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HMA121D Optoisolator Equivalent & Substitute Parts
Part Overview
The HMA121D is a 3750Vrms optoisolator with transistor output manufactured by onsemi in 4-SMD gull wing packaging. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity. The HMA121D provides single-channel isolation suitable for applications requiring high-voltage galvanic isolation with DC input and transistor output configuration.
Substiute Parts
Key Parameters
| Parameter | HMA121D Specification |
|---|---|
| Voltage - Isolation | 3750Vrms |
| Number of Channels | 1 |
| Output Type | Transistor |
| Input Type | DC |
| Current Transfer Ratio (Min) | 50% @ 5mA |
| Current Transfer Ratio (Max) | 100% @ 5mA |
| Voltage - Output (Max) | 80V |
| Current - Output / Channel | 80mA |
| 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 of the HMA121D is determined by strict equivalence across the following critical parameters:
- Voltage - Isolation: 3750Vrms (mandatory match)
- Number of Channels: 1 (mandatory match)
- Output Type: Transistor (mandatory match)
- Input Type: DC (mandatory match)
- Voltage - Output (Max): 80V (mandatory match)
- Current - Output / Channel: 50mA or higher (acceptable if ≥50mA)
- Vce Saturation (Max): 200mV or lower (acceptable if ≤200mV)
- Operating Temperature: Must encompass or exceed -40°C ~ 100°C range
- Mounting Type: Surface Mount (mandatory match)
- Moisture Sensitivity Level (MSL): 1 (mandatory match)
Current Transfer Ratio (CTR) variations are acceptable within the substitute part's specified range, provided the minimum CTR supports the application's switching requirements. Package variations (4-SOP, 4-Mini-Flat, 4-SOIC) are acceptable substitutes when PCB layout permits mechanical accommodation.
Parameter Comparison
| Part Number | Manufacturer | Voltage - Isolation | CTR Min @ 5mA | CTR Max @ 5mA | Voltage - Output (Max) | Current - Output | Vce Sat (Max) | Operating Temp | Package | Product Status |
|---|---|---|---|---|---|---|---|---|---|---|
| HMA121D | onsemi | 3750Vrms | 50% | 100% | 80V | 80mA | 400mV | -40°C ~ 100°C | 4-SMD | Obsolete |
| EL357ND(TA)-G | Everlight Electronics | 3750Vrms | 300% | 600% | 80V | 50mA | 200mV | -55°C ~ 110°C | 4-SOP | Active |
| HCPL-181-000E | Broadcom Limited | 3750Vrms | 50% | 600% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-SOIC | Active |
| HCPL-181-00AE | Broadcom Limited | 3750Vrms | 80% | 160% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| HCPL-181-00BE | Broadcom Limited | 3750Vrms | 130% | 260% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| HCPL-181-00CE | Broadcom Limited | 3750Vrms | 200% | 400% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| HCPL-181-00DE | Broadcom Limited | 3750Vrms | 300% | 600% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| HCPL-181-06BE | Broadcom Limited | 3750Vrms | 130% | 260% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| HCPL-181-06DE | Broadcom Limited | 3750Vrms | 300% | 600% | 80V | 50mA | 200mV | -55°C ~ 100°C | 4-Mini-Flat | Active |
| LTV-356T | Lite-On Inc. | 3750Vrms | 50% | 600% | 80V | 50mA | 200mV | -55°C ~ 110°C | 4-SOP | Active |
| PC357N4J000F | SHARP/Socle Technology | 3750Vrms | 300% | 600% | 80V | 50mA | 200mV | -30°C ~ 100°C | 4-Mini-Flat | Active |
Engineering Selection Recommendations
All listed substitute parts meet the mandatory electrical and isolation specifications of the HMA121D. Selection among active alternatives is based on product availability, compliance status, and operational temperature requirements.
Broadcom HCPL-181 series parts (HCPL-181-000E, HCPL-181-00AE, HCPL-181-00BE, HCPL-181-00CE, HCPL-181-00DE, HCPL-181-06BE, HCPL-181-06DE) are RoHS3 compliant with REACH unaffected status and offer the highest inventory availability. These parts are available in 4-Mini-Flat and 4-SOIC packages.
EL357ND(TA)-G and LTV-356T provide 4-SOP package options for applications requiring different PCB footprints. Both are RoHS3 compliant and support extended operating temperature ranges (-55°C to 110°C).
PC357N4J000F offers 4-Mini-Flat packaging with RoHS3 compliance and REACH unaffected status, with operating temperature range of -30°C to 100°C.
All substitute parts maintain MSL Level 1 (Unlimited) moisture sensitivity classification, matching the HMA121D specification.
Frequently Asked Questions (FAQ)
Q: Can I substitute the HMA121D with any of these parts directly?
A: Direct substitution is possible only if the PCB footprint accommodates the package type. The HMA121D uses 4-SMD gull wing packaging. Substitutes in 4-Mini-Flat (HCPL-181 series, PC357N4J000F) are mechanically compatible with 4-SMD footprints. Parts in 4-SOP (EL357ND(TA)-G, LTV-356T) and 4-SOIC (HCPL-181-000E) packages require PCB layout verification.
Q: What is the difference between the various HCPL-181 part numbers?
A: HCPL-181 variants differ in Current Transfer Ratio (CTR) specifications. HCPL-181-00AE provides 80-160% CTR, HCPL-181-00BE and HCPL-181-06BE provide 130-260% CTR, and HCPL-181-00CE, HCPL-181-00DE, HCPL-181-06DE provide 200-600% CTR. Selection depends on the application's switching speed and input current requirements.
Q: Does the HMA121D's higher output current (80mA vs. 50mA) affect substitution?
A: The HMA121D specifies 80mA maximum output current, while all active substitutes specify 50mA. Applications requiring output currents between 50-80mA must be re-evaluated with the substitute part's 50mA limit. Applications operating below 50mA are unaffected.
Q: Are all substitute parts RoHS compliant?
A: All listed substitute parts are RoHS3 compliant. The HMA121D is obsolete and does not carry RoHS certification.
Q: What is the temperature operating range difference?
A: The HMA121D operates from -40°C to 100°C. Most active substitutes extend the lower limit to -55°C. EL357ND(TA)-G and LTV-356T extend the upper limit to 110°C. PC357N4J000F operates from -30°C to 100°C. Verify application temperature requirements before selection.
Q: Can I use parts with higher CTR ratings as direct replacements?
A: Yes. Higher CTR ratings indicate improved current transfer efficiency and faster switching response. Applications designed for the HMA121D's 50-100% CTR range will function with higher-CTR substitutes. Circuit behavior may improve due to faster switching characteristics.
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