USERS MANUAL ISL8036ADUALEVAL1Z AN1618 Rev 0.00 Dual 3A Low Quiescent Current High Efficiency Synchronous Buck Regulator January 3, 2011 Description Quick Setup Guide The ISL8036ADUALEVAL1Z kit is intended for use by individuals 1. Ensure that the circuit is correctly connected to the supply with requirements for Point-of-Load applications sourcing from and loads prior to applying any power. 2.85V to 6V. The ISL8036ADUALEVAL1Z evaluation board is 2. Connect the bias supply to VIN1, the plus terminal to VIN1 used to demonstrate the performance of the ISL8036A low and the negative return to PGND1. quiescent current mode converter. 3. Verify that position is ON for SW2 and SW3. The ISL8036A is offered in a 4mmx4mm 24 Ld QFN package 4. Turn on the power supply. with 1mm maximum height. The complete converter occupies 2 5. Verify the output voltage is 1.8V for V and 1.8V for less than 5.46cm area. OUT1 V OUT2. Key Features Evaluating the Other Output Voltage Dual 3A High Efficiency Synchronous Buck Regulator with The ISL8036ADUALEVAL1Z kit outputs are preset to 1.8V for up to 95% Efficiency V and 1.8V for V however, output voltages can be OUT1 OUT2 180 Out-of-Phase adjusted from 0.8V to 3.3V. The output voltage programming resistor, RF12 (or RF22 in Channel 2), will depend on the Power-Goods (PG) Output with 1ms Delay desired output voltage of the regulator. The value for the 2.85V to 6V Supply Voltage feedback resistor is typically between 0 and 750k as 2% Output Accuracy Over-temperature/Load/Line shown in Equations 1 and 2. Lets set RF11/RF21 = 100k , then RF12/RF22 will be: Start-up with Pre-biased Output VOUT1 (EQ. 1) Internal Digital Soft-Start - 1.5ms RF12 = RF11 ------------------ 1 VFB Soft-Stop Output Discharge During Disabled VOUT2 (EQ. 2) RF22 = RF21 ------------------ 1 External Synchronization up to 6MHz VFB Typical 8A Logic Controlled Shutdown Current If the output voltage desired is 0.8V, then RF11 and RF21 should be left unpopulated and RF12 and RF22 should be 100% Maximum Duty Cycle for Lowest Dropout shorted. For faster response performance, add 47pF in parallel Internal Current Mode Compensation to RF12 and RF22. Peak Current Limiting, Hiccup Mode Short Circuit Protection and Over-temperature Protection Mode Control Negative Current Detection and Protection The ISL8036A has a SYNC pin, which connects to logic high or input voltage VIN for PWM internal synchronization. Connect to an external function generator for external Synchronization. Recommended Equipment Negative edge trigger. Do not leave this pin floating. Do not tie The following materials are recommended to perform testing: this pin low (or to GND). 0V to 10V Power Supply with at least 3A source current TABLE 1. SWITCH SETTINGS capability or 5V battery SW2, SW3 ENABLE ON/OFF CONTROL Electronic Loads capable of sinking current up to 3A 1OFF Disable V OUT1,2 Digital Multimeters (DMMs) 3ON Enable V OUT1,2 100MHz quad-trace oscilloscope Signal generator AN1618 Rev 0.00 Page 1 of 7 January 3, 2011ISL8036ADUALEVAL1Z AN1618 Rev 0.00 Page 2 of 7 January 3, 2011 ISL8036ADUALEVAL1Z Schematic LX2 S LX1 S LX2 LX1 A A VIN2 VIN1 VIN2 VIN1 R IN VIN2 VIN1 VIN2 VIN1 0 CIN2 CIN1 22UF A A 22UF PGND PGND PGND22 PGND11 A A LX2 LX1 LX2 LX1 R OUT VIN2 VIN1 VOUT2 VDD VDD VIN1 L1 U1 VIN2 L2 VIN1 OPEN EN2 VDD FB EN2 VDD FB R1 R2 R5 PG2 SS VOUT1 ISL8036AIRZ PG2 SS VOUT2 VOUT2 VOUT1 100K FB2 FB2 VOUT2 EN1 VOUT1 EN1 EP VOUT1 S SS VDD C3 C4 C9 C11 C6 C7 VOUT2 S 22UF 22UF 22UF 22UF OPEN OPEN VOUT2 S SS RF22 SYNC C5 A A VOUT1 S 124K 12PF PG1 SYNC R PH PWM A A A A SYNC C1 C2 CDC SYNC S1 PFM 0 OPEN OPEN OPEN CD1 R3 R7 RF12 C10 RF21 PGND1 OPEN OPEN 124K C PH 100K OPEN A A 12PF PGND A OPEN FB1 A PGND RF11 COMP PGND2 COMP 100K A A A A A R13 VDD VDD VIN PG VIN PG VIN1 R11 A 0 52.3K R4 R8 R12 R6 100K 2K C8 2K 100K 150PF R10 R14 ON/EX ON/EX D1 D2 EN1 EN2 OPEN OPEN A S2 S3 OFF OFF SGND SGND 2N7002 2N7002 EN1 EN2 PG2 PG1 EN1 EN2 PG2 Q1 PG1 Q2 A A A A A 0 0 CD2 OPEN COMP COMP LX2 R9 NC PGND2 0 FB1 PGND2 SGND PGND1 PG1 PGND1 SYNC LX1 FB1