Application Note 1550 ISL9440EVAL2Z: Triple PWM Step-Down Synchronous Buck Controller and One LDO ISL9440EVAL2Z Evaluation Board The ISL9440EVAL2Z evaluation board features the ISL9440. The ISL9440 is a quad-output controller that integrates three PWM synchronous buck controllers and one low-dropout linear regulator controller. The ISL9440 offers internal soft-start, independent enable functions and integrates UV/OV/OC/OT protection. Its current mode control architecture and internal compensation network keep peripheral component count minimal. Switching frequency of 300kHz minimizes losses while the strong gate drivers deliver up to 12A to each PWM channel. Table 1 shows the difference in terms of ISL944xx family features. TABLE 1. FEATURES OF ISL944xx FAMILY EARLY WARNING SWITCHING FREQUENCY (kHz) SOFT-STARTING TIME (ms) ISL9440 Yes 300 1.7 ISL9440A Yes 600 1.7 ISL9441 No 300 1.7 ISL9440B Yes 300 Programmable ISL9440C Yes 600 Programmable PART NUMBER The ISL9440EVAL2Z is easy to set up to evaluate the performance of the ISL9440. Please refer to the “Electrical Specifications” table on page 2 for typical performance summary. FIGURE 1. ISL9440EVAL2Z EVALUATION BOARD March 8, 2010 AN1550.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2010. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1550 Electrical Specifications Recommended operation conditions unless otherwise noted. Refer to the “Schematic” on page 7and “Typical Evaluation Board Performance Curves” on page 4. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 6.0 12 16 V VOUT1 1.45 1.50 1.54 V VOUT2 2.43 2.50 2.57 V VOUT3 4.85 5.0 5.15 V VOUT4 3.20 3.30 2.39 V 6 7 A 6 7 A 4 5 A 0.8 1.0 A VIN All outputs are in regulation VIN = 12V, TA = +25°C, No forced airflow, All three PWM outputs are fully loaded PWM1 Rated Current PWM2 Rated Current PWM3 Rated Current LDO Rated Current R4 = 0Ω, R7 is not populated VOUT1 Peak-to-Peak Ripple VIN = 12V, All three PWM outputs are fully loaded, Oscilloscope is with full bandwidth VOUT2 Peak-to-Peak Ripple VOUT3 Peak-to-Peak Ripple What’s Inside 29.4 mVP-P 15.7 mVP-P 31.4 mVP-P Quick Test Guide The evaluation board kit contains the following materials: • The ISL9440EVAL2Z • The ISL9440, ISL9440A, ISL9441 Datasheet FN6383 • This Evaluation Board Kit document (AN1550) Recommended Equipment The following materials are recommended to perform testing: • 0V to 20V Power Supply with at least 10A source current capability • Three electronic loads capable of sinking current up to 7A • Digital Multimeters (DMMs) 1. Ensure that the circuit is correctly connected to the supply and electronic loads prior to applying any power. Please refer to Figure 2 for proper set-up. 2. Connect Jumpers J3, J4 and J5 in the ENx positions. 3. Turn on the power supply. 4. Adjust input voltage VIN within the specified range and observe output voltage. The output voltage variation should be within 3%. 5. Adjust load current within the specified range and observe output voltage. The output voltage variation should be within 3%. 6. Use oscilloscope to observe output voltage ripple and phase node ringing. For accurate measurement, please follow setup shown in Figure 3. • 100MHz Quad-Trace Oscilloscope • Signal Generator (for load transient tests) 2 AN1550.0 March 8, 2010 Application Note 1550 FIGURE 2. PROPER TEST SET-UP Load Transient Circuit Set-up 1. Select a SOIC8 N-Channel MOSFET with VDS breakdown >20V. OUTPUT CAP OUTPUT OUTPUT CAP CAP OR MOSFET OR MOSFET FIGURE 3. PROPER PROBE SET-UP TO MEASURE OUTPUT RIPPLE AND PHASE NODE RINGING 2. Install the load transient circuit as indicated on the schematic. Refer to Figure 4 for detail. 