DS8922,DS8922A,DS8923A
DS8922/DS8922A/DS8923A TRI-STATE RS-422 Dual Differential Line Driver and
Receiver Pairs
Literature Number: SNLS373A
DS8922/DS8922A/DS8923A TRI-STATE®
RS-422 Dual Differential Line Driver and Receiver Pairs
General Description
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
assumes 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
control functions.
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.
Features
n12 ns typical propagation delay
nOutput skew — ±0.5 ns typical
nMeets the requirements of EIA Standard RS-422
nComplementary Driver Outputs
nHigh differential or common-mode input voltage ranges
of ±7V
n±0.2V receiver sensitivity over the input voltage range
nReceiver input fail-safe circuitry
nReceiver input hysteresis — 70 mV typical
nGlitch free power up/down
nTRI-STATE outputs
Connection Diagrams
DS8922A Dual-In-Line
00851101
Order Number DS8922M, DS8922N,
DS8922AM or DS8922AN
See NS Package Number M16A or N16E
TRI-STATE®is a registered trademark of National Semiconductor Corp.
July 2004
DS8922/DS8922A/DS8923A TRI-STATE RS-422 Dual Differential Line Driver and Receiver Pairs
© 2004 National Semiconductor Corporation DS008511 www.national.com
Connection Diagrams (Continued)
DS8923A Dual-In-Line
00851102
Order Number DS8923AM, DS8923AN,
See NS Package Number M16A or N16E
DS8922/22A
EN1 EN2 RO1 RO2 DO1 DO2
0 0 ACTIVE ACTIVE ACTIVE ACTIVE
1 0 HI-Z ACTIVE HI-Z ACTIVE
0 1 ACTIVE HI-Z ACTIVE HI-Z
1 1 HI-Z HI-Z HI-Z HI-Z
DS8923A
DEN REN RO1 RO2 DO1 DO2
0 0 ACTIVE ACTIVE ACTIVE ACTIVE
1 0 ACTIVE ACTIVE HI-Z HI-Z
0 1 HI-Z HI-Z ACTIVE ACTIVE
1 1 HI-Z HI-Z HI-Z HI-Z
DS8922/DS8922A/DS8923A
www.national.com 2
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 7V
Drive Input Voltage −0.5V to +7V
Output Voltage 5.5V
Receiver Output Sink Current 50 mA
Receiver Input Voltage ±10V
Differential Input Voltage ±12V
Maximum Package Power Dissipation @+25˚C
M Package 1300 mW
N Package 1450 mW
Derate M Package 10.4 mW/˚C above +25˚C
Derate N Package 11.6 mW/˚C above +25˚C
Storage Temperature Range −65˚C to +165˚C
Lead Temp. (Soldering, 4 seconds) 260˚C
ESD Rating (HBM) 2000V+
Recommended Operating
Conditions
Min Max Units
Supply Voltage 4.5 5.5 V
Temperature (T
A
) 0 70 ˚C
DS8922/22A and DS8923A Electrical Characteristics(Notes 2, 3, 4)
Symbol Conditions Min Typ Max Units
RECEIVER
V
TH
−7V ≤V
CM
≤+7V −200 ±35 +200 mV
V
HYST
−7V ≤V
CM
≤+7V 15 70 mV
R
IN
V
IN
= −7V, +7V (Other Input = GND) 4.0 6.0 kΩ
I
IN
V
IN
= 10V 3.25 mA
V
IN
= −10V −3.25 mA
V
OH
V
CC
= MIN, I
OH
= − 400 µA 2.5 V
V
OL
V
CC
= MAX, I
OL
= 8 mA 0.5 V
I
SC
V
CC
= MAX, V
OUT
= 0V −15 −100 mA
DRIVER
V
OH
V
CC
= MIN, I
OH
= −20 mA 2.5 V
V
OL
V
CC
= MIN, I
OL
= +20 mA 0.5 V
I
OFF
V
CC
= 0V, V
OUT
= 5.5V 100 µA
|VT|–| VT | 0.4 V
VT 2.0 V
|V
OS
–V
OS
| 0.4 V
I
SC
V
CC
= MAX, V
OUT
= 0V −30 −150 mA
DRIVER and RECEIVER
I
OZ
V
OUT
= 2.5V 50 µA
TRI-STATE V
CC
= MAX V
OUT
= 0.4V −50 µA
Leakage
I
CC
V
CC
= MAX ACTIVE 76 mA
TRI-STATE 78 mA
DRIVER and ENABLE INPUTS
V
IH
2.0 V
V
IL
0.8 V
I
IL
V
CC
= MAX, V
IN
= 0.4V −40 −200 µA
I
IH
V
CC
= MAX, V
IN
= 2.7V 20 µA
I
I
V
CC
= MAX, V
IN
= 7.0V 100 µA
V
CL
V
CC
= MIN, I
IN
= −18 mA −1.5 V
DS8922/DS8922A/DS8923A
www.national.com3
Receiver Switching Characteristics
(Figures 1, 2, 3)
Parameter Conditions Min Typ Max Units
8922 8922A/23A
T
pLH
CL = 30 pF 12 22.5 20 ns
T
pHL
CL = 30 pF 12 22.5 20 ns
|T
pLH
–T
pHL
| CL = 30 pF 0.5 5 3.5 ns
Skew (Channel to Channel) CL = 30 pF 0.5 3.0 2.0 ns
T
pLZ
CL = 15 pF S2 Open 15 ns
T
pHZ
CL = 15 pF S1 Open 15 ns
T
pZL
CL = 30 pF S2 Open 20 ns
T
pZH
CL = 30 pF S1 Open 20 ns
Driver Switching Characteristics
Parameter Conditions Min Typ Max Units
8922 8922A/23A
SINGLE ENDED CHARACTERISTICS (Figures 4, 5, 6, 8)
T
pLH
CL=30pF 12 15 15 ns
T
pHL
CL=30pF 12 15 15 ns
T
TLH
CL = 30 pF 5 10 10 ns
T
THL
CL = 30 pF 5 10 10 ns
|T
pLH
–T
pHL
| CL=30pF 0.5 ns
Skew CL = 30 pF (Note 5) 0.5 5 3.5 ns
Skew (Channel to Channel) 0.5 3.0 2.0 ns
T
pLZ
CL=30pF 15 ns
T
pHZ
CL=30pF 15 ns
T
pZL
CL=30pF 20 ns
T
pZH
CL=30pF 20 ns
DIFFERENTIAL SWITCHING CHARACTERISTICS (Note 6), (Figure 4)
T
pLH
CL=30pF 12 15 15 ns
T
pHL
CL=30pF 12 15 15 ns
|T
pLH
–T
pHL
| CL = 30 pF 0.5 6.0 2.75 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 device
should be operated at these limits. The Table of “Electrical Characteristics” provides conditions for actual device operation.
