IRDC3710-QFN SupIRBuck TM USER GUIDE FOR IRDC3710-QFN EVALUATION BOARD DESCRIPTION The IR3710M is a single phase sync-buck PWM controller IC optimized for efficiency in high performance portable electronics. The switching modulator uses constant ON-time control. Constant ON-time with diode emulation provides the highest light load efficiency required for all applications. Key features offered by the IR3710M include: programmable switching frequency, soft start, forced continuous conduction mode (FCCM) operation at light load and over current protection. Additional features include pre-bias startup, very precise 0.5V reference, over/under voltage fault protection, power good output, and enable input with voltage monitoring capability. The gate drive is designed to operate up to 7.5V to enhance over all system efficiency. This user guide contains the schematic and bill of materials for the IRDC3710-QFN evaluation board. The guide describes operation and use of the evaluation board itself. Detailed specifications and application information for IR3710M is available in the IR3710M data sheet. BOARD FEATURES • Vin = +12V Typical ( 8-19V input Voltage range. Pls. see note below) • PVcc= +5.0V • Vcc=+3.3V • Vout = +1.1V @ 0- 20A • Fs = 300kHz @ 20A • L = 0.5uH • Cin= 2x10uF (ceramic 1210) + 1x330uF (electrolytic) • Cout= 2x10uF (ceramic 1206) + 3x330uF(SP Cap) Note: At low input line an additional 10uF ceramic capacitor is recommended at input to handle higher ripple current) 1 IRDC3710-QFN CONNECTIONS and OPERATING INSTRUCTIONS A regulated +12V input supply should be connected to VIN+ and Vin-. A maximum 20A load should be connected to VOUT+ and VOUT-. The connection diagram is shown in Fig. 1 and inputs and outputs of the board are listed in Table I. IRDC3710-QFN has three input connectors, one for gate drive supply (PVcc),one for biasing (Vcc) and the third one as input voltage (Vin). Separate supplies should be applied to these inputs. PVcc input should be a well regulated 4.5V-5.5V supply and it would be connected to +5V and GROUND and Vcc input should be a well regulated 3.0V-3.6V supply and it would be connected to +3.3V and GROUND. An external signal can be provided as Enable signal to turn on or turn off the converter if desired. This signal is not required to power up the Evaluation board as EN pin is connected to a voltage divider from Vin. The absolute maximum voltage of Enable signal is +3.9V. The evaluation board is configured for use with 2x10uF (ceramic 1206) + 3x330uF (SP) capacitors. However, the design can be modified for an all ceramic output cap configuration by adding the inductor DCR sensing circuit as show in the schematic. Table 1: Connections Connection Signal Name VIN+ VIN (+12V) VIN- Ground of VIN +5V PVcc input (+5.0V) +3.3V Vcc input (+3.3V) GROUND Ground for PVcc and Vcc input VOUT+ Vout (+1.1V) VOUT+ Ground of Vout Enable Enable input LAYOUT The PCB is a 4-layer board. All layers are 2 Oz. copper. The IR3710M and other components are mounted on the top and bottom side of the board. Power supply decoupling capacitors, the Bootstrap capacitor and feedback components are located close to IR3710M. The feedback resistors are connected to the output voltage at the point of regulation and are located close to IR3710M. To improve efficiency, the circuit board is designed to minimize the length of the on-board power ground current path. 2 IRDC3710-QFN Vin = +12V Vin- Enable V out- PGood Vcc = +3.3V V = +1.1V out PVcc = +5.0V GROUND Figure 1: Connection diagram of IRDC3710-QFN evaluation board 3 IRDC3710-QFN Figure 2: PCB layout, top layer Figure 3: PCB layout, bottom layer 4 IRDC3710-QFN Figure 4: Board layout, mid-layer I Figure 5: Board layout, mid-layer II 5 Figure 6: Schematic of the IRDC3710-QFN Evaluation board IRDC3710-QFN 6 IRDC3710-QFN Bill of Materials Item Number Quanti ty Part Reference 1 4 C1 C2 C3 C4 0.1uF 2 1 C5 2.2uF 3 1 C7 4 2 5 Value Description Manufacturer1 Manufacturer Part Number Murata