SN54HC645, SN74HC645
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS304A – JANUARY 1996 – REVISED MAY 1997
D
D
D
True Logic
High-Current 3-State Outputs Can Drive up
to 15 LSTTL Loads
Package Options Include Plastic
Small-Outline (DW) and Ceramic Flat (W)
Packages, Ceramic Chip Carriers (FK), and
Standard Plastic (N) and Ceramic (J)
300-mil DIPs
SN54HC645 . . . J OR W PACKAGE
SN74HC645 . . . DW OR N PACKAGE
(TOP VIEW)
description
These octal bus transceivers are designed for
asynchronous two-way communication between
data buses. These devices transmit data from the
A bus to the B bus or from the B bus to the A bus,
depending upon the level at the direction-control
(DIR) input. The output-enable (OE) input can be
used to disable the device so the buses are
effectively isolated.
The SN54HC645 is characterized for operation
over the full military temperature range of –55°C
to 125°C. The SN74HC645 is characterized for
operation from –40°C to 85°C.
FUNCTION TABLE
INPUTS
OE
L
L
H
DIR
L
H
X
OPERATION
B data to A bus
A data to B bus
Isolation
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
V
CC
OE
B1
B2
B3
B4
B5
B6
B7
B8
SN54HC645 . . . FK PACKAGE
(TOP VIEW)
A2
A1
DIR
V
CC
A3
A4
A5
A6
A7
4
5
6
7
8
3 2 1 20 19
18
17
16
15
14
9 10 11 12 13
OE
B1
B2
B3
B4
B5
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.
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.
Copyright
©
1997, Texas Instruments Incorporated
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•
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A8
GND
B8
B7
B6
1
SN54HC645, SN74HC645
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS304A – JANUARY 1996 – REVISED MAY 1997
logic symbol
†
OE
DIR
19
1
G3
3 EN1 [BA]
3 EN2 [AB]
1
2
A2
A3
A4
A5
A6
A7
A8
3
4
5
6
7
8
9
17
16
15
14
13
12
11
B2
B3
B4
B5
B6
B7
B8
18
B1
A1
2
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
logic diagram (positive logic)
OE
19
DIR
1
A1
2
18
B1
To Seven Other Transceivers
2
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DALLAS, TEXAS 75265
SN54HC645, SN74HC645
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS304A – JANUARY 1996 – REVISED MAY 1997
absolute maximum ratings over operating free-air temperature range
†
Supply voltage range, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to 7 V
Input clamp current, I
IK
(V
I
< 0 or V
I
> V
CC
) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±20
mA
Output clamp current, I
OK
(V
O
< 0 or V
O
> V
CC
) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±20
mA
Continuous output current, I
O
(V
O
= 0 to V
CC
) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±35
mA
Continuous current through V
CC
or GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
±70
mA
Package thermal impedance,
θ
JA
(see Note 2): DW package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97°C/W
N package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67°C/W
Storage temperature range, T
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, except for through-hole packages, which use a trace
length of zero.
recommended operating conditions
SN54HC645
MIN
VCC
VIH
Supply voltage
High-level input voltage
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 2 V
VIL
VI
VO
tt
TA
Low-level input voltage
Input voltage
Output voltage
Input transition (rise and fall) time
Operating free-air temperature
VCC = 2 V
VCC = 4.5 V
VCC = 6 V
VCC = 4.5 V
VCC = 6 V
2
1.5
3.15
4.2
0
0
0
0
0
0
0
0
–55
0.5
1.35
1.8
VCC
VCC
1000
500
400
125
NOM
5
MAX
6
SN74HC645
MIN
2
1.5
3.15
4.2
0
0
0
0
0
0
0
0
–40
0.5
1.35
1.8
VCC
VCC
1000
500
400
85
°C
ns
V
V
V
V
NOM
5
MAX
6
UNIT
V
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SN54HC645, SN74HC645
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS304A – JANUARY 1996 – REVISED MAY 1997
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
2V
IOH = –20
µA
VOH
VI = VIH or VIL
IOH = –6 mA
IOH = –7.8 mA
IOL = 20
µA
VOL
VI = VIH or VIL
IOL = 6 mA
IOL = 7.8 mA
II
IOZ
ICC
Ci
DIR or OE
A or B
DIR or OE
VI = VCC or 0
VO = VCC or 0
VI = VCC or 0,
IO = 0
4.5 V
6V
4.5 V
6V
2V
4.5 V
6V
4.5 V
6V
6V
6V
6V
2 V to 6 V
3
TA = 25°C
MIN
TYP
MAX
1.9
4.4
5.9
3.98
5.48
1.998
4.499
5.999
4.3
5.8
0.002
0.001
0.001
0.17
0.15
±0.1
±0.01
0.1
0.1
0.1
0.26
0.26
±100
±0.5
8
10
SN54HC645
MIN
1.9
4.4
5.9
3.7
5.2
0.1
0.1
0.1
0.4
0.4
±1000
±10
160
10
MAX
SN74HC645
MIN
1.9
4.4
5.9
3.84
5.34
0.1
0.1
0.1
0.33
0.33
±1000
±5
80
10
nA
µA
µA
pF
V
V
MAX
UNIT
switching characteristics over recommended operating free-air temperature range, C
L
= 50 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC
2V
tpd
A or B
B or A
4.5 V
6V
2V
ten
OE
A or B
4.5 V
6V
2V
tdis
OE
A or B
4.5 V
6V
2V
tt
A or B
4.5 V
6V
TA = 25°C
MIN
TYP
MAX
40
15
12
125
23
20
74
25
21
20
8
6
105
21
18
230
46
39
200
40
34
60
12
10
SN54HC645
MIN
MAX
160
32
27
340
68
58
300
60
51
90
18
15
SN74HC645
MIN
MAX
130
26
22
290
58
49
250
50
43
75
15
13
ns
ns
ns
ns
UNIT
4
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
SN54HC645, SN74HC645
OCTAL BUS TRANSCEIVERS
WITH 3-STATE OUTPUTS
SCLS304A – JANUARY 1996 – REVISED MAY 1997
switching characteristics over recommended operating free-air temperature range, C
L
= 150 pF
(unless otherwise noted) (see Figure 1)
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
VCC
2V
tpd
A or B
B or A
4.5 V
6V
2V
ten
OE
A or B
4.5 V
6V
2V
tt
A or B
4.5 V
6V
TA = 25°C
MIN
TYP
MAX
54
18
15
150
31
25
45
17
13
135
27
23
270
54
46
210
42
36
SN54HC645
MIN
MAX
200
40
34
405
81
69
315
63
53
SN74HC645
MIN
MAX
170
34
29
335
67
56
265
53
45
ns
ns
ns
UNIT
operating characteristics, T
A
= 25°C
PARAMETER
Cpd
Power dissipation capacitance per transceiver
TEST CONDITIONS
No load
TYP
40
UNIT
pF
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