Texas Instruments SN74CBTD3384DW

Overview

SN74CBTD3384DW from Texas Instruments is a 10-bit high-speed TTL-compatible bus switch IC with dual 5-bit configurable ports, 5-Ω on-state resistance, 0.25 ns propagation delay, and integrated level-shifting diode enabling 5-V-to-3.3-V signal translation in mixed-voltage memory and data-path systems.

For engineers reviewing the SN74CBTD3384DW datasheet, SN74CBTD3384DW pinout, SN74CBTD3384DW application, or SN74CBTD3384DW equivalent, key selection criteria include on-resistance matching, OE-controlled bidirectional switching, thermal performance (θ_JA = 46°C/W), and SOIC-24 package compatibility with legacy 5-V/3.3-V interface designs.

Technical Context

The SN74CBTD3384DW implements two independent 5-bit bidirectional analog switches controlled by separate active-low output-enable (1OE, 2OE) inputs. Each switch operates with near-zero propagation delay due to low R_on, and internal V_CC-clamp diodes enable robust level shifting without external components.

Switching behavior follows a strict function table: when an OE input is low, its associated 5-bit port pair (e.g., 1A1–1A5 ↔ 1B1–1B5) conducts bidirectionally; when high, both sides enter high-impedance state. No internal latching or logic inversion is present - it is a pure analog pass-gate topology.

Key Specifications

Pinout & Package

SN74CBTD3384DW is housed in a 24-pin SOIC (DW) package with 0.300-inch body width, JEDEC MO-150 compliant, and 0.65 mm lead pitch. Pin 1 index is marked by a beveled corner or notch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD3384DW, SN74CBT3384DWR offers identical functionality in tape-and-reel form, while SN74LVC1G3157DCKR provides single-channel flexibility at the cost of added external components and reduced integration for multi-bit applications.

Availability

SN74CBTD3384DW is available at Aetrix Electronics and suitable for memory interfacing, bus isolation, hot-swap interface, and FPGA I/O expansion requiring stable component supply and industrial-temperature operation.

Supply support for SN74CBTD3384DW 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 connectivity technologies with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74CBTD3384DW belongs to TI's CBTD family of high-speed bus switches, designed specifically for low-latency, bidirectional voltage-domain bridging in mixed-supply digital systems.

FAQ

What is the primary function of the SN74CBTD3384DW?

The SN74CBTD3384DW is a 10-bit bidirectional bus switch IC that provides low-latency, TTL-compatible signal routing between two 5-bit ports. Its core function is to enable or isolate signal paths under active-low enable control, with integrated 5-V-to-3.3-V level shifting via on-die diodes. The SN74CBTD3384DW does not perform logic translation or voltage regulation - it acts as a controllable analog pass gate optimized for speed and signal fidelity.

Can the SN74CBTD3384DW operate with a 3.3-V supply voltage?

No, the SN74CBTD3384DW requires a 4.5-V to 5.5-V supply (VCC) and is not rated for 3.3-V operation. Its internal architecture - including the level-shifting diode and TTL-compatible input thresholds - is designed exclusively for 5-V systems. Using 3.3 V on VCC will result in undefined switching behavior, failure to meet VIH/VIL specifications, and potential damage to the internal clamp structures. The SN74CBTD3384DW must be powered from a stable 5-V rail.

How does the SN74CBTD3384DW achieve level shifting without external components?

The SN74CBTD3384DW achieves 5-V-to-3.3-V level shifting through an integrated diode connected from each input/output terminal to VCC. When a 5-V signal is applied to a port A pin, the diode clamps the voltage seen at the corresponding port B pin to approximately VCC − V_f (~4.3 V), which remains within the valid high-input range for 3.3-V logic. This passive clamping eliminates external resistors or translators. The SN74CBTD3384DW relies on load-side termination to define the final output voltage level.

What is the maximum continuous current per channel for the SN74CBTD3384DW?

The absolute maximum continuous channel current for the SN74CBTD3384DW is 128 mA per switch path, as specified in the Absolute Maximum Ratings table. Exceeding this value risks thermal runaway or metallization failure. At typical operating conditions (VCC = 5 V, TA = 25°C), the on-resistance of 5 Ω limits power dissipation to <100 mW per channel at 100 mA, ensuring reliable operation within SOIC-DW thermal limits (θ_JA = 46°C/W). The SN74CBTD3384DW must be used within these boundaries to maintain long-term reliability.

Are unused control inputs required to be terminated on the SN74CBTD3384DW?

Yes, all unused control inputs - specifically 1OE and 2OE - must be held at a defined logic level (either VCC or GND) to ensure predictable operation and prevent floating-node-induced shoot-through or increased ICC. TI's application report SCBA004 explicitly mandates this practice. Leaving 1OE or 2OE unconnected may cause erratic switching, elevated supply current, or unintended port activation. For default-on operation, tie the OE pin to GND; for default-off, tie to VCC. This requirement applies to every SN74CBTD3384DW in the design.