SN74AHC245Q
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SGDS018 FEBRUARY 2002
1
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
D
Q Devices Meet Automotive Performance
Requirements
D
Customer-Specific Configuration Control
Can Be Supported Along With
Major-Change Approval
D
Operating Range 2-V to 5.5-V V
CC
D
Latch-Up Performance Exceeds 250 mA Per
JESD 17
description
The SN74AHC245Q octal bus transceiver is
designed for asynchronous two-way
communication between data buses. The
control-function implementation minimizes
external timing requirements.
This device allows data transmission from the A bus to the B bus or from the B bus to the A bus, depending on
the logic level at the direction-control (DIR) input. The output-enable (OE) input can be used to disable the
device so that the buses are effectively isolated.
To ensure the high-impedance state during power up or power down, OE should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
ORDERING INFORMATION
TA
PACKAGE
ORDERABLE
PART NUMBER
TOP-SIDE
MARKING
40
C to 125
C
SOIC DW
Tape and reel
SN74AHC245QDWR
AHC245Q
40
C to 125
C
TSSOP PW
Tape and reel
SN74AHC245QPWR
HA245Q
Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines
are available at www.ti.com/sc/package.
FUNCTION TABLE
(each transceiver)
INPUTS
OPERATION
OE
DIR
OPERATION
L
L
B data to A bus
L
H
A data to B bus
H
X
Isolation
Copyright
2002, 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.
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.
DW OR PW PACKAGE
(TOP VIEW)
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
DIR
A1
A2
A3
A4
A5
A6
A7
A8
GND
V
CC
OE
B1
B2
B3
B4
B5
B6
B7
B8
SN74AHC245Q
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SGDS018 FEBRUARY 2002
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
logic symbol
This symbol is in accordance with ANSI/IEEE Std 91-1984 and IEC Publication 617-12.
B2
17
B3
16
B4
15
A5
6
A6
7
A7
8
A8
9
A2
3
A3
4
A4
5
OE
A1
2
G3
19
3 EN2 [AB]
B5
14
B6
13
B7
12
B8
11
B1
18
3 EN1 [BA]
1
DIR
1
2
logic diagram (positive logic)
DIR
OE
A1
B1
To Seven Other Channels
1
2
19
18
SN74AHC245Q
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SGDS018 FEBRUARY 2002
3
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
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, V
I
(see Note 1): Control inputs
0.5 V to 7 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O, output voltage range, V
O
(see Note 1)
0.5 V to V
CC
+ 0.5 V
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Input clamp current, I
IK
(V
I
< 0): Control inputs
20 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I/O, output clamp current, I
OK
(V
O
< 0 or V
O
> V
CC
)
20 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous output current, I
O
(V
O
= 0 to V
CC
)
25 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Continuous current through V
CC
or GND
75 mA
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Package thermal impedance,
JA
(see Note 2): DW package
58
C/W
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
PW package
83
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 51-7.
recommended operating conditions (see Note 3)
MIN
MAX
UNIT
VCC
Supply voltage
2
5.5
V
VCC = 2 V
1.5
VIH
High-level input voltage
VCC = 3 V
2.1
V
VCC = 5.5 V
3.85
VCC = 2 V
0.5
VIL
Low-level input voltage
VCC = 3 V
0.9
V
VCC = 5.5 V
1.65
VI
Input voltage
OE or DIR
0
5.5
V
VO
Output voltage
A or B
0
VCC
V
VCC = 2 V
50
m
A
IOH
High-level output current
VCC = 3.3 V
0.3 V
4
mA
VCC = 5 V
0.5 V
8
mA
VCC = 2 V
50
m
A
IOL
Low-level output current
VCC = 3.3 V
0.3 V
4
mA
VCC = 5 V
0.5 V
8
mA
t
/
v
Input transition rise or fall rate
VCC = 3.3 V
0.3 V
100
ns/V
t
/
v
Input transition rise or fall rate
VCC = 5 V
0.5 V
20
ns/V
TA
Operating free-air temperature
40
125
C
NOTE 3: All unused inputs of the device must be held at VCC or GND to ensure proper device operation. Refer to the TI application report,
Implications of Slow or Floating CMOS Inputs, literature number SCBA004.
