Application Note 1618 Author: Paul Orfanu ISL8036ADUALEVAL1Z Dual 3A Low Quiescent Current High Efficiency Synchronous Buck Regulator Description Quick Setup Guide The ISL8036ADUALEVAL1Z kit is intended for use by individuals with requirements for Point-of-Load applications sourcing from 2.85V to 6V. The ISL8036ADUALEVAL1Z evaluation board is used to demonstrate the performance of the ISL8036A low quiescent current mode converter. The ISL8036A is offered in a 4mmx4mm 24 Ld QFN package with 1mm maximum height. The complete converter occupies less than 5.46cm2 area. Key Features • Dual 3A High Efficiency Synchronous Buck Regulator with up to 95% Efficiency 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. 2. Connect the bias supply to VIN1, the plus terminal to VIN1 and the negative return to PGND1. 3. Verify that position is ON for SW2 and SW3. 4. Turn on the power supply. 5. Verify the output voltage is 1.8V for VOUT1 and 1.8V for VOUT2. Evaluating the Other Output Voltage • 2% Output Accuracy Over-temperature/Load/Line The ISL8036ADUALEVAL1Z kit outputs are preset to 1.8V for VOUT1 and 1.8V for VOUT2; however, output voltages can be adjusted from 0.8V to 3.3V. The output voltage programming resistor, RF12 (or RF22 in Channel 2), will depend on the desired output voltage of the regulator. The value for the feedback resistor is typically between 0Ω and 750kΩ, as shown in Equations 1 and 2. • Start-up with Pre-biased Output Let’s set RF11/RF21 = 100kΩ, then RF12/RF22 will be: • Internal Digital Soft-Start - 1.5ms VOUT1 RF12 = RF11 ⎛ ------------------ – 1⎞ ⎝ VFB ⎠ (EQ. 1) VOUT2 RF22 = RF21 ⎛ ------------------ – 1⎞ ⎝ VFB ⎠ (EQ. 2) • 180° Out-of-Phase • Power-Goods (PG) Output with 1ms Delay • 2.85V to 6V Supply Voltage • Soft-Stop Output Discharge During Disabled • External Synchronization up to 6MHz • Typical 8µA Logic Controlled Shutdown Current • 100% Maximum Duty Cycle for Lowest Dropout • Internal Current Mode Compensation • Peak Current Limiting, Hiccup Mode Short Circuit Protection and Over-temperature Protection • Negative Current Detection and Protection Recommended Equipment The following materials are recommended to perform testing: • 0V to 10V Power Supply with at least 3A source current capability or 5V battery • Electronic Loads capable of sinking current up to 3A • Digital Multimeters (DMMs) • 100MHz quad-trace oscilloscope If the output voltage desired is 0.8V, then RF11 and RF21 should be left unpopulated and RF12 and RF22 should be shorted. For faster response performance, add 47pF in parallel to RF12 and RF22. Mode Control The ISL8036A has a SYNC pin, which connects to logic high or input voltage VIN for PWM internal synchronization. Connect to an external function generator for external Synchronization. Negative edge trigger. Do not leave this pin floating. Do not tie this pin low (or to GND). TABLE 1. SWITCH SETTINGS SW2, SW3 ENABLE ON/OFF CONTROL 1 OFF Disable VOUT1,2 3 ON Enable VOUT1,2 • Signal generator January 3, 2011 AN1618.