3. R27, R22 and R25 are 10kΩ resistors for discharging the MOSFET gates. 4. R26, R23 and R24 are current sensing resistors to monitor the load step. For accurate measurement, please use 5% tolerance sensing resistor or better. To alleviate thermal stress, use 0.1Ω or smaller resistance. The resistance of the sensing resistors sets the current scale on the oscilloscope. 5. Apply pulse square waveform across R27, R22 or R25. The duty cycle of the pulse waveform should be small (<5%) to limit thermal stress on current sensing resistor and the MOSFETs (M8, M6 or M7). 6. The amplitude of the clock sets the current step amplitude. Adjust the clock amplitude and slew rate to set the current step and slew rate. 7. Monitor overshoot and undershoot at corresponding output. 3 AN1550.0 March 8, 2010 Application Note 1550 . OPT. LOAD TRAN. OPT R27 OPT M8 R26 OPT FIGURE 4. LOAD TRANSIENT CIRCUIT FOR PWM1 Typical Evaluation Board Performance Curves 95 100 VIN = 9V 90 95 VIN = 12V 80 EFFICIENCY (%) EFFICIENCY (%) 85 VIN = 16V 75 70 65 60 55 80 70 65 55 2 4 3 5 6 7 50 8 0 1 2 LOAD CURRENT (A) 95 4 5 6 7 FIGURE 6. PWM2 EFFICIENCY vs LOAD (VO = 2.5V) 1.510 VIN = 9V 90 VIN = 12V 85 1.505 VIN = 16V VOUT1 (V) EFFICIENCY (%) 3 LOAD CURRENT (A) FIGURE 5. PWM1 EFFICIENCY vs LOAD (VO = 1.5V) 100 VIN = 16V 75 45 1 VIN = 12V 85 60 0 VIN = 9V 90 50 40 VIN = 12V, Unless Otherwise Noted. 80 75 70 65 1.500 1.495 60 55 50 0 1 2 3 4 LOAD CURRENT (A) FIGURE 7. PWM3 EFFICIENCY vs LOAD (VO = 5.0V) 4 5 1.490 5 7 9 11 13 15 17 19 INPUT VOLTAGE (V) FIGURE 8. PWM1 LINE REGULATION (IO1 = IO2 = 6A, IO3 = 4A) AN1550.0 March 8, 2010 Application Note 1550 2.510 5.025 2.505 5.000 VOUT2 (V) VOUT2 (V) Typical Evaluation Board Performance Curves 2.500 VIN = 12V, Unless Otherwise Noted. (Continued) 4.975 4.950 2.495 2.490 5 4.925 7 9 11 13 15 17 19 5 7 9 13 15 17 19 FIGURE 10. PWM3 LINE REGULATION (IO1 = IO2 = 6A, IO3 = 4A) 1.510 2.510 1.505 2.505 VOUT2 (V) VOUT1 (V) FIGURE 9. PWM2 LINE REGULATION (IO1 = IO2 = 6A, IO3 = 4A) 1.500 2.500 2.495 1.495 1.490 11 INPUT VOLTAGE (V) INPUT VOLTAGE (V) 0 1 2 3 4 5 6 7 8 2.490 0 1 2 3 4 5 6 7 8 LOAD CURRENT (A) LOAD CURRENT (A) FIGURE 11. PWM1 LOAD REGULATION (VIN = 12V, IO2 = 6A, IO3 = 4A) FIGURE 12. PWM2 LOAD REGULATION (VIN = 12V, IO1 = 6A, IO3 = 4A) 5.025 VOUT1(AC), 10mV/DIV VOUT2 (V) 5.000 4.975 4.950 4.925 0 1 2 3 4 5 1µs/DIV LOAD CURRENT (A) FIGURE 13. PWM3 LOAD REGULATION (VIN = 12V, IO1 = 6A, IO2 = 3A) 5 FIGURE 14. PWM1 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) AT VO = 1.5V AN1550.0 March 8, 2010 Application Note 1550 Typical Evaluation Board Performance Curves VOUT2(AC), 10mV/DIV VIN = 12V, Unless Otherwise Noted. (Continued) VOUT3(AC), 20mV/DIV 1µs/DIV FIGURE 15. PWM2 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) AT VO = 2.5V VOUT1(AC), 50mV/DIV ISTEP, 2A/DIV 1µs/DIV FIGURE 16. PWM3 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) AT VO = 5V VOUT2(AC, 50mV/DIV) ISTEP, 2A/DIV 50µs/DIV 50µs/DIV FIGURE 17. PWM1 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1.5A TO 4.5A) AT VO = 1.5V FIGURE 18. PWM2 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1.5A TO 4.5A) AT VO = 2.5V VOUT1, 1V/DIV VOUT3(AC), 20mV/DIV VOUT2, 1V/DIV VOUT3, 2V/DIV VOUT4, 1V/DIV ISTEP, 1A/DIV 50µs/DIV FIGURE 19. PWM3 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1A TO 3A) AT VO = 5V 6 500µs/DIV FIGURE 20. SOFT-START