sy89843u Micrel Semiconductor, sy89843u Datasheet - Page 9

• Manufacturer Part Number: sy89843u
• Description: Precision Lvpecl Runt Pulse Eliminator 2 1 Mux With 1 2 Fanout And Internal Termination
• Manufacturer: Micrel Semiconductor

May 2007
Case #2 Input Clock Failure: Switching from a
selected clock stuck HIGH to a valid clock (RPE
enabled).
If CLK1 fails HIGH before the RPE MUX selects
CLK2 (using the SEL pin), then the switchover will
occur in three stages.
Note:
Output shows extended clock cycle during switchover. Pulse width for both high and low of this cycle will always be greater than 50% of
the CLK2 period.
Timing Diagram 2
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•
•
9
Stage 1: The output will remain HIGH for a
limited number of pulses of CLK2.
Stage 2: The output will switch to LOW and
then remain LOW for a limited number of
falling edges of CLK2.
Stage 3: The output will follow CLK2
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