Texas Instruments SN74CB3T3384DW

Overview

SN74CB3T3384DW from Texas Instruments is a 24-pin SOIC-packaged 10-bit FET bus switch with bidirectional signal flow, 5 Ω typical ON-state resistance, 0.25 ns max propagation delay at 3.3 V, and mixed-mode voltage translation supporting 0–5 V I/O levels across 2.3–3.6 V VCC. It enables level-shifting between 5-V TTL, 3.3-V LVTTL, and 2.5-V CMOS in memory interleaving and bus isolation systems.

For engineers reviewing the SN74CB3T3384DW datasheet, SN74CB3T3384DW pinout, SN74CB3T3384DW application, or SN74CB3T3384DW equivalent, key selection criteria include its dual 5-bit enable-controlled switching architecture, Ioff partial-power-down protection, 5 pF OFF-state I/O capacitance, and compatibility with TTL/CMOS control inputs driving 2.5–5 V logic levels.

Technical Context

The SN74CB3T3384DW implements two independent 5-bit FET bus switches, each controlled by dedicated OE pins (1OE, 2OE), enabling either dual 5-bit or single 10-bit operation. Its voltage-translation behavior tracks VCC, delivering output levels ≈VCC − 1 V when VIH ≥ VCC − 1 V and ≤ 5.5 V.

Each switch uses low-threshold FETs with gate drive derived internally from VCC and input signals, achieving near-zero propagation delay and supporting undervoltage operation down to 0 V on I/O ports. The device incorporates undershoot clamp diodes on all data and control inputs and meets JESD 17 latch-up immunity (>250 mA) and JESD 22 ESD ratings (2000-V HBM, 1000-V CDM).

Key Specifications

Pinout & Package

SN74CB3T3384DW is housed in a 24-pin SOIC (DW) package, 7.5 mm × 15.4 mm body size, 1.27 mm lead pitch, with gull-wing leads and RoHS-compliant NiPdAu finish. MSL Level-1 (unlimited floor life) and 260°C peak reflow rating support standard SMT assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CB3T3384DW, SN74CBTD3384CDW offers higher speed at 5 V but sacrifices voltage flexibility and Ioff safety, while SN74LVC1G3157DCKR provides compact analog switching but cannot replicate the dual-bank, translation-aware, high-density bus control of the SN74CB3T3384DW.

Availability

SN74CB3T3384DW is available at Aetrix Electronics and suitable for memory interleaving, bus isolation, legacy interface bridging, and low-power portable logic applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for SN74CB3T3384DW 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 decades of expertise in high-reliability logic and interface solutions.

The SN74CB3T3384DW belongs to TI's CB3T family of FET bus switches, engineered specifically for voltage-translation-critical applications in mixed-signal systems, industrial controllers, and portable electronics where power sequencing and logic-level interoperability are essential.

FAQ

What voltage levels can the SN74CB3T3384DW translate between?

The SN74CB3T3384DW supports bidirectional voltage translation across 0 V to 5.5 V on all I/O ports, with output levels tracking VCC (≈VCC − 1 V) when input exceeds VCC − 1 V. It operates with VCC from 2.3 V to 3.6 V, enabling translation from 5-V TTL to 3.3-V LVTTL, 3.3-V to 2.5-V CMOS, or user-defined intermediate levels like 1.8 V or 1.5 V-provided VCC is within spec and input thresholds are met. This makes SN74CB3T3384DW ideal for heterogeneous logic domain interfacing without external bias networks.

Does the SN74CB3T3384DW support partial-power-down operation?

Yes, the SN74CB3T3384DW features Ioff circuitry that limits power-off leakage to 10 µA maximum when VCC = 0 V, preventing damaging current backflow through the switch. This allows safe insertion or removal of modules while other system rails remain active. During partial-power-down, all I/O ports enter high-impedance isolation, and the device maintains this state without external components-making SN74CB3T3384DW suitable for hot-swap architectures and battery-backed subsystems where rail sequencing is uncontrolled.

How does the SN74CB3T3384DW handle control input voltage levels?

The SN74CB3T3384DW accepts TTL- and CMOS-compatible control inputs: VIH thresholds range from 1.7 V (at VCC = 2.3–2.7 V) to 2.0 V (at VCC = 2.7–3.6 V), and VIL stays ≤ 0.8 V across the full VCC range. Inputs tolerate up to 5.5 V regardless of VCC, allowing direct connection to 5-V microcontrollers or FPGAs without level-shifting circuitry. This robustness simplifies design integration and ensures reliable OE activation in mixed-voltage systems using SN74CB3T3384DW.

What is the thermal performance of the SN74CB3T3384DW in its SOIC (DW) package?

The SN74CB3T3384DW in the DW package has a junction-to-ambient thermal resistance (θJA) of 46°C/W under standard JEDEC test conditions. With a maximum ICC of 40 µA and typical ron of 5 Ω, self-heating is negligible (<0.1°C rise) under normal operation. The package is rated for −40°C to +85°C ambient operation and carries MSL Level-1 (unlimited floor life), supporting reflow profiles up to 260°C peak. This thermal profile confirms SN74CB3T3384DW suitability for compact, sealed enclosures and thermally constrained industrial PCB layouts.

Can the SN74CB3T3384DW be used as a 10-bit switch or only as two 5-bit switches?

The SN74CB3T3384DW is architecturally configurable: it contains two independent 5-bit switch banks (1A/1B and 2A/2B), each with its own OE pin (1OE, 2OE). When both OE pins are asserted low, the device functions as a unified 10-bit bidirectional bus switch. Alternatively, OE pins can be driven separately to isolate or route subsets of signals-for example, using one bank for address lines and the other for data lines. This dual-mode capability makes SN74CB3T3384DW adaptable to diverse routing topologies without redesigning the PCB layout.