DS89C21 Datasheet, PDF (1/6 Pages) National Semiconductor (TI) – Differential CMOS Line Driver and Receiver Pair

June 1998
DS89C21
Differential CMOS Line Driver and Receiver Pair
General Description
The DS89C21 is a differential CMOS line driver and receiver
pair, designed to meet the requirements of TIA/EIA-422-A
(RS-422) electrical characteristics interface standard. The
DS89C21 provides one driver and one receiver in a mini-
mum footprint. The device is offered in an 8-pin SOIC pack-
age.
The CMOS design minimizes the supply current to 6 mA,
making the device ideal for use in battery powered or power
conscious applications.
The driver features a fast transition time specified at 2.2 ns,
and a maximum differential skew of 2 ns making the driver
ideal for use in high speed applications operating above
10 MHz.
The receiver can detect signals as low as 200 mV, and also
incorporates hysteresis for noise rejection. Skew is specified
at 4 ns maximum.
The DS89C21 is compatible with TTL and CMOS levels (DI
and RO).
Features
n Meets TIA/EIA-422-A (RS-422) and CCITT V.11
recommendation
n LOW POWER design — 15 mW typical
n Guaranteed AC parameters:
— Maximum driver skew 2.0 ns
— Maximum receiver skew 4.0 ns
n Extended temperature range: −40˚C to +85˚C
n Available in SOIC packaging
n Operates over 20 Mbps
n Receiver OPEN input failsafe feature
Connection Diagram
Truth Tables
DS011753-1
Order Number DS89C21TM
See NS Package Number M08A
Driver
Input
DI
H
L
Outputs
DO
DO*
H
L
L
H
Receiver
Inputs
RI–RI*
V_DIFF ≥ +200 mV
V_DIFF ≤ −200 mV
OPEN†
†Non-terminated
Output
RO
H
L
H
© 1998 National Semiconductor Corporation DS011753
www.national.com