CP2108-B03-GM - USB 2.0 to Quad-UART Bridge | Silicon Labs
MPN: CP2108-B03-GM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.7973 | $3.80 |
| 10 | $3.7973 | $37.97 |
| 100 | $3.7973 | $379.73 |
| 500 | $3.7973 | $1,898.65 |
| 1,000 | $3.7973 | $3,797.30 |
CP2108-B03-GM Overview
A USB-to-UART bridge is an interface IC that connects a USB host to one or more legacy serial ports. Within the product hierarchy, the CP2108 belongs to interface bridges, then USB interface controllers, interface ICs, and integrated circuits. This integration lets equipment designers add four serial channels without implementing separate USB controllers, transceivers, oscillators, and discrete serial-interface circuitry on the printed circuit board.
The verified feature set includes USB 2.0 operation, four UART data buses, full modem-control signals, 16 digital I/O pins, and EEPROM fields for custom USB identifiers and descriptors. The EEPROM can store USB Vendor ID, Product ID, product description, power descriptor, release number, and interface strings. This configurability supports product differentiation while retaining a common USB-to-serial controller design.
Silicon Labs positions the CP2108 as a plug-and-play bridge with royalty-free drivers. The four UART channels provide independent asynchronous serial connections for control, data, instrumentation, or service functions, while the digital I/O pins add discrete digital signaling. Exact UART baud-rate limits, current consumption, operating-temperature limits, pin names, and electrical timing values were not included in the supplied verified data and therefore require confirmation from the manufacturer datasheet.
Typical applications include industrial test equipment, multiport serial adapters, instrumentation, POS terminals, embedded systems, and legacy RS-232 or RS-485 equipment being modernized through USB. In each design, the host driver enumerates the bridge and exposes its four UART interfaces while the on-board controller manages the USB transaction scheduling and asynchronous byte transfer.
The main PCB consideration is that a 64-QFN footprint requires a land pattern capable of routing USB, ground, UART, modem-control, and digital-I/O signals. Place the device near the USB connector, keep high-speed USB traces short and impedance-controlled, connect decoupling close to the supply pins, and maintain the datasheet-specified ground and exposed-pad connections.
This page combines verified manufacturer and distributor data, strict package-aware substitution screening, application guidance, and practical integration notes. The alternatives list intentionally excludes single-port bridges and devices with different packages because they are not verified pin-to-pin drop-in replacements.
Drop-in alternatives for CP2108-B03-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 CP2108-B03-GM (same form factor and footprint) — differing in RoHS Status, Package, Flow Control, Integrated Functions, Internal Oscillator.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
CP2108-B03-GMR
✅ Drop-In✓ In Stock
$4.61 / Unit
View Datasheet →CP2108-B01-GMR
✅ Drop-In✓ In Stock
$4.35 / Unit
View Datasheet →CP2108-B03-GM
✅ Drop-In✓ In Stock
$3.7973 / Unit
View Datasheet →CP2108-B03-GM
✅ Drop-In✓ In Stock
$3.7973 / Unit
View Datasheet →CP2108-B03-GM
✅ Drop-In✓ In Stock
$3.7973 / Unit
View Datasheet →CP2108-B03-GM Specifications
| Product Type | USB 2.0 full-speed to quad-UART bridge controller |
| Supply Voltage | 3 V to 3.6 V |
| USB Standard | USB 2.0 full-speed |
| UART Channel Count | 4 asynchronous serial data buses |
| Digital I/O Count | 16 pins |
| Integrated Functions | USB function controller, USB transceiver, oscillator, EEPROM, and four UARTs |
| Modem Control | Full modem-control signals |
| On-Chip EEPROM | Included |
| Customizable USB Vendor ID | Supported by on-chip EEPROM |
| Customizable USB Product ID | Supported by on-chip EEPROM |
| Customizable Product Description | Supported by on-chip EEPROM |
| Package | 64-QFN, 9 mm x 9 mm |
| Package Pin Count | 64 pins |
| Mounting Type | Surface mount |
| Host Driver Support | Royalty-free drivers |
| RoHS Status | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | not_applicable |
CP2108-B03-GM 64 pins Pin Configuration Guide
Pin configuration for CP2108-B03-GM (64 pins 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 CP2108-B03-GM.
Refer to the datasheet for full pin configuration.
Typical Applications
CP2108-B03-GM is suitable for 7 applications: Industrial Multiport Serial Adapters, RS-232 and RS-485 Legacy Equipment, Test and Measurement Instruments, Industrial Control and Data Acquisition, POS and Service Terminal Connectivity, Embedded USB-to-Multiple-UART Expansion, Secure Network and Communications Equipment.
Industrial Multiport Serial Adapters
The CP2108-B03-GM fits compact adapters that must expose four asynchronous serial ports through one USB connection. Its four UART channels and full modem-control signals provide more connectivity than a single-port USB-UART bridge, while the integrated USB controller, transceiver, oscillator, and EEPROM reduce the component count. The 64-QFN package measures 9 mm by 9 mm, making it useful where four separate bridge packages would consume excessive board area. Designers should preserve USB trace geometry, place decoupling near the device, and verify each external connector’s voltage levels before connecting legacy equipment.
Recommended
RS-232 and RS-485 Legacy Equipment
The CP2108-B03-GM can serve as the USB-facing controller in equipment originally designed around multiple serial interfaces. Silicon Labs identifies USB-to-quad-UART bridging as a compact way to update RS-232 and RS-485 designs, and the four independent UARTs can serve separate command, data, status, or service channels. External level translators or RS-485 transceivers remain necessary when the legacy connector does not already match CP2108 logic levels. Validate signal direction, baud compatibility, grounding, isolation, and surge protection for each port rather than treating the USB bridge as the complete physical-layer interface.
