Micropower pushbutton on/off controller delivers automatic turn-on/off capabilities

March 08, 2012 // Paul Buckley

Linear Technology Corporation is introducing a pushbutton on/off controller that manages 1.5V to 36 V system power via a pushbutton interface or the presence of a supply. Unlike typical pushbutton controllers that initiate system power-ups only with the toggle of a pushbutton, the LTC2955 automatically turns on a system when power is applied from a primary or secondary supply, such as a wall adapter or car battery.

When powered up, the LTC2955 can power down a system via pushbutton and optionally can use interrupt logic to request a system power-down in menu-driven applications ('soft' shutdown), or automatically power-down a system if the supply is removed. Absolutely no code is required to configure the device. The LTC2955 is a simple, yet configurable, high voltage pushbutton controller that provides a common set of on/off power options.     

The LTC2955's wide operating range of 1.5 V to 36 V caters to single cell, multicell and high voltage applications, including desktop and notebook computers, consumer electronics, portable instruments and automotive electronics. The robust pushbutton input handles wide voltage swings of up to ±36 V and ESD strikes up to ±25 kV, and is designed to operate in noisy environments. A mode select pin enables users to select automatic turn-on and turn-off combinations, and battery run time is maximized thanks to a low 1.2 µA quiescent current.

The LTC2955's power good output, interrupt output, and kill input provide simple interfacing with an optional microprocessor. In case a microprocessor fails to respond to an interrupt request, an adjustable turn-off timer enables users to set the required amount of time a pushbutton must be depressed in order to force a system power-down.     

The LTC2955 is available in both positive (LTC2955-1) and negative (LTC2955-2) enable polarities, and in a 10-pin 3 mm x 2 mm DFN or 8-lead ThinSOT package.   

www.linear.com/pushbutton

Technical papers     

• Lighting Applications – Lighting the Way with LEDs
• Risk Mitigation for Powering Low Voltage Processors & FPGAs Directly from Intermediate Bus Voltage
• Haswell - the 4th Generation Intel@ Core ™ Processor Platform
• 60V Buck-Boost Controller Drives High Power LEDs

December 15, 2011 | Texas instruments | 222901974

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