What risks should I check before replacing SM140A?

Before replacing SM140A, verify that the alternative's forward voltage (Vf) is not significantly higher, as this would increase power loss. Also, check junction capacitance (Cj) for high-frequency circuits and reverse leakage current (Ir) for low-power applications.

SM140A Alternatives, Datasheet & Cross Reference | LRC

The SM140A is a 40V, 1A Schottky barrier rectifier in a DO-214AC (SMA) package, widely used for rectification, freewheeling, and reverse polarity protection in low-voltage, high-frequency applications. This page provides a list of potential alternatives and replacements.

AI replacement insight

Electrical risklow

Many candidates match or exceed primary voltage/current ratings. Check Vf, Cj, and Ir from datasheets.

Package risklow

DO-214AC (SMA) is a highly standardized package, ensuring mechanical compatibility.

Sourcing risklow

This is a common diode type with many manufacturers, providing a robust supply chain.

Can it be replaced directly?

Direct replacement for SM140A should use only Datasheet verified or Strong match candidates; many approved options still require engineering review.

Best replacement path

Use a Schottky diode in a DO-214AC (SMA) package with V_rrm >= 40V and I_f >= 1A, such as SX34_R1_00001.

Main risk

The primary risk is mismatch in secondary parameters like junction capacitance or reverse leakage current, which can impact high-frequency or low-power circuits.

Recommended alternatives

A strong alternative with matching package and voltage, plus higher current rating and lower forward voltage.

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Alternative comparison matrix

Feature / factor	SM140A	SX34_R1_00001	SS36(SMA)	SS54-MS	Compatibility / risk
Package	DO-214AC	DO-214AC (SMA)	DO-214AC(SMA)	DO-214AC (SMA)	DO-214AC (SMA) / DO-214AC(SMA) — Same form and fit.; SS36(SMA): Same form and fit.; SS54-MS: Same form and fit.
Diode Type	Schottky	Schottky	Schottky	Schottky	Schottky — Both are Schottky rectifiers.; SS36(SMA): Both are Schottky rectifiers.; SS54-MS: Both are Schottky rectifiers.
Voltage	40V	40V	60V	40V	40V / 60V — Voltage rating is identical.; SS36(SMA): Higher voltage rating provides more margin.; SS54-MS: Voltage rating is identical.
Current	1A	3A	3A	5A	3A / 5A — Higher current rating provides more margin.; SS36(SMA): Higher current rating.; SS54-MS: Significantly higher current rating.
Forward Voltage	0.7V	0.5V	-	-	0.5V — Lower Vf reduces power loss.

Application & sourcing insights

Questions & answers

Verified drop-in options for SM140A 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.