74LCX646MTC

Overview

The onsemi 74LCX646MTC is a low voltage octal transceiver and register featuring 5V tolerant inputs and outputs. It operates within a supply voltage range of 2.3V to 3.6V, utilizing advanced CMOS technology for high-speed operation with low power dissipation. The device provides multiplexed transmission of data directly from the input bus or internal storage registers. Key electrical parameters include a maximum propagation delay of 7.0 ns at VCC = 3.3V, a quiescent supply current of 10 µA max, and an output drive capability of ±24 mA at VCC = 3.0V. It supports live insertion/withdrawal and includes patented noise/EMI reduction circuitry.

Feature Summary

• Features 5V tolerant inputs and outputs for seamless interfacing between low voltage (2.5V/3.3V) and 5V signal environments.
• Provides registered bus transceiver functionality with D-type flip-flops and control circuitry for multiplexed data transmission.
• Implements patented noise and EMI reduction circuitry to enhance signal integrity during high-speed operations.

Applications

• Bus management systems requiring real-time transfer and data storage capabilities
• Low voltage logic interfaces connecting 3.3V systems to 5V environments
• High-speed data routing in communication equipment

Procurement Notes

Verify the specific package variant, as the MTC suffix denotes the 24-Lead Thin Shrink Small Outline Package (TSSOP). Confirm that the ordering code matches the required pinout and physical dimensions for your PCB layout. Ensure compatibility with the 2.3V to 3.6V operating voltage range for your target application environment.

Selection Notes

Select this component when designing systems that require bidirectional data flow with optional latching between two 8-bit buses. It is suitable for applications needing 5V tolerance on both input and output pins while powered by lower voltages. Consider the TSSOP-24 package constraints and the requirement for pull-up resistors on the OE pin to ensure proper high-impedance states during power transitions.

Part Context

This device belongs to the LCX family of low-voltage CMOS logic integrated circuits. It functions as an octal bus transceiver with registered outputs, allowing data to be stored in internal registers or passed through transparently. The design facilitates efficient data handling in complex digital systems where multiple buses need controlled interaction.

Replacement Considerations

Check datasheets for equivalent octal transceivers with 5V tolerance and similar speed grades. Verify pin compatibility and logical truth tables before substitution. Note that the original manufacturer was Fairchild Semiconductor, now part of onsemi.

FAQ

How does the device handle data transmission?

It allows multiplexed transmission of data either directly from the input bus or from the internal storage registers based on control signals.

What is the purpose of the SAB and SBA pins?

These are Transmit/Receive inputs that control whether the device operates in real-time mode or stored mode for data transfer between buses A and B.