SN74CBT3345CDBQR

Overview

The SN74CBT3345CDBQR is an octal FET bus switch manufactured by Texas Instruments, housed in a 20-pin SSOP (QSOP) package. It operates within a supply voltage range of 4 V to 5.5 V and supports data I/O signaling levels from 0 V to 5 V. The device features bidirectional data flow with near-zero propagation delay, characterized by a maximum delay of 0.15 ns at 5 V. It includes active undershoot protection on A and B ports up to -2 V, low ON-state resistance (typical 3 Ω), and low input/output capacitance (typical 5.5 pF). Control inputs are compatible with TTL or 5-V/3.3-V CMOS outputs.

Feature Summary

• Active undershoot-protection circuitry ensures proper OFF state during negative voltage events up to -2 V on data ports.
• Supports partial-power-down mode via the Ioff feature, preventing damaging backflow current when powered down.
• Bidirectional data flow allows connection between A and B ports controlled by dual output-enable inputs.
• Low ON-state resistance minimizes signal distortion and loading effects for high-speed applications.

Applications

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

Procurement Notes

Verify the specific ordering suffix 'DBQR' corresponds to the SSOP (QSOP) package type and tape-and-reel packaging configuration. Confirm that the component meets RoHS compliance standards and Level-2 moisture sensitivity ratings as specified in the manufacturer's documentation. Ensure control inputs are properly biased to VCC or GND to maintain stable operation.

Selection Notes

Select this component for designs requiring an 8-bit wide bus switch with low insertion loss and high-speed performance. The device is suitable for mixed-voltage environments where control logic operates at 3.3 V while data lines support up to 5 V signaling. Consider the thermal impedance characteristics of the SSOP package for heat dissipation requirements in dense layouts.

Part Context

This part belongs to the SN74CBT3345C family of high-speed TTL-compatible FET bus switches. It shares functional similarities with other members like the SN74CBT3245 but offers specific electrical characteristics tailored for 4 V to 5.5 V operation. The device integrates internal enable signals and protection diodes to enhance reliability in digital and analog switching applications.

Replacement Considerations

Public confirmed substitute: SN74CBT3345CDWR (SOIC package variant).