CY74FCT2646ATQCT

Overview

The CY74FCT2646ATQCT is an 8-bit registered bus transceiver with 3-state outputs manufactured by Texas Instruments. It operates within a supply voltage range of 4.75 V to 5.25 V and supports an operating temperature range from -40°C to 85°C. The device features independent registers for A and B buses, allowing data storage and multiplexed transmission. Propagation delay ranges from 1.5 ns to 6.3 ns. Output drive capabilities include a maximum sink current of 12 mA and source current of 15 mA. It includes on-chip termination resistors and edge-rate control circuitry.

Feature Summary

• Independent D-type flip-flops for A and B buses enable simultaneous data storage and real-time transparent mode operation.
• Integrated edge-rate control circuitry and output series resistors reduce transmission-line reflection noise and improve signal integrity.
• Ioff circuitry supports partial-power-down mode by disabling outputs to prevent damaging backflow current when the device is unpowered.
• Multiplexing controls allow selection between stored register data and real-time input data for flexible bus management.

Applications

• Bus management systems requiring registered data transfer between memory modules
• Partial-power-down applications in portable electronic devices
• High-speed digital interfaces needing controlled edge rates to minimize noise

Procurement Notes

Verify the specific suffix 'ATQCT' corresponds to the required speed grade (6.3 ns max) and QSOP/SSOP package variant. Confirm RoHS compliance status as indicated in the ordering information table. Ensure design compatibility with the 24-pin DBQ package dimensions and moisture sensitivity level ratings before finalizing procurement orders.

Selection Notes

Select this component when registered bidirectional data transfer with independent latching is required. The integrated edge-rate control makes it suitable for high-speed designs where signal reflections must be minimized without external components. Verify that the 15 mA source and 12 mA sink currents meet the load requirements of the connected bus lines.

Part Context

This device belongs to the FCT logic family, offering CMOS performance with TTL-compatible input and output levels. It serves as a registered alternative to non-registered bus transceivers like the CY74FCT646T, providing additional data storage capabilities within the same functional pinout architecture for backward compatibility in existing designs.

Replacement Considerations

CY74FCT2646CTQCT

FAQ

How does the Ioff feature function?

The Ioff circuitry disables the outputs when the device is powered down, preventing damaging current backflow through the device into the power supply rails.

What is the purpose of the SAB and SBA inputs?

These are output data source select inputs that allow the user to multiplex between storing data in the registers and transmitting real-time data directly from the input bus.