HMHA281R2_F132 Optoisolator Equivalent & Substitute Parts

Part Overview

The HMHA281R2_F132 is a 3750Vrms optoisolator with transistor output, manufactured by onsemi in a 4-SOIC package. This part is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The device provides galvanic isolation for DC input signals with a single transistor output channel, suitable for applications requiring high voltage isolation in compact surface mount form factors.

Key Parameters

Parameter	Value
Voltage - Isolation	3750Vrms
Number of Channels	1
Output Type	Transistor
Current Transfer Ratio (Min)	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA
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

Substitute Part Grouping Explanation

Substitution for the HMHA281R2_F132 is determined by the following critical parameters:

Voltage - Isolation: 3750Vrms (mandatory match)
Number of Channels: 1 (mandatory match)
Output Type: Transistor (mandatory match)
Current Transfer Ratio range: 50% to 600% @ 5mA (mandatory match)
Voltage - Output (Max): 80V (mandatory match)
Vce Saturation (Max): 400mV (mandatory match)
Input Type: DC (mandatory match)

Substitute parts are grouped into two categories:

Parametric Equivalents (Same Package): Parts maintaining identical electrical specifications and 4-SOIC package form factor. These are direct replacements with no design modifications required.

Similar Substitute (Different Package): Parts with identical electrical specifications but different package geometry (4-SMD). Package substitution requires PCB layout verification and may affect thermal performance.

Parameter Comparison

Parameter	HMHA281R2_F132	HMHA281R2	HMHA281R2V	HMHA281R4	FODM121R2
Manufacturer	onsemi	onsemi	onsemi	onsemi	onsemi
Product Status	Obsolete	Active	Active	Active	Active
Voltage - Isolation	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms
Number of Channels	1	1	1	1	1
Current Transfer Ratio (Min)	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA	50% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA
Voltage - Output (Max)	80V	80V	80V	80V	80V
Current - Output / Channel	50mA	50mA	50mA	50mA	80mA
Rise / Fall Time (Typ)	3µs, 3µs	3µs, 3µs	3µs, 3µs	3µs, 3µs	3µs, 3µs
Vce Saturation (Max)	400mV	400mV	400mV	400mV	400mV
Operating Temperature	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-40°C ~ 110°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)	4-SMD, Gull Wing
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Primary Recommendation - HMHA281R2 or HMHA281R2V:

Both HMHA281R2 and HMHA281R2V are active production parts with identical electrical specifications and package geometry to the obsolete HMHA281R2_F132. Both are ROHS3 compliant and maintain the same operating temperature range (-55°C ~ 100°C). These parts provide direct substitution with no design modifications required. HMHA281R2V carries additional inventory availability (19,100 pcs vs. 18,100 pcs for HMHA281R2).

Secondary Recommendation - HMHA281R4:

HMHA281R4 maintains identical electrical specifications and package form factor. This part is active production status and ROHS3 compliant. Inventory availability is lower (829 pcs) compared to primary recommendations.

Alternative Recommendation - FODM121R2:

FODM121R2 provides identical electrical specifications with the exception of increased output current capability (80mA vs. 50mA) and extended operating temperature range (-40°C ~ 110°C). This part uses a 4-SMD package instead of 4-SOIC, requiring PCB layout modification. FODM121R2 is active production, ROHS3 compliant, and has higher inventory availability (7,600 pcs). Package substitution is suitable only when PCB redesign is feasible.

Frequently Asked Questions (FAQ)

Q: Can HMHA281R2_F132 be replaced with HMHA281R2?

A: Yes. HMHA281R2 is a direct replacement. Both parts share identical electrical specifications (3750Vrms isolation, 50-600% CTR @ 5mA, 80V max output, 50mA output current, 400mV Vce saturation) and 4-SOIC package geometry. HMHA281R2 is active production with ROHS3 compliance.

Q: What is the difference between HMHA281R2 and HMHA281R2V?

A: Electrical specifications and package geometry are identical. Both are 4-SOIC, active production, ROHS3 compliant, and maintain -55°C ~ 100°C operating temperature. The primary difference is inventory availability, with HMHA281R2V offering higher stock levels (19,100 pcs).

Q: Can FODM121R2 replace HMHA281R2_F132 in existing designs?

A: FODM121R2 provides equivalent electrical isolation, CTR, and output voltage specifications. However, it uses a 4-SMD package instead of 4-SOIC, requiring PCB layout modification. FODM121R2 offers higher output current (80mA vs. 50mA) and extended temperature range (-40°C ~ 110°C). Package substitution is valid only when PCB redesign is feasible.

Q: Are all substitute parts ROHS3 compliant?

A: HMHA281R2, HMHA281R2V, HMHA281R4, and FODM121R2 are all ROHS3 compliant. The original HMHA281R2_F132 RoHS status is not specified in available documentation.

Q: What are the critical parameters for substitution?

A: Substitution requires matching: 3750Vrms isolation voltage, 1 channel, transistor output type, 50-600% CTR @ 5mA, 80V maximum output voltage, and 400mV maximum Vce saturation. Package form factor (4-SOIC vs. 4-SMD) determines whether PCB modification is required.

Q: Which substitute part has the best inventory availability?

A: FODM121R2 has the highest inventory (7,600 pcs). Among 4-SOIC package alternatives, HMHA281R2V offers the highest availability (19,100 pcs).

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