54AC16823, 74AC16823
18-BIT BUS INTERFACE FLIP-FLOPS
WITH 3-STATE OUTPUTS

SCAS243A - APRIL 1991 - REVISED APRIL 1996

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

features

• Members of the Texas Instruments Widebus ^TM Family
• Provides Extra Data Width Necessary for Wider Address/Data Paths or Buses With Parity
• Flow-Through Architecture Optimizes PCB Layout
• Distributed V_CC and GND Pin Configuration Minimizes High-Speed Switching Noise
• EPIC ^TM (Enhanced-Performance Implanted CMOS) 1-m Process
• 500-mA Typical Latch-Up Immunity at 125°C
• Package Options Include Plastic 300-mil Shrink Small-Outline (DL) Package Using 25-mil Center-to-Center Pin Spacings and 380-mil Fine-Pitch Ceramic Flat (WD) Package Using 25-mil Center-to-Center Pin Spacings

EPIC and Widebus are trademarks of Texas Instruments Incorporated.

description

These 18-bit flip-flops feature 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. They are particularly suitable for implementing wider buffer registers, I/O ports, parity bus interfacing, and working registers.

The 'AC16823 can be used as two 9-bit flip-flops or one 18-bit flip-flop. With the clock-enable () input low, the D-type flip-flops enter data on the low-to-high transitions of the clock. Taking high disables the clock buffer, thus latching the outputs. Taking the clear () input low causes the Q outputs to go low independently of the clock.

The output enable input can be used to place the outputs in either a normal logic state (high or low) or a high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly.

does not affect the internal operation of the flip-flops. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

The 74AC16823 is packaged 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 54AC16374 is characterized for operation over the full military temperature range of -55°C to 125°C. The 74AC16823 is characterized for operation from -40°C to 85°C.