CP2108 Single-Chip USB-to-Quad-UART Bridge

Product catalog summary

System Overview: The CP2108 is a USB-to-Quad-UART Bridge Controller designed to facilitate the transition from RS-232/RS-485 to USB with minimal components. It integrates several features including a USB 2.0 full-speed function controller, USB transceiver, oscillator, EEPROM, and four UARTs with full modem control signals. The EEPROM allows for USB parameter customization and is programmable via USB, aiding in manufacturing integration. The device supports Virtual COM Port drivers, ensuring compatibility with existing PC applications without firmware changes. It also includes 16 GPIO signals for user-defined status and control.

Ordering Part Number Information: The CP2108 is available in two versions: CP2108-B02-GM, recommended for new designs, and CP2108-B01-GM, not recommended for new designs. Identification can be done via package marking or device querying.

Electrical Specifications: Operating with a supply voltage of 3.0 to 3.6 V, the CP2108 supports a temperature range of -40 to +85 °C. It features a 3.3 V voltage regulator output and supports both self-powered and USB bus-powered configurations.

UART Interface Features: Each UART supports hardware flow control, modem control signals, and data formats with baud rates from 300 bps to 2 Mbps. UART 3 can interface with devices up to 6 V.

GPIO Interface Features: The CP2108 includes 16 GPIO pins with configurable options, RS-485 bus transceiver control, and LED toggling upon data transmission and reception.

Throughput and Flow Control: The device supports typical throughput values based on bench testing. Hardware flow control is recommended for baud rates above 230,400 bps. UART 3 has lower throughput rates compared to UARTs 0-2 at higher baud rates.

Package Options and Temperature Range: Available in a RoHS-compliant 64-pin QFN package, the CP2108 operates within a temperature range of -40 to +85 °C.

Specifications: Detailed specifications include throughput rates for different UART configurations, varying from 180,300 bps to 388,000 bps depending on the number of UARTs in operation.

Pin Definitions and Packaging Information: Packaged in a QFN-64 format, the document includes a detailed pinout diagram and a table listing each pin's primary and alternate functions.

QFN-64 Package Specifications: Package dimensions conform to JEDEC MO-220 standards, with a recommended card reflow profile following JEDEC/IPC J-STD-020 specifications.

Connection Diagrams: Typical connection diagrams for bus-powered and self-powered configurations are provided, with or without using the on-chip voltage regulator.

USB Function Controller and Transceiver: The CP2108 is a USB 2.0 compliant full-speed device with an integrated transceiver, managing data transfers between USB and UARTs and supporting power management through USB Suspend and Resume signals.

Asynchronous Serial Data Bus (UART) Interfaces: The CP2108 contains four UART interfaces, each supporting various data formats and baud rates from 300 bps to 2.0 Mbps.

Key Recommendations: Use avalanche transient voltage suppression diodes for ESD protection, follow the recommended card reflow profile for assembly, and ensure proper configuration of USB descriptors to match device power usage.

CP2108 GPIO and UART Pins: The CP2108 supports 16 user-configurable GPIO pins, which can be set as inputs, open-drain outputs, or push-pull outputs. They are not recommended for real-time signaling due to USB bus timing constraints.

GPIO Alternate Clock Outputs: Four GPIO pins can output a configurable CMOS clock, synchronized with the CP2108 core clock.

Transmit and Receive Toggle: Certain GPIO pins can be configured as Transmit and Receive Toggle pins for UART interfaces, indicating data transfer with LEDs.

RS-485 Transceiver Bus Control: Specific GPIO pins can control RS-485 bus transceivers, with configurable active-high or active-low modes.

Hardware Flow Control: RTS and CTS pins are used for hardware flow control, indicating when data can be sent or received based on FIFO buffer levels.

High Drive Pins: UART 3 pins can handle higher input voltages, allowing direct connection to 5V devices.

Internal EEPROM: The CP2108 includes an EEPROM for customizing USB configuration data, such as VID/PID and serial numbers, to avoid driver conflicts.

Device Drivers: The CP2108 uses Virtual COM Port (VCP) drivers, allowing it to appear as four COM ports to PC applications. Drivers can be customized and certified through Microsoft processes.

Relevant Application Notes: Several application notes are available for device customization, serial communication, and driver installation.

Device Specific Behavior: The CP2108-B02-GM fixes a known issue with the CP2108-B01-GM related to USB command response after handle reopening.

