SN54ABT162823, SN74ABT162823
18-BIT BUS-INTERFACE FLIP-FLOPS
WITH 3-STATE OUTPUTS

SCBS473B - JUNE 1994 - REVISED JANUARY 1997

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

• Output Ports Have Equivalent 25- Series Resistors So No External Resistors Are Required
• Members of the Texas Instruments Widebus^TM Family
• State-of-the-Art EPIC-IIB^TM BiCMOS Design Significantly Reduces Power Dissipation
• ESD Protection Exceeds 2000 V Per MIL-STD-883, Method 3015; Exceeds 200 V Using Machine Model (C = 200 pF, R = 0)
• 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
• Package Options Include Plastic 300-mil Shrink Small-Outline (DL) Package and 380-mil Fine-Pitch Ceramic Flat (WD) Package Using 25-mil Center-to-Center Spacings

   

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

description

These 18-bit bus-interface 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, bidirectional bus drivers with parity, and working registers.

The 'ABT162823 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.

A buffered output-enable () input places the nine outputs in either a normal logic state (high or low logic level) or a high-impedance state. In the high-impedance state, the outputs neither load nor drive the bus lines significantly. The high-impedance state and increased drive provide the capability to drive bus lines without interface or pullup components. 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 outputs, which are designed to source or sink up to 12 mA, include equivalent 25- series resistors to reduce overshoot and undershoot.

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 SN54ABT162823 is characterized for operation over the full military temperature range of -55°C to 125°C. The SN74ABT162823 is characterized for operation from -40°C to 85°C.