DS89C21
DS89C21 Differential CMOS Line Driver and Receiver Pair
Literature Number: SNLS091B
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
nMeets TIA/EIA-422-A (RS-422) and CCITT V.11
recommendation
nLOW POWER design — 15 mW typical
nGuaranteed AC parameters:
— Maximum driver skew 2.0 ns
— Maximum receiver skew 4.0 ns
nExtended temperature range: −40˚C to +85˚C
nAvailable in SOIC packaging
nOperates over 20 Mbps
nReceiver OPEN input failsafe feature
Connection Diagram
01175301
Order Number DS89C21TM
See NS Package Number M08A
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
June 1998
DS89C21 Differential CMOS Line Driver and Receiver Pair
© 2004 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
,I
IL
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
= 100Ω2.0 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
= 150Ω2.1 3.1 V
V
OD4
Differential Output Voltage R
L
= 3.9 kΩ4.0 6.0 V
V
OC
Common Mode Voltage R
L
= 100Ω2.0 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
,V
TH
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
DS89C21
www.national.com 2
Electrical Characteristics (Notes 2, 3) (Continued)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Pin Min Typ Max Units
RECEIVER CHARACTERISTICS
V
OH
Output HIGH Voltage I
OH
=−6mA 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
DRIVER AND RECEIVER CHARACTERISTICS
I
CC
Supply Current No Load DI = V
CC
or GND V
CC
3.0 6 mA
DI = 2.4V or 0.5V 3.8 12 mA
Switching Characteristics (Note 3)
Over recommended supply voltage and operating temperature ranges, unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Units
DIFFERENTIAL DRIVER CHARACTERISTICS
t
PLHD
Propagation Delay LOW to HIGH R
L
= 100Ω(Figures 2, 3) 2 4.9 10 ns
t
PHLD
Propagation Delay HIGH to LOW C
L
= 50 pF 2 4.5 10 ns
t
SKD
Skew, |t
PLHD
–t
PHLD
| 0.4 2.0 ns
t
TLH
Transition Time LOW to HIGH (Figures 2, 4) 2.2 9 ns
t
THL
Transition Time HIGH to LOW 2.1 9 ns
RECEIVER CHARACTERISTICS
t
PLH
Propagation Delay LOW to HIGH C
L
=50pF (Figures 5, 6) 6 18 30 ns
t
PHL
Propagation Delay HIGH to LOW V
DIFF
= 2.5V 6 17.5 30 ns
t
SK
Skew, |t
PLH
–t
PHL
|V
CM
= 0V 0.5 4.0 ns
t
r
Rise Time (Figure 7) 2.5 9 ns
t
f
Fall Time 2.1 9 ns
Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The tables of “Electrical Characteristics” specify conditions for device operation.
Note 2: Current into device pins is defined as positive. Current out of device pins is defined as negative. All voltages are referenced to ground unless otherwise
specified.
Note 3: All typicals are given for VCC = 5.0V and T A= 25˚C.
Note 4: f = 1 MHz, trand tf≤6 ns.
Note 5: ESD Rating: HBM (1.5 kΩ, 100 pF) all pins ≥2000V.
EIAJ (0Ω, 200 pF) ≥250V
Parameter Measurement Information
01175302
FIGURE 1. V
OD
and V
OC
Test Circuit
DS89C21
www.national.com3
Parameter Measurement Information (Continued)
01175303
FIGURE 2. Driver Propagation Delay Test Circuit
01175304
FIGURE 3. Driver Differential Propagation Delay Timing
01175305
FIGURE 4. Driver Differential Transition Timing
01175306
FIGURE 5. Receiver Propagation Delay Test Circuit
DS89C21
www.national.com 4
Parameter Measurement Information (Continued)
01175307
FIGURE 6. Receiver Propagation Delay Timing
01175308
FIGURE 7. Receiver Rise and Fall Times
DS89C21
www.national.com5
Physical Dimensions inches (millimeters) unless otherwise noted
Order Number DS89C21TM
NS Package Number M08A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.
For the most current product information visit us at www.national.com.
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NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS
WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR
CORPORATION. As used herein:
1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform when
properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to result
in a significant injury to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be reasonably
expected to cause the failure of the life support device or
system, or to affect its safety or effectiveness.
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Substances’’ as defined in CSP-9-111S2.
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www.national.com
DS89C21 Differential CMOS Line Driver and Receiver Pair
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