1N5819WS(SL)
KEXIN
Needs validationmedium risk
A common 40V alternative in the same package. The higher forward voltage requires design review.
Best Alternatives to B5817WS-MS
B5817WS-MS is a 20V, 1A Schottky diode in a compact SOD-323 package, valued for its low forward voltage. While many alternatives exist with higher voltage ratings for improved robustness, engineers must carefully evaluate the impact of their typically higher forward voltage on system efficiency and thermal management.
AI replacement insight
Electrical riskmedium
Higher forward voltage in substitutes increases power loss (P=Vf*I), potentially requiring thermal re-evaluation.
Package risklow
All candidates use the same SOD-323 package, ensuring form and fit compatibility on the PCB.
Can it be replaced directly?
There are several potential pin-compatible replacements in the same SOD-323 package, but most have a slightly higher forward voltage. A full drop-in replacement is unlikely without verifying thermal performance.
Best replacement path
Upgrade to a 30V or 40V rated part like B1040WS or RB550V-30. These offer better voltage protection in the same package.
Main risk
The primary risk is increased power dissipation and heat due to the higher forward voltage (Vf) of most alternatives compared to the target's low 0.45V.
Recommended alternatives
6Alternative comparison matrix
| Feature / factor | B5817WS-MS | 1N5819WS(SL) | B1040WS | RB550V-30 | Compatibility / risk |
|---|---|---|---|---|---|
| Package | SOD-323 | SOD-323 | SOD-323 | SOD-323 | SOD-323 — Same package and pin count.; B1040WS: Same package and pin count.; RB550V-30: Same package and pin count.; PSBD3D40V1H: Same package and pin count. |
| Voltage | 20V | 40V | 40V | 30V | 40V / 30V — Higher reverse voltage provides more design margin.; B1040WS: Higher reverse voltage provides more design margin.; RB550V-30: Higher reverse voltage provides more design margin.; PSBD3D40V1H: Higher reverse voltage provides more design margin. |
| Current | 1A | 1A | 1A | 1A | 1A — Average forward current matches.; B1040WS: Average forward current matches.; RB550V-30: Average forward current matches.; PSBD3D40V1H: Average forward current matches. |
| Forward Voltage | 0.45V | 0.6V | ~0.58V | ~0.52V | 0.6V / ~0.58V / ~0.52V / 0.55V — Higher Vf will increase power loss.; B1040WS: Higher Vf may increase power loss.; RB550V-30: Slightly higher Vf may increase power loss.; PSBD3D40V1H: Higher Vf may increase power loss. |
Application & sourcing insights
Questions & answers
Parts like B1040WS or 1N5819WS are excellent alternatives. They offer a higher 40V rating in the same package, providing more design margin. However, you must verify that their slightly higher forward voltage is acceptable for your application's efficiency and thermal budget.