HD74HC674

HD74HC674 16-bit Shift Register Description The HD74HC674 is a 16-bit parallel-in, serial-out shift register. A three-state input/output (data I/O) port provides access for entering serial data or reading the shift-register word in a recirculating loop. The device has four basic modes of operation: 1. 2. 3. 4. Hold (do nothing) Write (serially via input/output) Read (serially) Load (parallel via data inputs) Low-to-high-level changes at the chip select input should be made only when the clock input is low to prevent false clocking. Features High Speed Operation: tpd (CLK to SER/Q15) = 17 ns typ (CL = 50 pF) High Output Current: Fanout of 15 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 (Ta = 25°C) Function Table Inputs CS H L L L R/W X L H H Mode X X L H CLK X SER/Q15 Z Z Q14n P15 Operation Do nothing Shift and write (serial load) Shift and read Parallel load HD74HC674 Pin Arrangement CS CLK R/W NC Mode SER/Q15 P0 P1 P2 1 2 3 4 5 6 7 8 9 24 VCC 23 P15 22 P14 21 P13 20 P12 19 P11 18 P10 17 P9 16 P8 15 P7 14 P6 13 P5 P3 10 P4 11 GND 12 (Top view) 2 HD74HC674 Logic Diagram IN PE CK P P0 Q P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 P13 P14 VCC P15 Mode CS CLK R/W SER/Q15 3 HD74HC674 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 ±5.0 µA µA µA I OL = 6 mA I OL = 7.8 ...