Is there a pin-compatible replacement for MMSZ5239BT1G?

No pin-compatible replacement with the exact same 9.1V Zener voltage is listed. While candidates like MMSZ5240BT1G share the same SOD-123 package and pinout, their different electrical parameters mean they are not drop-in replacements.

What risks should I check before replacing MMSZ5239BT1G?

Before replacing MMSZ5239BT1G, you must verify that your circuit can tolerate a different Zener voltage. The closest options are 10V or 8.2V. This change will affect the voltage regulation point and could impact system performance.

MMSZ5239BT1G Alternatives, Datasheet & Cross Reference | onsemi

MMSZ5239BT1G is a 9.1V, 500mW Zener diode in a SOD-123 package from onsemi. While no exact drop-in replacement is identified, several parametric alternatives from the same product family are available, requiring review of the Zener voltage.

AI replacement insight

Electrical riskmedium

Zener voltage difference requires circuit analysis to ensure proper regulation.

Package risklow

Top candidates share the same SOD-123 package, ensuring physical compatibility.

Sourcing risklow

Alternatives are from the same major manufacturer (onsemi) and are actively produced.

Can it be replaced directly?

No direct, drop-in replacement with an identical 9.1V Zener voltage has been identified. All suitable alternatives require an engineering review of the voltage difference.

Best replacement path

MMSZ5240BT1G (10V) or MMSZ5237BT1G (8.2V) are the closest parametric alternatives, depending on whether the application can tolerate a slightly higher or lower regulation voltage.

Main risk

The primary risk is the Zener voltage mismatch. Using a part with a different voltage will change the circuit's regulation point and may cause malfunction.

Recommended alternatives

A parametric alternative in the same SOD-123 package with a slightly higher Zener voltage of 10V.

View details

Alternative comparison matrix

Feature / factor	MMSZ5239BT1G	MMSZ5240BT1G	MMSZ5237BT1G	Compatibility / risk
Package	SOD-123	SOD-123	SOD-123	SOD-123 — Same package ensures form-fit compatibility.; MMSZ5237BT1G: Same package ensures form-fit compatibility.
Voltage	9.1V	10.0V	8.2V	10.0V / 8.2V — Higher Zener voltage.; MMSZ5237BT1G: Lower Zener voltage.
Power	0.5W	0.5W	0.5W	0.5W — Identical power rating.; MMSZ5237BT1G: Identical power rating.
Manufacturer	onsemi	onsemi	onsemi	onsemi — Same manufacturer and product family.; MMSZ5237BT1G: Same manufacturer and product family.

Application & sourcing insights

Questions & answers

The best alternatives for MMSZ5239BT1G are MMSZ5240BT1G (10V) and MMSZ5237BT1G (8.2V). Both are from onsemi in the same SOD-123 package but have different Zener voltages, requiring an engineering review.