STMicroelectronics ST75C176CDR

Overview

ST75C176CDR from STMicroelectronics is a low-power, half-duplex RS-485/RS-422 transceiver in an 8-pin DIP package, featuring 300 µA typical quiescent supply 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 serial bus systems requiring robust multipoint communication.

For engineers reviewing the ST75C176CDR datasheet, ST75C176CDR pinout, ST75C176CDR application, or ST75C176CDR equivalent, key selection criteria include bus loading capacity (up to 32 nodes), single 5 V supply operation, driver output enable control timing (≤70 ns), and receiver hysteresis (70 mV typical) for noise immunity in noisy factory-floor environments.

Technical Context

The ST75C176CDR implements a BiCMOS-based transceiver architecture optimized for half-duplex RS-485 bus topologies. Its driver supports short-circuit current limiting (35–250 mA) and automatic thermal shutdown, while the receiver includes fail-safe biasing that guarantees a logic-high RO when A/B inputs are floating or shorted.

Control logic uses independent DE (driver enable) and RE (receiver enable) pins to manage direction and tri-state behavior. The device maintains high-impedance outputs during power-off or 3-state mode, and its 70 mV input hysteresis and ±0.2 V differential threshold ensure reliable signal detection across the full -7 V to +12 V common-mode range.

Key Specifications

Pinout & Package

Package: Plastic DIP-8 (0.3 inch width), ECOPACK® compliant, lead-free second-level interconnect per JEDEC JESD97.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX485CPA+ and SN65HVD72DR, the ST75C176CDR uniquely balances legacy 5 V operation, thermal fault protection, and fail-safe receiver behavior - making it optimal for retrofitting or maintaining existing industrial RS-485 infrastructure without redesign.

Availability

ST75C176CDR is available at Aetrix Electronics and suitable for industrial PLC backplanes, building automation sensor buses, and point-of-sale terminal networks requiring stable component supply and long-term obsolescence management.

Supply support for ST75C176CDR 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 ST75C176 series belongs to ST's legacy RS-485 transceiver product line, engineered specifically for cost-effective, robust, and thermally protected half-duplex communication in industrial control and automation equipment.

FAQ

Is ST75C176CDR pin-compatible with ST75C176BN or ST75C176CN?

Yes - all ST75C176x variants (B/C/N/D/R suffixes) share identical pinout, electrical characteristics, and functional behavior. The suffix denotes temperature grade (C = 0–70 °C, B = –40–85 °C) and packaging (N = DIP-8 tube, R = SOIC-8 tape/reel, D = SOIC-8 tube). ST75C176CDR uses the same DIP-8 footprint as CN/BN but in tape-and-reel form.

Does ST75C176CDR support full-duplex RS-422 operation?

No - ST75C176CDR is strictly a half-duplex transceiver with shared A/B bus terminals and independent DE/RE controls. It lacks separate transmit and receive differential pairs required for full-duplex RS-422. For full-duplex, ST offers the ST75C180 or ST75C182, which provide dedicated driver and receiver channels.

What is the maximum recommended cable length at 2.5 Mbps?

At 2.5 Mbps, STMicroelectronics specifies ≤100 m for reliable operation with proper termination (120 Ω) and low-capacitance twisted-pair cable (≤50 pF/m). Longer runs require reduced data rates: e.g., 300 m at 1 Mbps or 1 km at 100 kbps - consistent with RS-485 standard timing and signal integrity constraints.

Can ST75C176CDR be used with 3.3 V logic controllers?

DI, RE, and DE inputs accept 3.3 V logic levels (VIH = 2.0 V min, VIL = 0.8 V max), so they interface directly with 3.3 V MCUs. However, VCC must remain at 5 V - the device does not operate from 3.3 V supply. Level-shifting is unnecessary for control signals, but RO output swings 0–5 V and may require buffering for 3.3 V–tolerant receivers.