Texas Instruments SN74LVC861APW

Overview

SN74LVC861APW 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 inputs, delivers 6.4-ns max propagation delay at 3.3 V, and supports partial-power-down via Ioff. It enables level translation in 3.3-V/5-V interfacing applications such as memory expansion and peripheral bridging.

For engineers reviewing the SN74LVC861APW datasheet, SN74LVC861APW pinout, SN74LVC861APW application, or SN74LVC861APW equivalent, key selection criteria include bidirectional 3-state control timing (ten/tdis), mixed-mode input tolerance, Ioff-enabled isolation during power sequencing, and TSSOP-24 package compatibility with high-density PCB layouts.

Technical Context

The SN74LVC861APW implements dual independent 3-state enable logic (OEAB and OEBA) to select direction: low on OEAB enables A→B transmission, low on OEBA enables B→A transmission, and both high isolates both buses. Its LVC-family CMOS process ensures rail-to-rail output swing and sub-100 µA ICC at 3.6 V.

It features robust ESD protection (2000-V HBM, 200-V MM, 1000-V CDM), latch-up immunity >250 mA per JESD 17, and guaranteed operation across –40°C to +85°C. Input thresholds scale with VCC (e.g., VIH = 0.65×VCC min at 1.65 V), enabling reliable interfacing with 1.8-V, 2.5-V, and 3.3-V logic families.

Key Specifications

Pinout & Package

TSSOP-24 (PW) package: 4.4 mm × 6.6 mm footprint, 0.65 mm lead pitch, 1.2 mm max height, RoHS-compliant NIPDAU finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC861APWR, the tube-packaged SN74LVC861APW offers identical performance but differs in logistics handling; versus SN74LVC16245ADGGR, it provides true bidirectional control essential for half-duplex bus sharing, whereas the 16245 is optimized for high-throughput unidirectional buffering with byte-level granularity.

Availability

SN74LVC861APW is available at Aetrix Electronics and suitable for memory expansion interfaces, industrial I/O modules, embedded peripheral bridges, automotive body control units, and mixed-voltage FPGA configuration buses requiring stable component supply and long-term manufacturability.

Supply support for SN74LVC861APW 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 logic interface solutions.

The SN74LVC861A belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for low-power, high-speed bidirectional bus interfacing in mixed-voltage embedded systems where reliability, ESD robustness, and power sequencing safety are critical.

FAQ

What is the maximum data rate supported by SN74LVC861APW?

The SN74LVC861APW does not specify a fixed data rate; instead, its 6.4-ns max propagation delay at 3.3 V enables reliable operation at bus clock frequencies up to ~100 MHz in well-terminated, low-capacitance layouts. Actual achievable rate depends on trace length, load capacitance, and noise margin-designers should verify timing margins using the published tpd, ten, and tdis values in their specific system context. SN74LVC861APW performance remains consistent across its 1.65–3.6-V VCC range.

Can SN74LVC861APW safely interface a 5-V microcontroller with a 3.3-V FPGA?

Yes. SN74LVC861APW accepts 5.5-V inputs while operating from a 3.3-V VCC, making it ideal for translating signals from 5-V microcontrollers to 3.3-V FPGAs. Its 5-V-tolerant inputs eliminate external level shifters, and its Ioff feature prevents current backflow if either side powers down independently. SN74LVC861APW maintains valid logic levels (VIH/VIL scaling with VCC) and drive strength (±24 mA) across the interface, ensuring robust signal integrity without added complexity.

How should unused control inputs be handled on SN74LVC861APW?

All unused control inputs-including OEAB and OEBA-must be held at a defined logic level (VCC or GND) to prevent floating states that could cause erratic output behavior or increased ICC. TI recommends tying OEAB and OEBA to VCC through pull-up resistors (value determined by driver sink capability) to ensure outputs remain in high-impedance state during power-up. This practice avoids unintended bus contention and meets SCBA004 guidelines for CMOS input stability. SN74LVC861APW reliability depends on proper biasing of all control pins.

Does SN74LVC861APW support hot-swap or live-insertion scenarios?

Yes. SN74LVC861APW supports partial-power-down operation via its Ioff circuitry, which disables outputs and blocks current flow when VCC = 0 V-even if 5.5-V signals remain present on I/O pins. This allows safe insertion or removal of boards containing SN74LVC861APW into live backplanes or modular systems without disrupting upstream/downstream logic. The device's ±10 µA Ioff current and 6.5-V absolute max I/O rating make SN74LVC861APW suitable for hot-swap architectures in industrial and telecom equipment.

What is the thermal resistance (θJA) of the SN74LVC861APW TSSOP package?

The SN74LVC861APW in the TSSOP-24 (PW) package has a junction-to-ambient thermal resistance (θJA) of 88°C/W, measured under standard JEDEC conditions (single-layer 1-oz copper, 1-in² pad). This value assumes minimal PCB copper area; actual θJA improves significantly with enhanced thermal vias and internal copper planes. For continuous operation at 3.3 V with full 10-bit loading, power dissipation remains below 100 mW, keeping junction temperature well within the –40°C to +85°C operating range. SN74LVC861APW thermal performance is validated per JESD 51-7 methodology.