Power supply sequencer enables combination of modules and DC/DC converter ICs

Milpitas, CA – January 12, 2005 – Linear Technology Corporation introduces the LTC2924, a power supply sequencer designed for use with power supplies, including shutdown pins or modules using external N-channel MOSFETS in series. Capable of input monitoring and enabling four supplies in sequence during both power up and power down, the IC provides a simple, flexible and compact solution in a 16-pin SSOP. Tailoring the LTC2924 to a specific application requires no software and designs can be fine tuned during system integration simply by changing resistor and capacitor values.

Multiple LTC2924s can be easily cascaded to sequence eight, twelve or virtually unlimited number of voltages. Yet, with minimal external circuitry, a single LTC2924 can sequence six power supplies. With its precise 1% input monitoring and versatile sequencing abilities, the LTC2924 is ideally suited for multi-supply systems, such as telecommunications equipment, optical systems, servers and base stations.

The LTC2924's comprehensive set of features greatly simplifies the supply sequencing task. For designs using modules or DC/DC converters without enabling inputs, an internally regulated charge pump provides gate drive voltage for the MOSFETs in series following the DC/DC converter. The Timer pin can provide an optional delay between the completion of Power On of one supply while enabling of the next supply. The PowerGood timer sets the time allowed for a power supply to turn on after it has been enabled and asserts a fault should a supply fail to enter regulation within the allotted time interval. The Done pin reports the successful completion of the power supply sequencing to a system controller.

Available from stock and screened to commercial and industrial temperature grades, the LTC2924 is offered at $2.65 for 1000 piece quantities.

Summary of LTC2924 Features:
* Fully sequence and monitor four supplies
* Six with minimal external circuitry
* Cascadable for additional supplies
* Accurate power supply voltage monitoring
* Power off in reverse order or simultaneously
* Charge pump drives external MOSFETs
* Drives power supply shutdown pins with no external pull-up resistors
* Done indicator for both power on and power off
* Power sequencing error detection and reporting
* Adjustable time delay between power supplies
* Power good timer
* 16-lead narrow SSOP

For more information call toll-free 1-800-4-LINEAR (for literature only), or go to the company's web site:

LTC2924 Data Sheet

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