SI53156 Datasheet, PDF (7/22 Pages) Silicon Laboratories – PCI-EXPRESS GEN 1, GEN 2, GEN 3, AND GEN 4 FANOUT BUFFER

Si53156
2. Functional Description
2.1. OE Pin Definition
The OE pins are active high inputs used to enable and disable the output clocks. To enable the output clock, the
OE pin needs to be logic high and the I²C output enable bit needs to be logic high. There are two methods to
disable the output clocks: the OE is pulled to a logic low, or the I²C enable bit is set to a logic low. The OE pins are
required to be driven at all times even though they have an internal 100 k resistor.
2.2. OE Assertion
The OE signals are active high inputs used for synchronous stopping and starting the DIFF output clocks
respectively while the rest of the clock generator continues to function. The assertion of the OE signal by making it
logic high causes stopped respective DIFF outputs to resume normal operation. No short or stretched clock pulses
are produced when the clock resumes. The maximum latency from the assertion to active outputs is no more than
two to six output clock cycles.
2.3. OE Deassertion
When the OE pin is deasserted by making it logic low, the corresponding DIFF output is stopped, and the final output
state is driven low.
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