Application Note 1713 ISL8126EVAL1Z Evaluation Board User Guide Hardware Description Recommended Equipment The ISL8126 integrates two voltage-mode synchronous buck PWM controllers. It can be used either for dual independent outputs or a 2-phase single-output regulator. • 0V to 22V power supply with at least 20A source current capability The ISL8126EVAL1Z evaluation board is used for performance demo of the 2-phase single-output application. This application note introduces the setup procedure and performance of the ISL8126EVAL1Z evaluation board. • Digital multimeters (DMMs) TABLE 1. ELECTRICAL SPECIFICATIONS PARAMETER VIN VOUT MIN TYP MAX UNITS 10 12 16 V 1.18 1.2 1.22 V Rated Current 50 A Switching Frequency 350 kHz 16 mVP-P VOUT Peak-to-Peak Ripple • Two electronic loads capable of sinking current up to 30A • 100MHz quad-trace oscilloscope. Quick Start 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. 2. Adjust the input supply to be 12V. Turn on the input power supply. 3. Verify the output voltage is 1.2V. If PGOOD is set high, the LED2 will be green. If PGOOD is set low, the LED2 will be red. TP4 is the test post to monitor PGOOD. FIGURE 1. ISL8126EVAL1Z EVALUATION BOARD December 23, 2011 AN1713.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2011. All Rights Reserved. Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. Application Note 1713 Circuits Description J1 and J2 are the input power terminals. J3 and J4 are output lugs for load connections. The input capacitors are used to handle the input current ripples. Two upper and two lower Renesas LFPAK MOSFETs are used for each phase. 320nH PULSE surface mount inductors are used for each phase. Under the 350kHz setup, the inductor current peak-to-peak ripple is 10A at 12V input and 1.2V output. Six SANYO POSCAP 2R5TPF470M7L are used as output E-capacitors. TP8 and TP10 are remote sense posts. These pins can be used to monitor and evaluate the system voltage regulations. If the user wants to use these test posts for remote sense, the R12 and R14 need to be changed to higher values, such as 10Ω. Also, the related voltage sense divider needs to be increased to a higher resistance, such as 1k. TP12 is a test socket to hold the scope probe to check the output waveforms. JP4 (not populated) is used to disable the part. JP5 is for connection of inputs of clock signal for the part to be synchronized with. Refer to equations on page 25 of the ISL8126 datasheet (FN7892) to program the UVLO falling threshold and hysteresis. The EN/FF1 and EN/FF2 pins are connected together in ISL8126EVAL1Z. The equations are re-stated here in Equations 1 and 2, where RUP and RDOWN are the upper and lower resistors of the voltage divider at EN/FF pin, VHYS is the desired UVLO hysteresis and VFTH is the desired