SN74CBTD3305CD

Overview

The SN74CBTD3305CD is a dual FET bus switch from the Texas Instruments CBT logic series, housed in an 8-pin SOIC (D) package. It operates within a supply voltage range of 4.5 V to 5.5 V and supports data I/O levels from 0 V to 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 when off. It provides integrated level shifting for 5-V inputs down to 3.3-V outputs and includes active undershoot protection up to -2 V on both ports.

Feature Summary

• Integrated diode connected to VCC enables level shifting from 5-V inputs to 3.3-V outputs
• Active undershoot-protection circuitry prevents false switching during signal transients
• Supports partial-power-down mode 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 against the Package Option Addendum to confirm the correct packaging format. The 'CD' designation indicates a tube package, whereas 'CDR' denotes tape and reel. Ensure the selected variant matches the required manufacturing assembly process and standard packing quantities defined by Texas Instruments.

Selection Notes

Select this component when interfacing between 5-V and 3.3-V domains requiring bidirectional data transfer. The integrated level-shifting diode eliminates external components for voltage translation. Verify that the application does not exceed the -2 V undershoot tolerance on the A and B ports to maintain proper OFF-state isolation.

Part Context

This device belongs to the SN74CBTD3305C family of high-speed TTL-compatible FET bus switches. It is designed for applications demanding minimal loading and signal distortion due to its low capacitance. The product line emphasizes low ON-state resistance and robust latch-up performance exceeding 100 mA per JESD 78 standards.

Replacement Considerations

SN74CBTD3305CDR serves as the tape-and-reel equivalent of the SN74CBTD3305CD tube variant.

FAQ

How does the device handle level shifting?

An integrated diode in series with VCC allows the device to shift 5-V input signals down to 3.3-V output levels automatically.

What is the function of the OE pins?

The OE pins act as output-enable controls; a high state connects the A port to the B port, while a low state disconnects them into a high-impedance state.