Texas Instruments SN74CBTD3384CDBQR

Overview

SN74CBTD3384CDBQR from Texas Instruments is a 24-pin SSOP (DBQ) 10-bit FET bus switch with bidirectional data flow, 3 Ω typical ON-state resistance, −2 V undershoot protection on A/B ports, and integrated 5-V-to-3.3-V level shifting. It operates from 4.5 V to 5.5 V and supports mixed-voltage signaling (0.8 V to 5 V) in memory interleaving and bus isolation applications.

For engineers reviewing the SN74CBTD3384CDBQR datasheet, SN74CBTD3384CDBQR pinout, SN74CBTD3384CDBQR application, or SN74CBTD3384CDBQR equivalent, this page delivers verified electrical parameters, package-specific thermal data (θ_JA = 61°C/W), I_off-enabled partial-power-down operation, and real-world use context for high-speed TTL-compatible signal gating.

Technical Context

The SN74CBTD3384CDBQR implements two independent 5-bit FET bus switches with separate 1OE and 2OE controls, enabling configurable 5-bit or consolidated 10-bit operation. Its active undershoot-protection circuitry monitors A/B port voltage and forces OFF-state retention during −2 V transients.

Level shifting is achieved via an integrated diode in series with V_CC, allowing 5-V inputs to drive 3.3-V outputs without external components. The device features I_off current ≤10 µA at V_CC = 0 V and input/output capacitance of 5 pF (OFF) and 12.5 pF (ON), minimizing signal distortion in high-frequency digital paths.

Key Specifications

Pinout & Package

SN74CBTD3384CDBQR uses a 24-pin SSOP (DBQ) package with 0.65 mm pitch, 7.9 mm × 6.2 mm body size, and 1.2 mm maximum height. Thermal resistance θ_JA is 61°C/W per TI package data.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bus switch applications.

Compared with SN74CBTD3384CDBQR, SN74CBT3384CPWR trades thermal performance for smaller footprint, while SN74CBTD3384CDBR offers equivalent functionality with slightly reduced thermal efficiency and alternate packaging compliance-both require no schematic changes but may impact thermal design or procurement logistics.

Availability

SN74CBTD3384CDBQR is available at Aetrix Electronics and suitable for memory interleaving, bus isolation, and low-distortion signal gating requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for SN74CBTD3384CDBQR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 50 years of innovation in high-reliability interface and signal-path ICs.

The SN74CBTD3384CDBQR belongs to TI's CBTD-series bus switches, engineered for high-speed, low-distortion digital signal routing in mixed-voltage systems where timing integrity and robustness against transients are critical.

FAQ

What is the maximum undershoot voltage the SN74CBTD3384CDBQR can withstand on its A and B ports?

The SN74CBTD3384CDBQR provides active undershoot protection up to −2 V on both A and B ports, as verified in the absolute maximum ratings and undershoot characteristics section of the datasheet. This protection is implemented via internal sensing circuitry that forces the switch into a guaranteed OFF state during transient events, preventing unintended conduction or latch-up. The SN74CBTD3384CDBQR maintains this rating across its full operating temperature range (−40°C to +85°C) and supply voltage range (4.5 V to 5.5 V).

Does the SN74CBTD3384CDBQR support true bidirectional signal flow without direction-control pins?

Yes, the SN74CBTD3384CDBQR supports fully bidirectional data flow between its A and B ports without requiring external direction-control logic. When 1OE or 2OE is low, the corresponding 5-bit switch section connects A and B terminals with near-zero resistance (3 Ω typical), allowing signals to pass in either direction. This architecture eliminates the need for dedicated direction pins or additional control circuitry, simplifying PCB layout and reducing component count in applications like memory bus switching and hot-swap interfaces.

Can the SN74CBTD3384CDBQR be used for level shifting between 5-V and 3.3-V logic domains?

Yes, the SN74CBTD3384CDBQR integrates a diode in series with V_CC to provide inherent 5-V-to-3.3-V level shifting. When a 5-V signal is applied to the A port, the internal diode drops ~1.7 V, resulting in approximately 3.3 V at the B port under typical conditions. This feature is explicitly documented in the device description and functional behavior sections of the datasheet, and requires no external components. The SN74CBTD3384CDBQR does not support reverse-direction (3.3-V-to-5-V) level shifting.

What is the thermal resistance (θ_JA) of the SN74CBTD3384CDBQR in its DBQ package?

The SN74CBTD3384CDBQR in the SSOP (DBQ) package has a specified junction-to-ambient thermal resistance (θ_JA) of 61°C/W, as published in the absolute maximum ratings table of the official Texas Instruments datasheet. This value assumes standard JEDEC test conditions (JESD 51-7) and is critical for calculating maximum allowable power dissipation in thermally constrained applications. The SN74CBTD3384CDBQR's low r_on (3 Ω typical) minimizes self-heating, making it suitable for high-density layouts where thermal management is limited.

How does the I_off feature of the SN74CBTD3384CDBQR protect systems during partial power-down?

The I_off feature of the SN74CBTD3384CDBQR limits current to ≤10 µA when V_CC = 0 V and any I/O pin is biased between 0 V and 5.5 V, preventing damaging backflow current between powered and unpowered subsystems. This enables safe partial-power-down operation in multi-rail systems-for example, allowing a 3.3-V microcontroller to remain active while a 5-V peripheral domain is shut down. The SN74CBTD3384CDBQR maintains high-impedance isolation under these conditions, eliminating the risk of latch-up or supply rail contamination.