DATASHEET ISL8033, ISL8033A FN6854 Rev 2.00 Dual 3A Low Quiescent Current High Efficiency Synchronous Buck Regulator March 24, 2011 ISL8033 is a dual integrated power controller rated for 3A per Features channel with a 1MHz step-down regulator that is ideal for any Dual 3A High Efficiency Synchronous Buck Regulator with low power low-voltage applications. The ISL8033A offers up to 95% Efficiency 2.5MHz operation for smaller more compacted design. The channels are 180 out-of-phase for input RMS current and EMI 2% Output Accuracy Over-Temperature/Load/Line reduction. It is optimized for generating low output voltages Internal Digital Soft-Start - 1.5ms down to 0.8V each. The supply voltage range is from 2.85V to External Synchronization up to 6MHz (ISL8033) 6V, allowing for the use of a single Li+ cell, three NiMH cells or a regulated 5V input. It has a guaranteed minimum output Internal Current Mode Compensation current of 3A each when ISET is connected to VDD. The output Peak Current Limiting and Hiccup Mode Short Circuit current of each output is selectable by setting ISET pin. Protection The ISL8033, ISL8033A includes a pair of low ON-resistance Adjustable Peak Overload Current P-Channel and N-Channel internal MOSFETs to maximize Negative Current Protection efficiency and minimize external component count. 100% duty-cycle operation allows less than 250mV dropout voltage Pb-Free (RoHS Compliant) at 3A. Applications The ISL8033, ISL8033A offers an independent 1ms Power- Good (PG) timer at power-up. When shutdown, ISL8033, DC/DC POL Modules ISL8033A discharges the output capacitor. Other features C/P, FPGA and DSP Power include internal digital soft-start, enable for power sequence, Plug-in DC/DC Modules for Routers and Switchers controllable soft-stop output discharge during disabled, start- up with pre-biased output, 100% maximum duty cycle for Test and Measurement Systems lowest dropout, 100% duty cycle operation for smooth Li-ion Battery Power Devices transition, less than 8A logic controlled shutdown current, Bar Code Readers independent enable, overcurrent protection, and thermal shutdown. Related Literature The ISL8033, ISL8033A is offered in a 24 Ld 4mmx4mm QFN See AN1606, ISL8033EVAL1Z Application Note package with 1mm maximum height. The complete converter 2 occupies less than 5.46cm area. See AN1611, ISL8033EVAL2Z Application Note 100 90 80 3.3V OUT 70 60 50 V = 5V IN 40 0.0 0.5 1.0 1.5 2.0 2.5 3.0 I (A) OUT FIGURE 1. EFFICIENCY vs LOAD FN6854 Rev 2.00 Page 1 of 18 March 24, 2011 EFFICIENCY (%) ISL8033, ISL8033A Typical Application Circuit L1 OUTPUT1 1.5H INPUT 2.85V TO 6V 1.8V/3A VIN1, 2 LX1 C2 2x22 F VDD C1 C3 PGND 2x22F R2 12pF ISET ISL8033 124k FB1 EN1 R3 100k PG1 SGND L2 SYNC OUTPUT2 1.5H 1.8V/3A LX2 C4 EN2 2x22F C5 PGND 12pF R5 124k PG2 FB2 R6 100k SGND FIGURE 2. TYPICAL APPLICATION DIAGRAM - DUAL INDEPENDENT OUTPUTS TABLE 1. ISL8033 COMPONENT VALUE SELECTION V 0.8V 1.2V 1.5V 1.8V 2.5V 3.3V OUT C1 2x22F 2x22F 2x22F 2x22F 2x22F 2x22F C2 (or C4) 2x22F 2x22F 2x22F 2x22F 2x22F 2x22F C3 (or C5) 12pF 12pF 12pF 12pF 12pF 12pF L1 (or L2) 1.0H~2.2H 1.0H~2.2H 1.0H~2.2H 1.0H~3.3H 1.0H~3.3H 1.0H~4.7H R2 (or R5) 0 50k 87.5k 124k 212.5k 312.5k R3 (or R6) 100k 100k 100k 100k 100k 100k TABLE 2. ISL8033A COMPONENT VALUE SELECTION V 0.8V 1.2V 1.5V 1.8V 2.5V 3.3V OUT C1 2x22F 2x22F 2x22F 2x22F 2x22F 2x22F C2 (or C4) 2x22F 2x22F 2x22F 2x22F 2x22F 2x22F C3 (or C5) 12pF 12pF 12pF 12pF 12pF 12pF L1 (or L2) 0.47~1.5H 0.47~1.5H 0.47~1.5H 0.47~1.5H 1.0~2.2H 1.0~3.3H R2 (or R5) 0 50k 87.5k 124k 212.5k 312.5k R3 (or R6) 100k 100k 100k 100k 100k 100k NOTE: The minimum output capacitor value is given for different output voltage to make sure the whole converter system is stable. Output capacitance should increase to support faster load transient requirement. TABLE 3. SUMMARY OF DIFFERENCES PART NUMBER SWITCHING FREQUENCY ISL8033 Internally fixed switching frequency F = 1MHz SW ISL8033A Internally fixed switching frequency F = 2.5MHz SW FN6854 Rev 2.00 Page 2 of 18 March 24, 2011