FODM121AR4 Equivalent & Substitute Parts

Part Overview

The FODM121AR4 is a single-channel optoisolator with transistor output manufactured by onsemi, designed for high-voltage isolation applications requiring 3750Vrms isolation rating. This component integrates a light-emitting diode (LED) input stage with a phototransistor output stage in a 4-SMD surface mount package. The part is currently in Last Time Buy status, indicating discontinued production with limited remaining inventory (1073 pcs). Finding equivalent substitute parts is necessary to ensure design continuity and long-term component availability for new production runs and system maintenance.

Substiute Parts

FODM121AR4

onsemiIn Stock: 1094FODM121AR4 Datasheet

Current PartRFQ

FODM121AR2

onsemiIn Stock: 29397FODM121AR2 Datasheet

Parametric EquivalentRFQ

FODM121AR2V

onsemiIn Stock: 37605FODM121AR2V Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the FODM121AR4 are determined by strict equivalence across the following critical parameters:

• Isolation Voltage: 3750Vrms (mandatory match)
• Number of Channels: 1 (mandatory match)
• Output Type: Transistor (mandatory match)
• Current Transfer Ratio Range: 100% - 300% @ 5mA (mandatory match)
• Maximum Output Voltage: 80V (mandatory match)
• Maximum Output Current: 80mA per channel (mandatory match)
• Rise / Fall Time: 3µs, 3µs (mandatory match)
• Operating Temperature Range: -40°C ~ 110°C (mandatory match)
• Package Type: 4-SMD, Gull Wing (mandatory match)
• Compliance: ROHS3 Compliant, MSL 1 (mandatory match)

The substitute parts FODM121AR2 and FODM121AR2V meet all electrical and mechanical parameters identically to the FODM121AR4. The primary differences are packaging format (Tape & Reel vs. Cut Tape & Digi-Reel) and product status (Active vs. Last Time Buy), which do not affect functional equivalence in circuit applications.

Parameter Comparison

Engineering Selection Recommendations

Both FODM121AR2 and FODM121AR2V are direct functional equivalents to the FODM121AR4 for circuit-level applications. Selection between these substitutes should be based on the following factors:

FODM121AR2: Recommended for applications requiring standard Tape & Reel packaging. This part maintains identical packaging format to the FODM121AR4 and carries Active product status, ensuring long-term availability and supply chain stability. Inventory levels (29294 pcs) support sustained production requirements.

FODM121AR2V: Recommended for applications compatible with Cut Tape and Digi-Reel packaging formats. This variant offers the highest inventory availability (37574 pcs) and Active product status. The alternative packaging format does not affect electrical performance or PCB footprint compatibility, only handling and tape configuration during assembly.

Both substitutes maintain full ROHS3 compliance and REACH unaffected status, meeting regulatory requirements equivalent to the original part. The transition from Last Time Buy (FODM121AR4) to Active status parts ensures design longevity and eliminates obsolescence risk.

Frequently Asked Questions (FAQ)

Q: Can FODM121AR2 and FODM121AR2V be used interchangeably with FODM121AR4 in existing designs?

A: Yes. All three parts are electrically and mechanically identical across all specified parameters. PCB footprint, pin configuration, and electrical performance are identical. The only differences are packaging format and product lifecycle status.

Q: What is the difference between Tape & Reel (TR) and Cut Tape (CT) & Digi-Reel packaging?

A: Tape & Reel is a continuous reel format suitable for high-volume automated assembly. Cut Tape is pre-cut tape supplied on a reel, offering flexibility for lower-volume or mixed-component orders. Digi-Reel is a proprietary packaging format. Both formats contain the same component with identical electrical specifications and PCB mounting characteristics.

Q: Why is FODM121AR4 listed as Last Time Buy?

A: Last Time Buy status indicates onsemi has discontinued production of this specific part number variant. Existing inventory is available but will not be replenished. FODM121AR2 and FODM121AR2V are Active equivalents and should be used for new designs and future production.

Q: Are there any thermal or reliability differences between these three part numbers?

A: No. All three parts share identical operating temperature ranges (-40°C ~ 110°C), thermal characteristics, and reliability specifications. Moisture Sensitivity Level (MSL 1) is identical across all variants.

Q: What compliance certifications apply to these substitute parts?

A: All three parts are ROHS3 compliant and REACH unaffected. Regulatory compliance is identical across FODM121AR4, FODM121AR2, and FODM121AR2V.

Q: Which substitute part should be selected for new production designs?

A: FODM121AR2 is recommended for new designs requiring standard Tape & Reel packaging. FODM121AR2V is an alternative if Cut Tape & Digi-Reel packaging is compatible with assembly processes. Both parts carry Active status and ensure long-term supply availability.