Analog Devices MAX1556 Product Info

• Up to 97% Efficiency
• 95% Efficiency at 1mA Load Current
• Low 16µA Quiescent Current
• 1MHz PWM Switching
• Tiny 3.3µH Inductor
• Selectable 3.3V, 2.5V, 1.8V, 1.5V, 1.3V, 1.2V, 1.0V, and Adjustable Output
• 1.2A Guaranteed Output Current (MAX1556/MAX1556A)
• Voltage Positioning Optimizes Load-Transient Response
• Low 27µA Quiescent Current in Dropout
• Low 0.1µA Shutdown Current
• No External Schottky Diode Required
• Analog Soft-Start with Zero Overshoot Current
• Small, 10-Pin, 3mm x 3mm TDFN Package

The MAX1556/MAX1556A/MAX1557 are low-operating-current (16µA), fixed-frequency step-down regulators. High efficiency, low-quiescent operating current, low dropout, and minimal (27µA) quiescent current in dropout make these converters ideal for powering portable devices from 1-cell Li-ion or 3-cell alkaline/NiMH batteries. The MAX1556 delivers up to 1.2A; has pin-selectable 1.8V, 2.5V, and 3.3V outputs; and is also adjustable. The MAX1557 delivers up to 600mA; has pin-selectable 1V, 1.3V, and 1.5V outputs; and is also adjustable.

The MAX1556/MAX1556A/MAX1557 contain a low-on-resistance internal MOSFET switch and synchronous rectifier to maximize efficiency and dropout performance while minimizing external component count. A proprietary topology offers the benefits of a high fixed-frequency operation while still providing excellent efficiency at both light and full loads. A 1MHz PWM switching frequency keeps components small. Both devices also feature an adjustable soft-start to minimize battery transient loading.

The MAX1556/MAX1556A/MAX1557 are available in a tiny 10-pin TDFN (3mm x 3mm) package.

Applications

• Cell Phones/Smartphones
• Digital Cameras and Camcorders
• Handheld Instruments
• PDAs and Palmtop Computers
• Portable MP3 and DVD Players