RN42NHCI-I/RM Equivalent & Substitute Parts

Part Overview

The RN42NHCI-I/RM 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 U.FL connector for external antenna integration and operates across a supply voltage range of 3V to 3.6V. The product is currently classified as obsolete, making identification of functionally compatible alternatives essential for ongoing system support, maintenance, and new design considerations where legacy specifications remain acceptable.

Substiute Parts

RN42NHCI-I/RM

Microchip TechnologyIn Stock: 758RN42NHCI-I/RM Datasheet

Current PartRFQ

RN4678-V/RM122

Microchip TechnologyIn Stock: 1149RN4678-V/RM122 Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the RN42NHCI-I/RM is determined by compatibility across the following critical parameters:

• RF Family and Protocol: Both the main part and substitute must operate within the Bluetooth standard family
• Frequency Band: 2.4GHz operation is mandatory for interoperability
• Serial Interface: UART connectivity must be maintained for system integration
• Mounting Type: Surface mount compatibility ensures PCB assembly compatibility
• Supply Voltage Range: Operating voltage must overlap or be compatible with existing power delivery systems
• Package Classification: Module-level form factor for direct replacement capability
• Compliance Standards: RoHS3 compliance ensures regulatory alignment

The RN4678-V/RM122 qualifies as a substitute based on these parameters, representing an evolution within the Microchip Bluetooth module family while maintaining core interface and operational characteristics.

Parameter Comparison

Engineering Selection Recommendations

The RN4678-V/RM122 is the manufacturer-recommended substitute for the obsolete RN42NHCI-I/RM. Both components maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory continuity. The substitute operates within the same 2.4GHz frequency band and maintains UART serial interface compatibility, supporting direct functional replacement in most applications.

Key considerations for selection:

• The RN4678-V/RM122 operates on Bluetooth v5.0 protocol, providing enhanced data rate capability (1Mbps versus 300kbps) and improved receiver sensitivity (-92dBm versus -80dBm)
• The substitute features an integrated antenna design, eliminating the external U.FL connector requirement of the main part
• Supply voltage range differs: the substitute requires 3.3V to 4.2V versus the main part's 3V to 3.6V range
• Operating temperature range is narrower on the substitute (-20°C to 70°C versus -40°C to 85°C)
• The substitute exhibits higher transmit current consumption (43mA versus 30mA)
• Moisture sensitivity is improved on the substitute (MSL 1 versus MSL 3)

Selection of the RN4678-V/RM122 is appropriate for applications where the active product status, enhanced performance characteristics, and improved reliability metrics align with system requirements.

Frequently Asked Questions (FAQ)

Q: Can the RN4678-V/RM122 directly replace the RN42NHCI-I/RM in existing designs?

A: Direct physical replacement is possible due to surface mount compatibility and module form factor alignment. However, design verification is necessary to confirm compatibility with supply voltage ranges, operating temperature requirements, and antenna integration approach. The substitute's integrated antenna eliminates the need for external U.FL connector management.

Q: What are the primary differences in wireless performance between these modules?

A: The RN4678-V/RM122 operates on Bluetooth v5.0 with 1Mbps data rate capability compared to the RN42NHCI-I/RM's Bluetooth v2.1 +EDR at 300kbps. The substitute provides superior receiver sensitivity (-92dBm versus -80dBm), enabling improved link budget performance in range-limited applications.

Q: Are there supply voltage compatibility concerns?

A: The RN42NHCI-I/RM operates from 3V to 3.6V, while the RN4678-V/RM122 requires 3.3V to 4.2V. Systems designed for the lower voltage range of the main part may require power supply adjustment to accommodate the substitute's minimum 3.3V requirement.

Q: How do operating temperature ranges compare?

A: The RN42NHCI-I/RM supports -40°C to 85°C operation, while the RN4678-V/RM122 operates from -20°C to 70°C. Applications requiring extended low-temperature operation below -20°C must retain the original part or identify alternative solutions.

Q: What is the impact of antenna configuration differences?

A: The RN42NHCI-I/RM uses an external U.FL connector for antenna attachment, providing flexibility in antenna selection. The RN4678-V/RM122 integrates the antenna on the chip, simplifying PCB layout and eliminating external connector requirements but reducing antenna customization options.

Q: Are both components RoHS3 compliant?

A: Yes, both the RN42NHCI-I/RM and RN4678-V/RM122 are ROHS3 compliant and REACH unaffected, ensuring regulatory alignment for applications subject to these standards.

Q: What is the significance of the MSL rating difference?

A: The RN42NHCI-I/RM carries MSL 3 (168 hours), while the RN4678-V/RM122 carries MSL 1 (unlimited). The substitute offers superior moisture resistance, reducing handling and storage constraints during manufacturing and assembly processes.