Electronics North America GRM188R61E105KA12D Ceramic, 6.3V, 0603, X7R, 10% Murata Electronics North America GRM185R60J225KE26D 1.0uF Ceramic, 25V, 0805, X5R, 10% Taiyo Yuden TMK212BJ105KG-T C8 C9 10uF Ceramic,25V,1210,X5R,10% Taiyo-Yuden TMK325BJ106MN-T 1 C10 330uF SMD Electrolytic, 25V, F-size,20% Panasonic EEE-FK1E331P 6 1 C12 1.0uF Ceramic,25V,0603,X5R,10% Murata Electronics North America GRM188R61E105KA12D 7 3 C13 C14 C15 330uF SP-Cap,Dcase,4V,20% Panasonic EEFUE0G331XE 8 2 C16 C17 10uF Ceramic,6.3V,1206,X5R,20% Murata Electronics North America GRM21BCB0G106ME19F Ceramic,25V,0603,X7R,10% C11,C18,C2 0,C22 N/S C21,23,C24, C25 N/S 9 1 C19 22000pF Ceramic,50V,0603,X7R,10% TDK Corporation C1608X7R1H223K 10 1 D1 BAT54S Diode,40V,BAT54S,SOT-23 Diodes, Inc. BAT54S 11 1 D2 BAS316 Diode 75V , 0.25A, SOD323 NXP BAS316 12 1 L1 500nH Toko FDUE1245-R50M 13 1 Q1 IRFH7921PbF Mosfet 30V 8.5mOhm PQFN International Rectifier IRFH7921PbF 14 1 Q2 IRFH7932PbF Mosfet 30V 3.3mOhm PQFN International Rectifier IRFH7932PbF 15 4 R13 R17 R18 10K Thick-film,0603,1/10W,1% Vishay/Dale CRCW060310K0FKEA R4 48.7K Thick-film,0603,1/10W,1% Rohm MCR03EZPFX4872 SMT-Inductor, 0.8mOhm,12.1x13.4mm,20% 16 1 R5 180K Thick-film,0603,1/10W,1% Rohm MCR03EZPFX1803 17 1 R7 7..5K Thick-film,0603,1/10 W,1% Rohm MCR03EZPFX7501 18 1 R12 1.96K Thick-film,0603,1/10W,1% Rohm MCR03EZPFX1961 19 3 R14 R19 0 Thick-film,0603,1/10 W,5% Vishay/Dale CRCW06030000Z0EA R9,R11,R16 N/S 20 1 R15 1.65K Thick-film,0603,1/10W,1% Panasonic - ECG ERJ-3EKF1651V 21 1 SW1 Switch, 2-Pos. Switch, DIP, 2-Pos., SPDT Copal Electronics Inc CJS-1200TB 22 1 U1 IR3710MPbF IR3710, Controller,PQFN,3x3mm International Rectifier IR3710MPbF 7 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow Ch1-Phase Voltage(10V/Div) Ch3-CPO(2V/Div) Ch2-Vout(50mV/div) Time: 10uS/Div) Figure 7: Charge Pump Off at Iout = 0.5A Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 9: Load Step (5A to 15A) Transient at 12Vin Ch1-Phase Voltage(10V/Div) Ch3-CPO(2V/Div) Ch2-Vout(50mV/div) Time: 2uS/Div) Figure 8: Charge Pump On at Iout =5A Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 10: Load Step (5A to 15A) Transient at 19Vin 8 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 20A, Room Temperature, No Air Flow Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 11: DCM/CCM transition from 1.0A to 5A at 12Vin Ch1-Phase Voltage (10V/Div) Ch3-EN(2V/Div) Ch2-Vout(500mV/Div) Ch4-PGood(2V/Div) Figure 13: Startup/Shutdown 12Vin at 0.5A Ch1-Phase Voltage (10V/Div) Ch2-Vout(50mV/Div) Figure 12: DCM/CCM transition from 1.0A to 5A at 19Vin Ch1-Phase Voltage (10V/Div) Ch3-EN(2V/Div) Ch2-Vout(500mV/Div) Ch4-PGood(2V/Div) Figure 14: Startup/Shutdown 12Vin at 5.0A 9 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow 92 5 90 4.5 4 88 Efficiency(%) 3 84 2.5 82 2 80 Power Loss(W) 3.5 86 1.5 78 1 76 0.5 74 0 0 4 8 12 16 20 Iout(A) Eff 12V Input CP ON Power Loss 12V Input CP ON Eff 12V input CP OFF Power Loss 12V Input CP OFF Figure 15: Typical Efficiency and Power Loss at Vin-12V 5 90 4.5 4 3.5 3 70 2.5 2 60 Power Loss(W) Efficiency(%) 80 1.5 1 50 0.5 40 0 0 4 8 12 16 Eff 19V Input CP ON Iout(A)Eff 8V Input CP ON Power Loss 19V Input CP ON Power Loss 8V Input CP ON 20 Figure 16: Typical Efficiency and Power Loss at Vin=8V and 19V 10 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow 1.1060 1.1040 1.1020 Vout(V) 1.1000 1.0980 1.0960 1.0940 1.0920 12V Input 8V Input 19V Input 1.0900 0 4 8 12 16 20 Iout(A) Figure 17: Typical Output Voltage Regulation Q1: 73.2°C, Q2:83.2°C, IC-64.2°C,Inductor: 53.5°C, PCB: 53.3°C Figure 18:Thermal Image @12Vin, 20A, With CP On 11 IRDC3710-QFN TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 20A, , Room Temperature, No Air Flow Q1: 82.5°C, Q2:94.8°C, IC-69.7°C,Inductor: 58.1°C, PCB: 56.4°C Figure 19: Thermal Image @19Vin, 20A, With CP On Q1:83.2°C,Q2:91.2°C, IC-68.7°C, Inductor: 57.1°C, PCB: 55.9°C Figure 20: Thermal Image @12Vin, 20A, With CP Off 12 IRDC3710-QFN PACKAGE INFORMATION 13