CD74AC238M96 [TI]
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER; 3线至8线译码器/多路解复用器
| 型号： | CD74AC238M96 |
| 厂家： | 
TEXAS INSTRUMENTS |
| 描述： | 3-LINE TO 8-LINE DECODER/DEMULTIPLEXER |
| 文件： | 总11页 (文件大小：219K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
M PACKAGE
(TOP VIEW)
AC Types Feature 1.5-V to 5.5-V Operation
and Balanced Noise Immunity at 30% of the
Supply Voltage
A
B
V
CC
1
2
3
4
5
6
7
8
16
Speed of Bipolar F, AS, and S, With
Significantly Reduced Power Consumption
15 Y0
14
13
12
11
10
9
C
Y1
Y2
Y3
Y4
Y5
Y6
Designed Specifically for High-Speed
Memory Decoders and Data-Transmission
Systems
G2A
G2B
G1
Incorporates Three Enable Inputs to
Simplify Cascading and/or Data Reception
Y7
GND
Balanced Propagation Delays
±24-mA Output Drive Current
– Fanout to 15 F Devices
SCR-Latchup-Resistant CMOS Process and
Circuit Design
Exceeds 2-kV ESD Protection Per
MIL-STD-883, Method 3015
description/ordering information
The CD74AC238 decoder/demultiplexer is designed for high-performance memory-decoding and data-routing
applications that require very short propagation-delay times. In high-performance memory systems, this
decoder can be used to minimize the effects of system decoding. When employed with high-speed memories
utilizing a fast enable circuit, the delay times of this decoder and the enable time of the memory usually are less
than the typical access time of the memory. This means that the effective system delay introduced by the
decoder is negligible.
The conditions at the binary-select inputs and the three enable inputs select one of eight output lines. Two
active-low and one active-high enable inputs reduce the need for external gates or inverters when expanding.
A 24-line decoder can be implemented without external inverters, and a 32-line decoder requires only one
inverter. An enable input can be used as a data input for demultiplexing applications (see Application
Information).
ORDERING INFORMATION
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
†
PACKAGE
T
A
–55°C to 125°C
SOIC – M
Tape and reel CD74AC238M96
AC238M
†
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines
are available at www.ti.com/sc/package.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 2003, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
FUNCTION TABLE
ENABLE INPUTS
SELECT INPUTS
OUTPUTS
G1
G2A
H
X
X
L
G2B
C
X
X
X
L
B
X
X
X
L
A
X
X
X
L
Y0
L
Y1
L
Y2
L
Y3
L
Y4
L
Y5
L
Y6
L
Y7
L
X
X
L
X
H
X
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
L
H
H
H
H
H
H
H
H
H
L
L
L
L
L
L
L
L
L
L
L
H
L
H
L
L
L
L
L
L
L
L
L
H
H
L
L
H
L
L
L
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
H
H
H
H
L
L
L
H
L
L
L
L
L
L
H
L
L
L
L
L
H
L
L
L
L
H
H
L
L
L
L
L
H
L
L
L
H
L
L
L
L
L
L
H
logic diagram (positive logic)
15
Y0
1
A
14
13
12
11
Y1
Y2
Y3
Y4
2
3
Select
Inputs
B
C
Data
Outputs
10
9
Y5
Y6
Y7
4
5
6
7
G2A
G2B
Enable
Inputs
G1
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
†
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage range, V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 6 V
CC
I
Input clamp current, I (V < 0 V or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±20 mA
IK
I
CC
Output clamp current, I
(V < 0 V or V > V ) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
OK
O O CC
Continuous output current, I (V > 0 V or V < V ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±50 mA
Continuous current through V
Package thermal impedance, θ (see Note 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73°C/W
Storage temperature range, T
O
O
CC
O
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±200 mA
JA
stg
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –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.
NOTES: 1. The input and output voltage ratings may be exceeded if the input and output current ratings are observed.
