Application Note 1551 ISL9440AEVAL1Z: Triple PWM Step-Down Synchronous Buck Controller and One LDO ISL9440AEVAL1Z Evaluation Board The ISL9440AEVAL1Z evaluation board features the ISL9440A. The ISL9440A is a a quad-output controller that integrates three PWM synchronous buck controllers and one low-dropout linear regulator controller. The ISL9440A 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 600kHz minimizes inductor size 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 ISL9440AEVAL1Z is easy to set up to evaluate the performance of the ISL9440A. Please refer to the “Electrical Specifications” table on page 2 for typical performance summary. FIGURE 1. ISL9440AEVAL1Z EVALUATION BOARD March 5, 2010 AN1551.0 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 1551 Electrical Specifications Recommended operation conditions unless otherwise noted. Refer to the “Schematic” on page 7 and “Typical Evaluation Board Performance Curves” on page 4. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 6.0 12 16 V VOUT1 0.97 1.00 1.03 V VOUT2 3.25 3.32 3.4 V VOUT3 4.85 5.0 5.15 V VOUT4 2.43 2.50 2.57 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 R7 = 0Ω, R4 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 19.4 mVP-P 36.6 mVP-P 32.2 mVP-P Quick Test Guide The Evaluation Board Kit contains the following materials: • The ISL9440AEVAL1Z • The ISL9440, ISL9440A, ISL9441 datasheet FN6383 • This Evaluation Board Kit document (AN1551) 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 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, refer to Figure 3 for proper test set-up. • Digital Multimeters (DMMs) • 100MHz Quad-Trace Oscilloscope • Signal Generator (for load transient tests) 2 AN1551.0 March 5, 2010 Application Note 1551 FIGURE 2. PROPER TEST SET-UP OUTPUT CAP OUTPUT OUTPUT CAP CAP OR MOSFET OR MOSFET FIGURE 3. PROPER PROBE SET-UP TO MEASURE OUTPUT RIPPLE AND PHASE NODE RINGING Load Transient Circuit Set-Up 1. Select a SOIC8 N-Channel MOSFET with VDS breakdown >20V. 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. 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. 3 AN1551.0 March 5, 2010 Application Note 1551 . OPT. LOAD TRAN. OPT R27 OPT M8 R26 OPT FIGURE 4. LOAD TRANSIENT CIRCUIT FOR PWM1 Typical Evaluation Board Performance Curves 100 85 VIN = 9V 95 80 90 EFFICIENCY (%) EFFICIENCY (%) 90 VIN = 12V 75 VIN = 16V 70 65 60 55 70 65 55 3 4 5 LOAD CURRENT (A) 7 6 50 8 0 1 2 4 5 3 LOAD CURRENT (A) 6 FIGURE 5. PWM1 EFFICIENCY vs LOAD (VO = 1.0V) FIGURE 6. PWM2 EFFICIENCY vs LOAD (VO = 3.3V) 100 1.010 95 VIN = 9V 85 VIN = 12V OUTPUT VOLTAGE 90 EFFICIENCY (%) 75 45 2 VIN = 16V VIN = 12V 80 60 1 VIN = 9V 85 50 40 0 VIN = 12V, Unless Otherwise Noted. VIN = 16V 80 75 70 65 60 7 1.005 VIN = 16V 1.000 VIN = 12V 0.995 VIN = 9V 55 50 0 1 2 3 4 LOAD CURRENT (A) FIGURE 7. PWM3 EFFICIENCY vs LOAD (VO = 5.0V) 4 5 0.990 0 2 4 6 8 LOAD CURRENT (A) FIGURE 8. PWM1 REGULATION CURVES (PWM2, PWM3 DISABLED) AN1551.0 March 5, 2010 Application Note 1551 Typical Evaluation Board Performance Curves 5.000 3.310 4.995 OUTPUT VOLTAGE OUTPUT VOLTAGE VIN = 16V 3.305 VIN = 12V 3.300 VIN = 9V 3.295 3.290 VIN = 12V, Unless Otherwise Noted. (Continued) 4.990 4.985 VIN = 12V 4.980 VIN = 16V 4.975 0 2 4 6 8 4.970 VIN = 9V 0 1 2 3 4 5 LOAD CURRENT LOAD CURRENT FIGURE 9. PWM2 REGULATION CURVES (PWM1, PWM3 DISABLED) FIGURE 10. PWM3 REGULATION CURVES (PWM1, PWM2 DISABLED) VOUT1, 500mV/DIV VOUT2, 2V/DIV VOUT1(AC), 10mV/DIV VOUT4, 2V/DIV VOUT3, 2V/DIV 200µs/DIV FIGURE 11. SOFT-START CURVES VOUT2(AC), 20mV/DIV VOUT3(AC), 20mV/DIV 500ns/DIV FIGURE 13. PWM2 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) 5 FIGURE 12. PWM1 