Note 2: All currents into device pins are shown as positive values; all currents out of the device are shown as negative; all voltages are referenced to ground unless
otherwise specified. All values shown as max or min are classified on absolute value basis.
Note 3: All typical values are VCC =5V,T
A= 25˚C.
Note 4: Only one output at a time should be shorted.
Note 5: Difference between complementary outputs at the 50% point.
Note 6: Differential Delays are defined as calculated results from single ended rise and fall time measurements. This approach in establishing AC performance
specifications has been taken due to limitations of available Automatic Test Equipment (ATE).
The calculated ATE results assume a linear transition between measurement points and are a result of the following equations:
Where:
Tcp = Crossing Point
Tra, Trb, Tfa and Tfb are time measurements with respect to the input.
DS8922/DS8922A/DS8923A
www.national.com 4
Switching Time Waveforms
00851103
AC Test Circuits and Switching Waveforms
00851104
FIGURE 1.
00851105
FIGURE 2.
DS8922/DS8922A/DS8923A
www.national.com5
AC Test Circuits and Switching Waveforms (Continued)
00851106
S1 S2 S3
T
PLZ
Closed Open +2.5V
T
PHZ
Open Closed −2.5V
T
PZL
Closed Open +2.5V
T
PZH
Open Closed −2.5V
FIGURE 3.
00851107
FIGURE 4.
00851108
FIGURE 5.
DS8922/DS8922A/DS8923A
www.national.com 6
AC Test Circuits and Switching Waveforms (Continued)
00851109
FIGURE 6.
00851110
FIGURE 7.
00851113
FIGURE 8.
DS8922/DS8922A/DS8923A
www.national.com7
Typical Performance Characteristics (DS8923A)
Driver V
OH
vs I
OH
vs Temperature Driver V
OH
vs I
OH
vs V
CC
00851114 00851115
Driver V
OL
vs I
OL
vs Temperature Driver V
OL
vs I
OL
vs V
CC
00851116 00851117
Receiver V
OH
vs I
OH
vs Temperature Receiver V
OH
vs I
OH
vs V
CC
00851118 00851119
DS8922/DS8922A/DS8923A
www.national.com 8
Typical Performance Characteristics (DS8923A) (Continued)
Receiver V
OL
vs I
OL
vs Temperature Receiver V
OL
vs I
OL
vs V
CC
00851120 00851121
Driver Differential Propagation
Delay vs Temperature
Driver Differential Propagation
Delay vs V
CC
00851122 00851123
Receiver Propagation
Delay vs Temperature
Receiver Propagation
Delay vs V
CC
00851124 00851125
DS8922/DS8922A/DS8923A
www.national.com9
Typical Performance Characteristics (DS8923A) (Continued)
Driver V
OD
vs Temperature Driver V
OD
vs V
CC
00851126 00851127
Driver V
OD
vs R
L
Driver Differential Transition
Time vs Temperature
00851128 00851129
Driver Differential Transition
Time vs V
CC
Supply Current vs
Temperature
00851130 00851131
DS8922/DS8922A/DS8923A
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Typical Performance Characteristics (DS8923A) (Continued)
Supply Current vs V
CC
I
CC
vs Driver Switching Frequency
00851132 00851133
Driver Short Circuit Current
vs Temperature
Driver Short Circuit
Current vs V
CC
00851134 00851135
Receiver Short Circuit
Current vs Temperature
Receiver Short Circuit
Current vs V
CC
00851136 00851137
DS8922/DS8922A/DS8923A
www.national.com11
Typical Applications
ESDI Application
00851111
ST504 and ST412 Applications
00851112
DS8922/DS8922A/DS8923A
www.national.com 12
Physical Dimensions inches (millimeters) unless otherwise noted
SO Package (M)
Order Number DS8922M, DS8922AM, or DS8923AM
NS Package Number M16A
Molded Dual-In-Line Package (N)
Order Number DS8922N, DS8922AN, or DS8923AN
NS Package Number N16E
DS8922/DS8922A/DS8923A
www.national.com13
Notes
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DS8922/DS8922A/DS8923A TRI-STATE RS-422 Dual Differential Line Driver and Receiver Pairs
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.
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