2. The package thermal impedance is calculated in accordance with JESD 51-7.
recommended operating conditions (see Note 3)
–55°C to
125°C
–40°C to
85°C
T
A
= 25°C
UNIT
MIN
1.5
MAX
MIN
1.5
MAX
MIN
MAX
V
V
Supply voltage
5.5
5.5
1.5
1.2
5.5
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
V
CC
= 1.5 V
= 3 V
1.2
1.2
High-level input voltage
2.1
2.1
2.1
V
V
IH
= 5.5 V
= 1.5 V
= 3 V
3.85
3.85
3.85
0.3
0.9
0.3
0.9
0.3
0.9
V
IL
Low-level input voltage
= 5.5 V
1.65
1.65
1.65
V
V
Input voltage
0
0
V
V
0
0
V
0
0
V
V
V
V
I
CC
CC
CC
Output voltage
V
CC
O
CC
CC
I
High-level output current
Low-level output current
V
CC
V
CC
V
CC
V
CC
= 4.5 V to 5.5 V
= 4.5 V to 5.5 V
= 1.5 V to 3 V
–24
24
–24
24
–24
24
mA
mA
OH
OL
I
50
50
50
∆t/∆v
Input transition rise or fall rate
ns/V
= 3.6 V to 5.5 V
20
20
20
NOTE 3: All unused inputs of the device must be held at V
or GND to ensure proper device operation. Refer to the TI application report,
CC
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
–55°C to
125°C
–40°C to
85°C
T
A
= 25°C
PARAMETER
TEST CONDITIONS
V
CC
UNIT
MIN
1.4
MAX
MIN
1.4
MAX
MIN
1.4
MAX
1.5 V
3 V
I
= –50 µA
2.9
2.9
2.9
OH
4.5 V
3 V
4.4
4.4
4.4
V
OH
V = V or V
I IH
I
I
I
I
= –4 mA
2.58
3.94
2.4
2.48
3.8
V
IL
OH
OH
OH
OH
= –24 mA
= –50 mA
= –75 mA
4.5 V
5.5 V
5.5 V
1.5 V
3 V
3.7
†
†
3.85
3.85
0.1
0.1
0.1
0.1
0.1
0.1
I
= 50 µA
OL
4.5 V
3 V
0.1
0.1
0.1
V
OL
V = V or V
I
I
I
I
= 12 mA
= 24 mA
0.36
0.36
0.5
0.44
0.44
V
I
IH
IL
OL
OL
OL
OL
4.5 V
5.5 V
5.5 V
5.5 V
5.5 V
0.5
†
= 50 mA
= 75 mA
1.65
†
1.65
±1
I
I
V = V
or GND
or GND,
±0.1
8
±1
160
10
µA
µA
pF
I
I
CC
CC
V = V
I
O
= 0
80
CC
I
C
10
10
i
†
Testoneoutputatatime, notexceeding1-secondduration. Measurementismadebyforcingindicatedcurrentandmeasuringvoltagetominimize
power dissipation. Test verifies a minimum 50-Ω transmission-line drive capability at 85°C and 75-Ω transmission-line drive capability at 125°C.
switching characteristics over recommended operating free-air temperature range,
V
= 1.5 V, C = 50 pF (unless otherwise noted) (see Figure 1)
CC
L
–55°C to
125°C
–40°C to
85°C
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
UNIT
MIN
MAX
MIN
MAX
t
t
t
t
t
t
187
187
208
208
149
149
170
170
189
189
135
135
PLH
PHL
PLH
PHL
PLH
PHL
A, B, C
Any Y
Any Y
Any Y
ns
ns
ns
G1
G2A, G2B
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
switching characteristics over recommended operating free-air temperature range,
V
= 3.3 V ± 0.3 V, C = 50 pF (unless otherwise noted) (see Figure 1)
CC
L
–55°C to
125°C
–40°C to
85°C
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
UNIT
MIN
5.3
5.3
5.8
5.8
4.2
4.2
MAX
MIN
5.4
5.4
6
MAX
t
t
t
t
t
t
21
21
19.1
19.1
21.1
21.1
15.2
15.2
PLH
PHL
PLH
PHL
PLH
PHL
A, B, C
Any Y
Any Y
Any Y
ns
ns
ns
23.2
23.2
16.7
16.7
G1
6
4.3
4.3
G2A, G2B
switching characteristics over recommended operating free-air temperature range,
V
= 5 V ± 0.5 V, C = 50 pF (unless otherwise noted) (see Figure 1)
CC
L
–55°C to
125°C
–40°C to
85°C
FROM
(INPUT)
TO
(OUTPUT)
PARAMETER
UNIT
MIN
3.8
3.8
4.2
4.2
3
MAX
MIN
MAX
13.6
13.6
15.1
15.1
10.7
10.7
t
t
t
t
t
t
15
15
3.9
3.9
4.3
4.3
3.1
3.1
PLH
PHL
PLH
PHL
PLH
PHL
A, B, C
Any Y
Any Y
Any Y
ns
ns
ns
16.6
16.6
11.9
11.9
G1
G2A, G2B
3
operating characteristics, V
= 5 V, T = 25°C
CC
A
PARAMETER
TYP
UNIT
C
Power dissipation capacitance
110
pF
pd
5
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
PARAMETER MEASUREMENT INFORMATION
2 × V
