Module Integration Manual
Page 11 of 18
Interrogator RF Board (400.00152.xxxx)
6
H
OST
I
NTERFACE
Every line entering from the host is clamped by a 6V TVS diode to CON_GND. Power lines
then pass through a PTC fuse, a Schottkey diode, and a common mode choke before passing
to the power management unit.
Signal lines (except I2CDAT and RST_SW) pass through common mode chokes, 2.2KΩ series
resistors, and a Schmidt trigger receiver or driver. RST_SW passes through a common mode
choke and an additional ferrite. This pan can either connect a physical reset switch to ground or
an open drain signal from the host. I2CDAT passes through a common mode choke, a 330Ω
series resistor, and a 10KΩ pull-up resistor before connecting to the open drain pin of the
communications processor. The host must protect this off-chip signal if it is to connect to a
wired humidity sensor.
