Is there a pin-compatible replacement for US1M?

Yes, US2M is a pin-compatible upgrade. Other parts like RS1M and M7 are also pin-compatible but are significant downgrades in speed, making them high-risk replacements that require careful review of the application's frequency.

What risks should I check before replacing US1M?

The main risk is substituting a diode with a slower recovery time. The US1M is an 'ultra-fast' diode (75ns), and replacing it with a 'fast' (e.g., 500ns) or 'standard' recovery diode can cause circuit failure in high-speed applications. Also, verify the package is SMA (DO-214AC) and not the larger SMB (DO-214AA).

US1M Alternatives, Datasheet & Cross Reference | Microdiode Semiconductor (Shenzhen) Co., Ltd.

US1M is a 1A, 1000V ultra-fast rectifier in a compact SMA package. It is designed for high-frequency power conversion and switching applications where a fast 75ns recovery time is critical for efficiency and performance.

AI replacement insight

Electrical riskhigh

Using a slower diode (trr > 75ns) can cause excessive heat and circuit failure.

Package riskmedium

Some alternatives are in the larger SMB package, which is not a drop-in fit for the SMA footprint.

Can it be replaced directly?

US2M from MDD is a strong candidate for replacing US1M. It is an upgrade offering 2A of current while matching the package, 1000V rating, and critical 75ns recovery time.

Best replacement path

The best replacement is an upgrade to a part like US2M, which offers higher 2A current in the same package while matching the critical 75ns recovery time.

Main risk

The primary risk is substituting a slower 'Fast' or 'Standard' recovery diode, which will likely fail in the high-frequency applications where US1M is used.

Recommended alternatives

Offers double the forward current (2A) in the same package with identical voltage and recovery speed.

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Alternative comparison matrix

Feature / factor	US1M	US2M	RS1M	M7	Compatibility / risk
Package	DO-214AC (SMA)	DO-214AC (SMA)	SMA (DO-214AC)	DO-214AC, SMA	DO-214AC (SMA) / SMA (DO-214AC) / DO-214AC, SMA — Package is physically identical.; RS1M: Package is a physical match.; M7: Package is a physical match.
Voltage	1000V	1000V	-	-	1000V — Voltage rating is identical.
Current	1.0A	2.0A	1.0A	-	2.0A / 1.0A — Higher current capability provides more design margin.; RS1M: Current rating is identical.
Recovery Time	75ns	75ns	500ns (Fast Recovery)	Standard Recovery	75ns / 500ns (Fast Recovery) / Standard Recovery — Ultra-fast recovery time matches the target's requirement.; RS1M: Significantly slower than target's ultra-fast speed.; M7: Standard recovery speed is a critical downgrade.

Application & sourcing insights

Questions & answers

The best alternative to US1M is US2M. It is an upgrade that provides a higher current rating (2A vs 1A) in the same SMA package and matches the critical 1000V and 75ns recovery time specifications.