Texas Instruments SN74CBTD3861PW

Overview

SN74CBTD3861PW from Texas Instruments is a 10-bit FET bus switch with integrated level shifting, designed for bidirectional 5-V-to-3.3-V signal translation in high-speed digital systems. It features 5-Ω on-state resistance, TTL-compatible inputs, single OE control, and operates from –40°C to 85°C. Used in memory expansion interfaces and mixed-voltage processor interconnects.

For engineers reviewing the SN74CBTD3861PW datasheet, SN74CBTD3861PW pinout, SN74CBTD3861PW application, or SN74CBTD3861PW equivalent, key selection criteria include on-resistance (5–7 Ω), propagation delay (0.35 ns), level-shifting capability, OE-controlled high-impedance isolation, and TSSOP-24 package compatibility with 0.65-mm pitch PCB layouts.

Technical Context

This device implements a single 10-bit FET-based analog switch array with integrated V_CC-clamping diodes enabling passive 5-V-to-3.3-V level translation without external components. The OE input controls all ten channels simultaneously using positive-logic enable (low = on).

It operates within a 4.5–5.5-V supply range and supports bidirectional signal flow between Port A and Port B. Input clamp current rating (–50 mA) and absolute max V_I (–0.5 V to 7 V) allow robust handling of overshoot/undershoot in fast-switching environments.

Key Specifications

Pinout & Package

TSSOP-24 (PW) package: 7.9 mm × 4.5 mm × 1.2 mm body, 0.65 mm lead pitch, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74CBTD3861PW, SN74CBT3861PW lacks on-die clamping diodes and cannot perform autonomous 5-V-to-3.3-V translation, while SN74LVC1G3157DCKR offers only one channel and no 5-V tolerance - making SN74CBTD3861PW uniquely suited for compact, self-contained 10-bit mixed-voltage bus bridging.

Availability

SN74CBTD3861PW is available at Aetrix Electronics and suitable for industrial control systems, memory expansion modules, and processor-FPGA interconnects requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74CBTD3861PW 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 SN74CBTD3861PW belongs to TI's 74CBT/74CBTD logic family, engineered for high-speed, low-distortion bus switching in mixed-voltage digital systems where signal integrity and voltage domain bridging are critical.

FAQ

What is the maximum continuous current rating per channel for the SN74CBTD3861PW?

The SN74CBTD3861PW supports a continuous channel current of 128 mA per switch path. This rating ensures reliable operation under sustained load conditions typical in memory bus and peripheral interface applications. Exceeding this value may cause thermal degradation or parametric shift. Derating is recommended above 70°C ambient.

Does the SN74CBTD3861PW require external pull-up or pull-down resistors on its control inputs?

No - the SN74CBTD3861PW OE input is TTL-compatible and does not require external biasing. However, TI recommends tying all unused control inputs directly to V_CC or GND to prevent floating states that could induce shoot-through current or erratic switching behavior. This guidance applies specifically to the SN74CBTD3861PW per SCBA004 application report.

Can the SN74CBTD3861PW be used for 3.3-V-to-5-V level shifting?

No - the SN74CBTD3861PW is asymmetric: its internal V_CC-clamp diodes enable only 5-V-to-3.3-V translation (A→B direction). Driving 3.3-V signals into Port B while powering V_CC at 5 V does not activate the clamping path for reverse translation. For bidirectional or 3.3-V-to-5-V use, an external solution or alternate device like SN74AVC4T245 is required.

What is the thermal resistance (θ_JA) of the SN74CBTD3861PW in its TSSOP-24 package?

The SN74CBTD3861PW has a junction-to-ambient thermal resistance (θ_JA) of 88°C/W in the TSSOP-24 (PW) package, as specified in the absolute maximum ratings table. This value assumes standard JEDEC 2-layer board conditions; actual performance improves with enhanced copper pour and thermal vias beneath the package body.

Is the SN74CBTD3861PW pin-compatible with other packages in the same family, such as SN74CBTD3861DBR or SN74CBTD3861DWR?

Yes - the SN74CBTD3861PW shares identical pinout and functional mapping with SN74CBTD3861DBR (SSOP), SN74CBTD3861DWR (SOIC), and all other variants in the SN74CBTD3861 family. All use the same 24-pin DB/DW/PW/DGV/DBQ pin assignment, including NC pins at positions 1 and 24, allowing direct PCB footprint reuse across package types.