Catalog excerpts

CP2108 Single-Chip USB-to-Quad-UART Bridge-1

CP2108 S INGLE - C HIP USB- T O - Q U A D - U A R T B R ID G E Single-Chip USB-to-QUAD UART Data Transfer UART Interface Features independent UART interfaces Integrated USB transceiver; no external resistor required Integrated clock; no external crystal required Integrated programmable EEPROM for storing customizable product information On-chip power-on reset circuit On-chip voltage regulator: 3.3 V output Each UART interface supports the following: Supports hardware flow control (RTS/CTS) Supports all modem control signals Data formats supported: - Data bits: 5, 6, 7, and 8 - Stop bits: 1, 1.5, and 2 - Parity: odd, even, set, mark and none Baud rates: 300 bps to 2 Mbps UART 3 (pins 1–6) supports interfacing to devices up to 6V USB Peripheral Function Controller USB USB Specification 2.0 compliant; full-speed (12 Mbps) suspend states supported via SUSPEND pins GPIO Interface Features Total of 16 GPIO pins with configurable options pin support Usable as inputs, open-drain or push-pull outputs 4 configurable clock outputs for external devices RS-485 bus transceiver control Toggle LED upon transmission Toggle LED upon reception Virtual COM Port Drivers with existing COM port PC applications distribution license Windows 8/7/Vista/XP/Server 2003 Mac OS X Linux Royalty-free Package Options Supply Voltage 3.0 to 3.6 V USB bus powered: 4.0 to 5.5 V VIO voltage: 3.0 to VDD VIOHD Ordering Part Number CP2108-B02-GM CP2108 Connect to VBUS or External Supply Voltage Regulator Baud Rate Generator Handshake Control VBUS D+ D- Full-Speed 12 Mbps Transceiver Peripheral Function Controller Data FIFO 18 EEPROM (Product Customization) I/O Power and Logic Levels UART0-2, GPIO, SUSPEND, RESET VIOHD High Drive UART 3(Pins 1-6) Figure 1. Example System Diagram Copyright © 2014 by Silicon Laboratories

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CP2108 Single-Chip USB-to-Quad-UART Bridge-3

CP2108 TABLE O F C ONTENTS Section 1. System Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 2. Ordering Part Number Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 3. Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 3.1. Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 3.2. Absolute Maximum Ratings . . . . . . . . ....

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CP2108 Single-Chip USB-to-Quad-UART Bridge-4

CP2108 1. System Overview The CP2108 is a highly integrated USB-to-Quad-UART Bridge Controller providing a simple solution for updating RS-232/RS-485 designs to USB using a minimum of components and PCB space. The CP2108 includes a USB 2.0 full-speed function controller, USB transceiver, oscillator, EEPROM, and four asynchronous serial data buses (UART) with full modem control signals in a compact 9 x 9 mm QFN-64 package (sometimes called “MLF” or “MLP”). The on-chip EEPROM may be used to customize the USB Vendor ID (VID), Product ID (PID), Product Description String, Power Descriptor, Device...

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CP2108 Single-Chip USB-to-Quad-UART Bridge-5

CP2108 3. Electrical Specifications 3.1. Electrical Characteristics All electrical parameters in all tables are specified under the conditions listed in Table 2, unless stated otherwise. Table 2. Recommended Operating Conditions1 VDD= 3.0 to 3.6 V, –40 to +85 °C unless otherwise specified. Operating Supply Voltage VREGIN Operating Supply Voltage VIO Operating Supply Voltage VIOHD Supply Current—Normal3 Supply Current—Suspended Operating Supply Voltage VDD Test Condition Normal Operation Self Powered Supply Current—USB Pull-up4 Operating Ambient Temperature Operating Junction Temperature Notes:...

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CP2108 Single-Chip USB-to-Quad-UART Bridge-6

CP2108 Table 3. UART, GPIO, and Suspend I/O VDD= 3.0 to 3.6 V, VIO=1.8 V to VDD, VIOHD = 2.7 V to 6.0 V, –40 to +85 °C unless otherwise specified. Output High Voltage (All pins except High Drive UART 3 pins 1–6) Test Condition Output Low Voltage (High Drive pins 1–6) Output Low Voltage (All pins except High Drive pins 1–6) Output High Voltage (High Drive UART 3 pins 1–6) Low Drive IOL = 3 mA High Drive IOL = 12.5 mA Input High Voltage Weak Pull-up Current (VIN = 0 V) Weak Pull-up Current UART 3 (pins 1–6) Test Condition Table 4. GPIO Output Specifications –40 to +85°C unless otherwise specified....

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CP2108 Single-Chip USB-to-Quad-UART Bridge-7

CP2108 Table 6. Voltage Regulator –40 to +85 °C unless otherwise specified. Test Condition Output Load Regulation Output Capacitance *Note: This is the total current the voltage regulator is capable of providing. Any current consumed by the CP2108 reduces the current available to external devices powered from VDD. Table 7. USB Transceiver –40 to +85 °C unless otherwise specified. Parameter Valid Supply Range (for USB Compliance) VBUS Pull-Down Leakage Current VBUS Detection Input Threshold Test Condition Transmitter Output High Voltage Output Crossover Point Output Impedance Driving High Driving...

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CP2108 Single-Chip USB-to-Quad-UART Bridge-8

CP2108 3.2. Absolute Maximum Ratings Stresses above those listed under Table 9 may cause permanent damage to the device. This is a stress rating only and functional operation of the devices at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability. Table 9. Absolute Maximum Ratings Parameter Test Condition Ambient Temperature under Bias Storage Temperature GPIO/UART pins except 1–6 UART,GPIO,Suspend I/O, RESET except for UART 3 pins1–6 UART,GPIO,Suspend...

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CP2108 Single-Chip USB-to-Quad-UART Bridge-9

CP2108 3.3. Throughput and Flow Control The throughput values in Table 10 are typical values based on bench testing and can serve as a guideline for expected performance. Other factors such as PC system performance and USB bus loading will have an effect on throughput. Each column in the table shows the typical throughput using 1, 2, 3 or all 4 UART interfaces for the set baud rate. 1. It is not necessary to use hardware flow control if all CP2108 interfaces are configured for 230,400 bps or lower. 2. For baud rates above 230,400 bps, hardware flow control should be used to guarantee reception...

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