TEST
S1
CC
Open
GND
S1
†
R1 = 500 Ω
t
/t
Open
PLH PHL
From Output
Under Test
t
/t
2 × V
CC
GND
PLZ PZL
t
/t
PHZ PZH
C
= 50 pF
†
L
R2 = 500 Ω
(see Note A)
t
w
V
CC
†
When V
= 1.5 V, R1 = R2 = 1 kΩ
CC
Input
50% V
50% V
CC
CC
0 V
LOAD CIRCUIT
VOLTAGE WAVEFORMS
PULSE DURATION
V
CC
Reference
Input
V
CC
50% V
CC
CLR
Input
50% V
CC
0 V
0 V
t
t
h
su
t
rec
V
CC
CC
0 V
Data
Input
90%
90%
V
CC
50%
10%
50% V
10%
50% V
CC
CLK
t
t
f
0 V
r
VOLTAGE WAVEFORMS
RECOVERY TIME
VOLTAGE WAVEFORMS
SETUP AND HOLD AND INPUT RISE AND FALL TIMES
V
CC
V
CC
Input
50% V
50% V
CC
CC
Output
Control
50% V
50% V
CC
CC
0 V
0 V
t
t
PLH
PHL
90%
t
t
PLZ
PZL
V
OH
In-Phase
Output
Output
Waveform 1
90%
≈V
CC
50%
10%
50% V
10%
CC
V
50% V
20% V
CC
CC
S1 at 2 × V
(see Note B)
OL
CC
V
OL
t
t
f
r
t
t
PHL
90%
PLH
t
t
PHZ
PZH
V
V
OH
Output
Waveform 2
S1 at GND
90%
Out-of-Phase
Output
50% V
10%
50%
10%
V
OH
CC
80% V
50% V
CC
OL
CC
t
f
t
≈0 V
r
(see Note B)
VOLTAGE WAVEFORMS
PROPAGATION DELAY AND OUTPUT TRANSITION TIMES
VOLTAGE WAVEFORMS
OUTPUT ENABLE AND DISABLE TIMES
NOTES: A.
C includes probe and test-fixture capacitance.
L
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. All input pulses are supplied by generators having the following characteristics: PRR ≤ 1 MHz, Z = 50 Ω, t = 3 ns, t = 3 ns.
O
r
f
Phase relationships between waveforms are arbitrary.
D. For clock inputs, f is measured with the input duty cycle at 50%.
max
E. The outputs are measured one at a time with one input transition per measurement.
F.
G.
H.
t
t
t
and t
and t
and t
are the same as t
.
pd
PLH
PZL
PLZ
PHL
PZH
PHZ
are the same as t
are the same as t
.
en
dis
.
I. All parameters and waveforms are not applicable to all devices.
Figure 1. Load Circuit and Voltage Waveforms
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
APPLICATION INFORMATION
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
1
2
3
4
6
4
5
&
V
CC
EN
7
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
8
A0
A1
A2
1
2
9
10
11
12
13
14
15
3
4
6
4
5
&
A3
A4
EN
7
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
16
17
18
19
20
21
22
23
1
2
3
4
6
4
5
&
EN
7
Figure 2. 24-Bit Decoding Scheme
7
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
CD74AC238
3-LINE TO 8-LINE DECODER/DEMULTIPLEXER
SCHS331 – FEBRUARY 2003
APPLICATION INFORMATION
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
A0
A1
A2
1
2
3
4
6
4
5
&
V
CC
A3
EN
A4
7
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
8
1
2
9
10
11
12
13
14
15
3
4
6
4
5
&
EN
7
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
16
17
18
19
20
21
22
23
1
2
3
4
6
4
5
&
EN
7
CD74AC238
BIN/OCT
15
14
13
12
11
10
9
1
2
0
1
2
3
4
5
6
7
24
25
26
27
28
29
30
31
1
2
3
4
6
4
5
&
EN
7
Figure 3. 32-Bit Decoding Scheme
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PACKAGE OPTION ADDENDUM
www.ti.com
30-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
Package Package
Pins Package Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3)
Qty
Type
Drawing
CD74AC238M96
ACTIVE
SOIC
D
16
2500
Pb-Free
(RoHS)
CU NIPDAU Level-2-260C-1 YEAR/
Level-1-235C-UNLIM
(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)
Eco Plan
-
The planned eco-friendly classification: Pb-Free (RoHS) or Green (RoHS
&
no Sb/Br)
-
please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
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Addendum-Page 1
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