onsemi MMSZ5241B

Overview

MMSZ5241B from Fairchild Semiconductor is a 5% tolerance, 500 mW surface-mount Zener diode with nominal zener voltage of 11.0 V (min 10.45 V, typ 11.0 V, max 11.55 V), dynamic impedance of 22 Ω at 5 mA test current, and reverse leakage current ≤0.25 µA at 8.4 V. It operates in SOD-123 package and serves as a precision voltage reference or overvoltage clamp in low-power analog and power supply feedback circuits.

For engineers reviewing the MMSZ5241B datasheet, pinout, applications, or equivalent options, key selection criteria include its 11.0 V zener voltage tolerance, 22 Ω zener impedance at 5 mA, thermal resistance of 340 °C/W, junction temperature limit of +150 °C, and compatibility with FR-4 PCB layouts using standard SOD-123 land patterns.

Technical Context

The MMSZ5241B functions as a two-terminal voltage regulation device operating in reverse breakdown mode. Its zener voltage exhibits ±0.55 V variation across the 10.45–11.55 V range at 25 °C, with temperature coefficient optimized for stability near 11 V - typical drift is <±0.07 %/°C over –25 to +125 °C per manufacturer characterization curves.

It delivers stable regulation under DC or low-frequency transient conditions up to 500 mW dissipation, limited by thermal resistance (340 °C/W) and ambient temperature. Forward voltage is ≤0.9 V at 10 mA, enabling use in dual-polarity protection schemes where forward conduction may occur during fault events.

Key Specifications

Pinout & Package

SOD-123 surface-mount package: 2-pin, cathode-banded end, JEDEC-standard footprint (3.5 × 1.5 inch test board recommended). Cathode marked by band; anode unmarked.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener diode applications.

Compared with BZX584C11 and 1N4740A, the MMSZ5241B offers optimal balance of SMT compatibility, 500 mW power capability, and 11.0 V regulation accuracy - making it preferred for modern industrial power supplies and embedded sensor interfaces where both thermal margin and board space matter.

Availability

MMSZ5241B is available at Aetrix Electronics and suitable for switch-mode power supply feedback, microcontroller voltage reference, and overvoltage protection applications requiring stable component supply, consistent parametric performance, and long-term lifecycle availability.

Supply support for MMSZ5241B includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete devices before its acquisition by ON Semiconductor in 2016. Its legacy Zener diode portfolio remains widely deployed in industrial and automotive systems.

The MMSZ52xxB series was designed for compact, reliable voltage regulation in space-constrained SMT applications - emphasizing tight tolerance, low leakage, and thermal robustness for use in power supplies, instrumentation, and sensor interfaces.

FAQ

What is the nominal zener voltage of the MMSZ5241B?

The MMSZ5241B has a nominal zener voltage of 11.0 V, with a guaranteed range of 10.45 V (minimum) to 11.55 V (maximum) at 5 mA test current and 25 °C ambient temperature. This 5% tolerance allows predictable clamping behavior in feedback and protection circuits without requiring calibration or selection.

Can the MMSZ5241B be used in place of a 12 V zener diode?

No - the MMSZ5241B is specified for 11.0 V regulation and should not substitute for a true 12 V zener like MMSZ5242B (12.0 V nominal). Using MMSZ5241B where 12 V is required risks undershoot in feedback loops or insufficient clamping margin, potentially causing system instability or overvoltage exposure.

What is the maximum power dissipation of the MMSZ5241B?

The MMSZ5241B has a maximum power dissipation of 500 mW at 25 °C ambient temperature. Derating is required above 25 °C at 1.47 mW/°C (based on 340 °C/W thermal resistance), reducing usable power to ~300 mW at 70 °C ambient - critical for thermal design in enclosed enclosures.

Does the MMSZ5241B have a specified temperature coefficient?

While no single numeric temperature coefficient is published for MMSZ5241B, manufacturer characterization curves (Figure 5: "12 Zener Voltage vs. Temperature") show typical drift of <±0.07 %/°C over –25 to +125 °C. This stability supports use in industrial environments where reference accuracy must hold across wide temperature swings.

Is the MMSZ5241B RoHS compliant?

Yes - the MMSZ5241B manufactured by Fairchild Semiconductor meets RoHS Directive 2011/65/EU requirements. Lead-free termination and halogen-free packaging were standard for this series at time of production, and Aetrix Electronics supplies only RoHS-compliant lots with full material declarations.