SD103AW S4
KUU
Needs validationlow risk
A direct cross-reference with identical key parameters in the same SOD-123 package.
Best Alternatives to 1N5819W S4
Finding replacements for the KUU 1N5819W S4, a 40V 350mA Schottky diode in a SOD-123 package, involves matching key electrical parameters like forward voltage and reverse recovery time. Several pin-compatible alternatives and upgrades are available from major manufacturers.
AI replacement insight
Electrical riskhigh
Using a standard diode instead of a Schottky will increase Vf and slow recovery time.
Package risklow
Most alternatives are in the same SOD-123 package, but variations like SOD-123FL exist.
Sourcing risklow
This is a common diode type with many available alternatives from major suppliers.
Can it be replaced directly?
Direct replacement for 1N5819W S4 should use only Datasheet verified or Strong match candidates; many approved options still require engineering review.
Best replacement path
The best path is selecting a Schottky diode with at least 40V reverse voltage and 350mA forward current in the same SOD-123 package. Parts like onsemi's MBR0540T3G or ST's STPS0540Z are strong candidates.
Main risk
The main risk is substituting with a non-Schottky diode, which would increase forward voltage drop and slow down switching, potentially causing circuit malfunction or inefficiency.
Recommended alternatives
4Alternative comparison matrix
| Feature / factor | 1N5819W S4 | SD103AW S4 | STPS0540Z | STPS0560Z | Compatibility / risk |
|---|---|---|---|---|---|
| Package | SOD-123 | SOD-123 | SOD-123 | SOD-123 | SOD-123 — Package matches.; STPS0540Z: Package matches, enabling form-fit compatibility.; STPS0560Z: Package matches, enabling form-fit compatibility.; MBR0540T3G: Package matches, enabling form-fit compatibility. |
| Voltage | 40V | 40V | 40V | 60V | 40V / 60V — Voltage matches.; STPS0540Z: Reverse voltage rating is identical.; STPS0560Z: Higher voltage rating provides more safety margin.; MBR0540T3G: Reverse voltage rating is identical. |
| Current | 350mA | 350mA | 0.5A | 0.5A | 350mA / 0.5A — Current matches.; STPS0540Z: Higher current rating provides more design margin.; STPS0560Z: Higher current rating provides more design margin.; MBR0540T3G: Higher current rating provides more design margin. |
| Manufacturer | KUU | KUU / TDSEMIC | - | - | KUU / TDSEMIC — May be the same part from a different vendor or a direct cross-reference. |
| Forward Voltage | 0.6V @ 200mA | - | 0.4V max | - | 0.4V max — Lower forward voltage improves efficiency. |
| Application | Schottky | - | - | - | Schottky — Both are Schottky diodes, ensuring similar low Vf and fast switching. |
Application & sourcing insights
Questions & answers
Verified drop-in options for 1N5819W S4 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.