SN65LBC184DR Datasheet, Pinout, Equivalents, and Specs

The SN65LBC184DR is a differential bus transceiver designed by Texas Instruments for bidirectional data communication on multipoint bus transmission lines. It is engineered to meet the requirements of both RS-485 and RS-422 standards, utilizing low-power BiCMOS technology for reduced power consumption. The device integrates robust transient voltage suppression, positioning it for use in electrically noisy industrial environments requiring reliable, long-distance data transmission.

What is the SN65LBC184DR?

The SN65LBC184DR is a half-duplex, single-channel RS-485/RS-422 transceiver. Its primary function is to convert single-ended logic signals, typically from a microcontroller's UART, into differential signals for transmission over a twisted-pair cable, and vice-versa. The internal architecture consists of a differential driver and a differential receiver, with separate enable pins (DE for Driver Enable and RE for Receiver Enable) that allow for precise control over the data direction. This component is specifically targeted for applications such as industrial automation, process control, building automation, and remote sensor interfaces where noise immunity and the ability to connect multiple nodes (up to 32 unit loads) on a single bus are critical engineering requirements.

SN65LBC184DR Component Overview

Pinout Configuration and Packaging

The SN65LBC184DR is most commonly available in an 8-pin SOIC (Small Outline Integrated Circuit) package, designated with the 'D' suffix. This surface-mount package is standard for automated manufacturing processes. Thermal management is typically handled through PCB copper planes connected to the GND pin. Critical I/O pins include the differential bus lines A (non-inverting) and B (inverting), the single-ended logic pins D (Driver Input) and R (Receiver Output), and the control pins DE (Driver Enable, active-high) and RE (Receiver Enable, active-low).

Core Architectural Features

• Integrated Transient Voltage Suppression (TVS): The device incorporates internal protection circuitry that provides high levels of electrostatic discharge (ESD) protection on the bus pins (A and B), rated up to ±30-kV HBM. This reduces the need for external TVS diodes in many applications, saving board space and component cost.
• Low-Power BiCMOS Process: The transceiver is fabricated using a BiCMOS process that combines the speed of bipolar transistors with the low power consumption of CMOS logic. This results in a low quiescent supply current (typically under 1 mA), making it suitable for power-sensitive applications.
• Failsafe Receiver Design: The receiver features a failsafe mechanism that guarantees a known logic-high state at the R output when the bus inputs are open, shorted, or terminated but idle. This prevents indeterminate states and potential bus lock-ups during fault conditions or when no nodes are actively driving the bus.
• Wide Common-Mode Voltage Range: The receiver is designed to operate reliably over a wide input common-mode voltage range of –7 V to 12 V. This allows the device to tolerate significant ground potential differences between nodes on the bus, a common issue in large-scale industrial installations.

Specifications Parameter Table

SN65LBC184DR Equivalents, Cross Reference, and Lifecycle

The SN65LBC184DR is currently in an "Active" production lifecycle status as of the latest data from Texas Instruments. For procurement managers and engineers facing allocation or long lead times, identifying pin-to-pin compatible alternatives is critical. A commonly referenced equivalent is the MAX485ESA from Analog Devices (formerly Maxim Integrated). The MAX485 is an industry-standard part and shares the same 8-pin SOIC pinout (R, RE, DE, D, GND, A, B, VCC) as the SN65LBC184DR, making it a potential drop-in replacement. However, engineers must verify key parametric differences; for example, the SN65LBC184DR offers significantly higher ESD protection (±30 kV HBM) compared to the standard MAX485 (typically ±15 kV HBM). Always consult both datasheets to ensure all electrical specifications meet the system's design requirements before committing to a substitution.

Typical Application & Circuit Considerations

In a typical application, the SN65LBC184DR interfaces a microcontroller's UART with a multipoint bus. The driver input (D) is connected to the microcontroller's transmit (TX) pin, and the receiver output (R) is connected to the receive (RX) pin. The DE and RE pins are often tied together and controlled by a single GPIO pin to toggle the transceiver between transmit and receive modes. For proper bus operation and signal integrity, a 120-ohm termination resistor must be placed across the A and B lines at the two furthest ends of the main bus trunk. A 0.1 µF ceramic bypass capacitor should be placed as close as possible to the VCC pin (Pin 8) and ground (Pin 5) to ensure a stable power supply and filter high-frequency noise. PCB layout should prioritize keeping the differential traces (A and B) short, parallel, and with controlled impedance.

Video Demonstration

Market Availability and Pricing Trends

As a mature component in the RS-485 transceiver market, the SN65LBC184DR is generally subject to standard semiconductor supply chain dynamics, including occasional lead-time extensions during periods of high demand. Sourcing from authorized distributors or verified independent suppliers is recommended to mitigate risks of counterfeit parts. To check real-time stock, pricing, or to request a quote for the SN65LBC184DR and its verified alternatives, upload your BOM to WWDParts for fast processing.

Alan Carter

Senior Hardware Engineer & Component Specialist

Alan has over 15 years of expertise in embedded systems design, FPGA architecture, and global semiconductor supply chains. He specializes in component cross-referencing, lifecycle management, and helping OEMs navigate supply shortages.