USERS MANUAL ISL8502AEVAL1Z AN1703 Rev 0.00 2A Synchronous Buck Regulator with Integrated MOSFETs October 21, 2011 The ISL8502A is a synchronous buck controller with internal Features MOSFETs packaged in a small 4mmx4mm QFN package. The 2A Continuous Output Current ISL8502A can support a continuous load of 2A and has a very wide input voltage range. With the switching MOSFETs Integrated MOSFETs for Small Regulator Footprint integrated into the IC, the complete regulator footprint can be Adjustable Switching Frequency, 500kHz to 1.2MHz very small and provide a much more efficient solution than a Tight Output Voltage Regulation, 1% Over-Temperature linear regulator. Wide Input Voltage Range, 5V 10% or 5.5V to 14V The ISL8502A is capable of standalone operation or it can be Wide Output Voltage Range, from 0.6V used in a master slave combination for multiple outputs that Simple Single-Loop Voltage-Mode PWM Control Design are derived from the same input rail. Multiple slave channels Input Voltage Feed-Forward for Constant Modulator Gain can be individually programmed such that the internal clocks Fast PWM Converter Transient Response are out-of-phase. This method minimizes the ripple on the Lossless r High Side and Low Side Overcurrent input rail. DS(ON) Protection The switching PWM controller drives two internal N-Channel Undervoltage Detection MOSFETs in a synchronous-rectified buck converter topology. Integrated Thermal Shutdown Protection The synchronous buck converter uses voltage-mode control Power-Good Indication with fast transient response. The switching regulator provides a maximum static regulation tolerance of 1% over line, load, Adjustable Soft-Start and temperature ranges. The output is user-adjustable by QFN Package means of external resistors down to 0.6V. - Compliant to JEDEC PUB95 MO-220 QFN (Quad Flat No Leads) package outline The output is monitored for undervoltage events. The switching - Near Chip Scale Package footprint, which improves PCB regulator also has over current protection. Thermal shutdown efficiency and has a thinner profile is integrated. The ISL8502A features a bidirectional Enable pin that allows the part to shut itself down and pull the enable pin Pb-Free (RoHS Compliant) low at the same time. PGOOD Rising Delay (measured from VOUT reaching regulation to PGOOD Rising) has been reduced Applications from 250ms (typical) for ISL8502 to 1ms (typical) for Point of Load Applications ISL8502A (measured at 500kHz switching frequency). Graphics Cards - GPU and Memory Supplies ASIC Power Supplies Pin Configuration Embedded Processor and I/O Supplies ISL8502A DSP Supplies (24 LD QFN) TOP VIEW Ordering Information PART PART TEMP. RANGE PACKAGE PKG. NUMBER MARKING (C) (Pb-free) DWG. 24 23 22 21 20 19 ISL8502AIRZ 85 02AIRZ -40 to +85 24 Ld 4x4 QFN L24.4x4D PGOOD 1 18 VIN (Notes 1, 2, 3) SGND 2 17 PHASE ISL8502AEVAL1Z Evaluation Board NOTES: 3 16 EN PHASE GND 1. Add -T* suffix for tape and reel. Please refer to TB347 for details on reel 29 SYNCH 4 15 PHASE specifications. 2. These Intersil Pb-free plastic packaged products employ special Pb-free 5 14 M/S PHASE material sets, molding compounds/die attach materials, and 100% matte tin plate plus anneal (e3 termination finish, which is RoHS FS 6 13 PGND compliant and compatible with both SnPb and Pb-free soldering 78 9 10 11 12 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. 3. For Moisture Sensitivity Level (MSL), please see device information page for ISL8502A. For more information on MSL please see tech brief TB363. AN1703 Rev 0.00 Page 1 of 10 October 21, 2011 COMP VCC FB PVCC SS BOOT PGND VIN PGND VIN PGND VINISL8502AEVAL1Z Evaluating Other Output Voltages Whats Inside The ISL8502AEVAL kit outputs are preset to 2.5V. For a quick The Evaluation Board Kit contains the following materials: evaluation of output voltages between 0.6V and V -1.7V, the IN The ISL8502A EVAL REVD board following resistors need to be changed in the feedback network as shown in Equations 1 and 2: The ISL8502A datasheet (EQ. 1) R =R ,V V 1 This EVAL KIT document 111 108 OU T FB 1 where R = 17.4k and V =0.6V 108 FB1 Recommended Equipment (EQ. 2) The following materials are recommended to perform testing: R =R ,V V 1 211 208 OU T 2 FB2 0V to 15V power supply with at least 5A source current capability, battery, notebook AC adapter where R = 17.4k and V =0.6V 208 FB2 Two Electronic Loads capable of sinking current up to 5A However, for reliable operation over the entire load and temperature range, it is highly recommended to follow the Digital Multimeters (DMMs) output filter and loop compensation network design guidelines 100MHz quad-trace Oscilloscope as listed in the ISL8502A datasheet. Signal generator (only if the SYNC function needs to be Frequency evaluated) The ISL8502AEVAL can operate at switching frequencies from 500kHz to1.2MHz. R and R are used to program the 104 204 Quick Setup Guide switching frequency through Equation 3: 1. Ensure that the circuit is correctly connected to the supply (EQ. 3) R andR = 48000 f o s ck H z and loads prior to applying any power. 104 204 2. Connect the bias supply to VIN. Plus terminal to J1(VIN) and TABLE 1. SWITCH 1 SETTINGS negative return to J2(GND). SW1 SKIP OPERATING MODE 3. Verify that all positions are ON for S1, EN all, EN 1, EN 2. 1 NC No Connect 4. Turn on the power supply. 2 EN ALL Enable or disable V and V 5. Verify the outputs voltages are 2.5V for V and V . OUT1 OUT2 OUT1 OUT2 3 EN1 Enable or disable V OUT1 4 EN2 Enable or disable V OUT2 Soft-start C107, C207 can be used to adjust the soft-start time. AN1703 Rev 0.00 Page 2 of 10 October 21, 2011