SN74AHC245Q
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SGDS018 FEBRUARY 2002
4
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
VCC
TA = 25
C
MIN
MAX
UNIT
PARAMETER
TEST CONDITIONS
VCC
MIN
TYP
MAX
MIN
MAX
UNIT
2 V
1.9
2
1.9
IOH = 50
m
A
3 V
2.9
3
2.9
VOH
4.5 V
4.4
4.5
4.4
V
IOH = 4 mA
3 V
2.58
2.48
IOH = 8 mA
4.5 V
3.94
3.8
2 V
0.1
0.1
IOL = 50
m
A
3 V
0.1
0.1
VOL
4.5 V
0.1
0.1
V
IOL = 4 mA
3 V
0.36
0.5
IOL = 8 mA
4.5 V
0.36
0.5
I
A or B inputs
V
5 5 V or GND
5.5 V
0.1
1
A
II
OE or DIR
VI = 5.5 V or GND
0 V to 5.5 V
0.1
1
m
A
IOZ
VO = VCC or GND,
VI (OE) = VIL or VIH
5.5 V
0.25
2.5
m
A
ICC
VI = VCC or GND,
IO = 0
5.5 V
4
40
m
A
Ci
OE or DIR
VI = VCC or GND
5 V
2.5
10
pF
Cio
A or B inputs
VI = VCC or GND
5 V
4
pF
The parameter IOZ includes the input leakage current.
switching characteristics over recommended operating free-air temperature range,
V
CC
= 3.3 V
0.3 V (unless otherwise noted) (see Figure 1)
PARAMETER
FROM
TO
LOAD
TA = 25
C
MIN
MAX
UNIT
PARAMETER
(INPUT)
(OUTPUT)
CAPACITANCE
MIN
TYP
MAX
MIN
MAX
UNIT
tPLH
A or B
B or A
CL = 15 pF
5.8
8.4
1
10
ns
tPHL
A or B
B or A
CL = 15 pF
5.8
8.4
1
10
ns
tPZH
OE
A or B
CL = 15 pF
8.5
13.2
1
15.5
ns
tPZL
OE
A or B
CL = 15 pF
8.5
13.2
1
15.5
ns
tPHZ
OE
A or B
CL = 15 pF
8.9
12.5
1
15.5
ns
tPLZ
OE
A or B
CL = 15 pF
8.9
12.5
1
15.5
ns
tPLH
A or B
B or A
CL = 50 pF
8.3
11.9
1
13.5
ns
tPHL
A or B
B or A
CL = 50 pF
8.3
11.9
1
13.5
ns
tPZH
OE
A or B
CL = 50 pF
11
16.7
1
19
ns
tPZL
OE
A or B
CL = 50 pF
11
16.7
1
19
ns
tPHZ
OE
A or B
CL = 50 pF
11.5
15.8
1
18
ns
tPLZ
OE
A or B
CL = 50 pF
11.5
15.8
1
18
ns
SN74AHC245Q
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SGDS018 FEBRUARY 2002
5
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
switching characteristics over recommended operating free-air temperature range,
V
CC
= 5 V
0.5 V (unless otherwise noted) (see Figure 1)
PARAMETER
FROM
TO
LOAD
TA = 25
C
MIN
MAX
UNIT
PARAMETER
(INPUT)
(OUTPUT)
CAPACITANCE
MIN
TYP
MAX
MIN
MAX
UNIT
tPLH
A or B
B or A
CL = 15 pF
4
5.5
1
6.5
ns
tPHL
A or B
B or A
CL = 15 pF
4
5.5
1
6.5
ns
tPZH
OE
A or B
CL = 15 pF
5.8
8.5
1
10
ns
tPZL
OE
A or B
CL = 15 pF
5.8
8.5
1
10
ns
tPHZ
OE
A or B
CL = 15 pF
5.6
7.8
1
9.2
ns
tPLZ
OE
A or B
CL = 15 pF
5.6
7.8
1
9.2
ns
tPLH
A or B
B or A
CL = 50 pF
5.5
7.5
1
8.5
ns
tPHL
A or B
B or A
CL = 50 pF
5.5
7.5
1
8.5
ns
tPZH
OE
A or B
CL = 50 pF
7.3
10.6
1
12
ns
tPZL
OE
A or B
CL = 50 pF
7.3
10.6
1
12
ns
tPHZ
OE
A or B
CL = 50 pF
7
9.7
1
11
ns
tPLZ
OE
A or B
CL = 50 pF
7
9.7
1
11
ns
noise characteristics, V
CC
= 5 V, C
L
= 50 pF, T
A
= 25
C (see Note 4)
PARAMETER
MIN
TYP
MAX
UNIT
VOL(P)
Quiet output, maximum dynamic VOL
0.9
V
VOL(V)
Quiet output, minimum dynamic VOL
0.9
V
VOH(V)
Quiet output, minimum dynamic VOH
4.3
V
VIH(D)
High-level dynamic input voltage
3.5
V
VIL(D)
Low-level dynamic input voltage
1.5
V
NOTE 4: Characteristics are for surface-mount packages only.
operating characteristics, V
CC
= 5 V, T
A
= 25
C
PARAMETER
TEST CONDITIONS
TYP
UNIT
Cpd
Power dissipation capacitance
No load,
f = 1 MHz
14
pF
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