CP2109-A01-GM - USB 2.0 to UART Bridge | Silicon Labs
MPN: CP2109-A01-GM ✗ End of Life| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
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| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
CP2109-A01-GM Overview
A USB-to-UART bridge is an interface controller that translates between a host computer's USB transaction protocol and a UART data stream using differential signaling on one side and logic-level serial signaling on the other. It belongs to the interface-controller and data-conversion hierarchy: USB bridge → UART interface controller → serial interface IC → semiconductor. Its primary engineering value is reducing firmware and hardware complexity while providing a standard serial connection for embedded products.
The CP2109 family integrates an internal USB transceiver, an integrated clock, and an on-chip power-on reset circuit. The verified CP2102/CP2109 datasheet summary also describes programmable on-chip memory for USB descriptors and device identification data. For CP2109, the one-time-programmable memory provides customized product information, while vendor configuration requirements and programming implications must be reviewed before production use.
The interface supports low-speed and full-speed USB operation according to the verified component summaries. USB 2.0 identifies the peripheral-side interface standard, while UART data is exposed through the device's serial pins. Designers should use the manufacturer's pinout, reference circuit, and interface guidelines because signal routing, grounding, exposed-pad connection, supply filtering, and host-driver behavior are essential to reliable operation.
Typical uses include industrial instrument service ports, machine controllers, test equipment, USB-to-serial adapters, embedded development boards, and field-upgrade interfaces. The 5 mm by 5 mm QFN package supports compact designs, but its exposed thermal pad requires careful PCB layout and an adequate ground or thermal plane. Unlike a large legacy serial connector implementation, the bridge can add USB connectivity while preserving the firmware-facing UART model.
For each new design, confirm the exact USB speed, UART baud-rate and electrical limits, supply sequencing, crystal-free clocking conditions, descriptor programming method, and exposed-pad layout against the current manufacturer datasheet. Do not infer those missing values from distributor category labels alone.
This page consolidates verified sourcing information, procurement context, technical gaps, and design cautions around the CP2109-A01-GM, helping engineers separate confirmed facts from parameters that still require manufacturer-documentation confirmation.
Drop-in alternatives for CP2109-A01-GM — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with CP2109-A01-GM (same form factor and footprint) — differing in Package, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
CP2109-A01-GMR
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View Datasheet →CP2109-A01-GM Specifications
| Device Type | Single-chip USB-to-UART bridge |
| USB Standard | USB 2.0 |
| Supported USB Speed | Low-speed and full-speed |
| UART Interface | 1 channel |
| Supply Voltage Range | 3.3 V to 3.6 V |
| Integrated USB Transceiver | Yes |
| External USB-Termination Resistors | Not required |
| Integrated Clock | Yes |
| External Crystal | Not required |
| On-Chip Power-On Reset | Yes |
| Programmable Memory | Internal 1024-byte programmable ROM |
| Configurable Descriptor Data | Vendor ID, product ID, serial number, power descriptor, release number, and product description strings |
| CP2109 Memory Type | One-time-programmable memory |
| Package | 28-QFN, 5 mm by 5 mm |
| Mounting Type | Surface mount |
| RoHS Status | EU RoHS compliant |
CP2109-A01-GM 28-qfn, 5 mm by 5 mm Pin Configuration Guide
Pin configuration for CP2109-A01-GM (28-qfn, 5 mm by 5 mm package). Pin numbering, functions, and connection diagrams are defined in the manufacturer datasheet. Refer to it for the exact footprint and soldering guidelines.
No detailed pinout data available for CP2109-A01-GM.
Refer to the datasheet for full pin configuration.
Typical Applications
CP2109-A01-GM is suitable for 6 applications: Industrial Instrument Service Port, Embedded USB-to-Serial Adapter, Firmware Update and Recovery Interface, Test and Measurement Console, Data Acquisition and Control Module, Programmable Controller Communication.
Industrial Instrument Service Port
The CP2109-A01-GM fits a compact service connection between a host computer and an instrument controller because it provides a USB 2.0 peripheral interface, one UART channel, and an integrated USB transceiver. Its 28-QFN package occupies 5 mm by 5 mm, while the verified family summary indicates that external USB termination resistors and a crystal are not required. The UART side can preserve an established embedded serial protocol, reducing host-side driver complexity compared with implementing a proprietary USB peripheral. Designers must follow the exact manufacturer pinout and layout because the supplied data does not establish baud-rate or temperature limits.
Recommended
Embedded USB-to-Serial Adapter
CP2109-A01-GM is suitable for an embedded USB-to-serial adapter because Silicon Labs describes it as a single-chip bridge with low-speed and full-speed USB support. The host sees USB, while the target controller continues to use its UART firmware model. Integration of the transceiver and clock lowers component count, and the confirmed 3.3 V to 3.6 V supply range simplifies compatibility with modern 3.3 V logic. Production validation should cover enumeration, programmed USB descriptors, cable behavior, ground strategy, and the manufacturer's exposed-pad layout.
