HMHA281R4V Optoisolator Equivalent & Substitute Parts

Part Overview

The HMHA281R4V is a 3750Vrms optoisolator with transistor output manufactured by onsemi. This component provides galvanic isolation for single-channel DC input applications with a maximum output current of 50mA per channel. The part is currently listed as obsolete, making identification of active equivalent models essential for design continuity and procurement planning. Substitute parts maintain identical electrical and mechanical specifications while offering improved availability through active product status.

Key Parameters

Parameter	Value
Voltage - Isolation	3750Vrms
Number of Channels	1
Current Transfer Ratio (Min)	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA
Output Type	Transistor
Voltage - Output (Max)	80V
Current - Output / Channel	50mA
Rise / Fall Time (Typ)	3µs, 3µs
Vce Saturation (Max)	400mV
Operating Temperature	-55°C ~ 100°C
Package / Case	4-SOIC (0.173", 4.40mm Width)
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the HMHA281R4V is determined by strict equivalence across all critical electrical and mechanical parameters. The following parameters define valid substitutes:

Voltage - Isolation: 3750Vrms (mandatory match)
Number of Channels: 1 (mandatory match)
Current Transfer Ratio range: 50% to 600% @ 5mA (mandatory match)
Output Type: Transistor (mandatory match)
Voltage - Output (Max): 80V (mandatory match)
Current - Output / Channel: 50mA (mandatory match)
Package / Case: 4-SOIC (0.173", 4.40mm Width) (mandatory match)
Operating Temperature: -55°C ~ 100°C (mandatory match)

All identified substitute parts meet these criteria. Packaging format (Tape & Reel vs. bulk) does not affect electrical or mechanical compatibility and represents a procurement variable only.

Parameter Comparison

Parameter	HMHA281R4V	HMHA281R2	HMHA281R2V	HMHA281R4
Manufacturer	onsemi	onsemi	onsemi	onsemi
Product Status	Obsolete	Active	Active	Active
Number of Channels	1	1	1	1
Voltage - Isolation	3750Vrms	3750Vrms	3750Vrms	3750Vrms
Current Transfer Ratio (Min)	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA
Output Type	Transistor	Transistor	Transistor	Transistor
Voltage - Output (Max)	80V	80V	80V	80V
Current - Output / Channel	50mA	50mA	50mA	50mA
Rise / Fall Time (Typ)	3µs, 3µs	3µs, 3µs	3µs, 3µs	3µs, 3µs
Vce Saturation (Max)	400mV	400mV	400mV	400mV
Operating Temperature	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C
Package / Case	4-SOIC (0.173", 4.40mm Width)	4-SOIC (0.173", 4.40mm Width)	4-SOIC (0.173", 4.40mm Width)	4-SOIC (0.173", 4.40mm Width)
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

The HMHA281R4V is obsolete and should be replaced with an active equivalent. All three substitute parts—HMHA281R2, HMHA281R2V, and HMHA281R4—are electrically and mechanically identical to the original part and maintain active product status with onsemi.

Selection between substitutes should be based on procurement requirements:

HMHA281R2 and HMHA281R2V are supplied in Tape & Reel (TR) packaging, suitable for automated assembly processes with higher inventory availability (18,100 and 19,100 units respectively).
HMHA281R4 is available in bulk packaging with lower inventory (829 units).

All substitute parts carry ROHS3 compliance, MSL Level 1 (unlimited moisture sensitivity), and REACH Unaffected status, matching the regulatory profile of the original component. Direct pin-for-pin and functional replacement is supported without design modification.

Frequently Asked Questions (FAQ)

Q: Can HMHA281R2, HMHA281R2V, and HMHA281R4 be used interchangeably with HMHA281R4V?

A: Yes. All three parts are parametric equivalents with identical electrical specifications, isolation voltage, output current rating, operating temperature range, and 4-SOIC package dimensions. Direct substitution is supported without circuit modification.

Q: What is the difference between HMHA281R2 and HMHA281R2V?

A: Both parts are electrically identical. The primary difference is packaging format: HMHA281R2 and HMHA281R2V are supplied in Tape & Reel (TR) format for automated assembly, while HMHA281R4V was supplied in bulk packaging. The "V" designation does not indicate a functional difference.

Q: Why is HMHA281R4V listed as obsolete?

A: Product obsolescence is a manufacturer lifecycle decision. Active equivalents with identical specifications are available from onsemi, ensuring design continuity without performance impact.

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

A: No. All parts maintain identical RoHS3 compliance, MSL Level 1 rating, and REACH Unaffected status. Regulatory and environmental compliance profiles are equivalent.

Q: What packaging considerations apply when selecting a substitute?

A: HMHA281R2 and HMHA281R2V are supplied in Tape & Reel format, optimized for pick-and-place assembly. HMHA281R4 is available in bulk format. Selection should align with your assembly process requirements. All parts use the same 4-SOIC (0.173", 4.40mm Width) package footprint.

Q: Can I mix substitute parts in the same production run?

A: Yes. All substitute parts are functionally and mechanically identical, supporting mixed sourcing strategies for supply chain flexibility.

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