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas Inc. 2011. All Rights Reserved. 1-888-INTERSIL or 1-888-468-3774 | 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. ISL8036ADUALEVAL1Z Schematic LX2_S LX1_S LX2 A VIN2 VIN1 VIN2 0 CIN2 22UF 0 S1 PWM PFM C_PH OPEN RF22 124K C5 C1 OPEN R3 OPEN A C2 OPEN A 12PF R7 RF21 100K A A A A R4 100K SGND SGND ON/EX OFF S3 ON/EX OFF EN2 EN1 A EN2 PG2 EN2 A PG2 A COMP NC FB1 SGND PG1 SYNC C11 22UF VOUT1_S A A RF12 124K C10 12PF PGND1 A A 2N7002 Q1 A PG1 PG1 0 R12 2K C8 150PF D1 R13 VIN_PG R11 52.3K R14 OPEN D2 2N7002 Q2 A VOUT1 VOUT1_S C6 C7 OPEN OPEN PGND RF11 100K R8 2K R10 OPEN C9 22UF A VIN_PG A R6 100K EN1 A A COMP A EN1 VOUT1 VOUT1 SYNC CD1 OPEN COMP VDD S2 PG1 FB1 VDD EN1 A CDC OPEN OPEN PGND PGND2 A 0 SYNC R_PH SYNC SS VOUT2 OPEN VDD SS VDD EN1 R9 VOUT2_S SS SYNC C3 C4 22UF 22UF VOUT2_S FB2 EP R_OUT L1 VIN1 ISL8036AIRZ COMP 0 VDD PG2 A VIN1 Application Note 1618 SS VOUT2 EN2 LX1 LX1 VIN1 U1 VIN2 EN2 PG2 FB2 FB FB VOUT2 VOUT2 CD2 R5 L2 OPEN R2 LX2 VIN2 VIN1 0 R1 100K LX2 PGND PGND11 LX2 PGND2 PGND2 PGND1 PGND1 LX1 2 A VIN1 CIN1 22UF A A PGND VDD VIN1 VIN1 PGND22 VDD A VIN2 FB1 R_IN VIN2 LX1 AN1618.0 January 3, 2011 Application Note 1618 TABLE 2. BILL OF MATERIALS PART NUMBER REFERENCE DESIGNATOR UNITS ISL8033_36EVAL1ZREVAPCB 1 ea a) PUT “X” IN ISL8036 PWB-PCB, BOX ON PCB ISL8033_36EVAL1Z, REVA, ROHS IMAGINEERING INC. ISL8033_36EVAL1ZREVAPCB ISL8033_36EVAL1ZREVAPCB 0 ea b) SEE LABEL-RENAME PWB-PCB, BOARD ISL8033_36EVAL1Z, REVA, ROHS IMAGINEERING INC. ISL8033_36EVAL1ZREVAPCB C2012X5R0J226M-T 6 ea C3, C4, C9, C11, CIN1, CAP, SMD, 0805, 22µF, 6.3V, TDK CIN2 20%, X5R, ROHS C2012X5R0J226M H1045-00120-50V5-T 2 ea C5, C10 CAP, SMD, 0603, 12pF, 50V, AVX 5%, COG, ROHS 06035A120JAT2A H1045-00151-50V5-T 1 C8 CAP, SMD, 0603, 150pF, 50V, PANASONIC 5%, NPO, ROHS ECJ-1VC1H151J H1045-DNP 0 ea C1, C2, C8, CD1, CD2, CDC, C_PH CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS H1046-DNP 0 ea C6, C7 CAP, SMD, 0805, DNP-PLACE HOLDER, ROHS FDV0630-R60M 2 ea L1, L2 COIL-PWR INDUCTOR, SMD, 7.4X6.7,0.6µH, 20%, ROHS TOKO FDV0630-R60M 131-4353-00 4 ea LX1, LX2, VOUT1_S, VOUT2_S CONN-SCOPE PROBE TEST PT, COMPACT, PCB MNT, ROHS TEKTRONIX 131-4353-00 1514-2 8 ea a) PGND1, PGND2, PGND11, PGND22, VIN1, VIN2 