HMA121FV Optoisolator Equivalent & Substitute Parts

Part Overview

The HMA121FV is a 3750Vrms optoisolator with transistor output manufactured by onsemi in a 4-SMD gull wing package. This component is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production support. The HMA121FV provides single-channel isolation suitable for DC input applications with 80V maximum output voltage and 80mA output current capability.

Key Parameters

Parameter	HMA121FV Value
Voltage - Isolation	3750Vrms
Number of Channels	1
Output Type	Transistor
Voltage - Output (Max)	80V
Current - Output / Channel	80mA
Input Type	DC
Current Transfer Ratio (Min)	100% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA
Vce Saturation (Max)	400mV
Operating Temperature	-40°C ~ 100°C
Mounting Type	Surface Mount
Package / Case	4-SMD, Gull Wing
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the HMA121FV is determined by the following critical parameters:

Isolation Voltage: All substitutes must maintain 3750Vrms isolation rating
Output Configuration: Single-channel transistor output required
Maximum Output Voltage: 80V capability maintained across all substitutes
Input Type: DC input compatibility required
Mounting: Surface mount technology with compatible package footprints
Current Transfer Ratio Range: Substitutes must fall within or overlap the 100–600% @ 5mA specification
Vce Saturation: Output saturation voltage must not exceed 400mV for direct pin-compatible replacement

Substitute parts are grouped by package type: 4-Mini-Flat (Broadcom HCPL-181 series), 4-SOP (Everlight EL357ND and Lite-On LTV-356T), and 4-SOIC (Broadcom HCPL-181-000E). Package differences require PCB layout verification but do not affect electrical compatibility when isolation voltage, output type, and current ratings are matched.

Parameter Comparison

Parameter	HMA121FV	EL357ND(TA)-G	HCPL-181-000E	HCPL-181-00AE	HCPL-181-00BE	HCPL-181-00CE	HCPL-181-00DE	HCPL-181-06BE	HCPL-181-06DE	LTV-356T	PC357N4J000F
Voltage - Isolation	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms	3750Vrms
Number of Channels	1	1	1	1	1	1	1	1	1	1	1
Output Type	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor	Transistor
Voltage - Output (Max)	80V	80V	80V	80V	80V	80V	80V	80V	80V	80V	80V
Current - Output / Channel	80mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA	50mA
Input Type	DC	DC	DC	DC	DC	DC	DC	DC	DC	DC	DC
Current Transfer Ratio (Min)	100% @ 5mA	300% @ 5mA	50% @ 5mA	80% @ 5mA	130% @ 5mA	200% @ 5mA	300% @ 5mA	130% @ 5mA	300% @ 5mA	50% @ 5mA	300% @ 5mA
Current Transfer Ratio (Max)	600% @ 5mA	600% @ 5mA	600% @ 5mA	160% @ 5mA	260% @ 5mA	400% @ 5mA	600% @ 5mA	260% @ 5mA	600% @ 5mA	600% @ 5mA	600% @ 5mA
Vce Saturation (Max)	400mV	200mV	200mV	200mV	200mV	200mV	200mV	200mV	200mV	200mV	200mV
Operating Temperature	-40°C ~ 100°C	-55°C ~ 110°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 100°C	-55°C ~ 110°C	-30°C ~ 100°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	4-SMD, Gull Wing	4-SOP (2.54mm)	4-SOIC (0.209", 5.30mm Width)	4-Mini-Flat	4-Mini-Flat	4-Mini-Flat	4-Mini-Flat	4-Mini-Flat	4-Mini-Flat	4-SOP	4-Mini-Flat
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Active	Active

Engineering Selection Recommendations

All listed substitute parts maintain the 3750Vrms isolation voltage and single-channel transistor output configuration required for HMA121FV replacement. All substitutes are active products with current manufacturing status, ensuring long-term availability and supply chain stability.

Output Current Consideration: The HMA121FV specifies 80mA maximum output current, while all substitute parts are rated at 50mA maximum. Applications requiring the full 80mA output current must be re-evaluated with the reduced 50mA rating of substitute parts.

