SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
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D OR N PACKAGE
(TOP VIEW)
Generate Either Odd or Even Parity for Nine
Data Lines
Cascadable for n-Bit Parity
Can Be Used to Upgrade Existing Systems
Using MSI Parity Circuits
Package Options Include Plastic
Small-Outline (D) Packages and Standard
Plastic (N) 300-mil DIPs
G
H
NC
I
Σ EVEN
Σ ODD
GND
description
1
14
2
13
3
12
4
11
5
10
6
9
7
8
VCC
F
E
D
C
B
A
NC − No internal connection
These universal 9-bit parity generators/checkers
utilize advanced Schottky high-performance
circuitry and feature odd (Σ ODD) and even (Σ EVEN) outputs to facilitate operation of either odd- or even-parity
applications. The word-length capability is easily expanded by cascading.
These devices can be used to upgrade the performance of most systems utilizing the SN74ALS180 and
SN74AS180 parity generators/checkers. Although the SN74ALS280 and SN74AS280 are implemented without
expander inputs, the corresponding function is provided by the availability of an input (I) at terminal 4 and the
absence of any internal connection at terminal 3. This permits the SN74ALS280 and SN74AS280 to be
substituted for the SN74ALS180 and SN74AS180 in existing designs to produce an identical function even if
the devices are mixed with existing SN74ALS180 and SN74AS180 devices.
All SN74AS280 inputs are buffered to lower the drive requirements.
The SN74ALS280 and SN74AS280 are characterized for operation from 0°C to 70°C.
FUNCTION TABLE
NO. OF INPUTS
A −I
THAT ARE HIGH
Σ EVEN
0, 2, 4, 6, 8
H
L
1, 3, 5, 7, 9
L
H
OUTPUTS
Σ ODD
logic symbol†
A
B
C
D
E
F
G
H
I
2k
8
9
10
5
11
Σ EVEN
12
13
6
1
Σ ODD
2
4
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
Copyright 1994, Texas Instruments Incorporated
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• DALLAS, TEXAS 75265
• HOUSTON, TEXAS 77251−1443
POST OFFICE BOX 655303
POST OFFICE BOX 1443
1
SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
logic diagram (positive logic)
A
B
C
8
9
10
5
D
E
F
11
12
13
6
G
H
I
Σ EVEN
Σ ODD
1
2
4
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Operating free-air temperature range, TA: SN74ALS280 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
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POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
recommended operating conditions
SN74ALS280
MIN
NOM
MAX
4.5
5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
IOH
Low-level input voltage
0.8
V
High-level output current
−2.6
mA
IOL
TA
Low-level output current
24
mA
70
°C
High-level input voltage
2
Operating free-air temperature
V
V
0
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
VOH
SN74ALS280
TYP†
MAX
TEST CONDITIONS
MIN
VCC = 4.5 V,
VCC = 4.5 V to 5.5 V,
II = − 18 mA
IOH = − 0.4 mA
VCC = 4.5 V,
IOH = − 2.6 mA
IOL = 12 mA
VOL
VCC = 4.5 V
II
IIH
VCC = 5.5 V,
VCC = 5.5 V,
IIL
IO‡
VCC = 5.5 V,
VCC = 5.5 V,
−1.5
VCC − 2
2.4
IOL = 24 mA
VI = 7 V
VO = 2.25 V
−30
V
V
3.3
0.25
0.4
0.35
0.5
0.1
VI = 2.7 V
VI = 0.4 V
UNIT
V
mA
20
µA
−0.1
mA
−112
mA
ICC
VCC = 5.5 V
10
16
mA
† All typical values are at VCC = 5 V, TA = 25°C.
‡ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
tPLH
tPHL
Any
Σ EVEN
tPLH
tPHL
Any
Σ ODD
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 500 Ω,
TA = MIN to MAX§
SN74ALS280
MIN
MAX
3
20
3
20
3
20
4
22
UNIT
ns
ns
§ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
3
SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†
Supply voltage, VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Input voltage, VI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 V
Operating free-air temperature range, TA: SN74AS280 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to 150°C
† Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and
functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
recommended operating conditions
SN74AS280
MIN
NOM
MAX
4.5
5
5.5
UNIT
VCC
VIH
Supply voltage
VIL
IOH
Low-level input voltage
0.8
V
High-level output current
−2
mA
IOL
TA
Low-level output current
20
mA
70
°C
High-level input voltage
2
Operating free-air temperature
V
V
0
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
SN74AS280
TYP‡
MAX
TEST CONDITIONS
MIN
VIK
VOH
VCC = 4.5 V,
VCC = 4.5 V to 5.5 V,
II = − 18 mA
IOH = − 2 mA
VOL
II
VCC = 4.5 V,
VCC = 5.5 V,
IOL = 20 mA
VI = 7 V
IIH
IIL
IO§
VCC = 5.5 V,
VCC = 5.5 V,
VI = 2.7 V
VI = 0.4 V
VCC = 5.5 V,
VCC = 5.5 V
VO = 2.25 V
−1.5
VCC − 2
UNIT
V
V
0.35
−30
0.5
V
0.1
mA
20
µA
−0.5
mA
−112
mA
ICC
25
35
mA
‡ All typical values are at VCC = 5 V, TA = 25°C.
