SN74CBTD3305CDR

Overview

The SN74CBTD3305CDR is a dual FET bus switch from the Texas Instruments CBT logic family, housed in an 8-pin SOIC (D) package. It operates within a VCC range of 4.5 V to 5.5 V and supports data I/O levels from 0 V to 5.5 V. The device features two independent 1-bit switches with separate output-enable inputs. Key electrical parameters include a typical ON-state resistance of 3 Ω, a maximum propagation delay of 0.25 ns at 5 V, and low input/output capacitance of 5 pF. It provides integrated level shifting for 5-V inputs down to 3.3-V outputs and includes active undershoot protection up to -2 V.

Feature Summary

• Integrated diode to VCC enables level shifting from 5-V inputs to 3.3-V outputs
• Active undershoot-protection circuitry on A and B ports protects against signals down to -2 V
• Supports partial-power-down mode operation via Ioff feature to prevent backflow current
• Bidirectional data flow with near-zero propagation delay characteristics

Applications

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

Procurement Notes

Verify the specific ordering suffix 'CDR' corresponds to the SOIC D package with tape-and-reel packaging containing 2500 units per reel. Confirm that the operating temperature range is specified as -40°C to +85°C. Ensure compatibility with standard surface-mount assembly processes by checking the moisture sensitivity level and peak reflow temperature ratings provided in the package materials information.

Selection Notes

Select this component when designing 5-V bus architectures requiring translation to lower voltage domains like 3.3 V. The integrated level-shifting diode eliminates external components for voltage translation. Consider the low ON-state resistance for minimizing signal attenuation and the high-speed switching capabilities for high-frequency data lines. Verify control input compatibility with TTL or CMOS drivers.

Part Context

This device belongs to the SN74CBT series of high-speed FET bus switches manufactured by Texas Instruments. It is part of the CBTD sub-family which specifically adds level-shifting and undershoot protection features not found in standard bus switches. The product is designed for applications demanding fast switching speeds and minimal signal distortion in mixed-voltage digital environments.

Replacement Considerations

SN74CBTD3305CD (SOIC tube)

FAQ

How does the device handle undershoot events?

The SN74CBTD3305CDR features active undershoot-protection circuitry on the A and B ports that senses undershoot events and ensures the switch remains in the proper OFF state, providing protection up to -2 V.

What is the function of the Ioff feature?

The Ioff feature supports partial-power-down mode operation by ensuring that damaging current will not backflow through the device when it is powered down, maintaining isolation during power-off states.