SN74CBT3345CPWR

Overview

The SN74CBT3345CPWR is an octal bus switch manufactured by Texas Instruments, housed in a 20-pin TSSOP package. It operates on a single supply voltage ranging from 4 V to 5.5 V and supports data I/O levels from 0 V to 5.5 V. The device features low ON-state resistance with a maximum of 12 Ω at 4 V and 6 Ω at 4.5 V. It provides bidirectional data flow with near-zero propagation delay, specified as a maximum of 0.15 ns at 5 V. The component includes active undershoot protection for off-isolation up to -2 V and supports partial-power-down mode via the Ioff feature.

Feature Summary

• Active undershoot-protection circuitry ensures proper OFF state during signal events down to -2 V
• Supports partial-power-down operation to prevent damaging backflow current when powered down
• Low input/output capacitance minimizes loading effects and reduces signal distortion
• Control inputs are compatible with TTL or 5-V/3.3-V CMOS outputs

Applications

• USB interface connections
• Memory interleaving circuits
• Bus isolation applications
• Low-distortion signal gating

Procurement Notes

Verify the specific ordering suffix 'PW' corresponds to the tape-and-reel packaging format required for automated assembly processes. Confirm that the moisture sensitivity level rating aligns with your facility's floor life management protocols before soldering. Ensure the lead finish specification meets your board assembly requirements.

Selection Notes

Select this component when designing systems requiring high-speed bidirectional data transfer between buses operating at 5-V logic levels. The low ON-state resistance makes it suitable for maintaining signal integrity across wide buses. Verify that the control input voltage thresholds match the driving logic family used in the design.

Part Context

This part belongs to the SN74CBT3345C series of high-speed FET bus switches. It is functionally similar to other octal bus transceivers but is optimized for low power consumption and minimal propagation delay. The device utilizes advanced FET technology to achieve superior switching performance compared to standard bipolar equivalents.

Replacement Considerations

SN74CBT3345CDWR (SOIC-20 Tape & Reel)

FAQ

How does the device handle undershoot events?

The SN74CBT3345CPWR includes active undershoot-protection circuitry on the A and B ports. This circuitry senses undershoot events and ensures the switch remains in the correct OFF state, providing protection up to -2 V.

What is the purpose of the Ioff feature?

The Ioff feature allows the device to be fully specified for partial-power-down applications. It ensures that no damaging current will backflow through the device when it is powered down while the system is active.