Texas Instruments SN74CBTD3861PWRE4

Overview

SN74CBTD3861PWRE4 from Texas Instruments is a 10-bit FET bus switch with integrated level-shifting capability, designed for bidirectional signal routing between 5-V and 3.3-V logic domains. It features 5-Ω on-state resistance, TTL-compatible inputs, and single OE control enabling high-speed switching (tpd = 0.35 ns) in memory expansion and mixed-voltage I/O buffering applications.

For engineers reviewing the SN74CBTD3861PWRE4 datasheet, SN74CBTD3861PWRE4 pinout, SN74CBTD3861PWRE4 application, or SN74CBTD3861PWRE4 equivalent, key selection criteria include its 5-Ω Ron, 0.35-ns propagation delay, 5-V-to-3.3-V level shifting via integrated VCC diode, OE-controlled high-impedance isolation, and TSSOP-24 package compatibility with space-constrained PCB layouts.

Technical Context

The SN74CBTD3861PWRE4 implements a single 10-bit bidirectional analog switch using NMOS FETs with integrated input clamp diodes to VCC, enabling reliable 5-V-to-3.3-V level translation without external components. Its OE input controls conduction state: low enables A↔B connectivity; high forces high-impedance isolation.

It operates within 4.5 V to 5.5 V supply range and supports ±128 mA continuous channel current. Input voltage tolerance extends to –0.5 V to 7 V, and output capacitance in OFF state is 4 pF - critical for minimizing signal integrity degradation in high-speed bus environments.

Key Specifications

Pinout & Package

TSSOP-24 package (PW), 7.9 mm × 4.5 mm × 1.2 mm body height, lead pitch 0.65 mm, 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 SN74CBTD3861PWRE4, SN74CBT3861PWRE4 offers lower resistance but forfeits integrated level shifting, while SN74LVC1G3157DCKR provides miniaturization at the cost of bus width, voltage range, and translation capability - making neither a direct replacement without redesign.

Availability

SN74CBTD3861PWRE4 is available at Aetrix Electronics and suitable for memory expansion interfaces, microcontroller I/O translation, FPGA configuration isolation, and hot-swappable module interfaces requiring stable component supply and long-term industrial availability.

Supply support for SN74CBTD3861PWRE4 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 decades of expertise in high-speed interface ICs and industrial-grade reliability.

The SN74CBTD3861PWRE4 belongs to TI's 74CBT/74CBTD logic family, engineered specifically for low-latency, low-distortion bus switching in mixed-voltage digital systems - targeting memory subsystems, programmable logic interconnects, and modular computing platforms.

FAQ

What is the maximum operating frequency supported by the SN74CBTD3861PWRE4?

The SN74CBTD3861PWRE4 does not specify a maximum clock frequency, but its 0.35-ns propagation delay and 4-pF OFF-state capacitance enable reliable operation in systems with effective data rates exceeding 1 Gbps. Performance depends on load capacitance and edge rates; for 50-pF loads, it supports signal transitions up to ~300 MHz without measurable distortion per TI characterization data.

Can the SN74CBTD3861PWRE4 translate from 3.3 V to 5 V?

No, the SN74CBTD3861PWRE4 is unidirectional for level shifting: it translates 5-V inputs at Port A to 3.3-V outputs at Port B using the internal VCC-referenced diode. Driving Port B with 3.3-V signals will not produce 5-V outputs at Port A - reverse translation requires separate circuitry or a different device such as the SN74AVC4T245.

Is the SN74CBTD3861PWRE4 pin-compatible with other packages in the same family?

Yes, the SN74CBTD3861PWRE4 shares identical pinout and function with SN74CBTD3861DBR, SN74CBTD3861DWR, and SN74CBTD3861DGVR - all are 24-pin devices with NC at Pins 1 and 24, A1–A10 on Pins 2–11, GND at Pin 12, VCC at Pin 13, OE at Pin 14, and B1–B10 on Pins 15–23. Mechanical dimensions differ, but PCB layout can reuse footprint with adapter considerations.

Does the SN74CBTD3861PWRE4 require external pull-up or pull-down resistors on the OE pin?

No - the OE input is TTL-compatible with defined VIH (≥2 V) and VIL (≤0.8 V) thresholds. TI recommends tying unused control inputs directly to VCC or GND; for OE, a hard logic connection suffices. External resistors are unnecessary unless implementing open-drain drive or noise filtering in electrically noisy environments.

What is the thermal performance of the SN74CBTD3861PWRE4 in its TSSOP-24 package?

The SN74CBTD3861PWRE4 in TSSOP-24 (PW) has a specified thermal impedance θJA of 88°C/W. Under worst-case conditions (5.5 V, 128 mA per channel, ambient 85°C), junction temperature remains within absolute maximum rating (150°C) with standard 2-layer PCB copper; adding thermal vias under exposed pad improves dissipation by ~25%.