SN74LVC646 OCTAL BUS TRANSCEIVER AND REGISTER WITH 3-STATE OUTPUTS

SCAS302A - JANUARY 1993 - REVISED JULY 1995

features

EPIC^TM (Enhanced-Performance Implanted CMOS) Submicron Process
Typical V_OLP (Output Ground Bounce) < 0.8 V at V_CC = 3.3 V, T_A = 25°C
Typical V_OHV (Output V_OH Undershoot) > 2 V at V_CC = 3.3 V, T_A = 25°C
Latch-Up Performance Exceeds 250 mA Per JEDEC Standard JESD-17
Package Options Include Plastic Small-Outline (DW), Shrink Small-Outline (DB), and Thin Shrink Small-Outline (PW) Packages
EPIC is a trademark of Texas Instruments Incorporated.

description

This octal bus transceiver and register is designed for 2.7-V to 3.6-V V_CC operation.

The SN74LVC646 consists of bus-transceiver circuits, 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 SN74LVC646.

Output-enable (OE\) and direction-control (DIR) inputs control the transceiver functions. In the transceiver mode, data present at the high-impedance port can be stored in either register or in both.

The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. DIR determines which bus receives data when OE\ is low. In the isolation mode (OE\ high), A data can be stored in one register and B data can be stored in the other register.

When an output function is disabled, the input function is still enabled and can be used to store and transmit data. Only one of the two buses, A or B, may be driven at a time.

To ensure the high-impedance state during power up or power down, OE\ should be tied to V_CC through a pullup resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.

The SN74LVC646 is characterized for operation from -40°C to 85°C

Title: OCTAL BUS TRANSCEIVER AND REGISTER WITH 3-STATE OUTPUTS
Product Family: REGISTERED TRANSCEIVERS
Device Functionality: OCTAL BUS TRANSCEIVER AND REGISTER

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