RS3MB
MDD(Microdiode Semiconductor)
Needs validationmedium risk
Matches package, voltage, and current, but has a much slower recovery time (500ns vs 75ns), requiring careful review for the application.
Best Alternatives to US3MB
The US3MB is an ultra-fast 1000V, 3A rectifier in a surface-mount SMB package. Its 75ns recovery time is critical for high-efficiency power supplies, and finding a substitute requires careful matching of this key performance parameter.
AI replacement insight
Electrical riskhigh
Mismatch in reverse recovery time (trr) is a critical functional failure for the intended applications.
Package risklow
The SMB (DO-214AA) package is standard, and many candidates match the form factor.
Can it be replaced directly?
No direct, drop-in replacement has been verified. While parts like RS3MB match the package and primary ratings, their slower recovery time presents a significant performance risk that requires engineering validation.
Best replacement path
Search for other ultra-fast rectifiers with trr <= 75ns, V_rrm >= 1000V, and I_f >= 3A in an SMB (DO-214AA) package. The 'U' prefix in similar part numbers often indicates ultra-fast.
Main risk
The primary risk is substituting the ultra-fast recovery time (75ns) with a much slower diode, which can cause increased power loss, overheating, and circuit failure in high-frequency applications.
Recommended alternatives
3Alternative comparison matrix
| Feature / factor | US3MB | RS3MB | S3MB | S5MB | Compatibility / risk |
|---|---|---|---|---|---|
| Package | SMB | SMB | SMB (DO-214AA) | SMB | SMB / SMB (DO-214AA) — Same package and pin count.; S3MB: Same package and pin count.; S5MB: Same package and pin count. |
| Voltage | 1000V | 1000V | 1000V | 1000V | 1000V — Voltage rating matches.; S3MB: Voltage rating matches.; S5MB: Voltage rating matches. |
| Current | 3.0A | 3.0A | 3.0A | 5.0A | 3.0A / 5.0A — Current rating matches.; S3MB: Current rating matches.; S5MB: Higher current rating is acceptable. |
| Recovery Time | 75ns | 500ns | - | - | 500ns — Significantly slower than target's 75ns. May cause excessive switching losses. |
| Diode Type | Ultra-Fast | - | Standard Recovery | General Purpose | Standard Recovery / General Purpose — Candidate is a very slow standard recovery diode, target is ultra-fast (75ns). This is a critical functional downgrade.; S5MB: Candidate is a slow general-purpose diode, target is ultra-fast (75ns). This is a critical functional downgrade. |
Application & sourcing insights
Questions & answers
Currently, no perfect alternative has been identified. RS3MB is a potential candidate that matches the package, voltage, and current, but its recovery time is much slower (500ns vs 75ns). This is a risky downgrade that requires careful testing in your specific circuit.