CY54FCT646CTLMB

Overview

The CY54FCT646CTLMB is an 8-bit registered bus transceiver with 3-state outputs manufactured by Texas Instruments. It utilizes Fast CMOS Technology (FCT) and features independent registers for A and B buses, allowing multiplexed transmission of data directly from inputs or internal storage. The device supports partial-power-down mode via Ioff circuitry to prevent backflow current. It operates within a supply voltage range of 4.5 V to 5.5 V and an ambient temperature range of -55°C to 125°C. Electrical characteristics include a maximum output sink current of 48 mA and source current of 12 mA. Propagation delays are specified between 2 ns and 11 ns depending on the signal path.

Feature Summary

• Independent register architecture for A and B buses enables flexible data storage and real-time transparent transfer modes.
• Integrated Ioff circuitry supports partial-power-down applications by disabling outputs to prevent damaging current backflow.
• Edge-rate control circuitry provides significantly improved noise characteristics compared to standard FCT functions.
• Fully compatible with TTL input and output logic levels while maintaining ESD protection exceeding JESD 22 standards.

Applications

• Bus management systems requiring isolated data storage and controlled directionality between two 8-bit buses.
• High-speed digital interfaces utilizing registered transceivers for data buffering and synchronization.
• Partial-power-down environments where output isolation is required during low-power states.

Procurement Notes

Verify that the specific suffix CTLMB corresponds to the LCC-28 package variant intended for your design. Confirm the operating temperature range requirement aligns with the -55°C to 125°C specification for this military-grade part. Ensure PCB layout accommodates the leaded ceramic package dimensions and thermal properties defined in the datasheet. Cross-reference the ordering information table to confirm availability status and manufacturing lifecycle stage before finalizing procurement plans.

Selection Notes

Select this component when an 8-bit registered transceiver with independent bus registers is required for high-reliability applications. The CY54FCT646CTLMB is suitable for designs needing robust ESD protection and compatibility with TTL logic levels. Consider the LCC-28 package constraints and the specific electrical drive capabilities of 48 mA sink and 12 mA source currents. Evaluate if the edge-rate control features meet the noise immunity requirements of the target system environment.

Part Context

This device belongs to the CY54FCT646T family of 8-bit registered transceivers produced by Texas Instruments following their acquisition of Cypress Semiconductor's FCT line. The CY54 prefix indicates a military-grade version compliant with MIL-PRF-38535 standards. The family includes variants with different speed grades and packages, such as the CY74FCT646T for commercial use. This specific part number denotes the LCC package variant optimized for extended temperature ranges.

Replacement Considerations

Public confirmed substitute part numbers include CY54FCT646ATLMB and CY54FCT646TLMB. These alternatives share the same functional description but differ in propagation delay specifications and operating temperature ranges. Verify pinout compatibility and electrical parameter alignment before substitution.