ISL8011EVAL1Z: 1.2A Integrated FETs, High Efficiency Synchronous Buck Regulator ® Application Note ISL8011 is an integrated FET, 1.2A synchronous buck regulator for general purpose point-of load applications. It is optimized for generating low output voltages down to 0.8V. The supply voltage range of 2.7V to 5.5V allows the use of common 3.3V or 5V supply rails and Lithium ion battery inputs. It has a guaranteed minimum output current of 1.2A and a 1.5MHz pulse-width modulation (PWM) switching frequency which allows the use of small external components. The ISL8011 includes a pair of low ON-resistance P-Channel and N-Channel internal MOSFETs to maximize efficiency and minimize external component count. 100% duty-cycle operation allows less than 200mV dropout voltage at 1.2A. The ISL8011 offers a 200ms Power-On-Reset (POR) timer at power-up. When shut down, the ISL8011 discharges the output capacitor. Other features include internal digital soft-start, enable for power sequence, overcurrent protection, and thermal shut-down. The ISL8011 is offered in a 10 Ld 3x3mm DFN package with 1mm maximum height. The complete converter occupies less than 1cm2 area. Ordering Information PART NUMBER PART (Note) MARKING TEMP. RANGE (°C) June 7, 2007 AN1329.0 Features • High Efficiency Synchronous Buck Regulator with up to 95% Efficiency • 2.7V to 5.5V Supply Voltage • 1.2A Guaranteed Output Current • 100% Maximum Duty Cycle • Peak Current Limiting, Short Circuit Protection • 200ms Power-On Reset • 3% Output Accuracy Over Temperature/Load/Line • Less than 1µA Logic Controlled Shut-down Current • Internal Loop Compensation • Internal Digital Soft-Start • Over-Temperature Protection • Enable • Small 10 Ld 3x3mm DFN Package • Pb-Free Plus Anneal Available (RoHS Compliant) Applications PACKAGE (Pb-Free) PKG. DWG. # • DC/DC POL Modules • µC/µP, FPGA and DSP Power ISL8011IRZ 011Z -40 to +85 10 Ld 3x3 DFN L10.3x3C • Plug-in DC/DC Modules for Routers and Switchers ISL8011IRZ-T 011Z -40 to +85 10 Ld 3x3 DFN L10.3x3C Tape and Reel • Portable Instruments • Test and Measurement Systems ISL8011EVAL1Z Evaluation Board NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020. 1 Pinout ISL8011 (10 LD 3x3 DFN) TOP VIEW PVIN 1 10 PHASE VCC 2 9 PGND EN 3 8 SGND POR 4 7 FB GND 5 6 N/C 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. 2007. All Rights Reserved All other trademarks mentioned are the property of their respective owners. Application Note 1329 What’s inside Evaluating the Other Output Voltage The Evaluation Board Kit contains the following materials: The ISL8011EVAL1Z kit output is preset to 1.6V; however, output voltages can be adjusted from 0.8V to 3.6V by the following equations: • The ISL8011EVAL1Z Rev A board • The ISL8011 datasheet R2 VOUT = 0.8 ⎛ 1 + --------⎞ ⎝ R1⎠ • This EVAL KIT document Recommended Equipment Let’s set R2= 100kΩ The following materials are recommended to perform testing: ( R2 ) R 1 = ------------------------------V OUT ⎛ ----------------⎞ – 1 ⎝ 0.8 ⎠ • 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) (EQ. 1) (EQ. 2) where the 0.8V is the reference voltage. To minimize the accuracy impact on the output voltage, select the R1 and R2 no larger than 100kΩ. TABLE 1. SWITCH 1 SETTINGS • 100MHz quad-trace Oscilloscope • Signal generator Quick Setup Guide J1 ENABLE 1 Center post to top Enable VOUT 2 Center post to bottom Disable VOUT 1. Ensure that the circuit is correctly connected to the supply and loads prior to applying any power. 2. Connect the bias supply to VIN. Plus terminal to (VIN) and negative return to (GND). 3. Verify that position is ON for JP1 jumper. 4. Turn on the power supply. VIN = 2.7V to 5.5V. 5. Verify the output voltage is 1.6V for VOUT 2 AN1329.0 June 7, 2007 Application Note 1329 Schematic TP1 U1 J1 1 VIN PVIN PHASE VCC PGND 2 C1 10µF/6.3V C3 0.1µF R3 100k 3 J2 4 POR 1 5 10 L1 22µH TP2 J4 VO 9 C2 10µF/6.3V EN ISL8011 SGND POR FB GND NC 8 7 R1 100k 6 2 J3 J5 3 GND R2 100k GND TABLE 2. COMPONENT LIST REF DES QTY VALUE TOL. VOLTAGE PACKAGE PART NUMBER MANUFACTURER DESCRIPTION C3 1 0.1µF 603 EMK107BJ104MA Taiyo Yuden Capacitor L1 1 2.2µH 4028 CDRH2D14-2R2 Sumida Inductor C1 1 10µF 20% 6.3V 805 C1608X5R0J106M Panasonic CAP, SMD, 0603, 10µF, 6.3V, 20%, X5R, ROHS C2 1 10µF 20% 6.3V 805 C1608X5R0J106M Panasonic CAP, SMD, 0603, 10µF, 6.3V, 20%, X5R, ROHS R2 1 100k 1% 100V 603 various RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS R3 1 100k 1% 100V 603 various RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS R1 1 100k 1% 100V 603 various RES, SMD, 0603, 100k, 1/10W, 1%, TF, ROHS U1 1 ISL8011 DFN-10 ISL8011 3 Intersil AN1329.0 June 7, 2007 Application Note 1329 ISL8011EVAL1Z Board Layout FIGURE 1. TOP COMPONENTS FIGURE 2. BOTTOM LAYER 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 4 AN1329.0 June 7, 2007