CP2101 Introduction
The CP2101 is a compact USB-to-UART bridge controller that simplifies upgrading RS-232 designs to USB. It integrates a USB 2.0 controller, transceiver, oscillator, EEPROM, and UART interface in a 5 x 5 mm package, requiring no external components. The on-board EEPROM allows customization of USB descriptors, while royalty-free Virtual COM Port (VCP) drivers enable seamless PC integration. Ideal for OEMs, the CP2101 is a cost-effective, space-saving solution for USB-enabled designs.
CP2101 Pinout
VDD: 3.0–3.6 V Power Supply Voltage Input. 3.3 V Voltage Regulator Output. See Section 9.
GND: Ground
RST: Device Reset. Open-drain output from internal POR or VDD monitor. External reset can be triggered by driving this pin low for ≥15 µs.
REGIN: 5V Regulator Input. Input to the on-chip voltage regulator.
VBUS: VBUS Sense Input. Connect to USB VBUS signal. 5V on this pin indicates USB network connection.
D+: USB D+
D–: USB D–
TXD: Asynchronous data output (UART Transmit)
RXD: Asynchronous data input (UART Receive)
CTS: Clear To Send control input (active low)
RTS: Ready to Send control output (active low)
DSR: Data Set Ready control input (active low)
DTR: Data Terminal Ready control output (active low)
DC: Data Carrier Detect control input (active low)
RI: Ring Indicator control input (active low)
SUSPEND: This pin is driven high when the CP2101 enters the USB suspend state.
SUSPEND: This pin is driven low when the CP2101 enters the USB suspend state.
NC: The pins should be left unconnected or tied to VDD.
CP2101 Symbol
CP2101 Footprint
CP2101 3D Model
CP2101 Connection Diagram
CP2101 Specification
| Parameter | Specification |
| Interface | UART |
| Standards | USB 2.0 |
| Protocol |
USB |
| Function | Bridge, USB to UART |
| Flow Control | RTS/CTS, XON/XOFF |
| Supply Voltage | 3V ~ 3.6V |
| Supply Current | 25mA |
| Operating Temperature | -40°C ~ 85°C |
| Package | 28-MLP |
CP2101 Features
No External Resistors Required for USB Connectivity
Eliminates the Need for an External Crystal
512-Byte EEPROM
On-Chip Power-On Reset
3.3V On-Chip Voltage Regulato
Supports Full-Speed Operation (12 Mbps)
UART Interface
Baud Rates Ranges from 300 bps to 921.6 kbps
512-Byte Buffers
Royalty-Free VCP Drivers
CP2101 Applications
Upgrade of RS-232 Legacy Devices to USB
Cellular Phone USB Interface Cable
PDA USB Interface Cable
USB to RS-232 Serial Adapter
How to Use CP2101?
To get started, connect the VDD pin to a 3.0–3.6 V power supply. The REGIN pin accepts a 5V input for the onboard voltage regulator, while VBUS senses the USB connection by monitoring the 5V signal from the USB bus. The D+ and D– pins are directly connected to the USB data lines for communication.
For UART functionality, connect the TXD and RXD pins to your microcontroller or serial device. The CP2101 also supports hardware flow control with pins like CTS, RTS, DSR, DTR, DC, and RI, which can be used for handshaking if needed. The SUSPEND pin indicates the USB suspend state, making it useful for power management. Pins marked NC should be left unconnected or tied to VDD.
To use the CP2101, install the royalty-free Virtual COM Port (VCP) drivers provided by Silicon Labs. These drivers allow the CP2101 to appear as a standard COM port on your PC, enabling seamless communication with serial applications.
CP2101 Package
The CP2101 is available in a 28-MLP package, a compact, surface-mount design ideal for space-constrained applications. This 28-pin leadless molded package (MLP) features enhanced thermal performance and electrical conductivity. With a small footprint, it supports efficient PCB layout and high-density integration in USB-to-UART bridge applications.
FAQs
What is CP2101?
The CP2101 is a USB-to-UART bridge that enables communication between USB-enabled devices and systems with a UART interface.
What operating systems are compatible with the CP2101?
The CP2101 is compatible with major operating systems including Windows, macOS, and Linux. Drivers for these systems are readily available for installation.
Can I use the CP2101 in embedded systems?
Yes, the CP2101 is ideal for embedded systems that require USB connectivity, such as microcontrollers, sensors, and data acquisition systems, due to its low power consumption and efficient design.
