Using the ISL6443EVAL2Z Evaluation Board ® Application Note March 7, 2008 AN1220.1 Using the Evaluation Board Power Good The ISL6443 is a high performance triple-output controller offering control and protection features for 2 synchronous buck PWMs and 1 linear regulator. When both PWMs are within ±10% of their set value and the linear regulator output is within 75% of its set value, the PGOOD signal will go high. The open drain PGOOD pin is pulled HIGH to VCC_5V on the board. The PGOOD circuitry monitors the FBx pin of each regulated output to determine if the outputs are in regulation. PGOOD can be monitored at post P8. The ISL6443 evaluation board highlights the operation of the IC in an embedded DC/DC converter application. Table 1 shows the available evaluation board. TABLE 1. EVALUATION BOARDS BOARD NAME ISL6443EVAL2Z IC ISL6443IRZ PACKAGE The overcurrent thresholds can be adjusted on the ISL6443 evaluation board. The current sense resistors, ISENSE, are set at 1.0kΩ. The overcurrent set resistor is 95.3kΩ. The overcurrent trip point can be adjusted by modifying ROCSET, R5 and R10: 28 Ld QFN Recommended Test Equipment • • • • Overcurrent Protection A 12V, 5A capable power supply An electronic load Four channel oscilloscope with probes Precision digital multimeters 7 ⋅ R CS R OCSET = ------------------------------------I OC ⋅ r DS ( ON ) Power and Load Connections Input Voltage To connect a +12V power supply to the evaluation board, connect the positive lead of the power supply to the VIN (P1) post and the ground lead of the supply to the GND (P2) post. (EQ. 3) ROCSET is the overcurrent set resistor, RCS is the current sense resistor, IOC is the desired overcurrent trip point, and rDS(ON) is the ON-resistance of the respective PWM’s lower MOSFET. Refer to the ISL6443 Data Sheet for more information on how to select the current sense and overcurrent select resistors. The input voltage to the linear controller is already taken from the 1.8V output of VOUT2. Output Adjustment Change the respective output voltage feedback resistors to modify the output voltage using Equation 1: R 1⎞ ⎛ V OUT1 = 0.8 ⋅ ⎜ 1 + -------⎟ R 2⎠ ⎝ R 3⎞ ⎛ V OUT2 = 0.8 ⋅ ⎜ 1 + -------⎟ R 4⎠ ⎝ R6 ⎞ ⎛ V OUT3 = 0.8 ⋅ ⎜ 1 + ----------⎟ R ⎝ 11⎠ (EQ. 1) Soft-Start and Shutdown The soft-start capacitors can be adjusted for sequencing of the output voltages, PWM start-up tracking, and/or to adjust the start-up current required to charge the output capacitors. 0.8V t SS ( PWM1 ) = C 2 ⋅ -----------5μA 0.8V t SS ( PWM2 ) = C 3 ⋅ -----------5μA (EQ. 2) To independently shutdown the PWMs, the SD1 or SD2 pin can be pulled to GND using the on-board posts, P9 and P10 respectively. 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. 2006. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL6443EVAL2Z Schematic P1 +12V +12V P2 GND C20 10uF GND C21 10uF R12 5.11k D1 BAT54HT1 C6 1uF D2 BAT54HT1 C1 4.7uF P11 PGOOD PGOOD Q2A Q1A 24 3 11 17 10 4 27 +3.3V, 2A 6.8uH, 27mOhm P4 GND GND R1 1K C31 10TPB220M 220uF, 10V, 40mOhm C5 0.1uF BOOT1 PGOOD SYNC SGND VIN VCC_5V BOOT2 L1 DO3316P-682ML R7 1k Q1B FDS6912A 23 22 21 25 20 15 14 UGATE1 PHASE1 ISEN1 LGATE1 PGND FB1 SGND 29 SGND L2 DO3316P-682ML 28 1 2 26 8 9 5 P5 +1.8V +1.8V, 2A 6.8uH, 27mOhm C30 10TPB220M 220uF, 10V, 40mOhm Q2B R3 1k P6 GND GND FDS6912A R4 806 R2 324 P10 SD1 SD2 P9 SD1 SD1 C4 10uF C2 0.01uF R5 95.3k R10 95.3k C3 0.01uF R8 100 Q3 IRLML6401 P7 +1.2V +1.2V, 0.2A R6 1k C32 10uF C33 DNP C34 DNP P8 GND GND R11 2k Application Note 1220 U1 ISL6443IRZ R9 1k UGATE2 PHASE2 ISEN2 LGATE2 FB2 SGND SD2 SD1 SS1 OCSET1 FB3 GATE3 OCSET2 SS2 P3 +3.3V 19 18 16 12 13 7 6 2 C7 0.1uF AN1220.1 March 7, 2008 Application Note 1220 ISL6443EVAL2Z Bill of Materials ITEM REFERENCE QTY PART NUMBER 1 P1 to P12 12 1514-2 Test Point Turret 0.281 Height Keystone 2 D1, D2 2 BAT54HT1G Diode, Schottky 30V, 200mA On Semi 3 C4 1 C1608X5R0J106 Cap, Ceramic, X5R 10µF, 6.3V, 0603, X5R TDK 4 C30, C31 2 10TPB220M Cap, POSCAP 220µF, 10V Panasonic 5 C20, C21 2 C3225X5R1C106KT Cap, Ceramic, 1210 10µF, 16V, 1210, X5R TDK 6 L1, L2 2 DO3316P-682ML SMT Power Inductor 6.8µH, ±20%, 4.6A, 27mΩ Coilcraft 7 C1 1 Capacitor, Ceramic, 0603 4.7µF, 20%, 6.3V, 0603 Generic 8 Q1, Q2 2 Dual NFET 6A, 30V, Dual NFET, SO8 Fairchild 9 C5, C7 2 Cap, Ceramic, 0603 0.1µF, 10%, 16V Generic C2, C3 2 Cap, Ceramic, 0603 0.01µF, 10%, 16V Generic 10 C6 1 Cap, Ceramic, 0603 1.0µF, 10%, 16V Generic 11 C32 1 Cap, Ceramic, 0805 10µF, 10%, 6.3V Generic 12 C33, C34 2 NOT POPULATED - 13 R8 1 Resistor, Film 100Ω, 0603, 1%, 1/16W Any 14 R1, R3, R6, R7, R9 5 Resistor, Film 1kΩ, 0603, 1%, 1/16W Any 15 R11 1 Resistor, Film 2kΩ, 0603, 1%, 1/16W Any 16 R2 1 Resistor, Film 324Ω, 0603, 1%, 1/16W Any 17 R5, R10 1 Resistor, Film 95.3kΩ, 0603, 1%, 1/16W Any 18 R12 1 Resistor, Film 5.11kΩ, 0603, 1%, 1/16W Any 19 R4 1 Resistor, Film 806Ω, 0603, 1%, 1/16W Any 20 Q3 1 IRLML6401PBF Single NFET Power MOSFET IR 21 U1 1 ISL6443IRZ 300kHz, Dual PWM Controller FDS6912A PART TYPE DESCRIPTION VENDOR Intersil ISL6443EVAL2Z Layout FIGURE 1. TOP SILK 3 FIGURE 2. TOP LAYER AN1220.1 March 7, 2008 Application Note 1220 ISL6443EVAL2Z Layout (Continued) FIGURE 3. LAYER 2 FIGURE 4. LAYER 3 FIGURE 5. BOTTOM LAYER FIGURE 6. BOTTOM SILK 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 4 AN1220.1 March 7, 2008