Application Note 1928 ISL78236CRSHEVAL1Z Current Share Evaluation Board User Guide Description Quick Setup Guide The ISL78236CRSHEVAL1Z kit is intended for use by individuals with requirements for Point-of-Load (POL) applications sourcing from 2.85V to 6V. The ISL78236CRSHEVAL1Z evaluation board is used to demonstrate the performance of the ISL78236 low quiescent current mode converter in current sharing configuration. The evaluation board is configured to deliver up to 6A output current with both outputs paralleled together. The ISL78236 can also be used in dual output 3A/3A configuration. For this application, reference ISL78236DUALEVAL1Z AN1927. The ISL78236 is offered in a 4mmx4mm 24 Ld QFN package with 1mm maximum height. The complete converter occupies less than 5.46cm2 area. 1. Ensure that the evaluation board is correctly connected to the supply and loads prior to applying any power. 2. Connect the bias supply to VIN: The positive terminal to VIN1 and the negative return to PGND1. 3. Verify that switch position is on PWM for S1. Verify that switch position is ON for S2 and S3. 4. Turn on the power supply. 5. Verify the output voltage is 1.8V for VOUT1, VOUT2. Evaluating Other Output Voltages • Current sharing 6A high efficiency synchronous buck regulator with up to 95% Efficiency The ISL78236CRSHEVAL1Z kit output is preset to 1.8V (VOUT1 = VOUT2); however, output voltage can be adjusted from 1.2V 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 50kΩ and 750kΩ as shown in Equation 1. • 180° out-of-phase channel switching Setting RF21 = 100k, then RF22 will be: Key Features • 2% output accuracy over-temperature/load/line • Externally adjustable soft-start time • Soft-stop output discharge during disabled • External synchronization up to 6MHz • Typical 8µA shutdown current • 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: • 5V or higher power supply with at least 6A source current capability or 5V battery • Electronic loads capable of sinking current up to 7A • Digital Multimeters (DMMs) V OUT RF22 = RF21 ------------- – 1 0.8 Mode Control The ISL78236 has a SYNC pin, which connects to logic high or input voltage VIN for internal 2.5MHz switching frequency. Connect the test point by the switch S1 to an external function generator for external synchronization on the negative edge trigger. A 100kΩ pull-up resistor to VIN normally pulls the SYNC pin high. Each channel’s switching frequency will be 1/2 of the synchronization frequency at 180° out-of-phase. Synchronization frequency range is 6MHz to 8MHz. Do not leave this pin floating. Do not tie this pin low (or to GND) Enable Control EN1 and EN2 pins should be tied together for current sharing operation. TABLE 1. SWITCH SETTINGS SWITCH POSITION S1 PFM DO NOT LEAVE IN THIS POSITION PWM 2.5MHz switching frequency if floating. External synchronization switching 6MHz to 8MHz range with generator. • 100MHz quad-trace oscilloscope • 10MHz signal generator Ordering Information PART NUMBER ISL78236CRSHEVAL1Z June 17, 2014 AN1928.0 DESCRIPTION (EQ. 1) S2/S3 MODE ON Enable VOUT. Both must be in ON state. OFF Disable VOUT. Current Sharing 6A Synchronous Buck Evaluation Board 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas LLC 2014. 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. LX2_S LX1_S LX1 LX2 R_IN VIN2 A VIN2 VIN1 0 CIN2 22UF 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 SS EN1 A CDC OPEN VDD VOUT2 0 PGND COMP R4 100K SGND FB2 EP ISL8036AIRZ ISL78236AIRZ R_OUT L1 COMP VDD EN1 PG2 0 PGND PGND2 EN2 A R14 OPEN D2 2N7002 Q2 A VIN1 Application Note 1928 SS VOUT2 EN2 PG2 FB2 FB FB VOUT2 VIN1 COMP NC FB1 SGND PG1 SYNC R5 LX1 LX1 VIN1 U1 VIN2 R9 R2 L2 COMP VIN1 CD2 DNP LX2 OPEN 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 VIN2 0 Submit Document Feedback ISL78236CRSHEVAL1Z Schematic AN1928.0 June 17, 2014 Submit Document Feedback BILL OF MATERIALS PART NUMBER REFERENCE DESIGNATOR QTY UNITS ISL8033_36EVAL1ZREVAPCB 1 ea. SEE LABEL-RENAME BOARD PWB-PCB, ISL8033_36EVAL1Z, REVA, ROHS DESCRIPTION MANUFACTURER C2012X5R0J226M-T 6 ea. C3, C4, C9, C11, CIN1, CIN2 CAP, SMD, 0805, 22µF, 6.3V, 20%, X5R, ROHS TDK C2012X5R0J226M H1045-00103-50V5-T 1 ea. C1 CAP, SMD, 0603, 0.01µF, 50V, 5%, X7R, ROHS VENKEL C0603X7R500-103JNE TBD MANUFACTURER PART ISL8033_36EVAL1ZREVAPCB KEMET C0603C103J5RACTU AVX 06035C103JAT2A C1608X7R1H103J 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 3 TDK H1045-00151-50V5-T 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, LITEON/VISHAY 40mA, 10mcd, ROHS ROHM LTST-C170CKT SML-210LTT86 STANLEY ELECTRIC BR112H-TR ISL78236IRZ AN1928.0 June 17, 2014 ISL78236IRZ 1 ea. U1 IC-DUAL 3A CONTROLLER, 2.5MHz, 24P, QFN,4X4, ROHS INTERSIL 2N7002-7-F-T 2 ea. Q1, Q2 TRANSISTOR,N-CHANNEL, 3 LD, SOT-23, 60V, 115mA, ROHS DIODES, INC. 2N7002-7-F ON SEMICONDUCTOR 2N7002LT1G Application Note 1928 KEMET Submit Document Feedback BILL OF MATERIALS (Continued) PART NUMBER REFERENCE DESIGNATOR UNITS DESCRIPTION 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 4 QTY H2511-01003-1/10W1-T H2511-01243-1/10W1-T 1 1 ea. ea. ea. R1, R4, R6 RF21 RF22 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RES, SMD, 0603, 124k, 1/10W, 1%, TF, ROHS MANUFACTURER PART 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 YAGEO 9C06031A1243FKHFT PANASONIC ERJ-3EK1243V RK73H1JTTD2001F CR0603-10W-2001FT H2511-02001-1/10W1-T 2 ea. R8, R12 RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS KOA VENKEL H2511-03012-1/10W1-T 1 ea. R11 RESISTOR, SMD, 0603, 30.1k, 1/10W, 1%, TF, ROHS VENKEL CR0603-10W-3012FT YAGEO RC0603FR-0730K1L VENKEL CR1210-4W-000 AN1928.0 June 17, 2014 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 GT11MSCBE-T 3 ea. S1-S3 SWITCH-TOGGLE, SMD, 6 PIN, SPDT, 2POS, ON- ITT INDUSTRIES/ ON, ROHS 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: ISL78236CRSHEVAL1Z LABEL, TO RENAME BOARD INTERSIL LABEL-RENAME BOARD LABEL-SERIAL NUMBER 1 ea. LABEL-FOR SERIAL NUMBER AND BOM REV # INTERSIL LABEL-SERIAL NUMBER Application Note 1928 H2511-01003-1/10W1-T 3 MANUFACTURER Application Note 1928 ISL78236CRSHEVAL1Z Board Layout FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH Submit Document Feedback 5 AN1928.0 June 17, 2014 Application Note 1928 ISL78236CRSHEVAL1Z 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 Submit Document Feedback 6 AN1928.0 June 17, 2014