Texas Instruments SN74LVC861APWR

Overview

SN74LVC861APWR from Texas Instruments is a 10-bit bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in mixed-voltage systems. It operates from 1.65 V to 3.6 V, accepts 5.5-V-tolerant inputs, and delivers 6.4 ns max propagation delay at 3.3 V - enabling reliable level translation in 3.3-V/5-V interface bridging applications.

For engineers reviewing the SN74LVC861APWR datasheet, SN74LVC861APWR pinout, SN74LVC861APWR application, or SN74LVC861APWR equivalent, key selection considerations include its dual output-enable control (OEAB/OEBA), Ioff partial-power-down support, 24-pin TSSOP package, and verified 3.3-V–5-V mixed-mode signal compatibility.

Technical Context

The SN74LVC861APWR implements independent directional control via two active-low output-enable inputs (OEAB and OEBA), allowing selective A→B or B→A data flow or full bus isolation. Its LVC logic family ensures CMOS-compatible input thresholds across the 1.65–3.6-V supply range.

It supports true partial-power-down operation via Ioff circuitry that disables outputs and blocks current backflow when VCC = 0 V, while maintaining 5.5-V input tolerance regardless of supply state - critical for hot-swap and power sequencing in multi-rail systems.

Key Specifications

Pinout & Package

TSSOP-24 (PW) package: 7.8 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm max height, 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 transceiver applications.

Compared with SN74LVC861ADBR and SN74LVC861ADGVR, the SN74LVC861APWR offers the best balance of compact size (7.8 mm × 4.4 mm), manufacturability (standard TSSOP pick-and-place compatibility), and thermal performance for mid-density industrial PCBs - making it the default choice for new designs targeting volume production.

Availability

SN74LVC861APWR is available at Aetrix Electronics and suitable for industrial PLC backplanes, embedded memory expansion subsystems, and automotive infotainment head units requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for SN74LVC861APWR 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 experience in high-reliability logic and interface solutions.

The SN74LVC861APWR belongs to TI's LVC logic family - engineered for low-voltage, high-speed, mixed-signal interface applications demanding robust voltage translation, power-aware operation, and industrial-grade ESD resilience.

FAQ

What is the maximum operating frequency supported by the SN74LVC861APWR?

The SN74LVC861APWR does not specify a maximum clock frequency, as it is an asynchronous bus transceiver. Its timing is governed by propagation delay (6.4 ns max at 3.3 V) and enable/disable times (5.9–8.2 ns). System-level frequency depends on bus loading, trace length, and controller timing margins - typically supporting reliable operation up to 100 MHz in well-designed 50-Ω-terminated interfaces. The SN74LVC861APWR datasheet provides detailed switching characteristics under defined load conditions.

Can the SN74LVC861APWR be used for unidirectional data transfer only?

Yes, the SN74LVC861APWR supports unidirectional operation by holding one output-enable input (e.g., OEBA) high while controlling the other (OEAB) to gate A→B flow. Its dual OE architecture allows flexible configuration - including A→B only, B→A only, bidirectional, or isolated - without hardware modification. This makes the SN74LVC861APWR suitable for both dedicated and reconfigurable data paths in programmable logic interfaces.

Does the SN74LVC861APWR require external pull-up resistors on OEAB and OEBA pins?

Yes - to ensure a defined high-impedance state during power-up or brown-out, OEAB and OEBA should each be tied to VCC through a pull-up resistor. TI recommends ≥10-kΩ for typical applications; the minimum value depends on the driver's current-sinking capability. This prevents undefined bus states before firmware initializes control lines. The SN74LVC861APWR's Ioff feature does not eliminate this requirement for OE pin biasing.

Is the SN74LVC861APWR pin-compatible with older 74-series transceivers like the 74LS245?

No - the SN74LVC861APWR is not pin-compatible with 74LS245 or other legacy 24-pin transceivers. It uses a unique pinout optimized for dual-direction control (separate OEAB/OEBA), whereas 74LS245 uses a single DIR pin and active-high OE. While functionally similar as a 10-bit transceiver, the SN74LVC861APWR requires PCB layout revision due to different signal assignment and voltage-domain design. Direct replacement is not possible without schematic and layout changes.

What is the thermal resistance (θJA) of the SN74LVC861APWR in its TSSOP-24 package?

The SN74LVC861APWR in the TSSOP-24 (PW) package has a specified junction-to-ambient thermal resistance (θJA) of 88°C/W under JEDEC-standard conditions (1-layer 1-in² copper pad). This value assumes standard PCB layout per TI's guidelines; actual thermal performance improves significantly with additional copper pour, thermal vias, or multi-layer routing. The SN74LVC861APWR's low static current (<10 µA ICC) minimizes self-heating under typical operation.