RS-422 Dual Differential Line Driver and Receiver Pairs
The DS8922/22A and DS8923A are Dual Differential Line
Driver and Receiver pairs. These devices are designed spe-
cifically for applications meeting the ST506, ST412 and
ESDI Disk Drive Standards. In addition, the devices meet the
requirements of the EIA Standard RS-422.
These devices offer an input sensitivity of 200 mV over a
±7V common mode operating range. Hysteresis is incorpo-
rated (typically 70 mV) to improve noise margin for slowly
changing input waveforms. An input fail-safe circuit is pro-
vided such that if the receiver inputs are open the output as-
sumes the logical one state.
The DS8922A and DS8923A drivers are designed to provide
unipolar differential drive to twisted pair or parallel wire trans-
mission lines. Complementary outputs are logically ANDed
and provide an output skew of 0.5 ns (typ.) with propagation
delays of 12 ns.
Both devices feature TRI-STATE outputs. The DS8922/22A
have independent control functions common to a driver and
receiver pair. The DS8923A has separate driver and receiver
Power up/down circuitry is featured which will TRI-STATE
the outputs and prevent erroneous glitches on the transmis-
sion lines during system power up or power down operation.
The DS8922/22A and DS8923A are designed to be compat-
ible with TTL and CMOS.
n 12 ns typical propagation delay
n Output skew — ±0.5 ns typical
n Meets the requirements of EIA Standard RS-422
n Complementary Driver Outputs
n High differential or common-mode input voltage ranges
n ±0.2V receiver sensitivity over the input voltage range
n Receiver input fail-safe circuitry
n Receiver input hysteresis — 70 mV typical
n Glitch free power up/down
n TRI-STATE outputs
Order Number DS8922M, DS8922N,
DS8922AM or DS8922AN
See NS Package Number M16A or N16E
TRI-STATE® is a registered trademark of National Semiconductor Corp.
© 1998 National Semiconductor Corporation DS008511