SN54HCT646

D Operating Voltage Range of 4.5 V to 5.5 V D Low Power Consumption, 80-µA Max ICC D Typical tpd = 12 ns D ±6-mA Output Drive at 5 V D Low Input Current of 1 µA Max D Inputs Are TTL-Voltage Compatible SN54HCT646 . . . JT OR W PACKAGE SN74HCT646 . . . DW OR NT PACKAGE (TOP VIEW) SN54HCT646, SN74HCT646 OCTAL BUS TRANSCEIVERS AND REGISTERS WITH 3-STATE OUTPUTS SCLS178C – MARCH 1984 – REVISED MARCH 2003 D Independent Registers for A and B Buses D Multiplexed Real-Time and Stored Data D True Data Paths D High-Current 3-State Outputs Can Drive Up To 15 LSTTL Loads SN54HCT646 . . . FK PACKAGE (TOP VIEW) DIR SAB CLKAB NC VCC CLKBA SBA CLKAB 1 SAB 2 DIR 3 A1 4 A2 5 A3 6 A4 7 A5 8 A6 9 A7 10 A8 11 GND 12 24 VCC 23 CLKBA 22 SBA 21 OE 20 B1 19 B2 18 B3 17 B4 16 B5 15 B6 14 B7 13 B8 4 3 2 1 28 27 26 A1 5 25 OE A2 6 24 B1 A3 7 23 B2 NC 8 22 NC A4 9 21 B3 A5 10 20 B4 A6 1112 13 14 15 16 17 1819 B5 A7 A8 GND NC B8 B7 B6 description/ordering information NC – No internal connection The ’HCT646 devices consist of bus-transceiver circuits with 3-state outputs, D-type flip-flops, and control circuitry arranged for multiplexed transmission of data directly from the input bus or from the internal registers. Data on the A or B bus is clocked into the registers on the low-to-high transition of the appropriate clock (CLKAB or CLKBA) input. Figure 1 illustrates the four fundamental bus-management functions that can be performed with the ’HCT646 devices. Output-enable (OE) and dire...