Recommended
Test and Measurement Instruments
The CP2108-B03-GM is appropriate for instruments that combine several asynchronous control channels with digital I/O. Four UART buses can organize commands, measurement data, status, and service functions, while 16 digital I/O pins provide additional hardware signaling from the same 9 mm by 9 mm controller. Its integrated oscillator and EEPROM simplify the USB interface implementation compared with a discrete multi-chip approach. The supplied data does not establish the operating-temperature range or precision timing limits, so laboratory and production instrumentation should be qualified against the full manufacturer electrical specification before release.
Recommended
Industrial Control and Data Acquisition
The CP2108-B03-GM can connect a host computer or embedded controller to multiple external serial devices through USB. Four UART channels reduce port-expansion overhead, and full modem-control signals help systems manage request, acknowledge, and peripheral-ready functions. The 3 V to 3.6 V operating range and surface-mount 64-QFN package suit compact controller boards, but external transceivers are generally required for RS-232, RS-485, or isolated field-bus connections. Design the board around verified pin assignments and place stable decoupling and grounding provisions near the bridge.
Recommended
POS and Service Terminal Connectivity
The CP2108-B03-GM can serve terminals that need more than one legacy serial connection but want a single USB interface to the host. One UART may carry printer traffic, another may support a reader or service function, and the remaining channels can provide control or status links. The four UARTs and 16 digital I/O pins provide a broad integration surface within a 9 mm by 9 mm package. Actual commercial suitability depends on host-driver compatibility, connector electrical levels, cable support, and operating-environment requirements not specified in the supplied verified extract.
Recommended
Embedded USB-to-Multiple-UART Expansion
The CP2108-B03-GM allows an embedded USB port to access four asynchronous serial channels without allocating four independent USB bridges. Its integrated USB function controller, transceiver, oscillator, EEPROM, and UART blocks form a complete bridge subsystem, while 16 digital I/O pins add parallel control capability. This arrangement is useful in service equipment, boards with legacy connectors, and compact embedded accessories. Firmware should enumerate the interfaces consistently, and hardware should reserve a clean USB connection close to the QFN while maintaining the manufacturer-specified pin assignments and supply bypassing.
Recommended
Secure Network and Communications Equipment
The CP2108-B03-GM can provide maintenance-console connectivity in network appliances or communications equipment that already retains legacy serial interfaces. Four UART channels can support console, management, diagnostic, and service connections while the host reaches the equipment through USB. The bridge simplifies enumeration and supplies four independent serial buses, but it does not replace network interfaces or provide galvanic isolation by itself. For field-deployed equipment, use protected connectors, appropriate surge protection, verified logic-level conversion, and a complete EMC and environmental qualification plan.
Recommended
Recommended Products Summary
Engineering reference data for CP2108-B03-GM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | CP2108-B03-GMR | CP2108-B01-GMR | CP2108-B03-GM | CP2108-B03-GM | CP2108-B03-GM |
|---|---|---|---|---|---|---|
| Brand | Silicon Labs | Silicon Labs | Silicon Labs | Silicon Labs | Silicon Labs | Silicon Labs |
| Package | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) | 64-QFN (9x9) |
| Function | USB 2.0 full-speed to quad-UART bridge | USB to quad-UART bridge | CP2108 USB bridge family; detailed function value not extracted | USB to quad-UART bridge | USB to quad-UART bridge | USB to quad-UART bridge |
| UART Count | 4 | 4 | 4 | 4 | 4 | 4 |
| Digital I/O Count | 16 pins | 16 pins | 16 pins | 16 pins | 16 pins | 16 pins |
Key Differentiators
- Four serial buses in one bridge (vs CP2102-GMR)
- Integrated digital I/O (vs MCP2221)
- Full modem-control signal integration (vs FT232R)
- On-chip product customization (vs CP2102-GMR)
Design Notes
Use the manufacturer land pattern and pin table directly when laying out the 64-QFN, 9 mm by 9 mm package. Place the device near the USB connector, route USB D+ and D- as a controlled-impedance pair, avoid stubs and test pads that are not part of the final board, and place decoupling capacitance at the supply pins. The verified data does not provide exact pin numbers or capacitor values, so those details must be taken from the CP2108 datasheet rather than inferred from a generic QFN layout.
Design the 3 V to 3.6 V supply with enough local decoupling and current margin for USB attachment and simultaneous activity on all four UART channels. Place bypass capacitors as close as practical to the corresponding power and ground pins, and keep return paths short. The supplied sources do not state absolute current consumption or USB current-limit behavior, so calculate against the full electrical table in the manufacturer datasheet and include host-powered versus self-powered protection requirements.
Treat the CP2108 as a mixed USB and serial-interface component. Keep high-speed USB routing away from external RS-232 and RS-485 connector currents, provide continuous ground-plane return paths, and place level translators or protection devices near their connectors. Four UARTs and 16 digital I/O lines can create a dense 64-QFN escape route; review every pin against the official package drawing before symbol creation and PCB release.
Do not treat a CP2102, FT232R, MCP2221, or CP2103 as a drop-in CP2108 replacement merely because all provide USB connectivity. Those parts have different channel counts, packages, or pin assignments, and the supplied cross-reference data does not establish pin-to-pin compatibility. Also confirm the exact ordering-code suffix and manufacturer package orientation before purchasing or substitution, especially when comparing CP2108-B03-GM with CP2108-B03-GMR.
Compliance Information
The supplied verified snippets mention RoHS and REACH only as comparison-page subject matter, not as confirmed status for CP2108-B03-GM. Automotive qualification, lead-free status, halogen-free status, and conflict-minerals information were not explicitly provided.
