NXP Semiconductors SC16C550IA44,518

Overview

SC16C550IA44,518 from NXP Semiconductors (formerly Philips) is a 16-byte FIFO UART IC with IrDA encoder/decoder, operating at 2.5 V/3.3 V/5 V and supporting up to 3 Mbit/s serial data rates at 5 V. It provides hardware/software flow control, auto-RTS/CTS, four programmable receive FIFO interrupt trigger levels (1/4/8/14 bytes), and full modem interface (DTR/RTS/CTS/DSR/DCD/RI/CD). It is used in industrial embedded systems requiring reliable asynchronous serial communication with legacy or modem-connected peripherals.

For engineers reviewing the SC16C550IA44,518 datasheet, SC16C550IA44,518 pinout, SC16C550IA44,518 application, or SC16C550IA44,518 equivalent, key selection considerations include its PLCC44 package compatibility with ST16C550/TL16C550, IrDA support for short-range wireless serial links, sleep mode for power-sensitive designs, and DMA-ready TXRDY/RXRDY signaling for high-throughput host CPU interfaces.

Technical Context

The SC16C550IA44,518 implements a dual-FIFO architecture with independent 16-byte transmit and receive buffers, enabling burst-mode data handling without CPU intervention. Its register set includes standard 16C450-compatible registers plus enhanced features accessible via LCR[7]=1 and EFR configuration - notably auto-flow control (AFE bits), Xon/Xoff character comparison, and programmable baud divisors using DLL/DLM.

It supports three voltage domains (2.5 V, 3.3 V, 5 V) with industrial temperature range (−40 °C to +85 °C), and integrates both standard modem control logic and infrared encoder/decoder circuitry compliant with IrDA 1.0 physical layer requirements. The internal clock generator accepts XTAL1 input (up to 48 MHz) and outputs BAUDOUT for synchronous receiver clocking.

Key Specifications

Pinout & Package

SC16C550IA44,518 is housed in a plastic leaded chip carrier (PLCC44) package with 44 leads, 1.27 mm pitch, and JEDEC MO-047A outline. Pin layout supports direct replacement of ST16C550IA44 and TL16C550IA44 in existing PCB footprints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ST16C550CJ44 and TL16C550CPTR, the SC16C550IA44,518 uniquely delivers integrated IrDA 1.0 capability in a drop-in PLCC44 package, enabling infrared serial connectivity without added components - a critical advantage for space-constrained or wireless-commissioning designs where external PHYs increase BOM cost and layout complexity.

Availability

SC16C550IA44,518 is available at Aetrix Electronics and suitable for industrial automation, legacy equipment modernization, and embedded communication hubs requiring stable component supply, long-term lifecycle assurance, and compatibility with established 16C550 software stacks.

Supply support for SC16C550IA44,518 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, formerly Philips Semiconductors, is a global leader in high-performance mixed-signal ICs for automotive, industrial, and communication applications.

The SC16C550IA44,518 belongs to NXP's legacy UART product line, designed specifically for robust, low-power, pin-compatible upgrades of 16C450/16C550-based systems in harsh industrial environments.

FAQ

What voltage levels does the SC16C550IA44,518 support?

The SC16C550IA44,518 operates across three supply rails: 2.5 V ±10%, 3.3 V ±10%, and 5 V ±10%. It maintains full functionality-including 3 Mbit/s operation at 5 V, 2 Mbit/s at 3.3 V, and 1 Mbit/s at 2.5 V-without requiring external level shifters. This triple-voltage capability simplifies integration into mixed-voltage industrial boards where legacy 5 V logic coexists with modern 3.3 V or low-power 2.5 V subsystems.

Does the SC16C550IA44,518 support IrDA communication out of the box?

Yes, the SC16C550IA44,518 includes a fully integrated IrDA 1.0 encoder/decoder. When configured via the Enhanced Feature Register (EFR), it generates and decodes 3/16 pulse-width-modulated IR signals directly on the TX/RX pins, eliminating the need for external IrDA PHY chips. This enables compact, low-cost infrared serial links for device pairing, firmware updates, or diagnostic access without additional components.

How does auto-RTS work in the SC16C550IA44,518?

In auto-RTS mode, the SC16C550IA44,518 asserts RTS when the RX FIFO has space above a user-programmed threshold (1/4/8/14 bytes) and de-asserts it when the FIFO reaches that level. This hardware handshake prevents overrun by signaling the remote device to pause transmission before buffer exhaustion. Unlike software-managed RTS, this occurs autonomously with sub-microsecond latency, ensuring deterministic flow control even under heavy CPU load.

Is the SC16C550IA44,518 pin-compatible with other 16C550-family UARTs?

Yes, the SC16C550IA44,518 is explicitly pin-compatible with ST16C550, TL16C550, and PC16C550 in the PLCC44 package. Its pin mapping matches the industry-standard 16C550 footprint-including identical D0–D7, A0–A2, IOR/IOW, CS0–CS2, and modem control signal locations-allowing direct substitution in existing designs without PCB changes or layout revision.

What is the purpose of the TXRDY and RXRDY signals on the SC16C550IA44,518?

TXRDY and RXRDY are active-low DMA handshake signals. TXRDY goes LOW when the transmit FIFO is not full, enabling continuous DMA writes; RXRDY goes LOW when the receive FIFO contains data, triggering DMA reads. Both support two modes (single/multi-transfer) selected via FCR[3], allowing flexible integration with DMA controllers in ARM, x86, or FPGA-based hosts to offload serial data movement from the CPU.