器件名称:
74HC298
功能描述:
Quad. 2-input Multiplexers (with storage)
文件大小:
34.98KB 共7页
简 介:
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 A max Low Quiescent Supply Current: ICC (static) = 4 A 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 A A I OL = 4 mA I OL = 5.2 mA Vin = VCC or GND Vin = VCC or GND, Iout = 0 A V I OH = –4 mA I OH = –5.2 mA Vin = VIH or VIL I OL = 20 A V Vin = VIH or VIL I OH = –20 A 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 4.4 5.9 4.……
