描述 Description

The 'ACT16646 are 16-bit bus transceivers consisting of D-type flip-flops and control circuitry with 3-state outputs arranged for multiplexed transmission of data directly from the data bus or from the internal storage registers. The devices 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 bus transceivers and registers.
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 controls (SAB and SBA) 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, may be driven at a time.
The 74ACT16646 is packaged in TI's shrink small-outline package, which provides twice the functionality of standard small-outline packages in the same printed-circuit-board area.
The 54ACT16646 is characterized for operation over the full military temperature range of -55°C to 125°C. The 74ACT16646 is characterized for operation from -40°C to 85°C.
?

特性 Features

? Members of the Texas Instruments WidebusTM Family
? Inputs Are TTL-Voltage Compatible
? Independent Registers for A and B Buses
? Multiplexed Real-Time and Stored Data
? Flow-Through Architecture Optimizes PCB Layout
? Distributed VCC and GND Pin Configuration MinimizesHigh-Speed Switching Noise
? EPICTM (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) Packages Using 25-mil Center-to-Center Pin Spacings and380-mil Fine-Pitch Ceramic Flat (WD) Packages Using 25-milCenter-to-Center Pin Spacings ?EPIC and Widebus are trademarks of Texas Instruments Incorporated.