RPM871-E4 Equivalent & Substitute Parts

Part Overview

The RPM871-E4 is a 115.2 kbps (SIR) IrDA transceiver module manufactured by Rohm Semiconductor in an 8-pin surface mount package. This component is classified as obsolete, indicating discontinued production and limited availability. The module operates across a 2.6 V to 3.6 V supply range with typical idle current of 73 µA and supports IrDA 1.2 standards with a low-power link range of 20 cm to 60 cm. Due to its obsolete status, identifying functionally equivalent active alternatives is essential for new designs and ongoing system support.

Key Parameters

Parameter	RPM871-E4
Data Rate	115.2 kbps (SIR)
Voltage Supply Range	2.6 V – 3.6 V
Idle Current (Typ @ 25°C)	73 µA
Link Range (Low Power)	20 cm – 60 cm
Operating Temperature	–20°C – 85°C
Package Size	7.60 mm × 2.72 mm × 2.00 mm
Orientation	Top View
Standards Compliance	IrDA 1.2
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level	3 (168 Hours)

Substitute Part Grouping Explanation

The TFDU4301-TT1 manufactured by Vishay Semiconductor Opto Division qualifies as a functional substitute for the RPM871-E4 based on the following critical parameters:

Data Rate Compatibility: Both components support 115.2 kbps (SIR) IrDA transceiver operation, ensuring protocol-level compatibility.
Supply Voltage: The TFDU4301-TT1 operates across 2.4 V to 5.5 V, which encompasses the RPM871-E4 operating range of 2.6 V to 3.6 V.
Standards Alignment: The TFDU4301-TT1 complies with IrPHY 1.0, which is compatible with IrDA 1.2 protocol requirements.
Package Configuration: Both components are 8-pin surface mount devices with top-view orientation, supporting equivalent PCB layout integration.
Regulatory Compliance: Both parts maintain ROHS3 compliance and REACH unaffected status, meeting current environmental standards.

Parameter Comparison

Parameter	RPM871-E4	TFDU4301-TT1	Notes
Data Rate	115.2 kbps (SIR)	115.2 kbps (SIR)	Identical
Voltage Supply Range	2.6 V – 3.6 V	2.4 V – 5.5 V	TFDU4301-TT1 range is broader; RPM871-E4 range is fully contained
Idle Current (Typ @ 25°C)	73 µA	100 µA	TFDU4301-TT1 draws 27 µA higher; acceptable for most applications
Link Range (Low Power)	20 cm – 60 cm	70 cm	TFDU4301-TT1 provides extended range
Operating Temperature	–20°C – 85°C	–30°C – 85°C	TFDU4301-TT1 supports lower minimum temperature
Orientation	Top View	Top View	Identical
Standards Compliance	IrDA 1.2	IrPHY 1.0	Compatible protocol versions
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Identical
Product Status	Obsolete	Active	TFDU4301-TT1 is actively manufactured
Shutdown Function	Not specified	Yes	TFDU4301-TT1 includes power management feature

Engineering Selection Recommendations

The TFDU4301-TT1 is the designated substitute for the obsolete RPM871-E4 based on functional equivalence and regulatory compliance. Selection criteria are as follows:

Product Availability: The TFDU4301-TT1 maintains active production status with 15,899 units in stock, whereas the RPM871-E4 is obsolete with limited remaining inventory (1,076 units).
Regulatory Alignment: Both components satisfy ROHS3 compliance and REACH unaffected requirements, ensuring compatibility with current environmental regulations.
Electrical Performance: The TFDU4301-TT1 operates within the RPM871-E4 supply voltage range and maintains protocol compatibility at 115.2 kbps (SIR) data rates.
Packaging Compatibility: Both components use 8-pin surface mount configuration with top-view orientation, permitting direct PCB layout substitution without redesign.
Enhanced Capabilities: The TFDU4301-TT1 provides extended operating temperature range (–30°C minimum versus –20°C), increased link range (70 cm versus 60 cm maximum), and integrated shutdown functionality.

Frequently Asked Questions (FAQ)

Q: Can the TFDU4301-TT1 directly replace the RPM871-E4 on existing PCBs?

A: Yes. Both components are 8-pin surface mount devices with identical top-view orientation and compatible pinout configuration. PCB layout modification is not required for substitution.

Q: What is the impact of the 27 µA higher idle current in the TFDU4301-TT1?

A: The TFDU4301-TT1 draws 100 µA typical idle current compared to 73 µA for the RPM871-E4. This 37% increase is acceptable for most applications unless the design operates under extreme power-constrained conditions. The TFDU4301-TT1 includes a shutdown function to mitigate idle power consumption when needed.

Q: Are the IrDA 1.2 and IrPHY 1.0 standards compatible?

A: Yes. IrPHY 1.0 is the physical layer specification that supports IrDA 1.2 protocol requirements. The TFDU4301-TT1 maintains full compatibility with systems designed for IrDA 1.2 operation.

Q: What packaging options are available for the TFDU4301-TT1?

A: The TFDU4301-TT1 is supplied in Cut Tape (CT) and Digi-Reel® packaging formats, supporting both manual assembly and automated reel-fed production processes.

Q: Does the extended operating temperature range of the TFDU4301-TT1 affect system design?

A: The TFDU4301-TT1 supports operation from –30°C to 85°C, compared to –20°C to 85°C for the RPM871-E4. This extended lower temperature limit provides additional design margin for applications operating in cold environments without requiring system modifications.

Q: What is the significance of the shutdown function in the TFDU4301-TT1?

A: The integrated shutdown function enables active power management, allowing the component to enter a low-power state when not in use. This feature is not specified for the RPM871-E4 and provides additional flexibility for battery-powered or energy-constrained applications.

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