Page 1
SN64BCT25244
25-Ω OCTAL BUFFER/DRIVER
WITH 3-STATE OUTPUTS
SCBS477 – DECEMBER 1992 – REVISED JANUARY 1994
Copyright 1994, Texas Instruments Incorporated
3–1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
• State-of-the-Art BiCMOS Design
Significantly Reduces I
CCZ
• High-Impedance State During Power Up and
Power Down
• ESD Protection Exceeds 2000 V Per
MIL-STD-883C, Method 3015; Exceeds
200 V Using Machine Model (C = 200 pF,
R = 0)
• Designed to Facilitate Incident-Wave
Switching for Line Impedances of 25 Ω or
Greater
• Distributed V
CC
and GND Pins Minimize
Noise Generated by the Simultaneous
Switching of Outputs
• Package Options Include Plastic
Small-Outline (DW) Packages and Standard
Plastic 300-mil DIPs (NT)
description
The SN64BCT25244 is a 25-Ω octal buffer and line driver designed specifically to improve both the performance
and density of 3-state memory address drivers, clock drivers, and bus-oriented transceivers.
When the output-enable (1OE and 2OE) inputs are low, the device transmits data from the A inputs to the
Y outputs. When 1OE and 2OE are high, the outputs are in the high-impedance state.
This buffer/driver is capable of sinking 188-mA IOL, which facilitates switching 25-Ω transmission lines on the
incident wave. The distributed VCC and GND pins minimize switching noise for more reliable system operation.
The outputs are in a high-impedance state during power up and power down while the supply voltage value is
less than approximately 3 V.
The SN64BCT25244 is characterized for operation from –40°C to 85°C and 0°C to 70°C.
FUNCTION TABLE
(each buffer/driver)
INPUTS
OUTPUT
OE A
Y
L H H
L LL
H X Z
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
1Y1
GND
1Y2
1Y3
GND
1Y4
2Y1
GND
2Y2
2Y3
GND
2Y4
1OE
1A1
1A2
V
CC
1A3
1A4
2A1
2A2
V
CC
2A3
2A4
2OE
DW OR NT PACKAGE
(TOP VIEW)
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.
Page 2
SN64BCT25244
25-Ω OCTAL BUFFER/DRIVER
WITH 3-STATE OUTPUTS
SCBS477 – DECEMBER 1992 – REVISED JANUARY 1994
3–2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
logic symbol
†
logic diagram (positive logic)
1OE
EN
24
23
1A1
22
1A2
20
1A3
19
1A4
1Y1
1
1Y2
3
1Y3
4
1Y4
6
18
2A1
17
2A2
15
2A3
14
2A4
2Y1
7
2Y2
9
2Y3
10
2Y4
12
1
1
†
This symbol is in accordance with ANSI/IEEE Std 91-1984
and IEC Publication 617-12.
2OE
EN
13
1OE
1A1
1Y1
24
23 1
1A2
1Y2
22 3
1A3
1Y3
20 4
1A4
1Y4
19 6
2OE
2A1
2Y1
13
18 7
2A2 2Y2
17 9
2A3
2Y3
15 10
2A4
2Y4
14 12
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
‡
Supply voltage range, V
CC
–0.5 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input voltage range, VI (see Note 1) –0.5 V to 7 V. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Voltage range applied to any output in the disabled or power-off state, V
O
–0.5 V to 5.5 V. . . . . . . . . . . . . . . .
Voltage range applied to any output in the high state, V
O
–0.5 V to V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input clamp current, I
IK
(V
I
< 0) –30 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Current into any output in the low state, I
O
376 mA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range –40°C to 85°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.
NOTE 1: The input and output negative-voltage ratings may be exceeded if the input and output clamp-current ratings are observed.
Page 3
SN64BCT25244
25-Ω OCTAL BUFFER/DRIVER
WITH 3-STATE OUTPUTS
SCBS477 – DECEMBER 1992 – REVISED JANUARY 1994
3–3
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
recommended operating conditions (see Note 2)
MIN NOM MAX UNIT
V
CC
Supply voltage 4.5 5 5.5 V
V
IH
High-level input voltage 2 V
V
IL
Low-level input voltage 0.8 V
I
IK
Input clamp current –18 mA
I
OH
High-level output current –80 mA
I
OL
Low-level output current 188 mA
T
A
Operating free-air temperature –40 85 °C
NOTE 2: Unused or floating inputs must be held high or low.
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP†MAX UNIT
V
IK
VCC = 4.5 V, II = –18 mA –1.2 V
VCC = 4.75 V , IOH = – 3 mA 2.7
V
OH
VCC = 4.5 V, IOH = –80 mA 2
V
IOL = 94 mA 0.42 0.55
V
OL
V
CC
= 4.5
V
IOL = 188 mA 0.7
V
VCC = 0 to 2.3 V (power up)
±50
I
OZ
VCC = 2.3 to 0 (power down)
V
O
=
2.7 V or 0.5 V
,
OE at 0.8 V
±50
µ
A
I
I
VCC = 5.5 V, VI = 5.5 V 0.1 mA
I
IH
VCC = 5.5 V, VI = 2.7 V 20 µA
I
IL
VCC = 5.5 V, VI = 0.5 V –0.6 mA
I
OZH
VCC = 5.5 V, VO = 2.7 V 50 µA
I
OZL
VCC = 5.5 V, VO = 0.5 V –50 µA
I
CCL
VCC = 5.5 V, Outputs open 90 119 mA
I
CCH
VCC = 5.5 V, Outputs open 59 78 mA
I
CCZ
VCC = 5.5 V, Outputs open 7 11 mA
C
i
VCC = 5 V, VI = 2.5 V or 0.5 V 5.5 pF
C
o
VCC = 5 V, VO = 2.5 V or 0.5 V 17 pF
†
All typical values are at VCC = 5 V, TA = 25°C.
switching characteristics over recommended ranges of supply voltage and operating free-air
temperature, C
L
= 50 pF (unless otherwise noted) (see Note 3)
PARAMETER
FROM
TO
VCC = 5 V,
TA = 25°C
TA = –40°C
to 85°C
TA = 0°C
to 70°C
UNIT
(INPUT)
(OUTPUT)
MIN TYP MAX MIN MAX MIN MAX
t
PLH
1 3.2 4.9 1 5.6 1 5.5
t
PHL
A
Y
2 4 5.6 2 6.3 2 6
ns
t
PZH
3.2 5.6 8.5 3.2 9.7 3.2 9.3
t
PZL
OE
Y
3.7 6.3 9.2 3.7 10.4 3.7 10.2
ns
t
PHZ
1.6 3.6 5.5 1.6 6.5 1.6 6.3
t
PLZ
OE
Y
3.1 5.3 7.8 3.1 9.5 3.1 8.4
ns
NOTE 3: Load circuits and voltage waveforms are shown in Section 1.
Page 4
SN64BCT25244
25-Ω OCTAL BUFFER/DRIVER
WITH 3-STATE OUTPUTS
SCBS477 – DECEMBER 1992 – REVISED JANUARY 1994
3–4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 5
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Copyright 1998, Texas Instruments Incorporated
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