Application Note 1554 Author: Huong Doan ISL8022EVAL1Z Dual 2A/1.7A Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck Regulator Description Quick Setup Guide The ISL8022EVAL1Z kit is intended for use by individuals with requirements for Point-of-Load applications sourcing from 2.8V to 5.5V. The ISL8022EVAL1Z evaluation board is used to demonstrate the performance of the ISL8022 low quiescent current mode converter. The ISL8022 is offered in a 4mmx3mm 12 Ld DFN package with 1mm maximum height. The complete converter occupies less than 1.8cm2 area. 2. Connect the bias supply to VIN2, the plus terminal to VIN2 and the negative return to PGND2. 3. Verify that position is ON for SW2 and SW3. 4. Turn on the power supply. 5. Verify the output voltage is 2.5V for VOUT1 and 1.8V for VOUT2. Evaluating the Other Output Voltage Key Features • Dual 2A/1.7A High Efficiency Synchronous Buck Regulator with up to 97% Efficiency • 180° Out-of-Phase • Power-Goods (PG) Output with 1ms Delay • 2.8V to 5.5V Supply Voltage • 3% Output Accuracy Over-temperature/Load/Line • Start-up with Pre-biased Output • Internal Digital Soft-Start - 5ms • Soft-Stop Output Discharge During Disabled • 40µA Quiescent Supply Current in PFM Mode • Selectable Forced PWM Mode and PFM Mode • External Synchronization up to 8MHz • Typical 6.5µA 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 • Signal generator October 27, 2010 AN1554.1 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. 1 The ISL8022EVAL1Z kit output is preset to 2.5V for VOUT1 and 1.8V for VOUT2; however, output voltages can be adjusted from 0.6V to 3.3V. The output voltage programming resistor, R2 (or R5 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 Equation 1. Let’s set R3/R6 = 100kΩ, then R2/R5 will be: VOUT R2 = R3 ⎛ ------------------ – 1⎞ ⎝ VFB ⎠ (EQ. 1) If the output voltage desired is 0.6V, then R3 is left unpopulated and short R2. For faster response performance, add 10pF in parallel to R2. Mode Control The ISL8022 has a SYNC pin that controls the operation mode. The SYNC pin connects to logic high or input voltage VIN for PFM mode; connect to logic low or ground for forced PWM mode. Connect to an external function generator for Synchronization. Negative edge trigger. Do not leave this pin floating. TABLE 1. SWITCH SETTINGS SW2, SW3 ENABLE ON/OFF CONTROL 1 OFF Disable VOUT 3 ON Enable VOUT SW1 SKIP 1 PWM Fixed PWM frequency at light load 3 PFM Force continuous mode FUNCTION 