Motorola MC74F657BJ, MC74F657BN, MC74F657AN, MC74F657BDW, MC74F657ADW Datasheet
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4-247
FAST AND LS TTL DATA
OCTAL BIDIRECTIONAL
TRANSCEIVER WITH 8-BIT PARITY
GENERATOR CHECKER
(3-STATE OUTPUTS)
The MC74F657A and MC74F657B are Octal Bidirectional Transceivers
with an 8-bit parity Generator/Checker and 3-state outputs.
The A and B options are faster versions of the F657 and contain eight noninverting buffers with 3-state outputs and an 8-bit parity generator/checker.
These devices are intended for bus-oriented applications. The buffers have
a guaranteed current sinking capability of 24 mA at the A ports and 64 mA at
the B ports. The Transmit/Receiver (T/R
) input determines the direction of the
data flow through the bidirectional transceivers. Transmit (active HIGH) enables data from A ports to B ports; Receive (active LOW) enables data from
B ports to A ports.
• High-Impedance NPN Base Input for Reduced Loading (20 µA in
HIGH and LOW States)
• Ideal in Applications Where High Output Drive and Light Bus Loading
are Required (IIL is 20 µA versus Fast std of 600 µA)
• Combines F245 and F280A Functions in One Package
• 3-State Outputs
• B Outputs, PARITY, ERROR, Sink 64 mA and Source 15 mA
• 15 mA Source Current
• Input Diodes for Termination Effects
• Glitchless Outputs During Power Up and Power Down
• High Impedance Outputs During Power Off
• ESD Protection > 4000 Volts
PIN ASSIGNMENT
22 21 20 19 18 17
1 2 3 4 5 6
7
24 23
8
OE
T/R
B0B1B2B
3
GNDGND B
4
A0A1A2A3A4VCCA
5
9 10
11
12
A6A
7
ERROR
16 15 14 13
B
5
B
7
B
6
PARITY
ODD/
EVEN
LOGIC SYMBOL
OE
EVEN/ODD
PARITY
T/R
B0B1B2B3B4B5B6B
7
24
11
1
23 22 21 20 17 16 15 14
13
ERROR
12
A0A1A2A3A4A5A6A
7
2 3 4 5 6 8 9 10
MC74F657A,B
OCTAL BIDIRECTIONAL
TRANSCEIVER WITH 8-BIT PARITY
GENERATOR CHECKER
(3-STATE OUTPUTS)
FAST SCHOTTKY TTL
ORDERING INFORMATION
MC74FXXXAJ/BJ Ceramic
MC74FXXXAN/BN Plastic
MC74FXXXADW/BDW SOIC
N SUFFIX
PLASTIC
CASE 724-03
DW SUFFIX
SOIC
CASE 751E-03
24
1
24
1
J SUFFIX
CERAMIC
CASE 758-01
24
1
4-248
FAST AND LS TTL DATA
MC74F657A, B
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
V
CC
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 74 –3.0/–15 mA
I
OL
Output Current — Low 74 24/64 mA
FUNCTION TABLE
Number of
Inputs That are High
Inputs Input/Output Outputs
OE T/R Even/Odd Parity Error Outputs Mode
L H H H Z Transmit
L H L L Z Transmit
L L H H H Receive
0, 2, 4, 6, 8 L L H L L Receive
L L L H L Receive
L L L L H Receive
Number of
Inputs That are High
Inputs Input/Output Outputs
OE T/R Even/Odd Parity Error Outputs Mode
L H H L Z Transmit
L H L H Z Transmit
L L H H L Receive
1, 3, 5, 7 L L H L H Receive
L L L H H Receive
L L L L L Receive
Don’t Care H X X Z Z Z
H = HIGH Voltage Level; L = LOW Voltage Level; X = Don’t Care; Z = HIGH impedance state.
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