NXP Semiconductors SC16C550IN40,112

Overview

SC16C550IN40,112 from NXP Semiconductors (formerly Philips) is a 40-pin DIP UART IC with 16-byte transmit/receive FIFOs, IrDA encoder/decoder, auto-RTS/CTS hardware flow control, and programmable baud rates up to 3 Mbit/s at 5 V. It operates across 2.5 V, 3.3 V, and 5 V supply rails within the industrial temperature range (−40 °C to +85 °C), and serves as a drop-in upgrade for legacy 16C450-based serial communication subsystems in embedded controllers and industrial gateways.

For engineers reviewing the SC16C550IN40,112 datasheet, SC16C550IN40,112 pinout, SC16C550IN40,112 application, or SC16C550IN40,112 equivalent, key selection considerations include FIFO trigger level configurability (1/4/8/14 bytes), dual-mode DMA signaling (TXRDY/RXRDY), IrDA physical-layer support, sleep mode power management, and register-level compatibility with ST16C550/TL16C550 families.

Technical Context

The SC16C550IN40,112 implements a dual-FIFO architecture with independent 16-byte transmit and receive buffers, enabling high-throughput asynchronous serial communication without CPU polling overhead. Its enhanced feature register (EFR) enables auto-flow control via RTS/CTS handshake logic tied directly to receiver FIFO fill level and transmitter readiness state.

It supports full modem interface signaling (DTR, DSR, RI, DCD, CTS, RTS), four selectable receive FIFO interrupt trigger levels, programmable Xon/Xoff software flow control, and an infrared encoder/decoder compliant with IrDA 1.0 physical layer specifications. The internal baud rate generator accepts reference clocks up to 48 MHz and delivers precise fractional divisors for DC–3 Mbit/s operation.

Key Specifications

Pinout & Package

SC16C550IN40,112 is housed in a 40-pin plastic dual in-line package (DIP40, 600 mil width, SOT129-1), compatible with standard through-hole PCB assembly and socket-based prototyping.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ST16C550CJ44 and TL16C550CPTR, the SC16C550IN40,112 uniquely integrates IrDA 1.0 PHY and supports triple-voltage operation (2.5/3.3/5 V), making it the only option among the three suitable for infrared-enabled, mixed-voltage industrial edge nodes requiring through-hole assembly.

Availability

SC16C550IN40,112 is available at Aetrix Electronics and suitable for industrial PLC gateways, legacy PC expansion cards, embedded modem interfaces, and IrDA remote control hubs requiring stable component supply and long-term obsolescence mitigation.

Supply support for SC16C550IN40,112 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

NXP Semiconductors (originally Philips Semiconductors) is a global leader in high-reliability interface and connectivity ICs, with deep expertise in industrial, automotive, and secure communication solutions.

The SC16C550IN40,112 belongs to NXP's legacy UART product line, engineered for robust serial communication in harsh environments where interoperability, long-lifecycle support, and hardware-accelerated flow control are critical.

FAQ

What voltage levels does the SC16C550IN40,112 support?

The SC16C550IN40,112 operates at 2.5 V, 3.3 V, or 5 V ±10%, with full specification compliance across all three supply rails. This triple-voltage capability allows seamless integration into mixed-signal systems and backward compatibility with legacy 5 V designs without level-shifting circuitry. Each voltage grade maintains its respective maximum data rate: 1 Mbit/s at 2.5 V, 2 Mbit/s at 3.3 V, and 3 Mbit/s at 5 V.

Does the SC16C550IN40,112 support IrDA communication?

Yes, the SC16C550IN40,112 includes a fully integrated IrDA 1.0 encoder/decoder compliant with the Serial Infrared (SIR) physical layer. It generates and decodes 3/16 carrier-modulated NRZ data at standard IrDA rates (up to 115.2 kbit/s), eliminating the need for external IR PHY ICs. The SC16C550IN40,112 drives standard IR LEDs directly via its TX pin when configured for IrDA mode.

How does auto-RTS flow control work in the SC16C550IN40,112?

In the SC16C550IN40,112, auto-RTS asserts RTS when the receiver FIFO has space and de-asserts it when the FIFO reaches a user-programmed trigger level (1, 4, 8, or 14 bytes). This hardware-controlled handshake prevents overrun without CPU intervention. When RTS is connected to the remote device's CTS, transmission halts automatically as the local FIFO fills - a key reliability feature in bursty industrial serial links.

Is the SC16C550IN40,112 pin-compatible with older UARTs?

Yes, the SC16C550IN40,112 is pin-compatible with ST16C550, TL16C550, and PC16C550 in the DIP40 package. Its pinout matches industry-standard 16C550 layouts, including identical placement of D0–D7, A0–A2, IOR/IOW, CS0–CS2, TX/RX, RTS/CTS, and INT. This enables drop-in replacement in existing 16C450/550-based designs without PCB revision.

What are the key differences between SC16C550IN40,112 and basic 16C450 UARTs?

The SC16C550IN40,112 adds 16-byte TX/RX FIFOs, auto-RTS/CTS hardware flow control, IrDA encoder/decoder, four selectable FIFO interrupt triggers, sleep mode, and programmable Xon/Xoff characters - all while maintaining 16C450 register compatibility on power-up. These enhancements reduce CPU interrupt load by >90%, eliminate software flow management, and enable infrared and high-speed modem interfaces absent in the original 16C450.