54ACT16841, 74ACT16841
20-BIT BUS-INTERFACE D-TYPE LATCHES
WITH 3-STATE OUTPUTS

SCAS174A - MAY 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
• Inputs Are TTL-Voltage Compatible
• 3-State Outputs Drive Bus Lines Directly
• Provide Extra Bus Driving/Latches 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 Thin Shrink Small-Outline (DGG) Packages, 300-mil Shrink Small-Outline (DL) Packages Using 25-mil Center-to-Center Pin Spacings, and 380-mil Fine-Pitch Ceramic Flat (WD) Packages Using 25-mil Center-to-Center Pin Spacings

EPIC and Widebus are trademarks of Texas Instruments Incorporated.

description

These 20-bit latches feature 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. They are particularly suitable for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers.

The 'ACT16841 can be used as two 10-bit latches or one 20-bit latch. The 20 latches are transparent D-type. While the latch-enable (1LE or 2LE) input is high, the Q outputs of the corresponding 10-bit latch follow the data (D) inputs. When LE is taken low, the Q outputs are latched at the levels that were set up at the D inputs.

A buffered output-enable (1 or 2) input can be used to place the outputs of the corresponding 10-bit latch in either a normal logic state (high or low logic levels) 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 latches. Old data can be retained or new data can be entered while the outputs are in the high-impedance state.

The 74ACT16841 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 54ACT16841 is characterized for operation over the full military temperature range of -55°C to 125°C. The 74ACT16841 is characterized for operation from -40°C to 85°C.