Diodes Incorporated MMSZ5235BQ-7-F

Overview

MMSZ5235BQ-7-F from Diodes Incorporated is an AEC-Q101-qualified 6.8 V, 500 mW surface-mount Zener diode in SOD123 package, rated for 20 mA test current, 5 Ω zener impedance at I_ZT, and 3.0 µA reverse leakage at 5.0 V. It serves as a precision voltage reference or overvoltage clamp in automotive power rail monitoring circuits.

For engineers reviewing the MMSZ5235BQ-7-F datasheet, MMSZ5235BQ-7-F pinout, MMSZ5235BQ-7-F application, or MMSZ5235BQ-7-F equivalent, key selection criteria include zener voltage tolerance (±5%), low dynamic impedance, AEC-Q101 qualification, thermal derating behavior above +25°C, and SOD123 footprint compatibility with automated reflow assembly.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage regulation under controlled current conditions. Its 6.8 V nominal zener voltage exhibits a temperature coefficient of approximately +0.04 %/°C (per Figure 6), enabling predictable drift compensation in mid-voltage reference designs.

The device delivers 500 mW power dissipation at lead temperature (T_L) = +75°C and 370 mW at ambient (T_A) = +25°C on FR-4 PCB with 1-inch copper pad. Thermal resistance junction-to-ambient is 338 °C/W, requiring careful layout for sustained 20 mA operation in thermally constrained environments.

Key Specifications

Pinout & Package

SOD123 package: molded green plastic case, matte tin-plated alloy 42 leadframe, cathode band marking, moisture sensitivity level 1 per J-STD-020.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C6V8LT1G and MMSZ4687T1G, MMSZ5235BQ-7-F offers superior thermal performance in automotive environments, tighter zener impedance for precision regulation, and guaranteed AEC-Q101 reliability-making it optimal for safety-critical voltage supervision where long-term parametric stability matters.

Availability

MMSZ5235BQ-7-F is available at Aetrix Electronics and suitable for automotive engine control units, industrial sensor signal conditioning, and medical portable diagnostic device power supervision requiring stable component supply, AEC-Q101 traceability, and SOD123 footprint consistency.

Supply support for MMSZ5235BQ-7-F 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

MMSZ5235BQ-7-F belongs to the MMSZ52xxB automotive Zener diode series, engineered specifically for robust voltage reference and clamping in harsh-environment automotive electronics, emphasizing AEC-Q101 qualification, green material compliance, and high-volume manufacturability.

FAQ

What is the maximum continuous Zener current for MMSZ5235BQ-7-F at +85°C ambient?

At +85°C ambient, the device's power derating curve (Figure 1) reduces allowable dissipation to ~250 mW. With V_Z ≈ 6.8 V, this limits continuous Zener current to approximately 37 mA - but practical design must account for PCB thermal resistance and ensure junction temperature remains ≤ +150°C.

Does MMSZ5235BQ-7-F support reflow soldering with lead-free profiles?

Yes - its matte tin finish is qualified per MIL-STD-202 Method 208 and compatible with standard Pb-free reflow profiles (peak 260°C, 10-second dwell). The SOD123 package's low mass (0.01 g) and green molding compound ensure reliable wetting and intermetallic formation without delamination.

How does the temperature coefficient affect regulation accuracy over -40°C to +125°C?

Per Figure 6, MMSZ5235BQ-7-F has a TC of ~+0.04 %/°C near 6.8 V. Over a 165°C span, this yields ~+6.6% total drift - i.e., V_Z shifts from ~6.36 V at -40°C to ~6.78 V at +125°C. For high-accuracy references, external compensation or tighter-tolerance variants should be considered.

Can MMSZ5235BQ-7-F replace MMSZ5234BQ-7-F in existing designs?

No - MMSZ5234BQ-7-F is rated for 6.2 V (5.89–6.51 V), while MMSZ5235BQ-7-F is 6.8 V (6.46–7.14 V). Swapping introduces a 0.6 V offset that may violate UVLO thresholds or bias point tolerances. Verify circuit functionality with SPICE simulation using the respective V_Z min/max ranges before substitution.