Is there a pin-compatible replacement for MM1Z18B?

MMSZ5248BT1G and MM1W18 use the same 2-pin SOD-123 package and are expected to be pin-compatible. However, always verify the datasheet pinout before board layout.

What risks should I check before replacing MM1Z18B?

Key risks include differences in Zener impedance (Zzt) and test current (Izt), which can affect regulation performance. Also, verify the full operating temperature range and tolerance.

MM1Z18B Alternatives, Datasheet & Cross Reference | Slkor(SLKORMICRO Elec.)

Finding a replacement for the MM1Z18B Zener diode involves matching the 18V Zener voltage, 500mW power rating, and SOD-123 package. Several alternatives exist with similar or improved characteristics.

AI replacement insight

Electrical risklow

Candidates have matching or better electrical specs.

Package risklow

All candidates share the same SOD-123 package.

Sourcing risklow

Candidates are available from major manufacturers.

Can it be replaced directly?

Yes, MMSZ5248BT1G is a strong candidate for direct replacement, sharing the same voltage, power, and package.

Best replacement path

MMSZ5248BT1G for a direct functional match, or MM1W18 for a power upgrade.

Main risk

Minor parametric differences, such as Zener impedance and test current, may require circuit validation.

Recommended alternatives

A form, fit, and functional alternative from onsemi with the same 18V Zener voltage and 500mW power rating in a SOD-123 package.

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Alternative comparison matrix

Feature / factor	MM1Z18B	MMSZ5248BT1G	MM1W18	Compatibility / risk
Package	SOD-123	SOD-123	SOD-123	SOD-123 — Same package ensures form-fit compatibility.; MM1W18: Same package ensures form-fit compatibility.
Voltage	18V	18V	18V	18V — Zener voltage matches the target's core function.; MM1W18: Zener voltage matches the target's core function.
Power	500mW	500mW	1.0W	500mW / 1.0W — Power dissipation rating is identical.; MM1W18: Higher power rating provides increased thermal margin.
Impedance	45Ω	21Ω	20Ω	21Ω / 20Ω — Lower Zener impedance offers better voltage regulation.; MM1W18: Lower Zener impedance offers better voltage regulation.
Manufacturer	Slkor	onsemi	-	onsemi — Cross-vendor alternative from a major manufacturer.
Current	5mA	-	14mA	14mA — Test current is different, may affect performance at lower currents.

Application & sourcing insights

Questions & answers

MMSZ5248BT1G from onsemi is a strong alternative, offering the same key parameters in a SOD-123 package. MM1W18 is a potential upgrade with a higher 1W power rating.