
4-264
FAST AND LS TTL DATA
OCTAL BIDIRECTIONAL
TRANSCEIVER WITH 3-STATE
INPUTS/OUTPUTS
The MC74F1245 contains eight noninverting bidirectional buffers with
3-state outputs and is intended for bus-oriented applications. Current sinking
capability is 24 mA at the A ports and 64 mA at the B ports. The Transmit/
Receive (T/R
) input determines the direction of data flow through the bidirectional transceiver. Transmit (active HIGH) enables data from A ports to B
ports; Receive (active LOW) enables data from B ports to A ports. The Output
Enable input, when HIGH, disables both A and B ports by placing them in a
high-Z condition.
• Noninverting Buffers
• Bidirectional Data Path
• B Outputs Sink 64 mA
• High Impedance Inputs for Reduced Loading
• Same Function and Pinout as the F245
• ESD Protection > 4000 Volts
PIN ASSIGNMENT
LOGIC SYMBOL
18 17 16 15 14 13
1 2 3 4 5 6
7
20 19
8
V
CC
T/R
OE B0B1B
2
B
4
B
3
B
5
A0A1A2A3A4A5A
6
9 10
A7GND
12 11
B6B
7
T/R
A0A1A2A3A4A5A6A
7
B0B1B2B3B4B5B6B
7
OE
2 3 4 5 6 7 8 9
19
1
18 17 16 15 14 13 12 11
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
V
CC
DC Supply Voltage 74 4.5 5.0 5.5 V
T
A
Operating Ambient Temperature Range 74 0 25 70 °C
I
OH
Output Current High An Outputs 74 — — –3.0 mA
I
OL
Output Current Low An Outputs 74 — — 24 mA
I
OH
Output Current High Bn Outputs 74 — — –15 mA
I
OL
Output Current Low Bn Outputs 74 — — 64 mA
MC74F1245
OCTAL BIDIRECTIONAL
TRANSCEIVER WITH 3-STATE
INPUTS/OUTPUTS
FAST SCHOTTKY TTL
ORDERING INFORMATION
MC74FXXXXJ Ceramic
MC74FXXXXN Plastic
MC74FXXXXDW SOIC
20
1
J SUFFIX
CERAMIC
CASE 732-03
20
1
N SUFFIX
PLASTIC
CASE 738-03
20
1
DW SUFFIX
SOIC
CASE 751D-03

4-265
FAST AND LS TTL DATA
MC74F1245
FUNCTION TABLE
Inputs
Inputs/Outputs
OE T/R A
n
B
n
L L A = B Inputs
L H Inputs B = A
H X Z Z
H = HIGH voltage level: L = LOW voltage level: X = Don’t care: Z = HIGH impedance “off” state.
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
B
0
B
1
B
2
B
3
B
4
B
5
B
6
B
7
2 3 4 5 6 7 8 9
1112131415161718
1
19
OE
T/R
VCC = PIN 20
GND = PIN 10
LOGIC DIAGRAM

4-266
FAST AND LS TTL DATA
MC74F1245
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
V
IH
Input HIGH Voltage 2.0 — — V Guaranteed Input HIGH Voltage
V
IL
Input LOW Voltage — — 0.8 V Guaranteed Input LOW Voltage
V
IK
Input Clamp Diode Voltage — –0.73 –1.2 V VCC = MIN, IIN = –18 mA
VOHOutput HIGH Voltage An Outputs
74 2.0 — — V IOH = –15 mA VCC = 4.5 V
V
OL
Output LOW Voltage An
Outputs
74 — 0.35 0.5 V IOL = 24 mA
V
OL
Output LOW Voltage Bn
Outputs
74 — — 0.55 V IOL = 64 mA
I
OZH
Output Off Current HIGH — — 70 µA VCC = MAX V
OUT
= 2.7 V
I
OZL
Output Off Current LOW — — –70 µA VCC = MAX, V
OUT
= 0.5 V
OE, T/R Inputs — — 40 µA VCC = MAX, VIN = 2.7 V
An, Bn Inputs — — 70 µA VCC = MAX, VIN = 2.7 V
OE, T/R Inputs — — 100 µA VCC = 0 V, VIN = 7.0 V
Bn Inputs — — 1.0 mA VCC = 0 V, VIN = 5.5 V
I
IHH
Input HIGH Current An Inputs — — 2.0 mA VCC = 0 V, VIN = 5.5 V
OE, T/R Inputs — — –40 µA
Output Short Circuit Current
(Note 2)
Bn Outputs –100 — –225 mA
NOTES:
1. For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions for the applicable device type.
2. Not more than one output should be shorted at a time, nor for more than 1 second.
AC ELECTRICAL CHARACTERISTICS
74F 74F
TA = +25°C
VCC = +5.0 V
CL = 50 pF
TA = 0°C to +70°C
VCC = +5.0 V ±10%
CL = 50 pF
Symbol Parameter Min Max Min Max Unit
t
PLH
t
PHL
Propagation Delay
Transparent Mode An to Bn or Bn to A
n
2.0
2.5
6.5
7.5
1.5
2.0
7.0
8.0
ns
t
PZH
t
PZL
Output Enable Time
3.0
4.0
8.0
10.0
2.5
3.5
9.0
11.0
ns
t
PHZ
t
PLZ
Output Disable Time
2.0
1.0
8.0
10.0
1.5
1.0
9.0
11.0
ns
V
OH
I
CC
Output HIGH Voltage Bn Outputs
Output Short Circuit Current
Power Supply Current
VCC = MAX