STMicroelectronics ST75C176CN

Overview

ST75C176CN from STMicroelectronics is a low-power, half-duplex RS-485/RS-422 transceiver in an 8-pin DIP package, featuring 300 µA typical quiescent current, ±7 V to +12 V common-mode input range, and 30 ns driver propagation delay. It integrates one driver and one receiver with fail-safe receiver inputs, thermal shutdown, and short-circuit protection - deployed in industrial automation networks for robust multi-drop serial communication.

For engineers reviewing the ST75C176CN datasheet, ST75C176CN pinout, ST75C176CN application, or ST75C176CN equivalent, key selection criteria include bus loading capacity (up to 32 nodes), single 5 V supply operation, receiver hysteresis (70 mV typ.), driver output enable/disable timing (40–70 ns), and DIP-8 through-hole compatibility for legacy control systems.

Technical Context

The ST75C176CN implements a BiCMOS-based transceiver architecture optimized for half-duplex RS-485 bus systems. Its driver uses current-limiting and thermal shutdown circuitry to maintain high-impedance outputs during overload or power-off conditions, while the receiver incorporates fail-safe biasing that guarantees logic-high RO when A/B lines are open or floating.

Control logic follows standard RS-485 enable conventions: DE controls driver output state (active-high), RE controls receiver output state (active-low), and both support 3-state operation. Propagation delays (30 ns driver, 130 ns receiver typ.) and skew (5 ns driver, 13 ns receiver) support reliable 2.5 Mbps data rates over twisted-pair cabling under load.

Key Specifications

Pinout & Package

ST75C176CN is housed in an 8-pin plastic dual in-line package (DIP-8) with 2.54 mm lead pitch, suitable for through-hole PCB assembly and prototyping. Package dimensions comply with JEDEC MS-001, including 9.8 mm body length and 3.3 mm height.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX485CPA+ and SN65HVD11DR, the ST75C176CN uniquely combines DIP-8 through-hole compatibility, thermal shutdown, fail-safe receiver, and sub-500 µA quiescent current - making it optimal for legacy industrial upgrades requiring reliability and serviceability.

Availability

ST75C176CN is available at Aetrix Electronics and suitable for industrial PLC networks, building automation systems, legacy CNC machine interfaces, and remote sensor aggregation nodes requiring stable component supply and long-term obsolescence management.

Supply support for ST75C176CN 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 microcontrollers, power ICs, sensors, and analog/mixed-signal components for industrial, automotive, and consumer markets.

The ST75C176 series belongs to ST's legacy RS-485 transceiver product line, engineered specifically for robust, low-power, half-duplex industrial communications where reliability, fail-safe behavior, and through-hole manufacturability are prioritized.

FAQ

Is ST75C176CN pin-compatible with MAX485?

No. While both are half-duplex RS-485 transceivers in 8-pin packages, ST75C176CN uses RE (active-low) and DE (active-high) enables, whereas MAX485 uses a single /RE/DE pin (active-low for both). Pin 2 (RE) and pin 3 (DE) functions differ, requiring PCB layout and firmware changes for substitution.

Does ST75C176CN support full-duplex RS-422 operation?

No. ST75C176CN contains one driver and one receiver sharing the same A/B bus lines - it is strictly half-duplex. Full-duplex RS-422 requires separate transmit (Y/Z) and receive (A/B) differential pairs, as implemented in devices like ST75C188 or SP3491.

What is the purpose of the 70 mV input hysteresis?

The 70 mV typical hysteresis in the receiver input comparator prevents oscillation or chatter when the differential input voltage (A–B) crosses the threshold near 0 V, especially under noisy conditions or slow signal edges - ensuring clean, glitch-free logic transitions at RO.

Can ST75C176CN operate with a 3.3 V supply?

No. The device is specified only for 5 V ±5 % operation. Supply voltage below 4.75 V may cause unreliable driver output swing, increased propagation delay, or failure to meet RS-485 voltage thresholds; no 3.3 V characterization data is provided in the datasheet.