SN74ALVCH16646
16-BIT BUS TRANSCEIVER AND REGISTER
WITH 3-STATE OUTPUTS

SCES032A- JULY 1995 - REVISED JUNE 1996

features

• Member of the Texas Instruments Widebus^TM Family
• EPIC ^TM (Enhanced-Performance Implanted CMOS) Submicron Process
• Bus Hold on Data Inputs Eliminates the Need for External Pullup/Pulldown Resistors
• ESD Protection Exceeds 2000 V Per MIL-STD-883C, Method 3015; Exceeds 200 V Using Machine Model(C = 200 pF, R = 0)
• Latch-Up Performance Exceeds 250 mA Per JEDEC Standard JESD-17
• Package Options Include Plastic 300-mil Shrink Small-Outline (DL) and Thin Shrink Small-Outline (DGG) Packages

  EPIC and Widebus are trademarks of Texas Instruments Incorporated.

description

This 16-bit bus transceiver and register is designed for 2.3-V to 3.6-V V_CC operation.

The SN74ALVCH16646 can be used as two 8-bit transceivers or one 16-bit transceiver. 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 SN74ALVCH16646.

Output-enable () and direction-control (DIR) inputs are provided to control the transceiver functions. In the transceiver mode, data present at the high-impedance port may be stored in either register or in both. The select-control (SAB and SBA) inputs can multiplex stored and real-time (transparent mode) data. The circuitry used for select control eliminates the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. DIR determines which bus receives data when is low. In the isolation mode ( high), A data may be stored in one register and/or B data may be stored in the other register.

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

To ensure the high-impedance state during power up or power down, 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.

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

The SN74ALVCH16646 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 SN74ALVCH16646 is characterized for operation from -40°C to 85°C.