NXP Semiconductors USB2SERA10CFK

Overview

USB2SERA10CFK from Freescale Semiconductor is a USB 2.0 Full-Speed (12 Mbps) to UART bridge IC in a 5 × 5 mm, 24-pin QFN package. It integrates a USB transceiver, 3.3 V regulator, PLL clock multiplier (2–48 MHz), and configurable UART supporting RS232/RS485 with hardware/software flow control, 300–115200 bps baud rates, and 8N1/8E1/8O1 data formats - deployed in industrial serial gateways and embedded diagnostics interfaces.

For engineers reviewing the USB2SERA10CFK datasheet, USB2SERA10CFK pinout, USB2SERA10CFK application, or USB2SERA10CFK equivalent, this page delivers verified technical context, exact pin roles, real-world UART/USB timing behavior, and validated alternative options for legacy serial migration projects requiring CDC-class compatibility and field-programmable VID/PID.

Technical Context

The USB2SERA10CFK implements a dedicated USB Communication Device Class (CDC) engine with bulk transfer mode, eliminating custom driver requirements on Windows/Linux when flow control is unused. Its internal 48 MHz system clock derives from an auto-detected external crystal (2–16 MHz) via a PLL, enabling precise UART baud generation with ±1.5% error at 115200 bps.

Power architecture includes dual-regulation paths: primary VDD (2.7–5.5 V) supplies logic and I/O, while the integrated 3.3 V regulator powers USB transceivers (USBDP/USBDN) and supports VUSB33MON-based startup configuration. Reset sequencing incorporates POR, external /RESET, and soft reset, with 48 ms crystal detection and 550 ms VUSB33 capacitor discharge delay for regulator enable decision.

Key Specifications

Pinout & Package

USB2SERA10CFK uses a RoHS-compliant, lead-free 24-pin QFN package (5 × 5 mm, Case 1897) with exposed thermal pad. Pin 1 is marked by a dot; pins are numbered counterclockwise starting from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar USB-to-UART bridge applications.

Compared with CP2102N-A02-GM and FT232RL, USB2SERA10CFK uniquely integrates RS485_TXEN, crystal auto-detection, and SUSPEND/RESUME signaling in a 5 × 5 mm QFN - reducing BOM count and PCB area for industrial RS485 gateway designs requiring USB wakeup and power management.

Availability

USB2SERA10CFK is available at Aetrix Electronics and suitable for industrial serial gateways, embedded diagnostic ports, USB-to-RS232 adapter modules, and IoT edge node bridges requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for USB2SERA10CFK 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

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, connectivity, and analog solutions for automotive, industrial, and consumer markets.

USB2SERA10CFK belongs to Freescale's Ready Play Solutions product line - designed specifically for rapid integration of certified USB functionality into resource-constrained embedded systems without custom driver development.

FAQ

What USB speed and device class does USB2SERA10CFK support?

USB2SERA10CFK supports USB 2.0 Full-Speed (12 Mbps) and operates as a CDC (Communication Device Class) device. It enumerates as a standard COM port on Windows and Linux without custom drivers when flow control is disabled. The USB2SERA10CFK implements bulk transfer mode with full CDC compliance, including ACM (Abstract Control Model) subclass support for modem control functions like DTR/RTS signaling.

Does USB2SERA10CFK support both RS232 and RS485 interfaces natively?

USB2SERA10CFK provides TTL-level UART signals (TXD, RXD, RTS, CTS, RS485_TXEN) but does not include integrated RS232 or RS485 transceivers. It supports both interface types through external transceivers: RS232 via MAX3232-type chips, and RS485 via SN65HVD72-type chips using the dedicated RS485_TXEN pin for automatic direction control. The USB2SERA10CFK datasheet confirms RS485_TXEN timing synchronization with UART TX activity to prevent bus contention.

Can the VID, PID, and device strings of USB2SERA10CFK be customized in the field?

Yes, USB2SERA10CFK includes 512 bytes of internal flash memory for storing custom VID, PID, manufacturer string, product string, and serial number. Configuration is performed using Freescale's GUI tool (available at freescale.com/usb2ser) with a 16-character hex password. The USB2SERA10CFK default password is "FFFFFFFFFFFFFFFF", and changing strings triggers requirement for USB-IF re-certification if the USB logo is to be used.

What crystal frequencies does USB2SERA10CFK support, and is configuration required?

USB2SERA10CFK supports 2 MHz, 4 MHz, 6 MHz, 8 MHz, 12 MHz, and 16 MHz external crystals in Pierce oscillator configuration. No manual configuration is required: the device performs automatic crystal frequency detection during power-on reset, completing within 48 ms. This eliminates firmware or hardware jumpers for clock source selection, and the USB2SERA10CFK PLL then generates a stable 48 MHz system clock for USB and UART timing.

How does USB2SERA10CFK handle power management and suspend/resume?

USB2SERA10CFK implements USB-defined power management with /SUSPEND output indicating suspend state and /RESUME input for remote wake-up requests. During suspend, the internal 3.3 V regulator remains active if VDD is present, and the device draws <100 µA. The USB2SERA10CFK SUSPEND signal can drive external power-gating circuits, while RESUME allows host-initiated recovery without physical disconnection - critical for battery-powered diagnostic tools.