STMicroelectronics ST75C176BDR

Overview

ST75C176BDR from STMicroelectronics is a low-power, half-duplex RS-485/RS-422 transceiver in an 8-pin SOIC package, featuring 300 µA typical quiescent current, ±7 V to +12 V common-mode input range, and 30 ns typical driver propagation delay. It integrates one driver and one receiver with thermal shutdown, current limiting, and fail-safe receiver logic for open-circuit inputs - deployed in industrial automation serial bus nodes.

For engineers reviewing the ST75C176BDR datasheet, ST75C176BDR pinout, ST75C176BDR application, or ST75C176BDR equivalent, key selection criteria include bus loading capacity (32-unit load), single 5 V supply operation, differential output voltage (≥1.5 V into 27 Ω), receiver hysteresis (70 mV typ.), and enable-controlled 3-state outputs for multi-drop line sharing.

Technical Context

The ST75C176BDR implements a BiCMOS-based half-duplex RS-485 transceiver architecture with independent driver and receiver enable controls (DE and RE). Its driver delivers ≥1.5 V differential output into 27 Ω (RS-485) or 50 Ω (RS-422), while the receiver features fail-safe biasing and 70 mV hysteresis to reject noise near threshold.

Thermal shutdown activates under sustained short-circuit conditions, forcing driver outputs into high-impedance state. The receiver maintains valid logic-high output when A/B inputs are floating or open-circuited, and supports common-mode voltages from –7 V to +12 V - enabling robust operation in electrically noisy industrial environments.

Key Specifications

Pinout & Package

ST75C176BDR uses an 8-pin SOIC (Small Outline Integrated Circuit) package with 1.27 mm pitch, RoHS-compliant and ECOPACK® certified. Pin 1 is marked with a dot or notch; device orientation follows JEDEC MS-012 standard.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar RS-485 transceiver applications.

Compared with MAX1487ESA+ and SN65HVD72DR, ST75C176BDR uniquely combines thermal shutdown, fail-safe receiver, and 5 V operation - making it optimal for retrofitting legacy industrial equipment without redesigning protection or biasing circuits.

Availability

ST75C176BDR is available at Aetrix Electronics and suitable for industrial PLC backplanes, building automation controllers, remote energy meter interfaces, and factory floor sensor hubs requiring stable component supply and long-term obsolescence management.

Supply support for ST75C176BDR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The ST75C176BDR belongs to ST's legacy RS-485 transceiver product line, engineered specifically for cost-sensitive, noise-immune industrial serial communication where reliability under electrical stress and long-term supply stability are mandatory.

FAQ

Is ST75C176BDR pin-compatible with ST75C176BN or ST75C176CN?

Yes - ST75C176BDR (SOIC-8), ST75C176BN (DIP-8), and ST75C176CN (DIP-8) share identical pinout, logic behavior, and electrical specifications. Only package type and temperature grade differ: BDR is SOIC-8 rated –40 °C to +85 °C, matching BN's industrial range but in surface-mount form.

Does ST75C176BDR support full-duplex RS-422 operation?

No - ST75C176BDR is strictly half-duplex. It integrates one driver and one receiver sharing the same A/B bus terminals, with separate DE and RE controls. Full-duplex RS-422 requires independent transmit and receive pairs, such as those found in ST75C180 or SP3485 devices.

What is the maximum recommended data rate for ST75C176BDR?

The datasheet specifies 2.5 Mbps maximum data rate under defined load and trace conditions (R_DIF = 54 Ω, C_L = 100 pF). At longer distances or higher capacitance, derating is required: e.g., 115.2 kbps is reliable over 1200 m, while 2.5 Mbps is limited to ≤10 m with proper termination and layout.

How does the fail-safe receiver function without external biasing resistors?

The internal fail-safe circuit ensures RO = HIGH when A–B differential voltage is < –0.2 V, > +0.2 V, or undefined (e.g., open or shorted). This is achieved via on-die biasing network - no external resistors needed - guaranteeing known idle state even if bus is disconnected or unterminated.