NXP Semiconductors SC16C550BIBS128

Overview

SC16C550BIBS128 from NXP Semiconductors is a 32-pin HVQFN-packaged Universal Asynchronous Receiver and Transmitter (UART) IC that converts parallel CPU data to serial streams and vice versa, supporting up to 3 Mbit/s at 5 V, 2 Mbit/s at 3.3 V, and 1 Mbit/s at 2.5 V. It integrates 16-byte transmit and receive FIFOs, programmable auto-RTS/CTS hardware flow control, and full modem interface signals (CTS, RTS, DTR, DSR, DCD, RI), enabling robust serial communication in industrial embedded systems.

For engineers reviewing the SC16C550BIBS128 datasheet, SC16C550BIBS128 pinout, SC16C550BIBS128 application, or SC16C550BIBS128 equivalent, key selection considerations include its HVQFN32 package footprint, absence of TXRDY/RXRDY signals (not supported in this variant), 5/3.3/2.5 V dual-supply operation, FIFO trigger level configurability, and compatibility with legacy 16C450 software stacks.

Technical Context

The SC16C550BIBS128 implements a register-compatible extension of the industry-standard 16C450 UART architecture, with enhanced FIFO buffering and hardware flow control logic. Its internal baud rate generator accepts up to 48 MHz clock input and divides by programmable 16-bit divisors to achieve precise serial rates-including 921.6 kbit/s standard and custom values-while BAUDOUT and RCLK are internally bonded in the HVQFN32 package.

It supports four receiver FIFO interrupt trigger levels (1/4/8/14 bytes), prioritized interrupt handling (transmit empty, receive ready, line status, modem status), and loopback diagnostics. The device operates across −40 °C to +85 °C and features 3-state TTL-compatible bus drivers for D0–D7, A0–A2, and control lines, with AS-address strobe enabling flexible memory-mapped or I/O-mapped CPU interfacing.

Key Specifications

Pinout & Package

HVQFN32 package (SOT617-1), 5 mm × 5 mm body, 0.5 mm pitch, 32 terminals, thermally enhanced with exposed center pad requiring soldering to PCB ground plane per NXP SOT617-1 mechanical spec.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TL16C550CPM and ST16C550CJ, the SC16C550BIBS128 trades DMA signaling and larger package options for ultra-compact HVQFN32 integration and simplified clock routing (bonded BAUDOUT/RCLK), making it optimal for space- and thermal-constrained industrial edge nodes.

Availability

SC16C550BIBS128 is available at Aetrix Electronics and suitable for industrial PLC serial ports, medical data loggers, point-of-sale terminals, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SC16C550BIBS128 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 is a global semiconductor leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface, power, and security ICs.

The SC16C550BIBS128 belongs to NXP's legacy industrial UART product line, designed specifically for reliable, software-compatible serial communication in harsh-environment embedded systems requiring long-term supply stability and broad voltage/temperature support.

FAQ

What is the maximum serial data rate supported by the SC16C550BIBS128?

The SC16C550BIBS128 supports up to 3 Mbit/s at 5 V, 2 Mbit/s at 3.3 V, and 1 Mbit/s at 2.5 V. This performance requires a 48 MHz input clock to the BAUDOUT/RCLK circuit. The actual achievable rate depends on the selected divisor value and crystal accuracy; for example, with a 1.8432 MHz crystal, standard rates like 115.2 kbit/s are achieved with zero error using divisor 12.

Does the SC16C550BIBS128 support hardware flow control, and how is it implemented?

Yes, the SC16C550BIBS128 supports programmable auto-RTS and auto-CTS hardware flow control. Auto-RTS asserts RTS when the RX FIFO falls below a user-configured trigger level (1/4/8/14 bytes); auto-CTS pauses transmission when CTS goes inactive mid-frame. Both functions are enabled via MCR[5] and MCR[1], eliminating software polling and preventing RX FIFO overrun in SC16C550BIBS128-based designs.

Why are TXRDY and RXRDY signals not available on the SC16C550BIBS128?

TXRDY and RXRDY signals are explicitly omitted in the HVQFN32 package variant of the SC16C550B, as confirmed in the NXP datasheet Section 5.2 Pin Description. These DMA-ready signals are present only in PLCC44, LQFP48, and DIP40 packages. The SC16C550BIBS128 relies on interrupt-driven or polling-based data transfer instead, consistent with its compact footprint optimization.

Is the SC16C550BIBS128 pin-compatible with older 16C450-based designs?

Yes, the SC16C550BIBS128 is functionally and register-compatible with the 16C450 after reset, and its HVQFN32 pinout maps core signals (D0–D7, A0–A2, IOR/IOW, INT, TX/RX, RTS/CTS, RESET, XTAL1/XTAL2, VDD/VSS) to dedicated pins. However, CS is consolidated to a single pin (replacing CS0/CS1/CS2), and AS is omitted - requiring minor PCB layout adaptation but preserving full software compatibility for SC16C550BIBS128 integration.

How does the SC16C550BIBS128 handle clocking, and what is the role of BAUDOUT and RCLK?

The SC16C550BIBS128 uses a single programmable baud rate generator fed by XTAL1 (crystal or external clock). BAUDOUT provides a 16× baud-rate output; in the HVQFN32 package, BAUDOUT and RCLK are internally bonded, meaning RCLK is driven by BAUDOUT - eliminating need for external connection. This simplifies clock routing and ensures synchronous TX/RX timing in SC16C550BIBS128 implementations.