Product category:
Standard Logic Devices
News Release from: Cypress Semiconductor | Subject: CY23FS04 and CY23FS08
Edited by the Electronicstalk Editorial
Team on 24 July 2003
Buffers provide mission-critical clocks
The CY23FS04 and CY23FS08 FailSafe buffers provide an uninterruptible clock source for applications such as storage area networking or wireless basestations.
The CY23FS04 and CY23FS08 FailSafe buffers provide an uninterruptible clock source for applications such as storage area networking or wireless basestations where continuous operation of the system is required to maintain mission-critical data in the event of a primary reference clock failure The unique FailSafe architecture allows for two user-selectable redundancy options: smooth switching to a secondary reference clock or maintaining the frequency of the failed primary reference clock as long as the power supply is operational
This article was originally published on Electronicstalk on 9 Jul 2008 at 8.00am (UK)
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In addition, the devices add another layer of redundancy by providing continuous clock outputs even when both the primary and secondary reference clock fail.
FailSafe buffers rely on an internal digitally controlled crystal oscillator (DCXO), which serves as the backup clock source and drives the output signals.
The DCXO maintains the last frequency and phase information from the reference clock prior to interruption; once the external clock source is restored, the DCXO automatically resynchronises with minimal phase error.
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Because the outputs are driven primarily by the DCXO circuit, and only indirectly through the reference clock, FailSafe buffers completely eliminate the abrupt phase changes that typically occur when the user switches between two asynchronous reference clock sources.
"FailSafe buffers provide a simple and reliable method for clock redundancy and smooth switching in a variety of applications that handle mission-critical data", said Tunc Cenger, Marketing Manager for Cypress's Timing Technology Division.
"In addition, the CY23FS04 and CY23FS08, with their dynamically controlled DCXO circuit, significantly reduce the jitter of the incoming reference clock.
Finally, selectable frequency multiplication and division options complement the rich feature set to create the ultimate clock distribution device for systems with redundancy needs".
FailSafe's internal DCXO allows the user to define a tracking window or range for reference clock phase variations.
This dynamic tuning range can be set to limit excessive input timing variations, such as jitter, as the signal is distributed in the system.
The elimination of such variations leads to more accurate timing topologies, which are therefore capable of operating at higher frequencies.
The CY23FS04 is a 2.5 or 3.3V, 170MHz zero-delay buffer with two reference clock inputs and four phase-aligned outputs.
The CY23FS08 is a 2.5 or 3.3V, 200MHz zero-delay buffer with two reference clock inputs and eight phase-aligned outputs, which can be configured to run at an integer multiple or factor of the reference frequency.
The CY23FS04 is available now in a space-saving 16-pin TSSOP.
The CY23FS08 is available now in a 28-pin SSOP.
Prices range from $4.35 to $6.55 per unit in 25,000 unit quantities.
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