Application Note 1615 Author: Paul Orfanu ISL8036ACRSHEVAL1Z Current Sharing 6A Low Quiescent Current High Efficiency Synchronous Buck Regulator Description Quick Setup Guide The ISL8036ACRSHEVAL1Z kit is intended for use by individuals with requirements for Point-of-Load applications sourcing from 2.85V to 6V. The ISL8036ACRSHEVAL1Z evaluation board is used to demonstrate the performance of the ISL8036A low quiescent current mode converter in current sharing configuration. 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 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, VOUT2. Evaluating the Other Output Voltage • Power-Goods (PG) Output with 1ms Delay The ISL8036ACRSHEVAL1Z kit output is preset to 1.8V (VOUT1 = VOUT2); however, output voltage can be adjusted from 0.8V to 3.3V. The output voltage programming resistor, RF22, 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 Equation 1. • 2.85V to 6V Supply Voltage Let’s set RF21 = 100kΩ, then RF22 will be: • Current Sharing 6A High Efficiency Synchronous Buck Regulator with up to 95% Efficiency • 180° Out-of-Phase Providing Low Output Noise • 2% Output Accuracy Over-temperature/Load/Line • Start-up with Pre-biased Output • Externally Adjustable Soft-Start Time • Soft-Stop Output Discharge During Disabled VOUT RF22 = RF21 ⎛ -------------- – 1⎞ ⎝ VFB ⎠ (EQ. 1) If the output voltage desired is 0.8V, then RF21 should be left unpopulated and RF22 should be shorted. For faster response performance, add 68pF in parallel to RF22. • External Synchronization up to 6MHz Mode Control • Typical 8µA Logic Controlled Shutdown Current 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) • 100% Maximum Duty Cycle for Lowest Dropout • External 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 7A source current capability or 5V battery • Electronic Loads capable of sinking current up to 7A Enable Control EN1 and EN2 pins should be tied together for current sharing operation. TABLE 1. SWITCH SETTINGS SW2, SW3 ENABLE ON/OFF CONTROL 1 OFF Disable VOUT 3 ON Enable VOUT • Digital Multimeters (DMMs) • 100MHz quad-trace oscilloscope • Signal generator November 29, 2010 AN1615.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas Inc. 2010. 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. ISL8036ACRSHEVAL1Z Schematic LX2_S LX1_S LX1 LX2 R_IN A VIN2 VIN1 0 CIN2 22UF A PGND VIN2 0 VOUT2 VDD VOUT2_S SS SYNC SYNC R_PH SYNC 0 S1 PWM PFM C_PH OPEN C3 C4 22UF 22UF VOUT2_S C1 R3 OPEN A C2 OPEN 0.01UF A C5 RF22 124K 22PF A R7 RF21 100K A A A A SGND A ON/EX OFF A EN2 R11 C9 22UF C11 22UF S3 ON/EX OFF PG2 PG2 A R10 OPEN VOUT1_S A A PGND1 A A 2N7002 Q1 A PG1 PG1 R13 0 R12 2K C8 150PF D1 VOUT1 VOUT1_S C6 C7 OPEN OPEN SYNC VIN_PG 30.1K R8 2K EN2 A EN1 VOUT1 VOUT1 A VIN_PG A EN2 EN1 VDD SS CD1 OPEN A A R6 100K EN1 PG1 FB1 VDD S2 EN1 A CDC OPEN SS VOUT2 0 PGND COMP R4 100K SGND FB2 EP VDD ISL8036AIRZ R_OUT L1 COMP VDD EN1 PG2 0 PGND PGND2 EN2 VIN1 A R14 OPEN D2 2N7002 Q2 A VIN1 Application Note 1615 SS VOUT2 EN2 PG2 FB2 FB FB VOUT2 LX1 LX1 COMP NC FB1 SGND PG1 SYNC R5 PGND PGND11 VIN1 U1 VIN2 R9 R2 L2 COMP VIN1 CD2 DNP LX2 OPEN R1 100K LX2 VIN1 CIN1 22UF A LX2 PGND2 PGND2 PGND1 PGND1 LX1 2 A VDD VIN1 VIN1 PGND22 VDD A VIN2 VIN2 0 VIN2 AN1615.0 November 29, 2010 Application Note 1615 TABLE 2. BILL OF MATERIALS PART NUMBER REFERENCE DESIGNATOR QTY UNITS