HIT HD74HC298 Datasheet
HD74HC298
Quad. 2-input Multiplexers (with storage)
Description
This circuit is controlled by the signals word select and clock. When the word select input is taken low
word 1 (A1, B1, C1 and D1) is presented to the inputs of the flip-flops, and when word select is high word 2
(A2, B2, C2 and D2) is presented to the inputs of the flip-flops. The selected word is clocked to the output
terminals on the negative edge of the clock pulse.
Features
• High Speed Operation: tpd (Clock to Q) = 19 ns typ (CL = 50 pF)
• High Output Current: Fanout of 10 LSTTL Loads
• Wide Operating Voltage: VCC = 2 to 6 V
• Low Input Current: 1 µA max
• Low Quiescent Supply Current: ICC (static) = 4 µA max
Function Table
Inputs Outputs
Word Select Clock Q
L a
H a
XH QA0Q
A
1
2
Q
B
b
1
b
2
B0
Q
C
c
1
c
2
Q
C0
Q
D
d
1
d
2
Q
D0
HD74HC298
Pin Arrangement
Data
inputs
1
B
2
B
2
A
2
3
A
1
2
A
A
Q
2
1
A
Q
B
16
15
14
V
CC
Q
A
Q
B
Outputs
4
B
1
5
C
2
6
D
2
B
C
D
Q
1
2
2
Q
CK
C
D
13
12
11
Q
C
Q
D
Clock
D
GND
7
1
D
WS
1
C
1
8
10
9
Word
select
Data
input
1
C
(Top view)
2
HD74HC298
DC Characteristics
Ta = –40 to
Ta = 25°C
Item Symbol V
Input voltage V
IH
(V) Min Typ Max Min Max Unit Test Conditions
CC
2.0 1.5 — — 1.5 — V
4.5 3.15 — — 3.15 —
6.0 4.2 — — 4.2 —
V
IL
2.0 — — 0.5 — 0.5 V
4.5 — — 1.35 — 1.35
6.0 — — 1.8 — 1.8
Output voltage V
OH
2.0 1.9 2.0 — 1.9 — V Vin = VIH or VILIOH = –20 µA
4.5 4.4 4.5 — 4.4 —
6.0 5.9 6.0 — 5.9 —
4.5 4.18 — — 4.13 — IOH = –4 mA
6.0 5.68 — — 5.63 — IOH = –5.2 mA
V
OL
2.0 — 0.0 0.1 — 0.1 V Vin = VIH or VILIOL = 20 µA
4.5 — 0.0 0.1 — 0.1
6.0 — 0.0 0.1 — 0.1
4.5 — — 0.26 — 0.33 IOL = 4 mA
6.0 — — 0.26 — 0.33 IOL = 5.2 mA
Input current Iin 6.0 — — ±0.1 — ±1.0 µA Vin = VCC or GND
Quiescent supply
I
CC
6.0 — — 4.0 — 40 µA Vin = VCC or GND, Iout = 0 µA
current
+85°C
3
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