an overriding “INHIBIT" input
provides for the removal of the
transmitter output from the line. A
logic “1” signal applied to the
“INHIBIT” takes priority over the
condition of the data inputs and
disables the transmitter (See
Transmitter
Logic
Waveform,
Figure 1). The Transmitter may be
safely operated for an indefinite
period with the bus (point A) short
circuited at 100% duty cycle.
Receiver:
The Receiver section accepts
bi-phase differential data at the
input and produces two TTL signals
at the output. The outputs are DATA
and DATA, and represent positive
and negative excursions of the input
beyond a pre-determined threshold
(See Receiver Logic Waveform,
Figure 2).
The pre-set internal thresholds will
detect data bus signals, point A
Figure 5, exceeding 1.20 Volts
P-P and reject signals less than
0.6 Volts P-P when used with a
transformer (See Figure 5 for
transformer data and typical
connection).
A low level at the RX Strobe
input inhibits the DATA and
DATA outputs. If unused, a 2K
pull-up to +5 Volts
is
recommended.
Figure 1 — Transmitter Logic Waveforms Idealized
DATA IN
DATA IN
INHIBIT
LINE TO LINE
OUTPUT
Note:
DATA and DATA inputs must be complementary waveforms or 50% duty cycle average, with no delays between them,
and must be in the same state during off times (both high or low).
Figure 2 — Receiver Logic Waveforms Idealized (ACT4436D)
LINE TO LINE
INPUT
STROBE
DATA OUT
DATA OUT
Note overlap
Aeroflex Circuit Technology
2
SCD4436D REV B 3/10/98/98 Plainview NY (516) 694-6700
AEROFLEX [ AEROFLEX CIRCUIT TECHNOLOGY ]
