EM3585-IRT Equivalent & Substitute Parts Reference

Part Overview

The EM3585-IRT is a Silicon Labs RF transceiver IC designed for 2.4GHz wireless applications including 802.15.4, Bluetooth, WiFi 802.11g, and Zigbee® protocols. This device operates as a TxRx Only module without integrated microcontroller functionality. The EM3585-IRT is classified as Obsolete, making identification of functionally compatible substitute components necessary for ongoing design support, legacy system maintenance, and production continuity.

Substiute Parts

EM3585-IRT

Silicon LabsIn Stock: 1191EM3585-IRT Datasheet

Current PartRFQ

EFR32MG24A010F1024IM48-B

Silicon LabsIn Stock: 685EFR32MG24A010F1024IM48-B Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the EM3585-IRT requires evaluation based on the following critical parameters:

Frequency Compatibility: The substitute must operate within the 2.4GHz band to maintain RF performance in existing circuit designs.

Package Compatibility: Both the EM3585-IRT and substitute utilize 48-VFQFN Exposed Pad surface mount packages, ensuring mechanical and thermal compatibility on PCB layouts.

Serial Interface Support: The EM3585-IRT implements I2C, SPI, UART, and USB interfaces. Substitute parts must support equivalent communication protocols for host microcontroller integration.

Supply Voltage Range: The EM3585-IRT operates across dual voltage ranges (1.18V ~ 1.32V and 1.7V ~ 1.9V). Substitute components must accommodate existing power supply designs.

RF Performance Metrics: Sensitivity (-100dBm), output power (8dBm), and modulation scheme (O-QPSK) define receiver and transmitter performance. Substitutes must meet or exceed these specifications.

Architectural Difference: The EM3585-IRT is a TxRx Only device without integrated MCU. Substitutes may include integrated microcontroller functionality, provided they maintain backward compatibility through equivalent interface definitions and pin assignments.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The EM3585-IRT is classified as Obsolete. The EFR32MG24A010F1024IM48-B is classified as Active, ensuring ongoing manufacturer support, availability, and compliance updates.

Compliance and Certification: The EFR32MG24A010F1024IM48-B carries ROHS3 compliance and MSL Level 2 rating, meeting current environmental and reliability standards. These certifications support long-term production and regulatory requirements.

Architectural Integration: The EFR32MG24A010F1024IM48-B integrates both RF transceiver and microcontroller functionality within a single package. This consolidation reduces component count and PCB area compared to discrete TxRx + external MCU configurations. Designs currently using the EM3585-IRT with external microcontroller may benefit from this integration.

Power Efficiency: The EFR32MG24A010F1024IM48-B demonstrates significantly lower current consumption during receive (4.4mA ~ 5.1mA vs. 28mA) and transmit (5mA ~ 19.1mA vs. 33.5mA) operations, resulting in extended battery life for portable applications.

Supply Voltage Flexibility: The EFR32MG24A010F1024IM48-B supports a wider supply voltage range (1.71V ~ 3.8V), accommodating both low-voltage and standard 3.3V system designs without additional regulation.

Package Dimensions: Both devices use 48-VFQFN packages with exposed pads. The EM3585-IRT uses a 7x7mm footprint while the EFR32MG24A010F1024IM48-B uses a 6x6mm footprint. PCB layout modifications may be required to accommodate the smaller package size.

Frequently Asked Questions (FAQ)

Q: Can the EFR32MG24A010F1024IM48-B directly replace the EM3585-IRT in existing designs?

A: Direct pin-for-pin replacement is not guaranteed due to architectural differences (TxRx Only vs. TxRx + MCU) and package footprint variations (7x7mm vs. 6x6mm). Schematic review and PCB layout modification are required. Serial interface compatibility (I2C, SPI, UART) supports functional substitution with appropriate firmware adaptation.

Q: What are the key differences in RF performance between these devices?

A: The EM3585-IRT provides higher sensitivity (-100dBm vs. -94.8dBm) and higher maximum data rate (5Mbps vs. 2Mbps). The EFR32MG24A010F1024IM48-B offers higher output power (10dBm vs. 8dBm) and broader modulation support. Protocol selection and link budget analysis determine which performance profile suits specific applications.

Q: Does the EFR32MG24A010F1024IM48-B support the same wireless protocols as the EM3585-IRT?

A: The EFR32MG24A010F1024IM48-B supports Bluetooth v5.3 with O-QPSK modulation compatibility. The EM3585-IRT supports 802.15.4, Bluetooth, WiFi 802.11g, and Zigbee® protocols. Protocol compatibility must be verified against specific application requirements and firmware implementation.

Q: What are the implications of the package footprint difference?

A: The EFR32MG24A010F1024IM48-B uses a smaller 6x6mm footprint compared to the EM3585-IRT's 7x7mm footprint. Both maintain 48-pin VFQFN configuration with exposed thermal pads. PCB layout redesign is necessary to accommodate the smaller package dimensions and maintain thermal management effectiveness.

Q: How does the integrated MCU in the EFR32MG24A010F1024IM48-B affect system design?

A: The integrated microcontroller eliminates the need for external MCU in applications where the EM3585-IRT was paired with a separate processor. This reduces component count, PCB area, and power consumption. Designs must accommodate the EFR32MG24A010F1024IM48-B's MCU capabilities and peripheral set, which differ from the EM3585-IRT's TxRx-only architecture.

Q: What supply voltage considerations apply when substituting these devices?

A: The EM3585-IRT operates across 1.18V ~ 1.32V and 1.7V ~ 1.9V ranges. The EFR32MG24A010F1024IM48-B operates across 1.71V ~ 3.8V. Existing power supply designs must be evaluated to ensure compatibility with the substitute device's voltage requirements. The wider range of the EFR32MG24A010F1024IM48-B may eliminate the need for dual-voltage regulation.

Q: Are there compliance or certification differences between these parts?

A: The EFR32MG24A010F1024IM48-B carries ROHS3 compliance and MSL Level 2 certification. The EM3585-IRT specifications do not include these certifications. For applications requiring environmental compliance or moisture sensitivity control, the EFR32MG24A010F1024IM48-B meets current standards.