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Rev.1.1 Nov.01, 2019

AX3703A

5V Input 2.5A/3A 1.5MHz Synchronous Step-Down

DC/DC Converter



GENERAL DESCRIPTION

AX3703A can operate with input voltage from 2.5V to 5.5V and provide output range from

0.6V to input level, thanks to its 100% duty cycle operation. AX3703A is a 1.5MHz, 2.5A/3A

constant on-time (COT) controlled synchronous step-down converter.

AX3703A consumes extremely low 15µA quiescent current hence achieves superior light

load efficiency. The constant on-time control scheme simplifies loop compensation and offers

excellent load transient response.

AX3703A has cycle-by-cycle current limit and hiccup mode to protect over-load or short

circuit fault conditions. The high gain error amplifier in the control loop provides excellent load and

line regulation. Proprietary adaptive on-time helps AX3703A to achieve nearly constant switching

frequency across load range.

AX3703A is available in low profile SOT23-5L, SOT23-6L and 8 leads DFN 2mm x 2mm

packages.



FEATURES

- AX3703AZ8A: Built-in 90mΩ/60mΩ Power Switches

- AX3703AZ8A: 3A Continuous Output Current

- AX3703ACA: 2.5A Continuous Output Current , 3A Peak Output Current

- AX3703ACA: Built-in 94mΩ/76mΩ Power Switches

- Wide Input Range from 2.5V to 6V

- Proprietary Fast Transient Constant On Time Architecture Stable with low ESR Ceramic

Output Capacitors

- 1.5MHz Switching Frequency

- 15µA Low Quiescent Current

- +/- 2% 0.6V Feedback Voltage

- 1.21V Accurate Enable Threshold

- Up to 95% Efficiency

- 100% Duty Cycle Operation

- Thermal Shutdown Protection

- Internal 1msec Soft-Start