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1PMT26AT1 Transient Voltage Suppressor Equivalent & Substitute Parts
Part Overview
The 1PMT26AT1 is a unidirectional Zener transient voltage suppressor (TVS) diode manufactured by onsemi, designed for general-purpose overvoltage protection in surface-mount applications. This component features a 26V reverse standoff voltage with a 42.1V maximum clamping voltage and 1000W peak pulse power rating in a DO-216AA (Powermite) package. The part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and procurement.
Substiute Parts
Key Parameters
| Parameter | Value |
|---|---|
| Manufacturer Part Number | 1PMT26AT1 |
| Manufacturer | onsemi |
| Category | Transient Voltage Suppressors (TVS) |
| Type | Zener |
| Unidirectional Channels | 1 |
| Voltage - Reverse Standoff (Typ) | 26V |
| Voltage - Breakdown (Min) | 28.9V |
| Voltage - Clamping (Max) @ Ipp | 42.1V |
| Power - Peak Pulse | 1000W (1kW) |
| Operating Temperature | -55°C ~ 150°C (TJ) |
| Package / Case | DO-216AA |
| Mounting Type | Surface Mount |
| Product Status | Obsolete |
| RoHS Status | RoHS non-compliant |
Substitute Part Grouping Explanation
Substitution of the 1PMT26AT1 is determined by the following critical electrical and mechanical parameters:
Primary Substitution Criteria:
- Reverse standoff voltage: 26V (exact match required)
- Unidirectional configuration: Single channel
- Package type: DO-216AA surface mount
- Peak pulse power rating: 1000W minimum
- Clamping voltage: Maximum 42.1V or lower (lower values provide better protection margin)
Secondary Compatibility Factors:
- Operating temperature range: Minimum -55°C to 150°C
- Zener diode type for transient suppression
- General-purpose application suitability
Substitute parts are grouped into two categories:
Category A - Direct Voltage Class Match (26V Standoff): The SMM4F26A-TR from STMicroelectronics maintains the identical 26V reverse standoff voltage specification. Although it exhibits a higher clamping voltage (54.6V vs. 42.1V), it remains functionally compatible for circuits tolerating this parameter variance. This part is active and RoHS3 compliant.
Category B - Lower Voltage Standoff (10V-15V Range): Microchip Technology UPT series parts (UPT10, UPT12, UPT15 variants) operate at reduced standoff voltages. These are not direct substitutes for 26V protection requirements but are listed as cross-reference alternatives from the original part's documented substitute list. Selection from this category requires circuit redesign validation.
Parameter Comparison
| Parameter | 1PMT26AT1 | SMM4F26A-TR | UPT10/TR13 | UPT12/TR13 | UPT15/TR13 |
|---|---|---|---|---|---|
| Manufacturer | onsemi | STMicroelectronics | Microchip Technology | Microchip Technology | Microchip Technology |
| Voltage - Reverse Standoff (Typ) | 26V | 26V | 10V | 12V | 15V |
| Voltage - Breakdown (Min) | 28.9V | 28.5V | 11V | 13.8V | 16.7V |
| Voltage - Clamping (Max) @ Ipp | 42.1V | 54.6V | 18V | 21.6V | 26V |
| Current - Peak Pulse (10/1000µs) | — | 43A (8/20µs) | 8.33A | 6.94A | 5.77A |
| Power - Peak Pulse | 1000W | 400W | 1000W | 1000W | 1000W |
| Operating Temperature | -55°C ~ 150°C | -55°C ~ 175°C | -65°C ~ 150°C | -65°C ~ 150°C | -65°C ~ 150°C |
| Package / Case | DO-216AA | DO-222AA | DO-216AA | DO-216AA | DO-216AA |
| Product Status | Obsolete | Active | Active | Active | Active |
| RoHS Status | RoHS non-compliant | ROHS3 Compliant | ROHS3 Compliant | ROHS3 Compliant | RoHS non-compliant |
Engineering Selection Recommendations
For Direct 26V Protection Requirement:
The SMM4F26A-TR from STMicroelectronics is the primary substitute for the 1PMT26AT1. Both parts maintain the 26V reverse standoff voltage specification required for equivalent circuit protection. The SMM4F26A-TR is currently in active production status with ROHS3 compliance, addressing the obsolescence and regulatory limitations of the original part. The higher clamping voltage (54.6V vs. 42.1V) represents a trade-off: reduced protection margin but improved availability and compliance posture. The package transition from DO-216AA to DO-222AA requires PCB layout verification for mechanical fit.
For Lower Voltage Applications:
If circuit requirements permit operation at reduced standoff voltages, the Microchip Technology UPT series provides active alternatives with full 1000W peak pulse power ratings and improved compliance status. UPT12E3/TR13 and UPT12RE3/TR7 carry ROHS3 compliance. UPT10RE3/TR7 and UPT10E3/TR13 offer the lowest standoff voltage (10V) with ROHS3 compliance. These selections require validation that the lower protection threshold does not compromise circuit integrity.
Compliance Considerations:
The original 1PMT26AT1 is RoHS non-compliant. Modern design standards favor the SMM4F26A-TR (ROHS3 compliant) or compliant UPT variants. Regulatory requirements for end-product applications should drive this selection criterion.
Frequently Asked Questions (FAQ)
Q: Can the SMM4F26A-TR directly replace the 1PMT26AT1 without circuit modification?
A: The SMM4F26A-TR maintains the critical 26V reverse standoff voltage and unidirectional Zener configuration. However, the clamping voltage difference (54.6V vs. 42.1V) and package change (DO-222AA vs. DO-216AA) require PCB layout verification and circuit simulation to confirm acceptable performance margins. The higher clamping voltage reduces overvoltage suppression effectiveness.
Q: What is the difference between DO-216AA and DO-222AA packages?
A: Both are surface-mount diode packages with similar footprints but different mechanical dimensions. DO-222AA is slightly larger. PCB layout compatibility must be verified before substitution. Consult package datasheets for precise dimensional specifications.
Q: Why are the UPT series parts listed as substitutes if they have different standoff voltages?
A: The UPT10, UPT12, and UPT15 variants are documented cross-references from the original 1PMT26AT1 substitute list. They are not direct functional equivalents for 26V protection circuits. These parts are suitable only for applications requiring lower voltage thresholds and represent alternative design solutions rather than drop-in replacements.
Q: Is the 1000W power rating maintained across all substitute options?
A: The SMM4F26A-TR provides 400W peak pulse power, which is lower than the 1PMT26AT1 specification (1000W). The Microchip UPT series maintains 1000W ratings. Power dissipation requirements in the target application determine whether the SMM4F26A-TR reduction is acceptable.
Q: What compliance advantages does the SMM4F26A-TR offer?
A: The SMM4F26A-TR is ROHS3 compliant and currently in active production, addressing both the regulatory non-compliance and obsolescence status of the 1PMT26AT1. This improves long-term supply chain reliability and regulatory alignment for end products.
Q: Can multiple lower-voltage UPT parts be used in series to achieve 26V protection?
A: Series configuration of TVS diodes is not a standard engineering practice for voltage addition. Each part must be independently rated for the application voltage. Consult application-specific design guidelines before considering non-standard configurations.
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