MAX1921

PRODUCTION

Low-Voltage, 400mA Step-Down DC-DC Converters in SOT23

Analog Devices MAX1921 Product Info

10 February 2026 7

Features

400mA Guaranteed Output Current

Internal Synchronous Rectifier for >90% Efficiency

Tiny 6-Pin SOT23 Package

Available in 6-Pin TDFN Package (MAX1920)

Up to 1.2MHz Switching Frequency for Small External Components

50µA Quiescent Supply Current

0.1µA Logic-Controlled Shutdown

2V to 5.5V Input Range

Fixed 1.5V, 1.8V, 2.5V, 3V, and 3.3V Output Voltages (MAX1921)

Adjustable Output Voltage (MAX1920)

±1.5% Initial Accuracy

Soft-Start Limits Startup Current

Part details & applications

The MAX1920/MAX1921 step-down converters deliver over 400mA to outputs as low as 1.25V. These converters use a unique proprietary current-limited control scheme that achieves over 90% efficiency. These devices maintain extremely low quiescent supply current (50µA), and their high 1.2MHz (max) operating frequency permits small, low-cost external components. This combination makes the MAX1920/MAX1921 excellent high-efficiency alternatives to linear regulators in space-constrained applications.

Internal synchronous rectification greatly improves efficiency and eliminates the external Schottky diode required in conventional step-down converters. Both devices also include internal digital soft-start to limit input current upon startup and reduce input capacitor requirements.

The MAX1920 provides an adjustable output voltage (1.25V to 4V). The MAX1921 provides factory-preset output voltages (see the Selector Guide). Both are available in space-saving 6-pin SOT23 packages. The MAX1920 is also available in a 6-pin TDFN package.

Applications

Battery-Powered Applications
CDMA Power Amplifier Supply
Next-Generation Wireless handsets
PDAs, Palmtops, and Handy Terminals

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