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. ISL8022EVAL1Z Schematic R15 VIN1 VIN2 1 2 C1 10UF C8 OPEN A 1.2UH 2 VIN2 1 VOUT1 0 SYNC 2 3 S1 1 3 C7 OPEN C9 OPEN A LX1 5 13 FB1 EN1 PG VIN1 LX1 PGND1 EP R14 20 C3 10PF PGND A 2 6 C2 22UF PGND1 A PGND2 FB2 EN2 SYNC VIN2 LX2 PGND2 12 11 10 9 8 FB2 EN2 SYNC L2 LX2 1 2 1.2UH 7 ISL8022IRZ A C4 22UF R13 20 C6 OPEN VIN2 A C5 10PF R5 200K PGND3 PGND3 A R6 100K VIN2 A R7 100K R10 2K 2 R4 100K 4 VOUT2_S R2 316K VIN2 VOUT2 VOUT2_S 1 2 A R3 100K A VOUT2 VOUT2 A A PFM PWM C10 10UF Application Note 1554 SYNC R11 4 VOUT1 VOUT1 VOUT1_S SYNC L1 VIN2 3 FB1 1 EN1 2 PG 3 A 1 2 C11 OPEN A U1 PGND VOUT1_S 4 LX2 PGND2 PGND R1 100K 4 3 4 LX1 3 VIN 0 LX1_S 1 2 SGND 2 3 S2 1 ON/EX OFF EN1 SGND EN2 2 3 S3 1 R9 OPEN ON/EX OFF EN2 PG EN2 1 PG 2N7002 Q2 2 EN1 D2 31 EN1 A NOTE: PLEASE KEEP FB1, FB2 PINS TRACES SHORT A A A DRAWN BY: RELEASED BY: DATE: 04/29/2008 DATE: UPDATED BY DATE HUONG DOAN TU BUI / HUONG DOAN ENGINEER: HUONG DOAN TITLE: ISL8022 DATE: 4/29/08 AN1554.1 Application Note 1554 TABLE 2. BILL OF MATERIALS PART NUMBER QTY UNITS REFERENCE DESIGNATOR DESCRIPTION PWB-PCB, ISL8022EVAL1Z, REVA, ROHS MANUFACTURER TBD ISL8022EVAL1ZREVAPCB 1 ea C2012X5R0J226M-T 2 ea C2, C4 TDK CAP, SMD, 0805, 22µF, 6.3V, 20%, X5R, ROHS H1045-00100-50V5-T 2 ea C3, C5 CAP, SMD, 0603, 10pF, 50V, 5%, COG, ROHS MANUFACTURER PART ISL8022EVAL1ZREVAPCB C2012X5R0J226M YAGEO CC0603JRNP09BN100 VENKEL C0603COG500-100JNE KEMET C0603C100J5GACTU MURATA GRM1885C1H100JA01D AVX 06035A100JAT2A H1045-DNP 0 ea C9 CAP, SMD, 0603, DNP-PLACE HOLDER, ROHS H1046-00106-6R3V10-T 2 ea C1, C10 VENKEL CAP, SMD, 0805, 10µF, 6.3V, 10%, X5R, KEMET ROHS C0805X5R6R3-106KNE C0805C106K9PACTU AVX 08056D106KAT2A MURATA GRM21BR60J106KE19L TAIYO YUDEN JMK212BJ106KD-T PANASONIC ECJ-2FB0J106K TDK C2012X5R0J106K JOHANSON DIELECTRICS 6R3R15X106KV4E INC H1046-DNP 0 ea C6-C8, C11 CAP, SMD, 0805, DNP-PLACE HOLDER, ROHS VLCF-4028T-1R2N2R7-2 2 ea L1, L2 COIL-PWR INDUCTOR, WW, SMD, 4mm, 1.2µH, 30%, 2.7A, ROHS 131-4353-00 4 ea 1514-2 8 1514-2 TDK VLCF4028T-1R2N2R7-2 CONN-SCOPE PROBE LX1, LX2, TEST PT, COMPACT, VOUT1_S, PCB MNT, ROHS VOUT2_S *(SEE ASSEMBLY NOTE) TEKTRONIX 131-4353-00 ea a) PGND, PGND1- CONN-TURRET, TERMINAL POST, TH, PGND3, VIN, ROHS VIN2 KEYSTONE 1514-2 0 ea b) VOUT1, VOUT2 CONN-TURRET, TERMINAL POST, TH, ROHS KEYSTONE 1514-2 5000 4 ea EN1, EN2, PG, SYNC CONN-MINI TEST PT, VERTICAL, RED, ROHS KEYSTONE 5000 5001 1 ea SGND CONN-MINI TEST PT, KEYSTONE VERTICAL, BLK, ROHS 5001 3 