SN74ALVC16269
12-BIT TO 24-BIT REGISTERED BUS TRANSCEIVER
WITH 3-STATE OUTPUTS

SCAS417A - OCTOBER 1993 - REVISED OCTOBER 1994

features

• EPIC^TM (Enhanced-Performance Implanted CMOS) Submicron Process
• Member of the Texas Instruments Widebus^TM Family
• Supports Unregulated Battery Operation Down to 2.7 V
• Typical V_OLP (Output Ground Bounce) < 0.8 V at V_CC = 3.3 V, T_A = 25°C
• Typical V_OHV (Output V_CC Overshoot) > 2 V at V_CC = 3.3 V, T_A = 25°C
• Bus Hold On Data Inputs Eliminates the Need for External Pullup/Pulldown Resistors
• Packaged in Plastic Shrink Small-Outline (DL) and Thin Shrink Small-Outline (DGG) Packages

  EPIC and Widebus are trademarks of Texas Instruments Incorporated.

description

The SN74ALVC16269 is a 12-bit to 24-bit registered bus transceiver, which is intended for applications where two separate ports must be multiplexed onto, or demultiplexed from, a single port. It is particularly suitable as an interface between synchronous DRAMs and high-speed microprocessors. The SN74ALVC16269 is designed specifically for low-voltage (3.3 V) V_CC operation.

Data is stored in the internal B-port registers on the low-to-high transition of the clock (CLK) input, provided that the appropriate clock-enable () inputs are low. Proper control of these inputs allows two sequential 12-bit words to be presented as a 24-bit word on the B port. For data

transfer in the B-to-A direction, a single storage register is provided. The select () line selects 1B or 2B data for the A outputs. The register on the A output permits the fastest possible data transfer, thus extending the period that the data is valid on the bus. The control terminals are registered so that all transactions are synchronous with the clock. Data flow is controlled by the active-low output enables (,, ).

Active bus-hold circuitry is provided t+o hold unused or floating data inputs at a valid logic level.

The SN74ALVC16269 is available in TI's shrink small-outline (DL) and thin shrink small-outline (DGG) packages, which provide twice the I/O pin count and functionality of standard small-outline packages in the same printed-circuit-board area.

The SN74ALVC16269 is characterized for operation from -40°C to 85°C.