Quad. 2-input Multiplexers
HD74HC298
Quad. 2-input Multiplexers (with storage)
Description
This circuit is controlled by the signals word select a...
Description
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 (A 1, B1, C1 and D 1) is presented to the inputs of the flip-flops, and when word select is high word 2 (A 2, B 2, 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 Word Select L H X H Clock Outputs QA a1 a2 QA0 QB b1 b2 QB0 QC c1 c2 QC0 QD d1 d2 QD0
HD74HC298
Pin Arrangement
B2 A2 A1 Data inputs B1 C2 D2 D1 GND
1 2 3 4 5 6 7 8 A2 A1 B1 C2 D2 D1 B2 QA QB QC QD CK WS
16 VCC 15 QA 14 QB Outputs 13 QC 12 QD 11 Clock 10 Word select 9 Data input C1
C1
(Top view)
2
HD74HC298
DC Characteristics
Ta = 25°C Item Input voltage Symbol VIH Ta = –40 to +85°C Max — — — 0.5 1.35 1.8 — — — — — 0.1 0.1 0.1 0.33 0.33 ±1.0 40 µA µA I OL = 4 mA I OL = 5.2 mA Vin = VCC or GND Vin = VCC or GND, Iout = 0 µA V I OH = –4 mA I OH = –5.2 mA Vin = VIH or VIL I OL = 20 µA V Vin = VIH or VIL I OH = –20 µA V Unit V Test Conditions
VCC (V) Min Typ Max Min 2.0 4.5 6.0 1.5 — 3.15 — 4.2 — — — — — — — — — — 0.5 1.5 3.15 4.2 —
VIL
2.0 4.5 6.0
1.35 — 1.8 — 1.9 ...
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