RN42-I/RMCOS477 Equivalent & Substitute Parts

Part Overview

The RN42-I/RMCOS477 is a Bluetooth v2.1 + EDR Class 2 transceiver module manufactured by Microchip Technology, designed for 2.4GHz wireless communication applications. This module features a PCB trace antenna and surface mount packaging in a 35-SMD form factor. The product is classified as obsolete, necessitating identification of active equivalent components for new designs and ongoing production requirements.

Substiute Parts

RN42-I/RMCOS477

Microchip TechnologyIn Stock: 944RN42-I/RMCOS477 Datasheet

Current PartRFQ

RN4678-V/RM122

Microchip TechnologyIn Stock: 1149RN4678-V/RM122 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RN42-I/RMCOS477 is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• RF Family/Standard: Bluetooth technology
• Frequency Band: 2.4GHz operation
• Mounting Type: Surface Mount configuration
• Manufacturer: Microchip Technology

Functional Compatibility Factors:

• Serial Interface capability (UART minimum requirement)
• Voltage supply range overlap or compatibility
• Operating temperature range suitability for application
• Package form factor compatibility with PCB layout

The RN4678-V/RM122 qualifies as a substitute based on shared RF family, frequency band, surface mount technology, and manufacturer origin. Both components operate in the 2.4GHz Bluetooth spectrum and utilize surface mount assembly methods compatible with modern manufacturing processes.

Parameter Comparison

Engineering Selection Recommendations

Product Status Consideration: The RN42-I/RMCOS477 carries obsolete status, indicating discontinued manufacturing and limited long-term availability. The RN4678-V/RM122 maintains active product status with current manufacturing support from Microchip Technology.

Compliance and Certification: The RN4678-V/RM122 provides ROHS3 compliance and REACH unaffected status, meeting current environmental and regulatory requirements for electronic components. The substitute part carries ECCN classification 5A992C and HTSUS code 8529.90.2100.

Design Integration Factors: Selection between these components depends on application-specific requirements regarding data rate, power output, temperature range, and serial interface needs. The RN4678-V/RM122 supports Bluetooth v5.0 protocol with improved sensitivity (-92dBm versus -86dBm), while the original RN42-I/RMCOS477 provides higher data rate capability (3Mbps versus 1Mbps) and dual serial interface support (SPI and UART).

Frequently Asked Questions (FAQ)

Q: Can the RN4678-V/RM122 directly replace the RN42-I/RMCOS477 in existing designs?

A: Direct replacement requires design review. Both components share 2.4GHz Bluetooth operation and surface mount technology. However, differences exist in protocol version (v5.0 versus v2.1 + EDR), data rate (1Mbps versus 3Mbps), serial interfaces (UART only versus SPI and UART), antenna implementation (integrated chip versus PCB trace), and package form factor (33-SMD versus 35-SMD). PCB layout modifications may be necessary.

Q: What are the voltage supply compatibility considerations?

A: The RN42-I/RMCOS477 operates at 3V to 3.6V, while the RN4678-V/RM122 requires 3.3V to 4.2V. The overlap range is 3.3V to 3.6V. Applications operating at the lower end of the original specification (3.0V to 3.3V) require voltage regulation adjustment for the substitute component.

Q: How do the antenna implementations differ between these modules?

A: The RN42-I/RMCOS477 uses a PCB trace antenna requiring external antenna design integration on the host PCB. The RN4678-V/RM122 features an integrated chip antenna, eliminating external antenna design requirements and reducing PCB layout complexity.

Q: What is the impact of the operating temperature range difference?

A: The RN42-I/RMCOS477 operates from -40°C to 85°C, while the RN4678-V/RM122 operates from -20°C to 70°C. Applications requiring operation below -20°C or above 70°C cannot use the substitute component.

Q: Are there serial interface compatibility issues?

A: The RN42-I/RMCOS477 supports both SPI and UART interfaces. The RN4678-V/RM122 supports UART only. Designs utilizing SPI communication require firmware and hardware modifications to operate with the substitute component.

Q: What packaging considerations apply to substitution?

A: The RN42-I/RMCOS477 uses 35-SMD packaging while the RN4678-V/RM122 uses 33-SMD packaging. PCB footprint redesign is required for component substitution. Pin configuration and signal routing must be verified against manufacturer datasheets.