CONN-TURRET, TERMINAL POST, TH, ROHS KEYSTONE 1514-2 1514-2 0 ea b) VOUT1, VOUT2 CONN-TURRET, TERMINAL POST, TH, ROHS KEYSTONE 1514-2 5000 6 ea a) EN1, EN2, PG1, PG2, SS, SYNC CONN-MINI TEST PT, VERTICAL, RED, ROHS KEYSTONE 5000 5000 0 ea b) SYNC located left of CONN-MINI TEST PT, C_PH VERTICAL, RED, ROHS KEYSTONE 5000 5001 1 ea SGND CONN-MINI TEST PT, VERTICAL, BLK, ROHS KEYSTONE 5001 5002 2 ea COMP, FB CONN-MINI TEST PT, VERTICAL, WHITE, ROHS KEYSTONE 5002 LTST-C170CKT 2 ea D1, D2 LED-GaAs RED, SMD, 2mmX1.25mm, 100mW, 40mA, 10mcd, ROHS LITEON/VISHAY LTST-C170CKT ISL8036AIRZ 1 ea U1 IC-DUAL 3A BUCK REGULATOR, 2.5MHz, 24P, QFN, 4X4, ROHS INTERSIL ISL8036AIRZ 2N7002-7-F-T 2 ea Q1, Q2 TRANSISTOR, N-CHANNEL, 3 DIODES, INC. LD, SOT-23, 60V, 115mA, ROHS 2N7002-7-F H2509-DNP 1 ea R9 RES, SMD, 0201, 0Ω, 1/20W, PANASONIC 0%, TF H2509-00R00-1/20W-T H2511-00R00-1/10W-T 4 ea R2, R5, R13, R_PH RES, SMD, 0603, 0Ω, 1/10W, VENKEL TF, ROHS CR0603-10W-000T H2511-01003-1/10W1-T 5 ea R1, R4, R6, RF11, RF21 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS 3 DESCRIPTION MANUFACTURER PART QTY MANUFACTURER AN1618.0 January 3, 2011 Application Note 1618 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER REFERENCE DESIGNATOR UNITS H2511-01243-1/10W1-T 2 ea RF12, RF22 RES, SMD, 0603, 124k, 1/10W, 1%, TF, ROHS H2511-02001-1/10W1-T 2 ea R8, R12 RES, SMD, 0603, 2k, 1/10W, KOA 1%, TF, ROHS RK73H1JTTD2001F H2511-05232-1/10W1-T 1 ea R11 RES,SMD,0603, 52.3k, 1/10W, 1%, TF, ROHS CR0603-10W-5232FT H2511-DNP 0 ea R3, R7, R10, R14 RES, SMD, 0603, DNP-PLACE HOLDER, ROHS H2514-00R00-1/4W-T 1 ea R_IN RES, SMD, 1210, 0Ω, 1/4W, VENKEL TF, ROHS H2514-DNP 0 ea R_OUT RES, SMD, 1210, DNP, DNP, DNP, TF, ROHS GT11MSCBE-T 3 ea S1-S3 SWITCH-TOGGLE, SMD, 6 PIN, ITT INDUSTRIES/C&K SPDT, 2POS, ON-ON, ROHS DIVISION GT11MSCBE SJ-5003-BLACK 4 ea Bottom four corners BUMPONS, 0.44”Wx0.20”H, DOMETOP, BLACK 3M SJ-5003SPBL 5X8-STATIC-BAG 1 ea Place assy in bag BAG, STATIC, 5X8, ZIP LOC INTERSIL 212403-013 LABEL-RENAME BOARD 1 ea RENAME PCB TO: LABEL, TO RENAME BOARD ISL8036ADUALEVAL1Z INTERSIL LABEL-RENAME BOARD LABEL-SERIAL NUMBER 1 ea 4 DESCRIPTION MANUFACTURER MANUFACTURER PART QTY YAGEO VENKEL 9C06031A1243FKHFT CR1210-4W-000 LABEL, FOR SERIAL NUMBER AND BOM REV # AN1618.0 January 3, 2011 Application Note 1618 ISL8036DUALEVAL1Z Board Layout FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH 5 AN1618.0 January 3, 2011 Application Note 1618 ISL8036DUALEVAL1Z Board Layout FIGURE 5. BOTTOM LAYER ETCH (Continued) FIGURE 6. BOTTOM COMPONENTS (MIRROR) 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 6 AN1618.0 January 3, 2011