5-1
FACT DATA
The MC74AC378/74ACT378 is a 6-bit register with a buffered common Enable.
This device is similar to the MC74AC174/74ACT174, but with common Enable
rather than common Master Reset.
• 6-Bit High-Speed Parallel Register
• Positive Edge-Triggered D-Type Inputs
• Fully Buffered Common Clock and Enable Inputs
• Outputs Source/Sink 24 mA
• ′ACT378 Has TTL Compatible Inputs
1516 14 13 12 11 10
21 3 4 5 6 7
V
CC
9
8
Q5D5D4Q4D3Q3CP
E
Q0D0D1Q1D2Q2GND
PIN NAMES
E
Enable Input
D0–D5Data Inputs
CP Clock Pulse Input
Q0–Q5Outputs
TRUTH TABLE
Inputs Outputs
E CP D
n
Q
n
H X No Change
L H H
L L L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
= LOW-to-HIGH Transition
PARALLEL
D REGISTER
WITH ENABLE
N SUFFIX
CASE 648-08
PLASTIC
D SUFFIX
CASE 751B-05
PLASTIC
LOGIC SYMBOL
E D0D1D2D3D4D
5
CP
Q0Q1Q2Q3Q4Q
5
MC74AC378 MC74ACT378
5-2
FACT DATA
FUNCTIONAL DESCRIPTION
The MC74AC378/74ACT378 consists of six edgetriggered D-type flip-flops with individual D inputs and Q
outputs. The Clock (CP) and Enable (E
) inputs are common to
all flip-flops.
When the E
input is LOW, new data is entered into the
register on the LOW-to-HIGH transition of the CP input. When
the E
input is HIGH, the register will retain the present data
independent of the CP input.
Please note that this diagram is provided only for the understanding of logic
operations and should not be used to estimate propagation delays.
LOGIC DIAGRAM
CP
Q
E
D CP
Q
E
D CP
Q
E
D CP
Q
E
D CP
Q
E
D CP
Q
E
D
D
0
D
1
D
2
D
3
D
4
D
5
Q
0
Q
1
Q
2
Q
3
Q
4
Q
5
CP
E
MAXIMUM RATINGS*
Symbol Parameter Value Unit
V
CC
DC Supply Voltage (Referenced to GND) –0.5 to +7.0 V
V
in
DC Input Voltage (Referenced to GND) –0.5 to VCC +0.5 V
V
out
DC Output Voltage (Referenced to GND) –0.5 to VCC +0.5 V
I
in
DC Input Current, per Pin ±20 mA
I
out
DC Output Sink/Source Current, per Pin ±50 mA
I
CC
DC VCC or GND Current per Output Pin ±50 mA
T
stg
Storage Temperature –65 to +150 °C
* Maximum Ratings are those values beyond which damage to the device may occur. Functional operation should be restricted to the Recommended
Operating Conditions.
MC74AC378 MC74ACT378
5-3
FACT DATA
RECOMMENDED OPERATING CONDITIONS
Symbol Parameter Min Typ Max Unit
Vin, V
out
DC Input Voltage, Output Voltage (Ref. to GND) 0 V
CC
V
Input Rise and Fall Time (Note 1)
′AC Devices except Schmitt Inputs
′AC Devices except Schmitt Inputs
VCC @ 5.5 V 25
VCC @ 4.5 V 10
Input Rise and Fall Time (Note 2)
′ACT Devices except Schmitt Inputs
T
J
Junction Temperature (PDIP) 140 °C
T
A
Operating Ambient Temperature Range –40 25 85 °C
I
OH
Output Current — High –24 mA
I
OL
Output Current — Low 24 mA
1. Vin from 30% to 70% VCC; see individual Data Sheets for devices that differ from the typical input rise and fall times.
2. Vin from 0.8 V to 2.0 V; see individual Data Sheets for devices that differ from the typical input rise and fall times.
DC CHARACTERISTICS
TA = +25°C
TA =
–40°C to +85°C
Typ Guaranteed Limits
V
IH
3.0 1.5 2.1 2.1 V
OUT
= 0.1 V
4.5 2.25 3.15 3.15 V or VCC – 0.1 V
5.5 2.75 3.85 3.85
V
IL
3.0 1.5 0.9 0.9 V
OUT
= 0.1 V
4.5 2.25 1.35 1.35 V or VCC – 0.1 V
5.5 2.75 1.65 1.65
V
OH
3.0 2.99 2.9 2.9 I
OUT
= –50 µA
4.5 4.49 4.4 4.4 V
5.5 5.49 5.4 5.4
*VIN = VIL or V
I
OH
–24 mA
5.5 4.86 4.76 –24 mA
V
OL
3.0 0.002 0.1 0.1 I
OUT
= 50 µA
4.5 0.001 0.1 0.1 V
5.5 0.001 0.1 0.1
*VIN = VIL or V
I
OL
24 mA
5.5 0.36 0.44 24 mA
I
IN
5.5 75 mA V
OLD
= 1.65 V Max
I
OHD
5.5 –75 mA V
OHD
= 3.85 V Min
I
CC
* All outputs loaded; thresholds on input associated with output under test.
†Maximum test duration 2.0 ms, one output loaded at a time.
Note: IIN and ICC @ 3.0 V are guaranteed to be less than or equal to the respective limit @ 5.5 V VCC.
tr, t
f
Input Rise and Fall Time (Note 2)
Minimum High Level
Input Voltage
Maximum Low Level
Input Voltage
Minimum High Level
Output Voltage
Maximum Low Level
Output Voltage
Maximum Input
Leakage Current
†Minimum Dynamic
Maximum Quiescent
Supply Current