Vce Saturation: All substitute parts feature 200mV maximum Vce saturation, which is superior to the HMA121FV specification of 400mV. This improvement reduces power dissipation in the output stage.

Current Transfer Ratio: Substitute parts exhibit varying CTR ranges. The HCPL-181-00AE has the narrowest range (80–160% @ 5mA), while HCPL-181-00DE, HCPL-181-06DE, EL357ND(TA)-G, LTV-356T, and PC357N4J000F all match the full 300–600% @ 5mA range of the HMA121FV.

Temperature Range: EL357ND(TA)-G and LTV-356T extend the upper operating temperature to 110°C, compared to 100°C for the HMA121FV and most other substitutes. PC357N4J000F has a reduced lower temperature limit of -30°C.

RoHS and Compliance: All active substitute parts carry ROHS3 compliance certification. The HMA121FV is marked as REACH Unaffected; all substitutes maintain REACH Unaffected status.

Package Compatibility: Broadcom HCPL-181 series parts in 4-Mini-Flat package offer the highest inventory availability (44,400–103,100 units). The 4-SOP variants (EL357ND and LTV-356T) and 4-SOIC option (HCPL-181-000E) require PCB layout modification but provide alternative footprint options.

Frequently Asked Questions (FAQ)

Q: Can I directly replace HMA121FV with any of these substitute parts without PCB modification?

A: Direct replacement without PCB modification is limited to parts with identical or compatible package footprints. The HMA121FV uses 4-SMD gull wing packaging. Broadcom HCPL-181 series parts in 4-Mini-Flat package share the same gull wing footprint and can be used as direct substitutes. The 4-SOP (EL357ND, LTV-356T) and 4-SOIC (HCPL-181-000E) variants require PCB layout changes.

Q: Why do all substitute parts have lower maximum output current (50mA vs. 80mA)?

A: The 50mA output current rating is the standard specification for this class of 3750Vrms optoisolators in active production. Applications designed for the HMA121FV's 80mA capability must be re-evaluated to operate within the 50mA limit of substitute parts or alternative higher-current isolation solutions must be selected.

Q: Which substitute part has the best availability?

A: HCPL-181-00BE and HCPL-181-00DE from Broadcom offer the highest inventory levels at 103,100 and 44,400 units respectively. Both are active products with ROHS3 compliance and 4-Mini-Flat packaging compatible with the HMA121FV footprint.

Q: Are there differences in Current Transfer Ratio (CTR) that affect circuit design?

A: Yes. The HCPL-181-00AE has a narrower CTR range (80–160% @ 5mA) compared to the HMA121FV (100–600% @ 5mA). Other substitutes like HCPL-181-00DE, EL357ND(TA)-G, LTV-356T, and PC357N4J000F match or exceed the full CTR range. Circuit designs relying on specific CTR values must account for the selected substitute's CTR specification.

Q: What is the significance of Vce Saturation differences?

A: The HMA121FV specifies 400mV maximum Vce saturation, while all substitutes specify 200mV. Lower saturation voltage reduces power dissipation in the output transistor, improving efficiency. This is a beneficial change for most applications and does not require circuit redesign.

Q: Can I use HCPL-181-00AE if my application requires a narrower CTR specification?

A: Yes. The HCPL-181-00AE provides a tightly controlled CTR range of 80–160% @ 5mA, making it suitable for applications requiring predictable gain characteristics. However, this narrower range may not be compatible with designs expecting the full 100–600% range of the HMA121FV.

Q: What is the operating temperature impact when selecting substitutes?

A: The HMA121FV operates from -40°C to 100°C. EL357ND(TA)-G and LTV-356T extend the upper limit to 110°C, providing additional thermal margin. PC357N4J000F has a reduced lower limit of -30°C. Select based on your application's temperature requirements.

Q: Are all substitutes RoHS compliant?

A: All active substitute parts listed carry ROHS3 compliance certification. The HMA121FV is obsolete and marked as REACH Unaffected; all substitutes maintain REACH Unaffected status, ensuring regulatory compliance for new designs.

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