AN1554.1 Application Note 1554 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER LTST-C170CKT QTY UNITS 1 ea REFERENCE DESIGNATOR D2 DESCRIPTION MANUFACTURER LED-GaAs RED, SMD, 2mmX1.25mm, 100mW, 40mA, 10mcd, ROHS LITEON/VISHAY LTST-C170CKT ROHM SML-210LTT86 STANLEY ELECTRIC BR112H-TR INTERSIL ISL8022IRZ ISL8022IRZ 1 ea U1 IC-2A/1.7A BUCK REGULATOR, 12P, DFN, 4X3, ROHS 2N7002-7-F-T 1 ea Q2 DIODES, INC. TRANSISTOR, N-CHANNEL, 3LD, ON SEMICONDUCTOR SOT-23, 60V, 115mA, ROHS H2511-00200-1/10W1-T H2511-00R00-1/10W-T 2 ea 1 ea R13, R14 R11 RES, SMD, 0603, 20Ω, 1/10W, 1%, TF, ROHS RES, SMD, 0603, 0Ω, 1/10W, TF, ROHS YAGEO RC0603FR-0720RL VENKEL CR0603-10W-20R0FT VENKEL CR0603-10W-000T KOA RK73Z1JTTD-T ROHM MCR03EZPJ000 PANASONIC ERJ-3GEY0R00V YAGEO RC0603JR-070RL VISHAY/DALE CRCW06030000Z0EA ea R1, R3, R4, R6, R7 RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS H2511-02001-1/10W1-T 1 ea R10 RES, SMD, 0603, 2k, KOA 1/10W, 1%, TF, ROHS VENKEL H2511-03163-1/10W1-T ea 1 ea R5 R2 2N7002LT1G ERJ-3EKF20R0V 5 1 2N7002-7-F PANASONIC H2511-01003-1/10W1-T H2511-02003-1/10W1-T MANUFACTURER PART VENKEL RES, SMD, 0603, 200k, 1/10W, 1%, TF, YAGEO ROHS RK73H1JTTD2001F CR0603-10W-2001FT CR0603-10W-2003FT RC0603FR-07200KL VISHAY/DALE CRCW0603200KFKEA PANASONIC ERJ-3EKF2003V ROHM MCR03EZPFX2003 PANASONIC RES, SMD, 0603, 316k, 1/10W, 1%, TF, VENKEL ROHS ERJ-3EKF3163V CR0603-10W-3163FT ROHM MCR03EZPFX3163 YAGEO RC0603FR-07316KL VISHAY/DALE CRCW0603316KFKEA H2511-DNP 0 ea R9 RES, SMD, 0603, DNP-PLACE HOLDER, ROHS H2514-00R00-1/4W-T 1 ea R15 RES, SMD, 1210, 0Ω, 1/4W, TF, ROHS VENKEL CR1210-4W-000 GT11MSCBE-T 3 ea S1-S3 SWITCH-TOGGLE, SMD, 6PIN, SPDT, 2POS, ON-ON, ROHS ITT INDUSTRIES/C&K DIVISION GT11MSCBE 4 AN1554.1 Application Note 1554 TABLE 2. BILL OF MATERIALS (Continued) PART NUMBER QTY UNITS REFERENCE DESIGNATOR DESCRIPTION MANUFACTURER MANUFACTURER PART SJ-5003-BLACK 4 ea Bottom four corners BUMPONS, 0.44’ W x 0.20’ H, DOMETOP, BLACK 3M SJ-5003SPBL 5X8-STATIC-BAG 1 ea Place assy in bag BAG, STATIC, 5X8, ZIP LOC INTERSIL 212403-013 ASSEMBLY-NOTE 1 ea ASSEMBLY NOTE a) LX1, LX2, VOUT1_S, VOUT2_S - Install ASSEMBLY-NOTE 0 ea b) on bottom of PCB ASSEMBLY NOTE ISL8022EVAL1Z Board Layout FIGURE 1. TOP COMPONENTS 5 FIGURE 2. TOP LAYER ETCH AN1554.1 Application Note 1554 ISL8022EVAL1Z Board Layout (Continued) FIGURE 3. 2ND LAYER ETCH FIGURE 4. 3RD LAYER ETCH FIGURE 5. BOTTOM LAYER COMPONENTS (MIRRORS) 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 AN1554.1