NSC DS89C21TMX, DS89C21TM Datasheet
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 minimum footprint. The device is offered in an 8-pin SOIC package.
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
Driver
Input Outputs
DI DO DO
*
HHL
LLH
Receiver
Inputs Output
RI–RI
*
RO
V
DIFF
≥ +200 mV H
V
DIFF
≤ −200 mV L
OPEN
†
H
†
Non-terminated
DS011753-1
Order Number DS89C21TM
See NS Package Number M08A
June 1998
DS89C21 Differential CMOS Line Driver and Receiver Pair
© 1998 National Semiconductor Corporation DS011753 www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
)7V
Driver Input Voltage (DI) −1.5V to V
CC
+ 1.5V
Driver Output Voltage (DO,
DO
*
) −0.5V to +7V
Receiver Input Voltage—V
CM
(RI, RI*)
±
14V
Differential Receiver Input
±
14V
Voltage—V
DIFF
(RI, RI*)
Receiver Output Voltage
(RO) −0.5V to V
CC
+0.5V
Receiver Output Current
(RO)
±
25 mA
Storage Temperature Range
(T
STG
) −65˚C to +150˚C
Lead Temperature (T
L
) +260˚C
(Soldering 4 sec.)
Maximum Junction
Temperature 150˚C
Maximum Package Power Dissipation
@
+25˚C
M Package 714 mW
Derate M Package 5.7 mW/˚C above
+25˚C
Recommended Operating
Conditions
Min Max Units
Supply Voltage (V
CC
) 4.50 5.50 V
Operating Temperature (T
A
) −40 +85 ˚C
Input Rise or Fall Time (DI) 500 ns
Electrical Characteristics (Notes 2, 3)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Pin Min Typ Max Units
DRIVER CHARACTERISTICS
V
IH
Input Voltage HIGH 2.0 V
CC
V
V
IL
Input Voltage LOW DI GND 0.8 V
I
IH,IIL
Input Current V
IN
=
V
CC
, GND, 2.0V, 0.8V 0.05±10 µA
V
CL
Input Clamp Voltage I
IN
=
−18 mA −1.5 V
V
OD1
Unloaded Output Voltage No Load DO,
DO
*
4.2 6.0 V
V
OD2
Differential Output Voltage R
L
=
100Ω 2.0 3.0 V
∆V
OD2
Change in Magnitude of V
OD2
5.0 400 mV
for Complementary Output States
V
OD3
Differential Output Voltage R
L
=
150Ω 2.1 3.1 V
V
OD4
Differential Output Voltage R
L
=
3.9 kΩ 4.0 6.0 V
V
OC
Common Mode Voltage R
L
=
100Ω 2.0 3.0 V
∆V
OC
Change in Magnitude of V
OC
2.0 400 mV
for Complementary Output States
I
OSD
Output Short Circuit Current V
OUT
=
0V −30 −115 −150 mA
I
OFF
Output Leakage Current V
CC
=
0V V
OUT
=
+6V 0.03 +100 µA
V
OUT
=
−0.25V −0.08 −100 µA
RECEIVER CHARACTERISTICS
V
TL,VTH
Differential Thresholds V
IN
=
+7V, 0V, −7V RI,
RI
*
−200±25 +200 mV
V
HYS
Hysteresis V
CM
=
0V 20 50 mV
R
IN
Input Impedance V
IN
=
−7V, +7V, Other=0V 5.0 9.5 kΩ
I
IN
Input Current Other Input=0V, V
IN
=
+10V +1.0 +1.5 mA
V
CC
=
5.5V and V
IN
=
+3.0V 0 +0.22 mA
V
CC
=
0V V
IN
=
+0.5V −0.04 mA
V
IN
=
−3V 0 −0.41 mA
V
IN
=
−10V −1.25 −2.5 mA
V
OH
Output HIGH Voltage I
OH
=
−6 mA V
DIFF
=
+1V RO 3.8 4.9 V
V
DIFF
=
OPEN 3.8 4.9 V
V
OL
Output LOW Voltage I
OL
=
+6 mA, V
DIFF
=
−1V 0.08 0.3 V
I
OSR
Output Short Circuit Current V
OUT
=
0V −25 −85 −150 mA
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