Product News I Power Management
Micropower pushbutton on/off controller provides automatic turn-on/off capabilities
Linear Technology has introduced the LTC2955 pushbutton on/off controller that can manage 1.5V to 36V system power via a pushbutton interface or the presence of a supply. Unlike other pushbutton controllers that initiate system power-ups only with the toggle of a pushbutton, the LTC2955 will automatically turn 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 device’s wide operating range of 1.5V to 36V 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 ±36V and ESD strikes up to ±25kV, 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 1.2µA 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 3mm x 2mm DFN or 8-lead ThinSOT package.
Linear Technology |
www.linear.com
Phihong extender provides gigabit data rates for devices in remote location
Phihong USA is releasing a new IEEE802.3at- powered extender for powering IEEE802.3af- compliant applications located up to 660 feet from a network switch. Designated the POE16S- 1AFG, the extender is powered by a PoE Plus input of 33.6W from a midspan or power injector for an output of 19.6W that is compliant with the IEEE802.3af standard. The POE16S- 1AFG may also operate at gigabit Base-T data rates for applications in remote locations including wireless access points and security devices such as IP cameras and sensors. “Users expanding their security or wireless networks may run into expensive installation costs when realising that they need to deploy devices outside the IEEE mandated perimeter of 100 meters from a network switch,” said Keith Hopwood, vice president of marketing for Phihong USA. “The new extender will allow users to place devices discriminately without needing to move existing switches or purchase new ones.”
For full functionality the extender is designed to be powered using an IEEE802.3at-compliant power injector or midspan with an output of 33.6W. The extender will then compensate for power drops, boosting voltage back up to 56V with 19.6W IEEE802.3af-compliant output for a device that may be 660 feet from the network switch.
Alternatively the extender can detect IEEE802.3af-compliant outputs and may be operated in tandem with other extenders to extend PoE or data to 990 feet and further. When the input on the extender is connected to another POE16S-1AFG or IEEE802.3af midspan with an output of 19.6W, the extender will have an output of 15.4W for an end device. Power will continue to degrade 20-25% per extension should users wish to extend to further distances. The POE16S-1AFG features over-current and
short-circuit protections and may operate from 0°C to 40°C at gigabit Base-T data rates. When operating at 10Mb or 100Mb Base-T data rates the extender may operate in ambient temperatures up to 55°C.
Phihong |
www.phihongusa.com
New 3A Rad-Hard LDO regulator delivers for high reliability systems
Intersil has enhanced its power management portfolio with the addition of the ISL75051SRH, a radiation tolerant ultra-low dropout voltage regulator (LDO) that can operate over the full military temperature range of -55C to +125C and is offered in a 18-lead hermetic package. The ISL75051SRH is an SMD-approved single output, ultra-low dropout linear regulator that is immune to high dose radiation up to 100krads (Si), and to single event effects without the need for additional diodes or filters, reducing board space and system cost. Dropout voltage is an ultra-low 65mV at 1A, and 225mV at 3A, permitting increased efficiency and battery life. They operate over an input voltage range of 2.2V to 6.0V and can provide output voltages of 0.8V to 5.0V.
The ISL75051SRH is suitable for DSP, FPGA
www.cieonline.co.uk
and microprocessor core power supplies, post- regulation of switch mode power supplies and down-hole oilfield drilling equipment.
Intersil |
www.intersil.com Components in Electronics March 2012 33
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