ISL8009AEVAL1Z: 1.5A Synchronous Buck Regulator with Integrated MOSFETs ® Application Note Description October 9, 2008 AN1388.1 Quick Setup Guide The ISL8009AEVAL1Z kit is intended for use by individuals with requirements for Point-of-Load applications sourcing from 2.7V to 5.5V. The ISL8009EVAL1Z evaluation board demonstrates the performance of the ISL8009A low quiescent current mode converter. 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. The ISL8009A is offered in a 2mmx3mm 8 Ld DFN package with 1mm maximum height. The complete converter occupies less than 1cm2 area. 4. Turn on the power supply. Key Features • High Efficiency Synchronous Buck Regulator With up to 95% Efficiency 2. Connect the bias supply to VIN. Plus terminal to P4(VIN) and negative return to P5(GND). 3. Verify that position is ON for SW1. 5. Verify the output voltage is 1.8V for VOUT Evaluating the Other Output Voltage The ISL8009AEVALIZ kit output is preset to 1.8V; however, output voltages can be adjusted from 0.8V to 3.3V by following Equations 1 and 2: R 1⎞ ⎛ V OUT = 0.8 ⎜ 1 + -------⎟ R 2⎠ ⎝ • 2ms Reset Timer • Soft Discharge Output Cap During Disable (EQ. 1) Let’s set R1= 124kΩ: • 2.7V to 5.5V Supply Voltage • 1.5A Guaranteed Output Current ( R1 ) R 2 = ------------------------------V OUT ⎛ ----------------⎞ – 1 ⎝ 0.8 ⎠ • 17µA Quiescent Supply Current in PFM Mode If desired output is 0.8V then short R1 and open R2. • Selectable Forced PWM Mode and PFM Mode Mode Control • Less Than 1µA Logic Controlled Shutdown Current The ISL8009A has a SKIP pin that controls the operation mode. When the SKIP pin is driven to low or shorted to ground, the regulator operates in a forced PWM mode. The forced PWM mode remains the fixed PWM frequency at light load instead of entering the skip mode. • 3% Output Accuracy Over-Temperature/Load/Line • 90% Maximum Duty Cycle for Lowest Dropout • Internal Current Mode Compensation • Internal Digital Soft-Start (EQ. 2) TABLE 1. SWITCH 1 SETTINGS • Peak Current Limiting, Short Circuit Protection SW1 SKIP 1 PWM Fixed PWM frequency at light load 3 PFM Force continuous mode SW2 ENABLE Recommended Equipment 1 OFF Disable VOUT The following materials are recommended to perform testing: 3 ON Enable VOUT • Over-Temperature Protection • Enable FUNCTION • Small 8 Ld 2mmx3mm DFN • Pb-Free (RoHS Compliant) ON/OFF CONTROL • 0V to 10V power supply with at least 5A source current capability, battery, notebook AC adapter • Two electronic loads capable of sinking current up to 5A • Digital Multimeters (DMMs) • 100MHz quad-trace oscilloscope • Signal generator 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. 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1388 Schematic 1 J1 3 4 5 4 3 1 J2 2 VIN 1 1 C1 10µF C2 10µF 2 2 1 2 3 4 EN POR SKIP 5 RSI 6 VFB 7 GND LX 8 VIN EN POR SKIP E ISL8009AIRZ-T 1 2 R1 124k A 9 1 C4 220pF P7 1 C5 10µF C6 10µF 2 1 A 3 11 RSI 2 P8 2 2 1 P5 5 4 L1 2.2µH 9 1 P4 5 4 3 A U1 A R2 100k A 1 A 11 P1 RSI R3 100k VIN VIN 2 2 2 VIN 2 R6 100k 2 R5 2k R7 100k 1 2 SKIP 3 SW2 1 2 21 2 2 R4 100k PG 31 1 31 1 Q1 A 2 2 3 SW1 1 1 ON/EX OFF 1 1 P6 2 R9 OPEN R8 OPEN OPEN 1 1 2 2 EN PWM 2 2N7002 22 1 P2 D1 D 1 P3 1 1 PFM 1 A A A AN1388.1 October 9, 2008 Application Note 1388 TABLE 2. COMPONENT LIST REF DES QTY VALUE TOL. VOLTAGE PACKAGE PART NUMBER MANUFACTURER DESCRIPTION C1, C2, C5, C6 4 10µF 10% 10V 1206 GRM31CR71A106KA01L-T MURATA CAP, SMD, 1206, 10µF, 10V, 10%, X7R, ROHS, MONOLITHIC C4 1 220pF 5% 50V 0603 H1045-00221-50V5-T VENKEL CAP, SMD, 0603, 220pF, 50V, 5%, C0G, ROHS L1 1 2.2µH 20% 7.6x6 DR73-2R2-R COOPER ELECTRONIC TECH. COIL-PWR INDUCTOR, SMD, 7.6x6, 2.2µH, 20%, 4.15A, ROHS D1 1 LITEON/VISHAY LED-GaAs RED, SMD, 2mmx1.25mm, 100mW, 40mA, 10mcd, ROHS U1 1 Q1 1 R2-R4, R6, R7 5 R1 2mmx1.25mm LTST-C170CKT 2x3 ISL8009AIRZ INTERSIL IC-1.5A SYNC BUCK REGULATOR, 8P, DFN, 2x3, ROHS 2N7002-7-F-T DIODES, INC. TRANSISTOR, N-CHANNEL, 3 LD SOT-23, 60V, 115mA, ROHS - 60V N-CHANNEL 100k 1% 100V 0603 H2511-01003-1/10W1-T 1 124k 1% 100V 0603 H2511-01243-1/10W1-T YAGEO RES, SMD, 0603, 124k,1/10W,1%, TF, ROHS R5 1 2k 1% 100V 0603 H2511-02001-1/10W1-T KOA RES, SMD, 0603, 2k, 1/10W, 1%, TF, ROHS R8, R9 0 100V 0603 H2511-DNP SW1, SW2 2 - - - - 3 GT11MSCBE-T RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS RES, SMD, 0603, DNP-PLACE HOLDER, ROHS C&K COMPONENTS SWITCH-TOGGLE, SMD, ULTRAMINI, 1P, SPST MINI AN1388.1 October 9, 2008 Application Note 1388 ISL8009AEVAL1Z Board Layout FIGURE 1. TOP COMPONENTS FIGURE 2. TOP LAYER ETCH 4 AN1388.1 October 9, 2008 Application Note 1388 ISL8009AEVAL1Z Board Layout (Continued) FIGURE 3. BOTTOM LAYER COMPONENTS (MIRRORED) FIGURE 4. BOTTOM LAYER ETCH (MIRRORED) 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 5 AN1388.1 October 9, 2008