SN54ABT16648, SN74ABT1664816-BIT TRANSCEIVERS AND REGISTERS
WITH 3-STATE OUTPUTS

SCBS213 - SEPTEMBER 1992 - REVISED OCTOBER 1992

features

• Members of the Texas Instruments Widebus^TM Family
• State-of-the-Art EPIC-IIB ^TM BiCMOS Design Significantly Reduces Power Dissipation
• Latch-Up Performance Exceeds 500 mA Per JEDEC Standard JESD-17
• Typical V_OLP (Output Ground Bounce)< 1 V at V_CC = 5 V, T_A = 25°C
• Distributed V_CC and GND Pin Configuration Minimizes High-Speed Switching Noise
• Flow-Through Architecture Optimizes PCB Layout
• High-Drive Outputs (-32-mA I_OH, 64-mA I_OL)
• Packaged in Plastic 300-mil Shrink Small-Outline Packages and 380-mil Fine-Pitch Ceramic Flat Packages Using 25-mil Center-to-Center Spacings

  Widebus and EPIC-IIB are trademarks of Texas Instruments Incorporated.

description

The ´ABT16648 is a 16-bit bus transceiver that consists of D-type flip-flops and control circuitry arranged for multiplexed transmission of data directly from the input bus or from the internal registers. The device 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 ´ABT16648.

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 will eliminate the typical decoding glitch that occurs in a multiplexer during the transition between stored and real-time data. The direction control (DIR) determines which bus will receive 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, may 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.

The SN74ABT16648 is available in TI's shrink small-outline package (DL), which provides twice the I/O pin count and functionality of standard small-outline packages in the same printed-circuit-board area.

The SN54ABT16648 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT16648 is characterized for operation from -40°C to 85°C.