UVLO falling threshold. V HYS R UP = --------------------2 ⋅ I HYS (EQ. 1) where IHYS = 30µA R UP ⋅ V ENREF R DOWN = -------------------------------------------- where VENREF = 0.8V V FTH – V ENREF (EQ. 2) NOTE: The ISL8126 EN/FF pin is a triple function pin and the voltages applied to the EN/FF pins are also fed to adjust the amplitude of each channel’s individual sawtooth. Evaluating the Other Output Voltage The ISL8126EVAL1Z kit output is preset to 1.2V/50A. VOUT can also be adjusted between 0.6V to 2V by changing the value of R11 and R8 for VOUT, as given by Equation 3. R 11 = [ ( V OUT ⁄ V REF ) – 1 ] ⋅ R 8 where VREF = 0.6V (EQ. 3) JP3 is the CLKOUT pin output of ISL8126. Programming the Input Voltage UVLO and its Hysteresis By programming the voltage divider at the EN/FF pin connected to the input rail, the input UVLO and its hysteresis can be programmed. The ISL8126EVAL1Z has R19 16.5k and R1 1.82k; the IC will be disabled when input voltage drops below 8V and will restart until VIN recovers to be above 9V. OUTPUT CAP OUTPUT OUTPUT CAP CAP OR MOSFET OR MOSFET FIGURE 3. PROPER PROBE SET-UP TO MEASURE OUTPUT RIPPLE AND PHASE NODE RINGING FIGURE 2. PROPER TEST SET-UP 2 AN1713.0 December 23, 2011 Application Note 1713 Load Transient Circuit Set-up 1. Install the load transient circuit as indicated in the schematic. Refer to Figure 4 for detail. 2. R50, R51 are resistors for charging/discharging the MOSFET gates. Their resistance determines the slew-rate of the load step. The slew-rate in this particular setup is 3A/µs. 3. When Q10 is fully turned on, its rDS(ON) in series with R48 sets the current step amplitude. For accurate measurement, please use 5% tolerance sensing resistor or better. R48 is also the current sensing resistor to monitor the load step. The resistance of the sensing resistor sets the current scale on the oscilloscope. The amplitude of the current step in this particular setup is 48A. 4. Apply 5V bias voltage between TP18 and TP17 (GND). Apply 3V pulse square waveform between TP15 an TP16 (GND). The duty cycle of the pulse waveform should be small (<5%) to limit thermal stress on R48 and Q10. 5. Monitor overshoot and undershoot at corresponding output. . FIGURE 4. LOAD TRANSIENT CIRCUIT Typical Evaluation Board Performance Curves 95 VIN = 12V, Unless Otherwise Noted. VIN EFFICIENCY (%) 90 VOUT 85 EN/FF 80 75 70 PH 65 60 0 10 20 30 40 50 LOAD CURRENT (A) FIGURE 5. EFFICIENCY vs LOAD (VO = 1.2V) 3 FIGURE 6. POWER-UP UNDER 50A LOAD AN1713.0 December 23, 2011 Application Note 1713 Typical Evaluation Board Performance Curves 1.1950 VIN = 12V, Unless Otherwise Noted. (Continued) 1.210 1.206 1.1945 OUTPUT VOLTAGE (V) OUTPUT VOLTAGE (V) 1.208 1.1940 1.1935 1.204 1.202 1.200 1.198 1.196 1.194 1.192 1.1930 10 12 14 16 18 20 22 24 1.190 0 