HD74BC373A
Octal D Type Transparent Latches With 3 State Outputs
ADE-205-009A(Z)
Rev. 1
March 1993
Description
The HD74BC373A provides high drivability and operation equal to or better than high speed bipolar
standard logic IC by using Bi-CMOS process. The device features low power dissipation that is about 1/5
of high speed bipolar logic IC, when the frequency is 10 MHz. The device has eight D type latches with
three state outputs in a 20 pin package. When the latch enable input is high, the Q outputs will follow the
D inputs. When the latch enable goes low, data at the D inputs will be retained at the outputs until latch
enable returns high again. When a high logic level is applied to the output control input, all outputs go to a
high impedance state, regardless of what signals are present at the other inputs and the state of the storage
elements.
Features
Input/Output are at high impedance state when power supply is off.
Built in input pull up circuit can make input pins be open, when not used.
TTL level input
Wide operating temperature range input pins
Ta = 40 to + 85C
Function Table
Inputs
G
LE
D
Output Q
H
X
X
Z
L
H
L
L
L
H
H
H
L
L
X
No change
H :
High level
L
:
Low level
X :
Immaterial
Z
:
High impedance
HD74BC373A
2
Pin Arrangement
(Top view)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
V
CC
GND
1Q
1D
2D
2Q
3Q
3D
4D
4Q
8Q
8D
7D
7Q
6Q
6D
5D
5Q
LE
G
Absolute Maximum Ratings
Item
Symbol
Rating
Unit
Supply voltage
V
CC
0.5 to +7.0
V
Input diode current
I
IK
30
mA
Input voltage
V
IN
0.5 to +7.5
V
Output voltage
V
OUT
0.5 to +7.5
V
Off state output voltage
V
OUT(off)
0.5 to +5.5
V
Storage temperature
Tstg
65 to +150
C
Note:
1. The absolute maximum ratings are values which must not individually be exceeded, and
furthermore, no two of which may be realized at the same time.
HD74BC373A
3
Recommended Operating Conditions
Item
Symbol
Min
Typ
Max
Unit
Supply voltage
V
CC
4.5
5.0
5.5
V
Input voltage
V
IN
0
--
V
CC
V
Output voltage
V
OUT
0
--
V
CC
V
Operating temperature
Topr
40
--
85
C
Input rise/fall time*
1
t
r
, t
f
0
--
8
ns/V
Note:
1. This item guarantees maximum limit when one input switches.
Waveform: Refer to test circuit of switching characteristics.
Logic Diagram
1Q
2Q
7Q
8Q
G
1D
2D
7D
8D
LE
D
Q
D
Q
D
Q
D
Q
HD74BC373A
4
Electrical Characteristics (Ta = 40C to +85C)
Item
Symbol
V
CC
(V)
Min
Max
Unit
Test Conditions
Input voltage
V
IH
2.0
--
V
V
IL
--
0.8
V
Output voltage
V
OH
4.5
2.4
--
V
I
OH
= 3 mA
4.5
2.0
--
V
I
OH
= 15 mA
V
OL
4.5
--
0.4
V
I
OL
= 24 mA
4.5
--
0.5
V
I
OL
= 48 mA
Input diode voltage
V
IK
4.5
--
1.2
V
I
IN
= 18 mA
Input current
I
I
5.5
--
250
A
V
IN
= 0 V
5.5
--
1.0
A
V
IN
= 5.5 V
5.5
--
100
A
V
IN
= 7.0 V
Short circuit output current*
1
I
OS
5.5
100
225
mA
V
IN
= 0 or 5.5 V
Off state output current
I
OZH
5.5
--
50
A
V
O
= 2.7 V
I
OZL
5.5
--
50
A
V
O
= 0.5 V
Supply current
I
CCL
5.5
--
29.5
mA
V
IN
= 0 or 5.5 V
All outputs is "L"
I
CCH
5.5
--
2.5
mA
V
IN
= 0 or 5.5 V
All outputs is "H"
I
CCZ
5.5
--
2.5
mA
V
IN
= 0 or 5.5 V
All outputs is "Z"
I
CCT
*
2
5.5
--
1.5
mA
V
IN
= 3.4 or 0.5 V
Notes : 1. Not more than one output should be shorted at a time and duration of the short circuit should not
exceed one second.
2. When input by the TTL level, it shows I
CC
increase at per one input pin.
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