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SN74F2245
25-Ω OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SDFS099 – MAY 1995
D
D
3-State Outputs Drive Bus Lines or Buffer
Memory Address Registers
Package Options Include Plastic
Small-Outline (DB) Packages and Plastic
300-mil DIPs (N)
DB OR N PACKAGE
(TOP VIEW)
description
The SN74F2245 is designed for asynchronous
communication between data buses. The devices
transmit data from the A bus to the B bus or from
the B bus to the A bus depending upon the logic
level at the direction-control (DIR) input. The
output-enable (OE) input disables the device so
the buses are effectively isolated.
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
Both A and B outputs can sink up to 12 mA; 25-Ω resistors are included in the lower output circuit to reduce
overshoot and undershoot.
The SN74F2245 is characterized for operation from 0°C to 70°C.
FUNCTION TABLE
INPUTS
OE
L
L
H
DIR
L
H
X
OPERATION
B data to A bus
A data to B bus
Isolation
logic symbol
†
OE
DIR
19
1
G3
3EN1[BA]
3EN2[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
logic diagram (positive logic)
DIR
1
19
OE
A1
2
A1
2
18
B1
To Seven Other Channels
† This symbol is in accordance with ANSI/IEEE Std 91-1984 and
IEC Publication 617-12.
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
©
1995, 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.
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1
SN74F2245
25-Ω OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SDFS099 – MAY 1995
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
(except I/O ports) (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 1.2 V to 7 V
Input current range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 30 mA to 5 mA
Voltage range applied to any output in the disabled or power-off state . . . . . . . . . . . . . . . . . . . – 0.5 V to 5.5 V
Voltage range applied to any output in the high state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to V
CC
Current into any output in the low state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 mA
Operating free-air temperature range, T
A
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
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.
NOTE 1: The input voltage ratings may be exceeded provided the input current ratings are observed.
recommended operating conditions
MIN
VCC
VIH
VIL
IIK
IOH
IOL
TA
Supply voltage
High-level input voltage
Low-level input voltage
Input clamp current
High-level output current
Low-level output current
Operating free-air temperature
0
4.5
2
0.8
– 18
–3
12
70
NOM
5
MAX
5.5
UNIT
V
V
V
mA
mA
mA
°C
electrical characteristics over recommended operating free-air temperature range (unless
otherwise noted)
PARAMETER
VIK
VOH
Any output
VCC = 4.5 V,
VCC = 4 5 V
4.5
VCC = 4.75 V,
VOL
II
IIH§
IIL§
IOS¶
ICC
Any output
A and B
DIR and OE
A and B
DIR and OE
A and B
DIR and OE
A and B
VCC = 4 5 V
4.5
VCC = 5 5 V
5.5
VCC = 5 5 V
5.5 V,
VCC = 5 5 V
5.5 V,
VCC = 5.5 V,
VCC = 5.5 V
TEST CONDITIONS
II = – 18 mA
IOH = – 1 mA
IOH = – 3 mA
IOH = – 1 mA to – 3 mA
IOL = 1 mA
IOL = 12 mA
VI = 5.5 V
VI = 7 V
VI = 2 7 V
2.7
VI = 0 5 V
0.5
VO = 0
Outputs high
Outputs low
Outputs disabled
– 50
62
73
72
MIN
2.5
2.4
2.7
0.2
0.5
0.5
0.75
1
0.1
70
20
– 0.5
– 0.5
– 120
90
105
100
mA
V
mA
µA
mA
mA
TYP‡
3.4
3.3
V
MAX
– 1.2
UNIT
V
‡ All typical values are at VCC = 5 V, TA = 25°C.
§ For I/O ports, the parameters IIH and IIL include the off-state output current.
¶ Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second.
2
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SN74F2245
25-Ω OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SDFS099 – MAY 1995
switching characteristics (see Figure 1)
VCC = 5 V,
CL = 50 pF,
R1 = 500
Ω,
R2 = 500
Ω,
TA = 25°C
MIN
tPLH
tPHL
tPZH
tPZL
tPHZ
tPLZ
A or B
B or A
A or B
A or B
2.5
3.1
2.4
3.6
2.3
2
TYP
3.9
4.6
4.8
6.6
4.3
4
MAX
5.5
6.6
7.3
10.6
6.3
5.8
VCC = 4.5 V to 5.5 V,
CL = 50 pF,
R1 = 500
Ω,
R2 = 500
Ω,
TA = MIN to MAX†
MIN
2.1
2.9
1.6
3
2
1.9
MAX
6.6
7.1
8.5
12
7.5
6.8
ns
ns
ns
PARAMETER
FROM
(INPUT)
TO
(OUTPUT)
UNIT
OE
OE
† For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
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3
SN74F2245
25-Ω OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUTS
SDFS099 – MAY 1995
PARAMETER MEASUREMENT INFORMATION
7 V (tPZL, tPLZ)
Open
(all others)
From Output
Under Test
CL
(see Note A)
Test
Point
R2
RL = R1 = R2
LOAD CIRCUIT FOR
TOTEM-POLE OUTPUTS
R1
Test
Point
S1
R1
From Output
Under Test
CL
(see Note A)
LOAD CIRCUIT FOR
3-STATE AND OPEN-COLLECTOR OUTPUTS
High-Level
Pulse
(see Note C)
3V
1.5 V
tw
3V
1.5 V
0V
Timing Input
(see Note C)
tsu
Data Input
(see Note C)
1.5 V
3V
1.5 V
0V
th
3V
1.5 V
0V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
Low-Level
Pulse
1.5 V
1.5 V
0V
VOLTAGE WAVEFORMS
PULSE DURATION
3V
Output
Control
(low-level enable)
Input
(see Note C)
tPLH
In-Phase
Output
(see Note E)
tPHL
Out-of-Phase
Output
(see Note E)
1.5 V
3V
1.5 V
1.5 V
0V
tPHL
VOH
1.5 V
1.5 V
VOL
tPLH
VOH
1.5 V
VOL
Waveform 2
(see Notes B and E)
tPZH
VOH
1.5 V
0.3 V
0V
VOLTAGE WAVEFORMS
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
tPHZ
Waveform 1
(see Notes B and E)
1.5 V
VOL
0.3 V
tPZL
tPLZ
3.5 V
1.5 V
1.5 V
0V
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES (see Note D)
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. All input pulses are supplied by generators having the following characteristics: PRR
≤
1 MHz, tr = tf
≤
2.5 ns, duty cycle = 50%.
D. When measuring propagation delay times of 3-state outputs, switch S1 is open.
E. The outputs are measured one at a time with one transition per measurement.
Figure 1. Load Circuit and Voltage Waveforms
4
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