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Datasheet: I74F657D (Philips Semiconductors)

Octal transceiver with 8-bit parit generator/checker

 

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Philips Semiconductors
Philips
Semiconductors
74F657
Octal transceiver with 8-bit parit
generator/checker
Process specification
IC15 Data Handbook
1990 Jul 30
INTEGRATED CIRCUITS
Philips Semiconductors
Product specification
74F657
Octal transceiver with 8-bit parity generator/checker
2
90 July 30
853 1117 00081
FEATURES
Combines 74F245 and 74F280A functions in one package
High impedance base input for reduced loading (70
A in
high and low states)
Ideal in applications where high output drive and light bus
loading are required (I
IL
is 70
A vs FAST std of 600
A)
3state buffer outputs sink 64mA and source 15mA
Input diodes for termination effects
24pin plastic slim DIP (300mil) package
Industrial temperature range available (40
C to +85
C)
DESCRIPTION
The 74F657 is an octal transceiver featuring noninverting
buffers with 3state outputs and an 8bit parity
generator/checker, and is intended for busoriented
applications. The buffers have a guaranteed current sinking
capability of 24mA at the A ports and 64mA at the B ports.
The transmit/receive (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.
The output enable (OE) input disables both the A and B ports by
placing them in a high impedance condition when the OE input is
high
.
The parity select (ODD/EVEN) input gives the user the option of
odd or even parity systems
.
The parity (PARITY) pin is an output from the generator/checker
when transmitting from the port A to B (T/R = high) and an input
when receiving from port B to A port ( T/R = low).
When transmitting (T/R = high) the parity select (ODD/EVEN) input
is set, then the A port data is polled to determined the number of
high bits. The parity (PARITY) output then goes to the logic state
determined by the parity select (ODD/EVEN) setting and by the
number of high bits on port A.
For example, if the parity select (ODD/EVEN) is set low (even
parity), and the number of high bits on port A is odd, then the parity
(PARITY) output will be high, transmitting even parity. If the number
of high bits on port A is even, then the parity (PARITY) output will
be low, keeping even parity.
When in receive mode (T/R = low) the B port is polled to determine
the number of high bits. If parity select (ODD/EVEN) is low (even
parity) and the number of highs on port B is:
(1) odd and the parity (PARITY) input is high, then ERROR will be
high, significantly no error.
(2) even and the parity (PARITY) input is high, then ERROR will be
asserted low, indicating an error.
TYPE
TYPICAL PROPAGA-
TION DELAY
TYPICAL SUPPLY
CURRENT( TOTAL)
74F657
8.0ns
100mA
ORDERING INFORMATION
ORDER CODE
COMMERCIAL RANGE
INDUSTRIAL RANGE
DESCRIPTION
V
CC
= 5V
10%,
V
CC
= 5V
10%,
PKG DWG #
T
amb
= 0
C to +70
C
T
amb
= 40
C to +85
C
24pin plastic slim
DIP (300mil)
N74F657N
I74F657N
SOT222-1
24pin plastic SOL
N74F657D
I74F657D
SOT137-1
24pin plastic SSOP
N74F657DB
I74F657DB
SOT340-1
INPUT AND OUTPUT LOADING AND FAN OUT TABLE
PINS
DESCRIPTION
74F (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
A0 A7
A ports 3state inputs
3.5/0.117
70
A/70
