ISL8036ACRSHEVAL1Z

USERS MANUAL ISL8036ACRSHEVAL1Z AN1615 Rev 0.00 Current Sharing 6A Low Quiescent Current High Efficiency Synchronous Buck Nov 29, 2010 Regulator Description Quick Setup Guide The ISL8036ACRSHEVAL1Z 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 ISL8036ACRSHEVAL1Z 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 in current sharing 3. Verify that position is ON for SW2 and SW3. configuration. 4. Turn on the power supply. The ISL8036A is offered in a 4mmx4mm 24 Ld QFN package 5. Verify the output voltage is 1.8V for V , V with 1mm maximum height. The complete converter occupies OUT1 OUT2. 2 less than 5.46cm area. Evaluating the Other Output Voltage The ISL8036ACRSHEVAL1Z kit output is preset to 1.8V Key Features (V = V ) however, output voltage can be adjusted from OUT1 OUT2 Current Sharing 6A High Efficiency Synchronous Buck 0.8V to 3.3V. The output voltage programming resistor, RF22, will Regulator with up to 95% Efficiency depend on the desired output voltage of the regulator. The value 180 Out-of-Phase Providing Low Output Noise for the feedback resistor is typically between 0 and 750k as shown in Equation 1. Power-Goods (PG) Output with 1ms Delay Lets set RF21 = 100k , then RF22 will be: 2.85V to 6V Supply Voltage VOUT (EQ. 1) -------------- RF22 = RF21 1 2% Output Accuracy Over-temperature/Load/Line VFB Start-up with Pre-biased Output If the output voltage desired is 0.8V, then RF21 should be left unpopulated and RF22 should be shorted. For faster response Externally Adjustable Soft-Start Time performance, add 68pF in parallel to RF22. Soft-Stop Output Discharge During Disabled External Synchronization up to 6MHz Mode Control Typical 8A Logic Controlled Shutdown Current The ISL8036A has a SYNC pin, which connects to logic high or input voltage VIN for PWM internal synchronization. Connect to 100% Maximum Duty Cycle for Lowest Dropout an external function generator for external Synchronization. External Current Mode Compensation Negative edge trigger. Do not leave this pin floating. Do not tie this pin low (or to GND) Peak Current Limiting, Hiccup Mode Short Circuit Protection and Over-temperature Protection Enable Control Negative Current Detection and Protection EN1 and EN2 pins should be tied together for current sharing operation. Recommended Equipment TABLE 1. SWITCH SETTINGS The following materials are recommended to perform testing: SW2, SW3 ENABLE ON/OFF CONTROL 0V to 10V Power Supply with at least 7A source current 1OFF Disable V capability or 5V battery OUT 3ON Enable V Electronic Loads capable of sinking current up to 7A OUT Digital Multimeters (DMMs) 100MHz quad-trace oscilloscope Signal generator AN1615 Rev 0.00 Page 1 of 7 Nov 29, 2010ISL8036ACRSHEVAL1Z AN1615 Rev 0.00 Page 2 of 7 Nov 29, 2010 ISL8036ACRSHEVAL1Z 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 0 EN2 VDD FB EN2 VDD R2 FB PG2 SS VOUT1 R1 R5 ISL8036AIRZ PG2 SS DNP VOUT2 VOUT2 VOUT1 100K FB2 VOUT2 FB2 EN1 VOUT1 EP EN1 VOUT1 S SS VDD C3 C4 C9 C11 C6 C7 VOUT2 S 22UF 22UF 22UF 22UF OPEN OPEN VOUT2 S SS C5 RF22 SYNC A A VOUT1 S 22PF 124K SYNC PWM C1 A A PG1 A A R PH SYNC C2 CDC SYNC S1 PFM 0 OPEN OPEN CD1 R3 0.01UF R7 RF21 PGND1 OPEN OPEN C PH 100K 0 A A PGND A OPEN FB1 A PGND COMP PGND2 COMP A A A A A R11 R13 VDD VDD VIN PG VIN PG VIN1 A 30.1K 0 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 CD2 OPEN COMP COMP LX2 R9 NC PGND2 0 FB1 PGND2 SGND PGND1 PG1 PGND1 SYNC LX1