Is there a pin-compatible replacement for US1D?

While several parts like STTH1R06A share the same SMA package and 2-pin layout, no part can be guaranteed as a drop-in replacement without verifying its dynamic performance (trr, Vf) in your circuit.

What risks should I check before replacing US1D?

The main risks are using a slower diode, which causes inefficiency and heat, or using a Schottky diode, which has much higher reverse leakage current that can disrupt circuit operation.

US1D Alternatives, Datasheet & Cross Reference | MDD(Microdiode Semiconductor)

US1D is a 200V, 1A ultra-fast rectifier in a common SMA package, used in high-speed switching power supplies. Finding a replacement requires matching the reverse recovery time (trr) and low reverse leakage.

AI replacement insight

Electrical riskhigh

Mismatch in reverse recovery time or reverse leakage can cause circuit malfunction.

Package risklow

The SMA package is standardized, ensuring mechanical compatibility.

Can it be replaced directly?

No guaranteed direct replacement exists. STTH1R06A is a strong candidate that matches the form and function but requires engineering review for the specific application.

Best replacement path

Upgrade to an Ultrafast diode with equal or better voltage, current, and reverse recovery time (trr), such as STTH1R06A.

Main risk

Substituting with a diode of a different type (Schottky) or slower speed (Fast Recovery) can lead to circuit inefficiency, overheating, or failure.

Recommended alternatives

A form-fit-function alternate with a higher voltage rating (600V) and faster reverse recovery time (25ns).

View details

Alternative comparison matrix

Feature / factor	US1D	STTH1R06A	STTH1L06A	Compatibility / risk
Package	SMA	SMA	SMA	SMA — Package matches target.; STTH1L06A: Package matches target.
Voltage	200V	600V	600V	600V — Higher voltage rating provides more design margin.; STTH1L06A: Higher voltage rating provides more margin.
Current	1.0A	1.0A	-	1.0A — Average forward current matches.
Trr	50ns	25ns (max)	80ns (max)	25ns (max) / 80ns (max) — Faster reverse recovery time improves efficiency.; STTH1L06A: Potentially slower recovery time may impact efficiency.
Vf	1.0V	1.0V (typ)	1.05V (max)	1.0V (typ) / 1.05V (max) — Forward voltage is comparable.; STTH1L06A: Slightly higher forward voltage increases power loss.

Application & sourcing insights

Questions & answers

STTH1R06A is a strong alternative. It offers a higher voltage rating (600V) and faster recovery time (25ns) in the same SMA package, but should be verified by an engineer.