10 20 INPUT VOLTAGE (V) FIGURE 7. LINE REGULATION 30 40 50 LOAD CURRENT (A) FIGURE 8. LOAD REGULATION VOUT VOUT FIGURE 9. OUTPUT RIPPLE AT 0A LOAD FIGURE 10. OUTPUT RIPPLE AT 50A LOAD VOUT VOUT 3A/µs SLEW RATE 3A/µs SLEW RATE 7 FIGURE 11. LOAD TRANSIENT (0A TO 48A STEP) 4 FIGURE 12. LOAD TRANSIENT (48A TO 0A STEP) AN1713.0 December 23, 2011 Schematic TP3 PVIN VCC COMP COMP2 9 10 PHASE1 ISET 5 1 2 3 4 7 R51 DNP 6 5 R50 BAT54S/SOT DNP TP18 NC_ NC OUTA INA V+ GND OUTB INB 1 2 3 4 ISL89410 R48 DNP C49 TP16 TP12 TRAN2 TP10 VSEN_REM1+ C50 1µF TP17 DNP TP8 VSEN_REM1- VCC R11 200 R8 200 R30 4.99k 1 3 R31 4.99k VMON1 FB1 10nF LED1 TP4 PGOOD DNP R12 0 R14 0 1 COMP PGOOD R9 0 1nF GREEN RED Q9 2N7002LT1 1 R10 0 C29 DNP VIN R1 1.82k C1 1nF C3 18nF 316 R17 274 C28 DNP C30 1µF JP4 R18 5.23k R19 16.5k C4 R4 C17 0.22µF VOUT TP15 C11 2 R5 2k C23 2.2µF U2 8 D1 3 I FB C27 Q10 DNP R20 0 R21 105k C2 330pF PVCC R28 2.74k 4 EN/FF1 R2 2.67k 32 VMON 31 VSEN1VSEN1- 30 VSEN1+ ISEN1B ISEN1A BOOT1 C16 0.22µF R6 Q3 2k RJK0328 COMP1 JP5 5 FSYNC 2 FB2 12 11 VMON2 13 VMON 14 ISEN2B VSEN2+ ISHARE VSEN1+ 29 4 Q4 RJK0328 EN/VFF1 LGATE1 R3 5.1 VOUT 6 EN/FF2 2 3 2 1 C36 JP3 7 CLKOUT 34 3 2 1 5 4 DNP PVCC ISEN1B 28 R13 DNP LGATE1 22 ISL8126IRZ ISEN1A 27 C47 100µF Q2 RJK0305 3 2 1 C42 100µF C10 0.1µF 1 PA1513.321 10µF PVCC 21 4 Q1 RJK0305 5 C8 0.1µF 2 C15 UGATE1 24 UGATE1 4 3 2 1 C7 0.1µF C48 100µF FSYNC PGND (PAD) 2.2µF EN/VFF2 LGATE2 BOOT1 25 2.2µF LGATE2 20 PHASE1 23 5 C5 0.1µF C44 100µF C24 0.1µF C9 0.1µF C26 0.1µF L1 320nH PHASE2 8 PGOOD 5 3 2 1 DNP R32 C21 5 DNP C22 C18 C6 0.1µF Q8 RJK0328 R7 Q7 RJK0328 2k PVIN JP2 470µF, 7mΩ CLKOUT/REFIN Application Note 1713 1 JP1 C35 DNP PGOOD UGATE2 33 2R5TPF470M7L R29 DNP 4 3 2 1 C45 2R5TPF470M7L C31 2R5TPF470M7L DNP C46 2R5TPF470M7L 0.22µF UGATE2 18 PHASE2 19 4 5 C33 C32 2R5TPF470M7L 4 BOOT2 3 2 1 C34 2R5TPF470M7L 1.2V @50A J3 GND(VOUT-) R15 DNP C14 BOOT2 17 4 Q5 RJK0305 Q6 RJK0305 1 PA1513.321 3 2 1 1 VOUT L2 320nH C12 5 5 5 2 15 ISEN2A C25 2.2µF ISEN2B 2.2µF VIN C20 ISEN2A R47 2 C19 2.2µF 16 VIN PVIN U1 J4 VOUT R34 274 R33 2.74k C40 10µF C43 C38 1000µF 10µF TP1 GND J2 GND C13 0.22µF C39 10µF VCC 12V C37 10µF VSEN2- PVIN C41 1000µF VCC 26 J1 VIN AN1713.0 December 23, 2011 Application Note 1713 TABLE 2. BILL OF MATERIALS ITEM QTY PART REFERENCE VALUE DESCRIPTION PART # MANUFACTURER ESSENTIAL COMPONENTS 1 2 C1, C11 2 1 C4 3 8 4 1nF CAP Ceramic Y7R, 50V, SMD, 0603 Generic 0.01µF CAP Ceramic Y5R, 50V, SMD, 0603 Generic C5, C6, C7, C8, C9, C10, C24, C26 0.1µF CAP Ceramic X7R, 50V, SMD, 0603 Generic 1 C3 18nF CAP Ceramic X7R, 50V, SMD, 0603 Generic 5 4 C12, C13, C16, C17 0.22µF CAP Ceramic X7R, 50V, SMD, 0603 Generic 6 1 C23 2.2µF CAP Ceramic X5R, 25V, SMD, 0603 Generic 7 1 C2 330pF CAP Ceramic X5R, 25V, SMD, 0603 Generic 8 2 C30, C50 1µF CAP Ceramic