WT41U-E-AI55 Equivalent & Substitute Parts

Part Overview

The WT41U-E-AI55 is a Bluetooth v2.1 +EDR transceiver module manufactured by Silicon Labs, designed for 2.4GHz wireless communication applications. This module features a U.FL connector for external antenna integration and operates at 3.3V supply voltage with 44mA receiving current. The product is classified as Obsolete, making identification of functionally compatible alternatives essential for ongoing system support, maintenance, and new design implementations where legacy protocol support is required.

Substiute Parts

WT41U-E-AI55

Silicon LabsIn Stock: 796WT41U-E-AI55 Datasheet

Current PartRFQ

BT122-A-V2R

Silicon LabsIn Stock: 998BT122-A-V2R Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the WT41U-E-AI55 is determined by the following critical parameters:

RF Compatibility: Both the main part and substitute must operate within the 2.4GHz ISM band and support Bluetooth protocol standards.

Voltage Supply Range: The WT41U-E-AI55 operates at 3.3V. Substitute parts must accommodate this supply voltage within their specified operating range.

Serial Interface Support: The main part provides UART and USB interfaces. Substitute parts must include at least UART capability for host communication.

Mounting and Environmental Compliance: Surface mount packaging and operating temperature range of -40°C ~ 85°C are baseline requirements. RoHS compliance and MSL rating must be maintained.

Antenna Configuration: The U.FL connector allows external antenna attachment. Substitutes with integrated antenna solutions represent a functional alternative for applications where external antenna flexibility is not required.

The BT122-A-V2R qualifies as a substitute based on these parameters: it operates in the 2.4GHz band, supports a compatible voltage supply range (2.2V ~ 3.6V encompasses 3.3V), includes UART interface, maintains surface mount packaging, operates across the required temperature range, is RoHS compliant, and carries the same MSL rating.

Parameter Comparison

Engineering Selection Recommendations

The BT122-A-V2R is an active product from the same manufacturer, providing continuity of supply and technical support compared to the obsolete WT41U-E-AI55. Both parts maintain RoHS compliance and identical MSL ratings, ensuring equivalent handling and storage requirements.

The BT122-A-V2R operates across a wider voltage supply range (2.2V ~ 3.6V), providing greater design flexibility while remaining compatible with 3.3V systems. The integrated trace antenna eliminates the need for external antenna components and associated U.FL connectors, reducing board space and assembly complexity. The substitute part expands serial interface options with ADC, GPIO, and I2C capabilities while retaining UART functionality.

Power output differs between the two parts (17dBm versus 11dBm). Applications requiring maximum transmit power from the WT41U-E-AI55 must evaluate whether the reduced output of the BT122-A-V2R meets link budget requirements. Sensitivity specifications are comparable, with the BT122-A-V2R providing marginally improved receive performance (-95dBm versus -94dBm).

Both parts are certified to the same ECCN and HTSUS classifications, maintaining regulatory equivalence for export and trade purposes.

Frequently Asked Questions (FAQ)

Q: Can the BT122-A-V2R directly replace the WT41U-E-AI55 in existing designs?

A: Direct replacement requires evaluation of three factors: (1) antenna configuration—the WT41U-E-AI55 uses an external U.FL connector while the BT122-A-V2R has an integrated trace antenna, necessitating PCB layout modifications; (2) transmit power requirements—the BT122-A-V2R outputs 11dBm compared to 17dBm; (3) interface requirements—the BT122-A-V2R provides additional GPIO, I2C, and ADC interfaces not present in the original part. Firmware and host communication protocols must be verified for compatibility.

Q: What are the key differences in antenna implementation?

A: The WT41U-E-AI55 requires an external antenna connected via U.FL connector, allowing antenna selection and optimization for specific applications. The BT122-A-V2R uses an integrated trace antenna on the module PCB, eliminating external antenna components and reducing assembly steps. Integrated antenna performance is fixed and cannot be modified post-manufacture.

Q: Are both parts suitable for the same operating temperature range?

A: Yes. Both the WT41U-E-AI55 and BT122-A-V2R operate across -40°C to 85°C, meeting identical environmental specifications for industrial and commercial applications.

Q: What is the significance of the voltage supply range difference?

A: The WT41U-E-AI55 operates at a fixed 3.3V supply. The BT122-A-V2R accepts 2.2V to 3.6V, providing design flexibility for systems with variable supply voltages or lower-power battery applications. Both parts function correctly at 3.3V, ensuring compatibility with existing power distribution networks.

Q: How do the Bluetooth protocol versions affect substitution?

A: The WT41U-E-AI55 implements Bluetooth v2.1 +EDR, while the BT122-A-V2R supports Bluetooth v4.2 +EDR. Bluetooth v4.2 is backward compatible with v2.1 +EDR for legacy device communication. However, host firmware and application software must be evaluated to confirm support for the newer protocol version and any enhanced features utilized by the substitute part.

Q: Are packaging and handling requirements identical?

A: Both parts carry MSL rating 3 (168 hours), requiring identical moisture control and storage conditions. The WT41U-E-AI55 is packaged as a generic Module, while the BT122-A-V2R is specified as a 20-SMD Module. Both are surface mount components suitable for automated assembly processes.

Q: What certifications apply to both parts?

A: Both the WT41U-E-AI55 and BT122-A-V2R are RoHS compliant and carry identical ECCN (5A992C) and HTSUS (8517.62.0090) classifications, ensuring regulatory equivalence for procurement, export, and trade compliance.