§ The output conditions have been chosen to produce a current that closely approximates one half of the true short-circuit output current, IOS.
switching characteristics (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
RL = 500 Ω,
TA = MIN to MAX¶
UNIT
SN74AS280
tPLH
tPHL
Any
Σ EVEN
tPLH
tPHL
Any
Σ ODD
MIN
MAX
3
12
3
11
3
12
3
11.5
¶ For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
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ns
ns
SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
APPLICATION INFORMATION
25-LINE
PARITY GENERATOR/CHECKER
81-LINE
PARITY GENERATOR/CHECKER
A
B
C
A
B
C
Σ EVEN
D
D
E
F
E
F
G
Σ ODD
G
H
I
H
I
A
A
B
C
B
C
Σ EVEN
D
H - Even
L = Odd
E
F
G
Σ ODD
H
I
H - Odd
L = Even
A
B
C
A
Σ ODD
B
C
D
D
E
F
E
F
G
G
H
I
H
I
Σ EVEN
H - Even
L = Odd
Σ ODD
H - Odd
L = Even
A
B
C
Σ EVEN
D
D
E
F
E
F
G
Σ ODD
Σ ODD
Σ ODD
To Other
SN74AS280s
G
H
I
H
I
Three SN74ALS280/SN74AS280 devices can be
used to implement a 25-line parity generator/
checker.
Longer word lengths can be implemented by cascading SN74ALS280/SN74AS280
devices. Parity can be generated for word lengths up to 81 bits.
As an alternative, the Σ ODD outputs of two or three
parity generators/checkers can be decoded with a
2-input (′AS86A or ′ALS86) exclusive-OR gate for
18- or 27-line parity applications.
•
POST OFFICE BOX 655303 DALLAS, TEXAS 75265
POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
5
SDAS038C − DECEMBER 1982 − REVISED DECEMBER 1994
PARAMETER MEASUREMENT INFORMATION
SERIES 54ALS/74ALS AND 54AS/74AS DEVICES
7V
RL = R1 = R2
VCC
S1
RL
R1
Test
Point
From Output
Under Test
CL
(see Note A)
From Output
Under Test
RL
Test
Point
CL
(see Note A)
CL
(see Note A)
LOAD CIRCUIT FOR
BI-STATE
TOTEM-POLE OUTPUTS
LOAD CIRCUIT
FOR OPEN-COLLECTOR OUTPUTS
3.5 V
Timing
Input
Test
Point
From Output
Under Test
LOAD CIRCUIT
FOR 3-STATE OUTPUTS
3.5 V
High-Level
Pulse
1.3 V
R2
1.3 V
1.3 V
0.3 V
0.3 V
tsu
Data
Input
tw
th
3.5 V
1.3 V
3.5 V
Low-Level
Pulse
1.3 V
0.3 V
1.3 V
0.3 V
VOLTAGE WAVEFORMS
PULSE DURATIONS
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
3.5 V
Output
Control
(low-level
enabling)
1.3 V
1.3 V
0.3 V
tPZL
Waveform 1
S1 Closed
(see Note B)
tPLZ
3.5 V
Input
tPZH
1.3 V
0.3 V
tPHL
tPLH
VOH
In-Phase
Output
VOL
0.3 V
1.3 V
1.3 V
VOL
tPLH
tPHL
VOH
1.3 V
1.3 V
[3.5 V
1.3 V
tPHZ
Waveform 2
S1 Open
(see Note B)
1.3 V
VOH
Out-of-Phase
Output
(see Note C)
0.3 V
[0 V
1.3 V
1.3 V
VOL
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
NOTES: A. CL includes probe and jig capacitance.
B. Waveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control.
Waveform 2 is for an output with internal conditions such that the output is high except when disabled by the output control.
C. When measuring propagation delay items of 3-state outputs, switch S1 is open.
D. All input pulses have the following characteristics: PRR ≤ 1 MHz, tr = tf = 2 ns, duty cycle = 50%.
E. The outputs are measured one at a time with one transition per measurement.
Figure 1. Load Circuits and Voltage Waveforms
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POST OFFICE BOX 1443 HOUSTON, TEXAS 77251−1443
•
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
SN74AS280N
ACTIVE
PDIP
N
14
25
RoHS & Green
NIPDAU
N / A for Pkg Type
0 to 70
SN74AS280N
SN74AS280NSR
ACTIVE
SO
NS
14
2000
RoHS & Green
NIPDAU
Level-1-260C-UNLIM
0 to 70
74AS280
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of