SN74CBT3345CDBR

Overview

The SN74CBT3345CDBR is an octal FET bus switch manufactured by Texas Instruments, housed in a 20-pin SSOP 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 tpd of 0.24 ns at 4 V and 0.15 ns at 5 V. It exhibits low ON-state resistance (ron) ranging from 3 Ω to 12 Ω depending on conditions, and maintains a typical off-state input/output capacitance of 5.5 pF. Designed for industrial environments, it functions reliably between -40°C and +85°C.

Feature Summary

• Active undershoot protection circuitry on A and B ports ensures proper OFF state during signal events down to -2 V.
• Supports partial-power-down mode operation via the Ioff feature to prevent damaging backflow current when powered down.
• Control inputs are compatible with TTL or 5-V/3.3-V CMOS outputs for flexible logic interfacing.

Applications

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

Procurement Notes

Verify that the specific orderable part number matches the required SSOP-20 package configuration. Confirm compliance with RoHS standards and lead finish specifications (CU NIPDAU). Ensure the operating temperature range aligns with system requirements (-40°C to +85°C). Cross-reference moisture sensitivity level ratings and recommended storage conditions prior to assembly.

Selection Notes

Select this component for applications requiring high-speed bidirectional switching with minimal signal distortion. The low ON-state resistance and capacitance make it suitable for maintaining signal integrity across data buses. Verify control input compatibility with existing logic families, as the device accepts TTL or 5-V/3.3-V CMOS signals directly without additional level shifting.

Part Context

This device belongs to the SN74CBT3345C series of high-speed TTL-compatible FET bus switches. It is designed to provide efficient data path management in digital systems. The 'DBR' suffix indicates the specific SSOP package type and tape-and-reel packaging format, distinguishing it from tube-packed variants like the CDB or CPW.

Replacement Considerations

SN74CBT3345CDWR

FAQ

How does the device handle undershoot events?

The SN74CBT3345C includes active undershoot-protection circuitry on the A and B ports. This circuitry senses undershoot events up to -2 V and ensures the switch remains in the correct OFF state to maintain isolation.

What is the function of the Ioff feature?

The Ioff feature allows the device to be fully specified for partial-power-down applications. It prevents damaging current from backflowing through the device when it is powered down, ensuring isolation during power-off states.