DESCRIPTION MANUFACTURER TBD MANUFACTURER PART ISL8033_36EVAL1ZREVAPCB ISL8033_36EVAL1ZREVAPCB 1 ea SEE LABEL-RENAME BOARD PWB-PCB, ISL8033_36EVAL1Z, REVA, ROHS C2012X5R0J226M-T 6 ea C3, C4, C9, C11, CIN1, CIN2 CAP, SMD, 0805, 22µF, 6.3V, TDK 20%, X5R, ROHS C2012X5R0J226M H1045-00103-50V5-T 1 ea C1 CAP, SMD, 0603, 0.01µF, 50V, 5%, X7R, ROHS VENKEL C0603X7R500-103JNE KEMET C0603C103J5RACTU AVX 06035C103JAT2A TDK C1608X7R1H103J H1045-00151-50V5-T 1 ea C8 CAP, SMD, 0603, 150pF, 50V, 5%, NPO, ROHS PANASONIC VENKEL ECJ-1VC1H151J C0603C0G500-151JNE H1045-00220-50V5-T 1 ea C5 CAP, SMD, 0603, 22pF, 50V, 5%, C0G, ROHS VENKEL C0603C0G500-220JNE KEMET C0603C220J5GACTU TDK C1608C0G1H220J MURATA GRM1885C1H220JA01D ROHM MCH185A220JK H1045-DNP 0 ea C2, C10, 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 C_PH CONN-MINI TEST PT, 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 POINT, 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 ROHM SML-210LTT86 STANLEY ELECTRIC BR112H-TR INTERSIL ISL8036AIRZ ISL8036AIRZ 1 ea 3 U1 IC-DUAL 3A CONTROLLER, 2.5MHz, 24P, QFN ,4X4, ROHS AN1615.0 November 29, 2010 Application Note 1615 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER 2N7002-7-F-T REFERENCE DESIGNATOR QTY UNITS 2 ea Q1, Q2 DESCRIPTION MANUFACTURER TRANSISTOR,N-CHANNEL, 3 LD, SOT-23, 60V, 115mA, ROHS DIODES, INC. MANUFACTURER PART 2N7002-7-F ON SEMICONDUCTOR 2N7002LT1G H2509-00R00-1/20W-T 1 ea R9 RESISTOR, SMD, 0201, 0Ω, 1/20W, 0%, TF PANASONIC H2509-00R00-1/20W-T H2511-00R00-1/10W-T 4 ea R7, R5, R13, R_PH RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS VENKEL CR0603-10W-000T ROHM MCR03EZPJ000 PANASONIC ERJ-3GEY0R00V YAGEO RC0603JR-070RL VISHAY/DALE CRCW06030000Z0EA VENKEL CR0603-10W-1003FT PANASONIC ERJ-3EKF1003V ROHM MCR03EZPFX1003 YAGEO RC0603FR-07100KL STACKPOLE RMCF 1/16 100K 1% R VISHAY/DALE CRCW0603100KFKEA VENKEL CR0603-10W-1003FT PANASONIC ERJ-3EKF1003V ROHM MCR03EZPFX1003 YAGEO RC0603FR-07100KL STACKPOLE RMCF 1/16 100K 1% R VISHAY/DALE CRCW0603100KFKEA RES, SMD, 0603, 124k, 1/10W, 1%, TF, ROHS YAGEO 9C06031A1243FKHFT PANASONIC ERJ-3EK1243V H2511-01003-1/10W1-T H2511-01003-1/10W1-T H2511-01243-1/10W1-T 3 ea 1 ea 1 ea R1, R4, R6 RF21 RF22 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS H2511-02001-1/10W1-T 2 ea R8, R12 RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS KOA VENKEL RK73H1JTTD2001F CR0603-10W-2001FT H2511-03012-1/10W1-T 1 ea R11 RESISTOR, SMD, 0603, VENKEL 30.1k, 1/10W, 1%, TF, ROHS YAGEO CR0603-10W-3012FT RC0603FR-0730K1L H2511-DNP 0 ea R2, R3, R10, R14, RF11, RF12 RES, SMD, 0603, DNP-PLACE HOLDER, ROHS H2514-00R00-1/4W-T 2 ea R_IN, R_OUT RES, SMD, 1210, 0Ω, 1/4W, TF, ROHS VENKEL CR1210-4W-000 GT11MSCBE-T 3 ea S1-S3 SWITCH-TOGGLE, SMD, 6 PIN, SPDT, 2POS, ON-ON, ROHS ITT INDUSTRIES/ C&K 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, ZIPLOC, ROHS INTERSIL 212403-013 LABEL-RENAME BOARD 1 ea RENAME PCB TO: LABEL, TO RENAME BOARD ISL8036ACRSHEVAL1Z INTERSIL LABEL-RENAME BOARD LABEL-SERIAL NUMBER 1 ea LABEL-FOR SERIAL NUMBER INTERSIL AND BOM REV # LABEL-SERIAL NUMBER 4 AN1615.0 November 29, 2010 Application Note 1615 ISL8036ACRSHEVAL1Z Board Layout FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH 5 AN1615.0 November 29, 2010 Application Note 1615 ISL8036ACRSHEVAL1Z 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 AN1615.0 November 29, 2010