• High Efficiency Synchronous Buck Regulator with up to 95% Efficiency
• Selectable Forced PWM Mode and SKIP Mode
• 25μA Quiescent Supply Current in SKIP Mode
• 2.7V to 5.5V Supply Voltage
• 216ms POR Timer
• 3% Output Accuracy Over Temperature/Line/Load
• 600mA Guaranteed Output Current
• Less than 1μA Logic Controlled Shutdown Current
• 100% Maximum Duty Cycle for Lowest Dropout
• Discharge Output Capacitor when Shutdown
• Internal Loop Compensation
• Internal Digital Soft-Start
• Peak Current Limit Protection, Short Circuit Protection
• Over-Temperature Protection
• Enable
• Small 8 Ld 2mmx3mm DFN
• Pb-free (RoHS Compliant)

ISL9105 is a 600mA, 1.6MHz step-down regulator that is ideal for powering low-voltage microprocessors in handheld devices such as PDAs and cellular phones. It is optimized for generating low output voltages down to 0.8V. The supply voltage range is from 2.7V to 5.5V, allowing for the use of a single Li+ cell, three NiMH cells or a regulated 5V input. It has a guaranteed minimum output current of 600mA. 1.6MHz pulse-width modulation (PWM) switching frequency allows for use of small external components. It has flexible operation mode selection of forced PWM mode and low IQ mode with typical 25μA quiescent current for highest light load efficiency to maximize battery life.

The ISL9105 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 600mA output current.

The ISL9105 offers a typical 216ms Power-On-Reset (POR) timer at power-up. The timer output can be reset by RSI. When shutdown, ISL9105 discharges the output capacitor. Other features include internal digital soft-start, enable for power sequence, overcurrent protection, and thermal shutdown.

The ISL9105 is offered in a 2mmx3mm 8 Ld DFN package with 1mm maximum height. The complete converter occupies less than 1cm² area.

• Single Li-Ion Battery-Powered Equipment
• DSP Core Power
• PDAs and Palmtops