AN-6047 Datasheet, PDF (1/4 Pages) Fairchild Semiconductor – FIN324C Reset and Standby

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AN-6047 FIN324C Reset and Standby
Summary
The FIN324C is designed with both a reset and a standby pin.
These two pins are similar in function, but allow versatility in
the system design. This application note discusses the
differences between the two pins, system implementation, and
how to debug issues.
Deserializer enabled
Reset vs. Standby
Although very similar, the reset and standby pins function
differently. Unlike the standby pin, both the serializer and
deserializer have the reset pin. When reset is in LOW state, the
device is in a power-down mode. The power-down mode
consumes less than 10µA of power. When reset is asserted
HIGH, all registers and outputs are reset to initial states. The
reset is designed with an input filter, which delays the internal
reset by 15µs to ensure that voltage transients do not cause an
unwanted reset of the device.
Only the serializer is designed with the standby pin. The
deserializer monitors the level of the CTL lines to enter or exit
standby. When the serializer’s standby pin is in the LOW state,
the serializer pulls all four CTL lines to the rail. This CTL
voltage level puts the deserializer into standby mode. When
the serializer’s standby pin is asserted HIGH, the serializer
drives all four CTL lines to ground. This LOW state enables
the deserializer (see Figure 1). Unlike reset, standby does not
reset the register and outputs; they remain in their last-known
state.
Figure 1 – CTL Enable Pulse
To assert the serializer and deserializer into reset or standby,
only one of the pins must be pulled LOW. For example, if
reset is LOW on both the serializer and deserializer and
standby is HIGH, the devices are reset. To enable the device,
both reset and standby must be HIGH. To enable the serializer
and deserializer, the deserializer’s reset pin must be HIGH and
the serializer’s reset and standby pins must be HIGH. See
Tables 1&2 for serializer and deserializer comparisons.
© 2006 Fairchild Semiconductor Corporation
Rev. 1.0.3 • 8/22/07
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