20 100K R1 TP8 R14 30.9k(300kHz) 0.1uF 100K R4 PGD1 C21 100K R3 C17 29 28 VCC RT SYNC SS2 33 22 2 17 26 VREF SS1 25 24 21 VP2 SEQ 31 23 EN 27 PGD2 30 0.1uF C18 PGD1 VO3 open R22 1uF VO3 RT SYNC SS2 SS1 VREF VP2 VP1 SEQ ENABLE VCC PGD2 PGD1 TRK 1uF 0 VCH C16 U1 iP1206 PGND VIN FB2S CC2 FB2 VSW2 OC2 VCB2 FB1S CC1 FB1 VSW1 OC1 VCB1 OC2 8 FB2 CC2 FB1S 1 34 5.76K 35 5 VCB2 7 ROC2 FB1S CC1 18 20 FB1 5.76K ROC1 OC1 VCB1 19 14 11 12 10uF 16V C1 8200pF C15 5600pF C26 100pF C25 10uF 16V C2 R7 VSW2 0.1uF C28 4.22K R13 20K 100pF 20K R5 R6 4.22K VP2 10uF 16V C4 C27 VSW1 0.1uF C22 10uF 16V C3 R9 C23 C24 1.0uF 10uF 16V C6 1.0uF C29 1500pF 1.0uH L2 10K R11 402 R8 10K R16 750 R12 0 L1 1.0uH 402 R10 0 R15 10uF 16V C5 0 R17 10uF 16V C7 10uF 16V C8 Fig. 27. Reference Design Circuit Schematic 0 R2 VIN1 R21 36 3 VIN2 VCC_VIN 9 VCH AGND 10 VCL PGND 4 16 PGND 6 12 13 32 DH_ ON PGND www.irf.com 15 TP1 100uF 100uF TP4 +1.2V TP3 (no stuff) 100uF C11 680uF C30 16 14 13 15 12 10 8 6 4 2 11 9 7 5 3 1 CON1 1.2V (no stuff) 100uF C12 VIN SS1 PGND J4 VOUT J3 10uF C13 VOUT PGND J2 VIN J1 SMT16_CONNECTOR VOUT VSW2 VSW1 PGNDS VINS PGND C10 C9 PGND TP2 +12V 10uF C14 330uF C31 (no stuff) 330uF C32 330uF C33 (no stuff) 330uF C34 (no stuff) IRDCiP1206-A_______ _____ Quantity Designator 10 C1, C2, C3, C4, C5, C6, C7, C8, C13, C14 2 C9, C10 1 C15 3 C16, C17, C19 4 C18, C21, C22, C28 3 C20, C25, C27 2 C23, C29 1 C24 1 C26 1 C30 1 C32 2 L1, L2 3 R1, R3, R4 2 R10, R11 1 R12 2 R7, R13 1 R14 3 R15, R16, R17 3 R2, R18, R21 3 R8, R9, R19 1 R20 2 R5, R6 2 ROC1, ROC2 1.2V_EN, PGD1, PGNDS, PGNDS, SS1, 8 SYNC, VINS, VOUTS 1 U1 *Red - Top Side Components *Blue - Bottom Side Components 13 www.irf.com - - Tolerance 10% 20% 10% 10% 10% 5% 10% 10% 10% 20% 20% 20% 1% 1% 1% 1% 1% 1% <50m 1% 1% 1% 1% 9.25 x 15.5mm SMT Package 1206 1210 0603 0805 0603 0603 0603 0603 0603 SMD 7343 SMT 0603 0603 0603 0603 0603 0603 0805 0603 0603 0603 0603 Table 1: Bill of Materials for the Reference design - LGA unit iP1206 rev- b 90 mils 112 x 150 mils test point hardware Value 2 16V 6.3V 50V 16V 16V 50V 16V 50V 50V 16V 2.5V 25A 1/10W 1/10W 1/10W 1/10W 1/10W 1/10W 1/8W 1/10W 1/10W 1/10W 1/10W Value 1 10.0uF 100uF 8200pF 1.00uF 0.100uF 100pF 1.00uF 1500pF 5600pF 680uF 330uF 1.00uH 100K 402 750 4.22K 30.9K 0 0 10.0K 1.43K 20.0K 5.76K Type 1 Type 2 capacitor X7R capacitor X5R capacitor X7R capacitor X7R capacitor X7R capacitor NPO capacitor X7R capacitor X7R capacitor X7R capacitor electrolytic capacitor tantalum polymer inductor ferrite resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film resistor thick film IRF Keystone rev- b 5016 Manufac 1 Manufac 1No TDK C3216X7R1C106KT TDK C3225X5R0J107M KOA X7R0603HTTD822K MuRata GRM40X7R105K016 MuRata GRM188R71C104KA01D Phycomp 0603CG101J9B20 TDK C1608X7R1C105KT KOA X7R0603HTTD152K KOA X7R0603HTTD562K Panasonic EEV-FK1C681GP Sanyo 2R5TPE330M9 Delta Electronics MPL105-1R0IR KOA RK73H1J1003F KOA RK73H1JLTD4020F KOA RK73H1JLTD7500F KOA RK73H1JLTD4221F KOA RK73H1J3092F KOA RK73Z1JLTD ROHM MCR10EZHJ000 KOA RK73H1J1002F KOA RK73H1JLTD1431F KOA RK73H1J2002F KOA RK73H1JLTD5761F _____________ __IRDCiP1206-A IRDCiP1206-A_______ _____ Refer to the following application notes for detailed guidelines and suggestions when implementing iPOWIR Technology products: AN-1028: Recommended Design, Integration and Rework Guidelines for International Rectifier's iPowIR Technology BGA and LGA and Packages This paper discusses optimization of the layout design for mounting iPowIR BGA and LGA packages on printed circuit boards, accounting for thermal and electrical performance and assembly considerations. Topics discussed includes PCB layout placement, and via interconnect suggestions, as well as soldering, pick and place, reflow, inspection, cleaning and reworking recommendations. AN-1030: Applying iPOWIR Products in Your Thermal Environment This paper explains how to use the Power Loss and SOA curves in the data sheet to validate if the operating conditions and thermal environment are within the Safe Operating Area of the iPOWIR product. AN-1047: Graphical solution for two branch heatsinking Safe Operating Area Detailed explanation of the dual axis SOA graph and how it is derived. Use of this design for any application should be fully verified by the customer. International Rectifier cannot guarantee suitability for your applications, and is not liable for any result of usage for such applications including, without limitation, personal or property damage or violation of third party intellectual property rights. IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105 TAC Fax: (310) 252-7903 www.irf.com 14