X5R, 25V, SMD, 0805 Generic 9 1 C15 10µF CAP Ceramic X5R, 50V, SMD, 0805 Generic 10 4 C37, C38, C39, C40 10µF CAP Ceramic X5R, 50V, SMD, 1210 Generic 11 4 C42, C44, C47, C4 100µF CAP Ceramic X5R, 6.3V, SMD, 1210 Generic 12 5 C19, C20, C21, C22, C25 2.2µF Generic 13 6 C31, C32, C33, C34, C45, C46 14 2 C41, C43 15 2 L1, L2 16 4 Q1, Q2, Q5, Q6 17 4 Q3, Q4, Q7, Q8 18 1 R3 5.1Ω RESISTOR, SMD, 0603, 10% Generic 19 5 R9, R10, R12, R14, R20 0Ω RESISTOR, SMD, 0603, 10% Generic 20 1 R21 105kΩ RESISTOR, SMD, 0603, 1% Generic 21 1 R19 16.5kΩ RESISTOR, SMD, 0603, 1% Generic 22 1 R1 1.82kΩ RESISTOR, SMD, 0603, 1% Generic 232 2 R8, R11 200Ω RESISTOR, SMD, 0603, 1% Generic 24 3 R5, R6, R7 2kΩ RESISTOR, SMD, 0603, 1% Generic 25 1 R2 2.67kΩ RESISTOR, SMD, 0603, 1% Generic 26 2 R17, R34 27 2 R28, R33 28 1 R4 29 1 R18 30 1 R47 31 1 U1 CAP Ceramic X7R, 50V, SMD, 1210 470µF POSCAP, 6.3V, SMD, D3L 2R5TPF470M7L Sanyo 1000µF Alum. Elec. CAP 35V ECA-1VM102B Panasonic 320nH Inductor PA1513.321NLT PULSE TRANSISTOR, N-CHANNEL, LFPAK, 30V RJK0305DPB RENESAS TECHNOLOGY TRANSISTOR, N-CHANNEL, LFPAK, 30V RJK0328DPB RENESAS TECHNOLOGY 274Ω RESISTOR, SMD, 0603, 1% Generic 2.74kΩ RESISTOR, SMD, 0603, 1% Generic 316Ω RESISTOR, SMD, 0603, 1% Generic 5.23kΩ RESISTOR, SMD, 0603, 1% Generic 2Ω RESISTOR, SMD, 1206, 1% IC-DUAL PHASE PWM CONTROLLER, 32P, QFN, 5x5, ROHS Generic ISL8126IRZ iNTERSIL OPTIONAL COMPONENTS OR RESISTOR JUMPERS 40 1 LED1 41 1 Q9 42 2 R30, R31 DNP LED, SMD, 3x2.5mm, 4P, RED/GREEN SSL-LXA3025IGC-TR LUMEX TRANSISTOR, SOT23, 60V 2N7002LT1G 4.99kΩ RESISTOR, SMD, 0603, 1% HIGH SPEED POWER MOSFET DRIVER ON SEMICONDUCTOR Generic 42 U2 43 C49 2.2µF CAP Ceramic X5R, 25V, SMD, 0603 Generic 44 R51 16kΩ RESISTOR, SMD, 0603, 1% Generic 6 ISL89410IPZ Intersil AN1713.0 December 23, 2011 Application Note 1713 TABLE 2. BILL OF MATERIALS (Continued) ITEM QTY PART REFERENCE VALUE DESCRIPTION PART # 7.06kΩ RESISTOR, SMD, 0603, 1% MANUFACTURER 45 R50 Generic 46 D1 DUAL SCHOTTKY DIODE, SOT-23 BAT54S Generic 47 Q10 TRANSISTOR, N-CHANNEL, LFPAK, 30V RJK0305DPB RENESAS TECHNOLOGY 48 R48 15mΩ RESISTOR, SMD, 2512, 1W Generic EVALUATION BOARD HARDWARE 46 1 J1 BINDING POST, RED 111-0702-001 JOHNSON COMPONENTS 47 1 J2 BINDING POST, BLACK 111-0703-001 JOHNSON COMPONENTS 48 1 J3, J4 CABLE TERMINAL, 6 -14AWG, LUG&SCREW KPA8CTP BERG/FCI 48 1 TP1, TP3, TP4, TP8, TP10, TP15, TP16, TP17, TP18 TEST POINT 5002 Keystone 7 AN1713.0 December 23, 2011 Application Note 1713 FIGURE 13. ISL8126EVAL1Z EVALUATION BOARD TOP LAYER FIGURE 14. ISL8126EVAL1Z EVALUATION BOARD 2 ND LAYER 8 AN1713.0 December 23, 2011 Application Note 1713 FIGURE 15. ISL8126EVAL1Z EVALUATION BOARD 3 RD LAYER FIGURE 16. ISL8126EVAL1Z EVALUATION BOARD BOTTOM LAYER Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 9 AN1713.0 December 23, 2011