Philips 74f621 DATASHEETS
INTEGRATED CIRCUITS
74F621
Octal bus transceiver, non-inverting
(open collector)
Product specification 1996 Jan 05
IC15 Data Handbook
Philips Semiconductors Product specification
74F621Octal bus transceiver, non-inverting (open collector)
FEA TURES
•High-impedance NPN base inputs for reduced loading
(20µA in High and Low states)
•Octal bidirectional bus interface
•Open collector outputs sink 64mA
•Non-inverting
DESCRIPTION
The 74F621 is an octal transceiver featuring non-inverting open
collector bus-compatible outputs in both send and receive
directions. The outputs are capable of sinking 64mA, providing very
good capacitive drive characteristics.
This octal bus transceiver is designed for asynchronous two-way
communication between data buses. The control function
implementation allows for maximum flexibility in timing.
The device allows data transmission from the A bus to the B bus or
from the B bus to the A bus, depending upon the logic levels at the
Enable inputs (OEBA
disable the device so that the buses are effectively isolated.
The dual-enable configuration gives the 74F621 the capability to
store data by the simultaneous enabling of OEBA
output reinforces its input in this transceiver configuration. Thus,
when both control inputs are enabled and all other data sources to
the two sets of the bus lines are at high impedance, both sets of bus
lines (16 in all) will remain in their last states.
and OEAB). The Enable inputs can be used to
and OEAB. Each
PIN CONFIGURATION
1
OEAB
2
A0
3
A1
4
A2
5
A3
6
A4
7
A5
8
A6
9
A7
10 11
GND
TYPICAL
TYPE
PROPAGATION
DELAY
74F621 8.0ns 105mA
20
V
CC
19
OEBA
B0
18
B1
17
B2
16
B3
15
B4
14
B5
13
B6
12
B7
SF01135
TYPICAL SUPPLY CURRENT
(TOTAL)
ORDERING INFORMATION
COMMERCIAL RANGE
DESCRIPTION
VCC = 5V ±10%,
T
= 0°C to +70°C
amb
20-pin plastic DIP N74F621N SOT146-1
20-pin plastic SOL N74F621D SOT163-1
PKG
DWG #
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS DESCRIPTION
74F(U.L.)
HIGH/LOW
A0 - A7, B0 - B7 Data inputs 1.0/0.033 20µA/20µA
OEBA, OEAB Output Enable inputs 1.0/0.033 20µA/20µA
A0 - A7 Data outputs OC/40 OC/24mA
B0 - B7 Data outputs OC/106.7 OC/64mA
NOTE: One (1.0) FAST unit load is defined as: 20µA in the High state and 0.6mA in the Low state. OC = Open Collector.
LOAD VALUE
HIGH/LOW
1996 Jan 05 853–0380 16185
2
Philips Semiconductors Product specification
OPERATING MODES
L
H
74F621Octal bus transceiver, non-inverting (open collector)
LOGIC SYMBOL
23
A0 A1
1
OEAB
19
OEBA
B0 B1 B2 B3
18 17 16 15 14 13 12 11
VCC= Pin 20
GND = Pin 10
LOGIC DIAGRAM
19
OEBA
1
OEAB
2
A0
3
A1
4
A2
5
A3
456
A2 A3
A4 A5 A67A7
B4 B5 B6 B7
89
SF01126
18
B0
17
B1
16
B2
15
B3
LOGIC SYMBOL (IEEE/IEC)
19
1
2
3
4
5
6
7
9
EN1
EN2
1
2
8
18
17
16
15
14
13
12
11
SF01137
FUNCTION TABLE
INPUTS
OEBA OEAB
L L B data to A bus
H H A data to B bus
H L OFF
B data to A bus
A data to B bus
H = High voltage level
L = Low voltage level
X = Don’t care
OFF= High if pull-up resistor is connected to open collector output
VCC= Pin 20
GND = Pin 10
1996 Jan 05
6
A4
7
A5
8
A6
9
A7
14
13
12
11
SF01130
B4
B5
B6
B7
3
Loading...