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) 500ns/DIV FIGURE 14. PWM3 OUTPUT RIPPLE UNDER MAX LOAD (VIN = 12V, IO1 = IO2 = 6A, IO3 = 4A, FULL BANDWIDTH) AN1551.0 March 5, 2010 Application Note 1551 Typical Evaluation Board Performance Curves VIN = 12V, Unless Otherwise Noted. (Continued) ISTEP, 2A/DIV ISTEP, 2A/DIV VOUT1(AC), 50mV/DIV VOUT2(AC, 100mV/DIV) 50µs/DIV 50µs/DIV FIGURE 15. PWM1 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1.5A TO 4.5A) FIGURE 16. PWM2 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1.5A TO 4.5A) ISTEP, 1A/DIV VOUT3(AC), 100mV/DIV 50µs/DIV FIGURE 17. PWM3 LOAD TRANSIENT RESPONSE (LOAD STEP FROM 1A TO 3A) 6 AN1551.0 March 5, 2010 Schematic 7 Application Note 1551 AN1551.0 March 5, 2010 Application Note 1551 TABLE 2. BILL OF MATERIALS ESSENTIAL COMPONENTS ITEM QTY PART REFERENCE VALUE DESCRIPTION PART # MANUFACTURER 1 3 CB1, CB2, CB3 0.1µF CAP Ceramic X5R, 16V, SMD, 0603 Generic 2 1 CFIN1 0.47µF CAP Ceramic X5R, 25V, SMD, 0603 Generic 3 2 CIN1, CIN2 100µF Alum. Elec. CAP 35V 4 4 CIN3, CIN4, CIN5, CIN6 10µF CAP Ceramic X5R, 35V, SMD, 1206 Generic 5 3 CL1, CL2, CL3 820pF CAP Ceramic X5R, 50V, SMD, 0603 Generic 6 1 CO11 330µF POSCAP, 2.5V, SMD, D2E 7 5 CO13, CO14, CO24, CO33, CO41 10µF 8 2 CO21, CO31 220µF POSCAP, 6.3V, SMD, D2E 6TPE220MI Sanyo 9 1 CO42 100µF POSCAP, 4.0V, SMD, B 4TPE100MZB Sanyo 10 1 CVCC1 4.7µF CAP Ceramic X5R, 6.3V, SMD, 0805 Generic 11 1 Cff1 2.2nF CAP Ceramic, SMD, 0603 Generic 12 2 Cff2, Cff3 100pF CAP Ceramic, SMD, 0603 Generic 13 1 Cp1 3.3nF CAP Ceramic, SMD, 0603 Generic 14 1 C1 0.22µF CAP Ceramic X5R, 16V, SMD, 0603 Generic 15 1 C2 22pF CAP Ceramic X5R, 16V, SMD, 0603 Generic 16 1 C3 1µF CAP Ceramic X5R, 16V, SMD, 0603 Generic 17 1 L1 1.0µH SHIELDED INDUCTOR #919AS-1R0N TOKO 18 1 L2 1.8µH SHIELDED INDUCTOR #919AS-1R8N TOKO 19 1 L3 2.8µH SHIELDED INDUCTOR #919AS-2R8M TOKO 20 3 M1, M2, M3 Dual N MOSFET, 30V, SOIC8 IRF7907 International Rectifier 21 1 M4 P MOSFET, SOIC8 Si4423DY Vishay 22 1 RFIN1 10Ω RESISTOR, SMD, 0805, 10% Generic 23 3 RL1, RL2, RL3 1.2Ω RESISTOR, SMD, 0603, 10% Generic 24 2 RPG1, ROC1 100kΩ RESISTOR, SMD, 0603, 1% Generic 25 2 ROC2, ROC3 200kΩ RESISTOR, SMD, 0603, 1% Generic 26 1 RSEN1 1.82kΩ RESISTOR, SMD, 0603, 1% Generic 27 2 RSEN2, RSEN3 3.32kΩ RESISTOR, SMD, 0603, 1% Generic 28 1 R1 25.5kΩ RESISTOR, SMD, 0603, 1% Generic 29 1 R2 102kΩ RESISTOR, SMD, 0603, 1% Generic 30 1 R3 105kΩ RESISTOR, SMD, 0603, 1% Generic 31 1 R5 51Ω RESISTOR, SMD, 0603, 1% Generic 32 1 R6 20kΩ RESISTOR, SMD, 0603, 1% Generic 33 1 R8 107kΩ RESISTOR, SMD, 0603, 1% Generic 34 1 R9 21.5kΩ RESISTOR, SMD, 0603, 1% Generic 35 1 R10 10kΩ RESISTOR, SMD, 0603, 1% Generic 8 EEU-FC1V101 2R5TPE330M7 CAP Ceramic X5R, 6.3V, SMD, 0805 Panasonic Sanyo Generic AN1551.0 March 5, 2010 Application Note 1551 TABLE 2. BILL OF MATERIALS (Continued) ESSENTIAL COMPONENTS ITEM QTY PART REFERENCE VALUE 34kΩ 36 1 R11 37 1 U1 DESCRIPTION PART # RESISTOR, SMD, 0603, 1% QUAD OUTPUT CONTROLLER MANUFACTURER Generic ISL9440AIRZ Intersil OPTIONAL COMPONENTS OR RESISTOR JUMPERS ITEM QTY REFERENCE VALUE DESCRIPTION RESISTOR Jumpers, SMD, 0603, 10% 38 10 R7, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21 0 39 3 CO12, CO22, CO32 DNP 40 2 CO23, CO34 DNP 41 2 Cp2, Cp3 DNP 42 1 M5 DNP P MOSFET TO-252 43 3 M6, M7, M8 DNP N MOSFET 44 4 R4, 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 AN1551.0 March 5, 2010 ISL9440CEVAL1Z PCB Layout 10 Application Note 1551 FIGURE 18. TOP LAYER FIGURE 19. SECOND LAYER (SOLID GROUND) AN1551.0 March 5, 2010 ISL9440CEVAL1Z PCB Layout (Continued) 11 Application Note 1551 FIGURE 20. THIRD LAYER FIGURE 21. BOTTOM LAYER (MIRRORED) AN1551.0 March 5, 2010