33661 Datasheet, PDF (13/21 Pages) Freescale Semiconductor, Inc – Local Area Network (LIN) Enhanced Physical Interface with Selectable Slew Rate

WAKE INPUT PIN (WAKE)
The WAKE pin is a high-voltage input used to wake up the
device from the Sleep mode. WAKE is usually connected to
an external switch in the application. The typical wake
thresholds are V_SUP / 2.
The WAKE pin has a special design structure and allows
wake-up from both HIGH-to-LOW or LOW-to-HIGH
transitions. When entering into Sleep mode, the LIN monitors
the state of the WAKE pin and stores it as a reference state.
The opposite state of this reference state will be the wake-up
event used by the device to enter again into Normal mode.
FUNCTIONAL DESCRIPTION
FUNCTIONAL PIN DESCRIPTION
An internal filter is implemented (40 µs typical filtering time
delay). WAKE pin input structure exhibits a high impedance,
with extremely low input current when voltage at this pin is
below 14 V. When voltage at the WAKE pin exceeds 14 V,
input current starts to sink into the device. A serial resistor
should be inserted in order to limit the input current mainly
during transient pulses. Recommended resistor value is
33 kΩ.
Important The WAKE pin should not be left open. If the
wake-up function is not used, WAKE should be connected to
ground to avoid false wake-up.
Analog Integrated Circuit Device Data
Freescale Semiconductor
33661
13