GAB
A1
A2 B2
B1
TO OTHER SIX
TRANSCEIVERS
GBA
BLOCK DIAGRAM
1/4 LS623
5-1
FAST AND LS TTL DATA
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUT
The SN54/74LS623 series is an octal bus transceiver designed for
asynchronous two-way communication between data buses. Control function
implementation allows maximum timing flexibility . Enable inputs may be used
to disable the device so that buses are effectively isolated. Depending on the
Logic Levels at the enable inputs, Data transmission is allowed from the A bus
to the B bus or from the B bus to the A bus. The dual-enable configuration
gives the LS623 the capability to store data by simultaneous enabling of GBA
and GAB. Each output reinforces its input in this transceiver configuration.
Thus, when both control inputs are enabled all other data sources to the two
sets of bus lines (16 in all) will remain at their last states.
CONNECTION DIAGRAM (TOP VIEW)
18 17 16 15 14 13
1 2 3 4 5 6 7
20 19
8
VCC
ENABLE
GAB
ENABLE
GBA B1 B2 B3 B5B4 B6
A1 A2 A3 A4 A5 A6 A7 9 10
A8 GND
12 11
B7 B8
FUNCTION TABLE
ENABLE INPUTS OPERATION
GBA GAB LS623
L L B data to A bus
H H A data to B bus
H L Isolation
L H B data to A bus,
A data to B bus
H = HIGH Level, L = LOW Level, X = Irrelevant
SN54/74LS623
OCTAL BUS TRANSCEIVER
WITH 3-STATE OUTPUT
LOW POWER SCHOTTKY
ORDERING INFORMATION
SN54LSXXXJ Ceramic
SN74LSXXXN Plastic
SN74LSXXXDW 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
5-2
FAST AND LS TTL DATA
SN54/74LS623
GUARANTEED OPERATING RANGES
Symbol Parameter Min Typ Max Unit
VCC Supply Voltage 54
74 4.5
4.75 5.0
5.0 5.5
5.25 V
TAOperating Ambient Temperature Range 54
74 –55
025
25 125
70 °C
IOH Output Current — High
54, 74 –3.0 mA
OH
54
74 –12
–15 mA
IOL Output Current — Low 54
74 12
24 mA
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE (unless otherwise specified)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min Typ Max
Unit
Test Conditions
VIH Input HIGH Voltage 2.0 V Guaranteed Input HIGH Voltage for
All Inputs
VIL
Input LOW Voltage
54 0.5
V
Guaranteed Input LOW Voltage for
All Inputs
VIL
Input LOW Voltage
74 0.6
V
Guaranteed Input LOW Voltage for
All Inputs
VT+–VT– Hysteresis 0.2 0.4 V VCC = MIN
VIK Input Clamp Diode Voltage –0.65 –1.5 V VCC = MIN, IIN = –18 mA
VOH
Output HIGH Voltage
54, 74 2.4 3.4 V VCC = MIN, IOH = ± 3.0 mA
VOH
Output HIGH Voltage
54, 74 2.0 V VCC = MIN, IOH = MAX
VOL
Output LOW Voltage
54, 74 0.25 0.4 V IOL = 12 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
VOL
Output LOW Voltage
74 0.35 0.5 V IOL = 24 mA
VIN = VIL or VIH
per Truth Table
IOZH Output Off Current HIGH 20 µA VCC = MAX, VOUT = 2.7 V
IOZL Output Off Current LOW –400 µA VCC = MAX, VOUT = 4.0 V
IIH
Input HIGH Current
A, or B, GBA or
GAB 20 µA VCC = MAX, VIN = 2.7 V
IIH
Input HIGH Current
GAB or GAB 0.1 mA VCC = MAX, VIN = 7.0 V
A or B 0.1 mA VCC = MAX, VIN = 5.5 V
IIL Input LOW Current –0.4 mA VCC = MAX, VIN = 0.4 V
IOS Short Circuit Current (Note 1) –40 –225 mA VCC = MAX
ICC
Power Supply Current
Total Output HIGH 70
mA
VCC = MAX
ICC
Total Output LOW 90
mA
VCC = MAX
Total at HIGH Z 95
Note 1: Not more than one output should be shorted at a time, nor for more than 1 second.
5-3
FAST AND LS TTL DATA
SN54/74LS623
AC CHARACTERISTICS (TA = 25°C, VCC = 5.0 V)
Parameter
Limits
Unit
Test Conditions
Parameter
Min Typ Max
Unit
Test Conditions
tPLH
tPHL Propagation Delay
A to B 8.0
11 15
15 ns
CL = 45 pF,
RL = 667 Ω
tPLH
tPHL Propagation Delay
B to A 8.0
11 15
15 ns
C
L = 45 pF,
RL = 667 Ω
tPZL
tPZH Output Enable Time
GBA to A 31
26 40
40 ns
CL = 45 pF,
RL = 667 Ω
tPZL
tPZH Output Enable Time
GAB to B 31
26 40
40 ns
tPLZ
tPHZ Output Disable Time
GBA to A 15
15 25
25 ns
CL = 5.0 pF
tPLZ
tPHZ Output Disable Time
GAB to B 15
15 25
25 ns
CL = 5.0 pF