IRDC3710-DF SupIRBuck TM USER GUIDE FOR IRDC3710-DF EVALUATION BOARD DESCRIPTION The IR3710M is 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-DF 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. See note below) • PVcc= +5.0V • Vcc=+3.3V • Vout = +1.1V @ 0- 24A • Fs = 300kHz @ 24A • L = 0.5uH • Cin= 2x10uF (ceramic 1210) + 1x330uF (electrolytic) • Cout= 2x10uF (ceramic 1206) + 2x330uF(SP Cap) Note: At low input line an additional 10uF ceramic capacitor is recommended at input to handle higher ripple current) 1 IRDC3710-DF CONNECTIONS and OPERATING INSTRUCTIONS A regulated +12V input supply should be connected to VIN+ and Vin-. A maximum 24A 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-DF 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 PGND and Vcc input should be a well regulated 3.0V-3.6V supply and it would be connected to +3.3V and AGND. 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) + 2x330uF (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) PGND Ground for PVcc input AGND Ground for 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-DF Vin = +12V Vin- V out- Enable Vcc = +3.3V Vout = +1.1V GROUND PVcc = +5.0V GROUND Figure 1: Connection diagram of IRDC3710-DF evaluation board 3 IRDC3710-DF Figure 2: PCB layout, top layer Figure 3: PCB layout, bottom layer 4 IRDC3710-DF Figure 4: Board layout, mid-layer I Figure 5: Board layout, mid-layer II 5 Figure 6: Schematic of the IRDC3710-DF Evaluation board IRDC3710-DF 6 IRDC3710-DF Bill of Materials 1 4 C1,C2,C3,C4 0.1uF Ceramic,25V,0603,X7R,10% 2 1 C5 2.2uF Ceramic, 6.3V, 0603, X7R, 10% 3 1 C7 1.0uF Ceramic, 25V, 0805, X5R, 10% 4 2 C8,C9 10uF Ceramic,25V,1210,X5R,10% 5 1 C10 330uF SMD Elecrolytic, 25V,F-size,20% 6 5 C11,C15C18,C20,C22 7 1 C12 1.0uF Ceramic,25V,0603,X5R,10% 8 2 C13,C14 330uF SP-Cap,Dcase,4V,20% 9 2 C16,C17 10uF Ceramic,6.3V,1206,X5R,20% 10 1 C19 22000pF Ceramic,50V,0603,X7R,10% 11 4 C21,C23,C24,C25 12 1 D1 BAT54S Dual Diode,40V,BAT54S,SOT-23 13 1 D2 BAS316 Phillips 30V , 0.25A 14 1 L1 500nH 15 1 Q1 IRF6720S2TRPBF IRF6720 30V 16 1 Q2 IRF6729MTRPBF IRF6729 30V 17 1 R4 48.7K Thick-film,0603,1/10W,1% 18 1 R5 180K Thick-film,0603,1/10W,1% 19 1 R7 4.75k Thick-film,0603,1/10 W,1% 20 3 R9,R11,R16 21 1 R12 22 3 R13,R17,R18 23 1 24 N/S N/S N/S No Stuff No Stuff SMT-Inductor,0.8mOhms,Toko FDUE1245-R50M No Stuff 1.96K Thick-film,0603,1/10W,1% 10K Thick-film,0603,1/10W,1% R14 0 Thick-film,0603,1/10 W,5% 1 R15 1.65K Thick-film,0603,1/10W,1% 25 1 SW1 Switch, 2-Pos. Switch, DIP, 2-Pos., SPDT 31 1 U1 IR3710MMPbF IR3710M, Controller,PQFN,3x3mm 7 IRDC3710-DF TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 24A, , 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-DF TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V,Vo=1.1V, Io=0- 24A, 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 1.0A 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-DF TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 24A, , Room Temperature, No Air Flow 95 6 90 5 4 80 3 75 2 Power Los(w) Efficiency(%) 85 70 1 65 60 0 0 4 8 12 16 20 24 Iout(A) Eff 12V Input CP ON Power Loss 12V Input with CP Eff 12V Input No CP Power Loss 12V input No CP Figure 15: Typical Efficiency and Power Loss at Vin-12V 5 95 90 4 3 80 75 2 Power Loss(W) Efficiency(%) 85 70 1 65 60 0 0 4 8 12 16 20 24 Iout(A) 19V Input CP ON Power Loss 8V Input 8V Input CP ON Power Loss 19V Input Figure 16: Typical Efficiency and Power Loss at Vin=8V and 19V 10 IRDC3710-DF TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 24A, , Room Temperature, No Air Flow 1.105 1.103 1.101 Vout(V) 1.099 1.097 1.095 1.093 1.091 1.089 12V input 1.087 8V Input 19V Input 16 20 1.085 0 4 8 12 24 Iout(A) Figure 17: Typical Output Voltage Regulation Q1: 73.0°C, Q2:77.3°C, Inductor: 51.6°C, PCB: 52.8°C Figure 18:Thermal Image @12Vin, 24A, With CP On 11 IRDC3710-DF TYPICAL OPERATING WAVEFORMS Vin=12V, PVcc=5.0V, Vcc=3.3V, Vo=1.1V, Io=0- 24A, , Room Temperature, No Air Flow Q1: 77.7°C, Q2:82.4°C,Inductor: 53.3°C, PCB: 54.1°C Figure 19: Thermal Image @19Vin, 24A, With CP On Q1:81°C,Q2:83.6°C, Inductor: 53.1°C, PCB: 53.6°C Figure 20: Thermal Image @12Vin, 24A, With CP Off 12 IRDC3710-DF PACKAGE INFORMATION 13