NSC DS8923AN, DS8923AM, DS8922N, DS8922M, DS8922AN Datasheet
...
June 1998
DS8922/DS8922A/DS8923A TRI-STATE RS-422 Dual Differential Line Driver and Receiver Pairs
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 specifically 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 incorporated (typically 70 mV) to improve noise margin for slowly
changing input waveforms. An input fail-safe circuit is provided 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 transmission 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.
Connection Diagrams
DS8922A Dual-In-Line
Power up/down circuitry is featured which will TRI-STATE
the outputs and prevent erroneous glitches on the transmission lines during system power up or power down operation.
The DS8922/22A and DS8923A are designed to be compatible with TTL and CMOS.
Features
n 12 ns typical propagation delay
n Output skew —
n Meets the requirements of EIA Standard RS-422
n Complementary Driver Outputs
n High differential or common-mode input voltage ranges
±
of
7V
±
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
±
0.5 ns typical
DS008511-1
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 www.national.com
Connection Diagrams (Continued)
DS8923A Dual-In-Line
DS008511-2
Order Number DS8923AM, DS8923AN,
See NS Package Number M16A or N16E
Truth Tables
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
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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
Differential Input Voltage
@
Maximum Package Power Dissipation
+25˚C
M Package 1300 mW
±
10V
±
12V
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
Recommended Operating
Conditions
Supply Voltage 4.5 5.5 V
Temperature (T
) 0 70 ˚C
A
Min Max Units
DS8922/22A and DS8923A Electrical Characteristics(Notes 2, 3, 4)
Symbol Conditions Min Typ Max Units
RECEIVER
V
TH
V
HYST
R
IN
I
IN
V
OH
V
OL
I
SC
−7V ≤ VCM≤ +7V −200
−7V ≤ VCM≤ +7V 15 70 mV
=
V
−7V, +7V (Other Input=GND) 4.0 6.0 kΩ
IN
=
V
10V 3.25 mA
IN
=
V
−10V −3.25 mA
IN
=
V
CC
=
V
CC
=
V
CC
MIN, I
MAX, I
MAX, V
=
− 400 µA 2.5 V
OH
=
8 mA 0.5 V
OL
=
0V −15 −100 mA
OUT
DRIVER
V
OH
V
OL
I
OFF
=
V
CC
=
V
CC
=
V
CC
MIN, I
MIN, I
0V, V
=
−20 mA 2.5 V
OH
=
+20 mA 0.5 V
OL
=
5.5V 100 µA
OUT
|VT|–| VT |
VT 2.0 V
|V
I
SC
| 0.4 V
OS–VOS
=
V
MAX, V
CC
=
0V −30 −150 mA
OUT
DRIVER and RECEIVER
I
OZ
TRI-STATE V
=
MAX V
CC
=
V
2.5V 50 µA
OUT
=
0.4V −50 µA
OUT
Leakage
I
CC
=
V
MAX ACTIVE 76 mA
CC
TRI-STATE 78 mA
DRIVER and ENABLE INPUTS
V
IH
V
IL
I
IL
I
IH
I
I
V
CL
=
V
MAX, V
CC
=
V
MAX, V
CC
=
V
MAX, V
CC
=
V
MIN, I
CC
=
0.4V −40 −200 µA
IN
=
2.7V 20 µA
IN
=
7.0V 100 µA
IN
=
−18 mA −1.5 V
IN
2.0 V
±
35 +200 mV
0.4 V
0.8 V
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Receiver Switching Characteristics
(
Figures 1, 2, 3
)
Parameter Conditions Min Typ Max Units
8922 8922A/23A
T
pLH
T
pHL
|T
pLH–TpHL
|CL
CL=30 pF 12 22.5 20 ns
CL=30 pF 12 22.5 20 ns
=
30 pF 0.5 5 3.5 ns
Skew (Channel to Channel) CL=30 pF 0.5 3.0 2.0 ns
T
pLZ
T
pHZ
T
pZL
T
pZH
CL=15 pF S2 Open 15 ns
CL=15 pF S1 Open 15 ns
CL=30 pF S2 Open 20 ns
CL=30 pF S1 Open 20 ns
Driver Switching Characteristics
Parameter Conditions Min Typ Max Units
8922 8922A/23A
SINGLE ENDED CHARACTERISTICS (
T
pLH
T
pHL
T
TLH
T
THL
|T
pLH–TpHL
|CL
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
T
pHZ
T
pZL
T
pZH
DIFFERENTIAL SWITCHING CHARACTERISTICS (Note 6), (
T
pLH
T
pHL
|T
pLH–TpHL
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 intodevicepinsareshown 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 V
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:
|CL
=
5V, T
CC
Figures 4, 5, 6, 8
)
CL=30 pF 12 15 15 ns
CL=30 pF 12 15 15 ns
CL=30 pF 5 10 10 ns
CL=30 pF 5 10 10 ns
=
30 pF 0.5 ns
CL=30 pF 15 ns
CL=30 pF 15 ns
CL=30 pF 20 ns
CL=30 pF 20 ns
Figure 4
)
CL=30 pF 12 15 15 ns
CL=30 pF 12 15 15 ns
=
30 pF 0.5 6.0 2.75 ns
=
25˚C.
A
Where:
Tcp=Crossing Point
Tra, Trb, Tfa and Tfb are time measurements with respect to the input.
www.national.com 4
Switching Time Waveforms
AC Test Circuits and Switching Waveforms
FIGURE 1.
DS008511-3
DS008511-4
FIGURE 2.
DS008511-5
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