Recommended
Firmware Update and Recovery Interface
The CP2109-A01-GM can provide a convenient production and field-recovery path when an embedded controller exposes bootloader commands through UART. USB-to-UART conversion allows a technician to program, diagnose, or recover a board without adding a legacy connector or proprietary USB firmware stack. Its single-channel bridge, integrated clock, and internal descriptor memory make the connection electrically compact. The one-time-programmable CP2109 memory requires careful production provisioning, so identity strings and device credentials should be defined before programming and controlled through the manufacturing process.
Recommended
Test and Measurement Console
CP2109-A01-GM can connect a test console to equipment that retains a UART command interface. USB provides the operator-facing connection, while UART transports existing commands, results, and status data. The integrated transceiver and clock help keep the console electronics compact, and the 28-QFN package is practical for densely assembled instruments. For metrology equipment, engineers should still evaluate isolation, earth leakage, electromagnetic interference, and enclosure grounding because those requirements are not established by the supplied component data.
Recommended
Data Acquisition and Control Module
CP2109-A01-GM is suitable for a data-acquisition module that sends commands and returns samples through an embedded UART. Its one UART channel can act as a maintenance and configuration path alongside the module's primary sensor interface, while USB 2.0 connectivity supports easy attachment to a laptop or control computer. The confirmed 3.3 V to 3.6 V operating range and compact QFN package help with board-area constraints. Firmware must implement framing, error handling, and device descriptors, and USB signal integrity must follow the manufacturer's reference layout.
Recommended
Programmable Controller Communication
CP2109-A01-GM can provide a PC-to-controller programming link for programmable automation, building-control, or laboratory equipment. The UART side integrates with a controller's existing serial peripheral, allowing existing command sets and bootloaders to remain intact. Low-speed and full-speed USB support covers the confirmed peripheral operating modes, while the integrated USB transceiver and clock reduce external support components. Developers should verify host compatibility, driver strategy, descriptor customization, and production programming workflow before release because those implementation details are not fully present in the verified search data.
Recommended
Recommended Products Summary
Engineering reference data for CP2109-A01-GM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CP2109-A01-GMR |
|---|---|---|
| Package | 28-QFN, 5 mm by 5 mm | QFN-28 |
| Brand | Silicon Labs | Silicon Labs |
| Function | Single-chip USB-to-UART bridge | USB-to-UART bridge |
| UART Channels | 1 channel | 1 channel |
| Verified Difference | Baseline | Some electrical characteristics differ according to the verified comparison |
Key Differentiators
- Integrated single-chip USB-to-UART implementation (vs Discrete USB-to-serial interface implementation)
- Compact board footprint (vs Larger 28-pin through-hole interface options)
- One-time-programmable descriptor identity (vs CP2102-family bridge with different memory implementation)
Design Notes
Use the manufacturer's CP2109 reference layout and complete pinout before routing the board. The verified data confirms a 28-QFN with an exposed pad but does not provide pin assignments, so USB differential pairs, supply connections, UART routes, ground vias, and pad-connection geometry must be copied from the official datasheet rather than inferred. Keep the exposed pad electrically connected as specified and provide adequate thermal and return-current paths.
Design the supply path for the confirmed 3.3 V to 3.6 V operating range. Follow the manufacturer recommendation for local decoupling, USB bus-power components, and power-state transitions. The verified data does not provide current consumption, absolute maximum ratings, or startup timing, so do not select regulators, bulk capacitance, or protection devices from assumptions. Validate these values against the official datasheet and the host's USB current budget.
CP2109 uses one-time-programmable memory according to the verified family documentation. Treat USB vendor ID, product ID, serial identity, release information, and product strings as controlled manufacturing data rather than fields that can be casually changed after programming. Establish identity allocation, programming fixtures, traceability, and failure recovery before volume production to prevent cloned or incorrectly provisioned USB devices.
Route USB as a controlled differential interface and follow the manufacturer's reference geometry. Keep the pair continuous over a compact, quiet portion of the PCB, provide a continuous ground reference, and minimize stubs and switching-node proximity. Although the bridge integrates its USB transceiver, external routing quality still affects enumeration and data integrity. Compliance testing should include cable attachment, hot-plug behavior where supported, and operation across the intended host and peripheral-use cases.
Compliance Information
The supplied Abacus Technologies result identifies the part as EU RoHS Compliant. No verified REACH, automotive-qualification, lead-free, halogen-free, or conflict-minerals declaration was supplied, so those fields remain unknown.
