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Fairchild |
May 1988
Revised August 1999
74F373
Octal Transparent Latch with 3-STATE Outputs
General Description
The 74F373 consists of eight latches with 3-STATE outputs
for bus organized system applications. The flip-flops
appear transparent to the data when Latch Enable (LE) is
HIGH. When LE is LOW, the data that meets the setup
times is latched. Data appears on the bus when the Output
Enable (OE) is LOW. When OE is HIGH the bus output is in
the high impedance state.
Features
s Eight latches in a single package
s 3-STATE outputs for bus interfacing
s Guaranteed 4000V minimum ESD protection
Ordering Code:
Order Number Package Number
Package Description
74F373SC
M20B
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
74F373SJ
M20D
20-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
74F373MSA
MSA20
20-Lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3mm Wide
74F373PC
N20A
20-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
© 1999 Fairchild Semiconductor Corporation DS009523
www.fairchildsemi.com
Unit Loading/Fan Out
Pin Names
D0–D7
LE
OE
O0–O7
Description
Data Inputs
Latch Enable Input (Active HIGH)
Output Enable Input (Active LOW)
3-STATE Latch Outputs
U.L.
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
150/40 (33.3)
Input IIH/IIL
Output IOH/IOL
20 µA/−0.6 mA
20 µA/−0.6 mA
20 µA/−0.6 mA
−3 mA/24 mA (20 mA)
Functional Description
The 74F373 contains eight D-type latches with 3-STATE
output buffers. When the Latch Enable (LE) input is HIGH,
data on the Dn inputs enters the latches. In this condition
the latches are transparent, i.e., a latch output will change
state each time its D input changes. When LE is LOW, the
latches store the information that was present on the D
inputs a setup time preceding the HIGH-to-LOW transition
of LE. The 3-STATE buffers are controlled by the Output
Enable (OE) input. When OE is LOW, the buffers are in the
bi-state mode. When OE is HIGH the buffers are in the high
impedance mode but this does not interfere with entering
new data into the latches.
Truth Table
Inputs
LE OE
HL
HL
LL
XH
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance State
Dn
H
L
X
X
Output
On
H
L
On (no change)
Z
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
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