AX3702

1.5MHz, 2A, VFB=0.6V Synchronous

Step-Down Converter



GENERAL DESCRIPTION

AX3702 is a high efficiency monolithic synchronous buck regulator using a constant

on-time (COT) architecture. The device is available in an adjustable version. Supply current

with no load is about 30uA and drops to <1uA in shutdown. The 2.5V to 6.0V input voltage

range makes AX3702 ideally suited for single Li-Ion, two to four AA battery-powered

applications. 100% duty cycle provides low dropout operation, extending battery life in

portable systems. The constant on-time control scheme simplifies loop compensation and

offers excellent load transient response. The high gain error amplifier in the control loop

provides excellent load and line regulation. Proprietary adaptive on-time helps AX3702 to

achieve nearly constant switching frequency across load range. AX3702 has cycle-by-cycle

current limit and hiccup mode to protect over-load or short circuit fault conditions. Switching

frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and

capacitors. The internal synchronous switch increases efficiency and decreases need of an

external Schottky diode. Low output voltages are easily supported with the 0.6V feedback

reference voltage. AX3702 is available in small SOT-23-5L, SOT-23-6L, TDFN-10L (3*3),

and SOP-8L-EP packages.



FEATURES

- 2.5V to 6.0V Input Voltage Range

- Output Voltage from 0.6V to VIN

- High Efficiency: Up to 92%

- 1.5MHz Switching Frequency Operation

- 2A Output Current

- Quiescent Current: 30uA (input < 4.2V)

- No Schottky Diode Required

- 100% Duty Cycle in Dropout

- 0.6V Reference Allows Low Output Voltages

- Internal 1msec Soft-Start

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

Output Capacitors

- Cycle-by cycle Current limit Protection

- Hiccup Mode for Short Circuit and Over-Load Protect

- ≤ 1µA Shutdown Current

- SOT-23-5L, SOT-23-6L, TDFN-10L (3*3), and SOP-8L-EP Pb-Free packages

- RoHS and Halogen free compliance.

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Rev1.4 Sep.30, 2021