FODM121GR4 Equivalent & Substitute Parts

Part Overview

The FODM121GR4 is an optoisolator with phototransistor output manufactured by onsemi. This component provides galvanic isolation with a 3750Vrms isolation voltage rating and is designed for single-channel DC input applications requiring transistor output switching. The part is actively produced and widely stocked, with 2964 units available in inventory. Alternative part numbers within the same product family are available to support supply chain flexibility and design requirements.

Substiute Parts

FODM121GR4

onsemiIn Stock: 3027FODM121GR4 Datasheet

Current PartRFQ

FODM121R2

onsemiIn Stock: 7614FODM121R2 Datasheet

Parametric EquivalentRFQ

FODM121R2V

onsemiIn Stock: 23407FODM121R2V Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FODM121GR4 are qualified based on matching the following critical electrical and mechanical parameters:

• Voltage - Isolation: 3750Vrms
• Number of Channels: 1
• Current Transfer Ratio range: 50% to 600% @ 5mA
• Rise / Fall Time: 3µs, 3µs
• Input Type: DC
• Output Type: Transistor
• Voltage - Output (Max): 80V
• Current - Output / Channel: 80mA
• Vce Saturation (Max): 400mV
• Operating Temperature: -40°C ~ 110°C
• Package / Case: 4-SMD, Gull Wing
• Mounting Type: Surface Mount

The substitute parts FODM121R2 and FODM121R2V are members of the same FODM121 base product family and maintain identical electrical specifications and mechanical compatibility with the FODM121GR4.

Parameter Comparison

Engineering Selection Recommendations

All three parts—FODM121GR4, FODM121R2, and FODM121R2V—are active products manufactured by onsemi with identical electrical and mechanical specifications. Each part is ROHS3 compliant and carries MSL Level 1 (Unlimited) moisture sensitivity rating, indicating equivalent environmental handling requirements.

Selection between these parts is based on inventory availability and supply chain considerations rather than technical performance differences. The FODM121R2V variant offers the highest inventory level at 23,300 units, followed by FODM121R2 at 7,600 units, and FODM121GR4 at 2,964 units. All three parts are suitable for direct substitution in applications requiring single-channel optoisolation with 3750Vrms isolation voltage and transistor output switching.

Frequently Asked Questions (FAQ)

Q: Can FODM121R2 and FODM121R2V be used interchangeably with FODM121GR4?

A: Yes. All three parts share identical electrical specifications, isolation voltage rating, current transfer ratio range, output switching characteristics, and 4-SMD Gull Wing package configuration. They are direct substitutes within the FODM121 product family.

Q: What determines substitution eligibility for optoisolator parts?

A: Substitution is determined by matching isolation voltage rating, number of channels, current transfer ratio specifications, rise and fall time characteristics, maximum output voltage and current ratings, saturation voltage, operating temperature range, and physical package type. All these parameters are identical across the three parts.

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

A: No. All three parts carry identical RoHS3 compliance status, REACH Unaffected designation, and MSL Level 1 moisture sensitivity rating. They meet the same environmental and regulatory requirements.

Q: Which part should be selected for new designs?

A: Selection should be based on current inventory availability and supply chain lead times. From a technical standpoint, all three parts are equivalent and suitable for new designs requiring single-channel 3750Vrms optoisolation with transistor output.

Q: Are package dimensions identical across all three parts?

A: Yes. All three parts use the 4-SMD Gull Wing surface mount package configuration with identical mechanical specifications, ensuring compatibility with the same PCB footprint and assembly process.