sy89464u Micrel Semiconductor, sy89464u Datasheet - Page 13

• Manufacturer Part Number: sy89464u
• Description: Sy89464u Precision Lvpecl Runt Pulse Eliminator 2 1 Mux With 1 10 Fanout And Internal Termination
• Manufacturer: Micrel Semiconductor

Power-On Reset (POR) Description
The SY89464U includes an internal power-on reset
(POR) function to ensure the RPE logic starts-up in
a known logic state once the power-supply voltage is
stable. An external capacitor connected between
V
the power-on reset function.
The required capacitor value calculation is based
upon the time the system power supply needs to
power up to a minimum of 2.3V. The time constant
for the internal power-on-reset must be greater than
the time required for the power supply to ramp up to
a minimum of 2.3V.
December 2007
CC
and the CAP pin (pin 12) controls the delay for
13
The following formula describes this relationship:
As an example, if the time required for the system
power supply to power up past 2.3V is 12ms, then
the required capacitor value on pin 12 would be:
C(µF) • 1µF
C( F)
C( F)
µ
µ
≥
≥
12(ms/ F)
12(ms/ F)
t
dPS
12ms
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(ms)
µ
µ
M9999-120607-B
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