WAVEFORMS AN1550.0 March 8, 2010 Schematic 7 Application Note 1550 AN1550.0 March 8, 2010 Application Note 1550 TABLE 2. BILL OF MATERIALS ESSENTIAL COMPONENTS ITEM QTY PART REFERENCE VALUE DESCRIPTION PART # MANUFACTURER 1 3 CB1, CB2, CB3 0.1µF CAP Ceramic X7R, 16V, SMD, 0603 Generic 2 1 CFIN1 0.47µF CAP Ceramic Y5V, 50V, SMD, 0603 Generic 3 2 CIN1, CIN2 100µF Alum. Elec. CAP 35V 4 4 CIN3, CIN4, CIN5, CIN6 10µF CAP Ceramic X5R, 35V, SMD, 1210 Generic 5 3 CL1, CL2, CL3 820pF CAP Ceramic X5R, 50V, SMD, 0603 Generic 6 2 CO11, CO12 330µF POSCAP, 2.5V, SMD, D2E 7 5 CO13, CO14, CO24, CO33, CO41 10µF 8 2 CO21, CO22 330µF POSCAP, 6.3V, SMD, D3L 6TPF330M9L Sanyo 9 1 CO31 220uF POSCAP, 6.3V, SMD 6TPE220MI Sanyo 10 1 CO42 100µF POSCAP, 4.0V, SMD, B 4TPE100MZB Sanyo 11 1 CVCC1 4.7µF CAP Ceramic X5R, 6.3V, SMD, 0805 Generic 12 1 Cff1 220pF CAP Ceramic X7R, 50V, SMD, 0603 Generic 13 1 Cff2 1200pF CAP Ceramic X7R, 50V, SMD, 0603 Generic 14 1 Cff3 270pF CAP Ceramic X7R, 50V, SMD, 0603 15 1 C1 0.22µF CAP Ceramic X5R, 16V, SMD, 0603 Generic 16 1 C2 22pF CAP Ceramic X5R, 16V, SMD, 0603 Generic 17 1 C3 1µF CAP Ceramic X5R, 16V, SMD, 0603 Generic 18 1 L1 2.0µH SHIELDED INDUCTOR #744325550 Wurth 19 1 L2 2.8µH SHIELDED INDUCTOR #7443552280 Wurth 20 1 L3 5.5µH SHIELDED INDUCTOR #744325550 Wurth 21 3 M1, M2, M3 Dual N MOSFET, 30V, SOIC8 IRF7907 International Rectifier 22 1 M4 P MOSFET, SOIC8 Si4423DY Vishay 23 1 RFIN1 10Ω RESISTOR, SMD, 0805, 10% Generic 24 3 RL1, RL2, RL3 1.2Ω RESISTOR, SMD, 0603, 10% Generic 25 1 RPG1 100kΩ RESISTOR, SMD, 0603, 1% Generic 26 1 ROC1, ROC3 120kΩ RESISTOR, SMD, 0603, 1% Generic 27 1 ROC2 160kΩ RESISTOR, SMD, 0603, 1% Generic 28 2 RSEN1, RSEN3 1.5kΩ RESISTOR, SMD, 0603, 1% Generic 29 1 RSEN2 2kΩ RESISTOR, SMD, 0603, 1% Generic 30 1 R1 9.31kΩ RESISTOR, SMD, 0603, 1% Generic 31 1 R2 10.7kΩ RESISTOR, SMD, 0603, 1% Generic 32 1 R3 105kΩ RESISTOR, SMD, 0603, 1% Generic 33 1 R5 51Ω RESISTOR, SMD, 0603, 1% Generic 34 1 R6 20kΩ RESISTOR, SMD, 0603, 1% Generic 35 1 R8 24.3kΩ RESISTOR, SMD, 0603, 1% Generic 36 1 R9 15kΩ RESISTOR, SMD, 0603, 1% Generic 37 1 R10 4.75kΩ RESISTOR, SMD, 0603, 1% Generic 8 EEU-FC1V101 2R5TPE330M7 CAP Ceramic X5R, 6.3V, SMD, 0805 Panasonic Sanyo Generic AN1550.0 March 8, 2010 Application Note 1550 TABLE 2. BILL OF MATERIALS (Continued) ESSENTIAL COMPONENTS ITEM QTY PART REFERENCE VALUE 11.5kΩ 38 1 R11 39 1 U1 DESCRIPTION PART # RESISTOR, SMD, 0603, 1% QUAD OUTPUT CONTROLLER MANUFACTURER Generic ISL9440IRZ Intersil OPTIONAL COMPONENTS OR RESISTOR JUMPERS ITEM QTY REFERENCE VALUE DESCRIPTION RESISTOR Jumpers, SMD, 0603, 10% 40 10 R4, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21 0 41 2 CO23, CO32 CO34 DNP 42 3 Cp1, Cp2, Cp3 DNP 42 1 M5 DNP P MOSFET TO-252 43 3 M6, M7, M8 DNP N MOSFET 44 4 R7, R22, R25, R27 DNP RESISTOR, SMD, 0603 45 3 R23, R24, R26 DNP RESISTOR, SMD, 1206 PART # MANUFACTURER Generic EVALUATION BOARD HARDWARE ITEM QTY REFERENCE 46 3 J3, J4, J5 47 11 TP1, TP2, TP3, TP4, TP6, TP17, TP11, TP12, TP13, TP14, TP7 48 9 TP8, TP10, TP16, TP19, TP21, TP9, TP5, TP15, TP20 VALUE GND DESCRIPTION PART # MANUFACTURER 3 Head Jumper 68000-236HLF Generic TEST POINT 5007 Keystone TURRET 1514-2 Keystone 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 AN1550.0 March 8, 2010 ISL9440EVAL2Z PCB Layout 10 Application Note 1550 FIGURE 21. TOP LAYER FIGURE 22. SECOND LAYER (SOLID GROUND) AN1550.0 March 8, 2010 ISL9440EVAL2Z PCB Layout (Continued) 11 Application Note 1550 FIGURE 23. THIRD LAYER FIGURE 24. BOTTOM LAYER AN1550.0 March 8, 2010