What risks should I check before replacing US1K?

The most critical risk is mismatching the reverse recovery time (trr). The US1K is an ultrafast diode (75ns); using a standard recovery diode will cause circuit failure. Also, ensure the replacement's voltage and current ratings are equal to or greater than the original.

US1K Alternatives, Datasheet & Cross Reference | Diotec Semiconductor

US1K is an 800V, 1A ultrafast rectifier in a common SMA package, designed for high-frequency power applications like switch-mode power supplies. Finding a substitute requires matching its critical 75ns reverse recovery time.

AI replacement insight

Electrical riskhigh

Substituting with a slower diode (trr > 100ns) will likely cause circuit failure.

Package risklow

The SMA (DO-214AC) package is very common with many compatible options available.

Sourcing risklow

Ultrafast 800V/1A diodes are a common component type available from numerous vendors.

Can it be replaced directly?

Direct replacement for US1K should use only Datasheet verified or Strong match candidates; many approved options still require engineering review.

Best replacement path

ES1K is the best path for a direct replacement. HS2MA is the recommended path for an upgrade with improved current handling.

Main risk

Using a standard recovery diode (e.g., S1M) instead of an ultrafast one, which will lead to excessive heat and component failure in the intended high-frequency applications.

Recommended alternatives

ES1K is a strong pin-compatible alternative with identical key electrical ratings, including the critical 75ns recovery time.

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Alternative comparison matrix

Feature / factor	US1K	ES1K	HS2MA	Compatibility / risk
Package	SMA (DO-214AC)	SMA (DO-214AC)	SMA (DO-214AC)	SMA (DO-214AC) — Package appears identical, enabling pin compatibility.; HS2MA: Package appears identical, enabling pin compatibility.
Voltage	800V	800V	1000V	800V / 1000V — Voltage rating is identical.; HS2MA: Higher voltage rating provides more margin.
Current	1A	1A	2A	1A / 2A — Current rating is identical.; HS2MA: Higher current rating provides more margin.
Recovery Time (Trr)	75ns	75ns	75ns	75ns — Ultrafast recovery time matches, crucial for function.; HS2MA: Ultrafast recovery time matches, crucial for function.

Application & sourcing insights

Questions & answers

Verified drop-in options for US1K are limited in the current batch. Review candidates marked Strong match or Datasheet verified, and validate package, pinout, and electrical limits before committing a BOM change.