A
B0 B7
B ports 3state inputs
3.5/0.117
70
A/70
A
PARITY
Parity input
3.5/0.117
70
A/70
A
T/R
Transmit/receive input
2.0/0.066
40
A/40
A
ODD/EVEN
Parity select input
1.0/0.033
20
A/20
A
OE
Output enable input (active low)
2.0/0.066
40
A/40
A
A0 A7
A ports 3state outputs
150/40
3.0mA/24mA
B0 B7
B ports 3state outputs
750/106.7
15mA/64mA
PARITY
Parity output
750/106.7
15mA/64mA
ERROR
Error output
750/106.7
15mA/64mA
Note to input and output loading and fan out table
1. One (1.0) FAST unit load is defined as: 20
A in the high state and 0.6mA in the low state.
Philips Semiconductors
Product specification
74F657
Octal transceiver with 8-bit parity generator/checker
90 July 30
3
PIN CONFIGURATION
24
23
22
21
20
19
18
17
16
15
14
13
12
10
11
9
8
7
6
5
4
3
2
1
OE
ERROR
ODD/EVEN
T/R
B0
B1
B2
B3
B4
B5
B6
B7
A0
A1
A2
A3
A4
V
CC
A5
A6
A7
PARITY
GND
GND
SF00414
IEC/IEEE SYMBOL
2
1
G3
3 EN1/3G5 (REC)
N4
24
1
11
3 EN2 (XMIT)
2
3
4
5
6
8
9
10
23
22
21
20
17
16
15
14
2 k
4, 2
4, 1
13
5
12
Z11
11
18
.
.
.
SF00416
LOGIC SYMBOL
T/R
OE
B0 B1
B2 B3
ODD/EVEN
B4 B5
B6 B7
1
24
11
A0 A1
A2 A3
A4 A5
A6 A7
2
3
4
5
6
8
9
10
23
22
21
20
17
16
15
14
13
12
PARITY
V
CC
= Pin 7
GND = Pin 18, 19
ERROR
SF00415
Philips Semiconductors
Product specification
74F657
Octal transceiver with 8-bit parity generator/checker
90 July 30
4
LOGIC DIAGRAM
VCC =
Pin 7,
GND = Pin 18, 19
B0
B1
B2
B3
B4
B5
B6
B7
A0
A1
A2
A3
A4
A5
A6
A7
PARITY
ERROR
ODD/EVEN
T/R
OE
2
3
4
5
6
8
9
10
23
22
21
20
17
16
15
14
1
24
13
12
11
SF00417
Philips Semiconductors
Product specification
74F657
Octal transceiver with 8-bit parity generator/checker
90 July 30
5
FUNCTION TABLE
NUMBER OF INPUTS THAT ARE HIGH
INPUTS
INPUT/OUTPUT
OUTPUTS
OE
T/R
ODD/EVEN
PARITY
ERROR
OUTPUTS MODE
0, 2, 4, 6, 8
L
L
L
L
L
L
H
H
L
L
L
L
H
L
H
H
L
L
H
L
H
L
H
L
Z
Z
H
L
L
H
Transmit
Transmit
Receive
Receive
Receive
Receive
1, 3, 5, 7
L
L
L
L
L
L
H
H
L
L
L
L
H
L
H
H
L
L
L
H
H
L
H
L
Z
Z
L
H
H
L
Transmit
Transmit
Receive
Receive
Receive
Receive
Don't care
H
X
X
Z
Z
Z
Notes to function table
1. H = High voltage level
2. L
= Low voltage level
3. X = Don't care
4. Z = High impedance "'off" state
ABSOLUTE MAXIMUM RATINGS
(Operation beyond the limit set forth in this table may impair the useful life of the device. Unless otherwise noted these limits are over the
operating free air temperature range.)
SYMBOL
PARAMETER
RATING
UNIT
V
CC
Supply voltage
0.5 to +7.0
V
V
IN
Input voltage
0.5 to +7.0
V
I
IN
Input current
30 to +5
mA
V
OUT
Voltage applied to output in high output state
0.5 to V
CC
V
I
OUT
Current applied to output in low output state
A0
A7
48
mA
B0
B7, PARITY, ERROR
128
mA
T
amb
Operating free air temperature range
Commercial range
0 to +70
C
Industrial range
40 to +85
C
T
stg
Storage temperature range
65 to +150
C
RECOMMENDED OPERATING CONDITIONS
SYMBOL
PARAMETER
LIMITS
UNIT
MIN
NOM
MAX
V
CC
Supply voltage
4.5
5.0
5.5
V
V
IH
Highlevel input voltage
2.0
V
V
IL
Lowlevel input voltage
0.8
V
I
Ik
Input clamp current
18
mA
I
OH
Highlevel output current
A0 A7
3
mA
B0
B7, PARITY, ERROR
15
mA
I
OL
Lowlevel output current
A0 A7
24
mA
B0 B7, PARITY, ERROR
64
mA
T
amb
Operating free air temperature range
Commercial range
0
+70
C
Industrial range
40
+85
C
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