74ABT646CMTCX

Buffers, Drivers, Receivers, Transceivers Overview

The onsemi 74ABT646CMTCX is an octal bus transceiver and register featuring 3-STATE outputs in a 24-lead TSSOP package. It operates within a supply voltage range of 4.5V to 5.5V, supporting TTL input and output levels. The device provides independent registers for A and B buses with multiplexed real-time and stored data capabilities. Key electrical parameters include a maximum propagation delay of 5.6 ns at 50 pF load, high impedance glitch-free bus loading during power cycles, and nondestructive hot insertion capability.

Buffers, Drivers, Receivers, Transceivers Feature Summary

• Independent registers for A and B buses allow storage and retrieval of data from either direction.
• Multiplexed real-time and stored data modes enable flexible signal routing between buses.
• High impedance glitch-free bus loading ensures stable operation throughout the entire power up and power down cycle.
• Nondestructive hot insertion capability protects the circuit during live connection events.

Buffers, Drivers, Receivers, Transceivers Applications

• Multiplexed transmission of data directly from input bus or internal registers
• Storage of data present at the high impedance port in either A or B register
• Controlled transceiver function using OE and direction pins

Buffers, Drivers, Receivers, Transceivers Procurement Notes

Verify the specific ordering code suffix 'X' confirms tape and reel packaging as documented in the datasheet. Confirm that the component meets RoHS requirements by checking the manufacturer's environmental information sheet. Ensure the selected package variant matches the required PCB footprint specifications for the 24-lead Thin Shrink Small Outline Package.

Buffers, Drivers, Receivers, Transceivers Selection Notes

Select this component when designing systems requiring octal bidirectional data transfer with integrated storage. The ABT logic series supports high-speed applications with guaranteed output skew and simultaneous switching noise levels. Consider the 64 mA sink and 32 mA source output currents for driving moderate loads without external buffering.

Buffers, Drivers, Receivers, Transceivers Part Context

This part belongs to the 74ABT logic family, which utilizes BiCMOS technology for high-speed performance. The base model 74ABT646 is manufactured by onsemi (formerly Fairchild Semiconductor). The CMTCX designation specifically indicates the TSSOP package style combined with tape and reel shipping configuration.

Buffers, Drivers, Receivers, Transceivers Replacement Considerations

Check for direct pin-compatible alternatives within the same logic family if availability is constrained. Verify that any substitute maintains the 4.5V to 5.5V operating voltage range and similar propagation delay characteristics to ensure system timing integrity.

Buffers, Drivers, Receivers, Transceivers FAQ

How does the device handle data isolation?

In isolation mode, when the OE control is HIGH, data can be stored in the A or B register independently while the bus outputs remain in a high impedance state.

What determines the data flow direction?

The DIR (Direction) control input determines which bus receives data when the enable control OE is active LOW.

Is the device protected against latchup?

Yes, the datasheet guarantees latchup protection under specified conditions.