Diodes Incorporated MMBZ5239BW-7

Overview

MMBZ5239BW-7 from Diodes Incorporated is a 9.1 V, 200 mW surface-mount Zener diode in SOT323 package, with nominal zener voltage tolerance ±5%, zener impedance 10 Ω at 20 mA test current, and maximum reverse leakage of 3.0 μA at 7.0 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.

For engineers reviewing the MMBZ5239BW-7 datasheet, MMBZ5239BW-7 pinout, MMBZ5239BW-7 application, or MMBZ5239BW-7 equivalent, key selection criteria include zener voltage accuracy, low dynamic impedance, thermal resistance (625 °C/W), RoHS-compliant lead-free construction, and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This device operates as a two-terminal voltage reference, clamping reverse-biased voltage at 9.1 V with tight 8.65–9.56 V range under 20 mA test current. It exhibits low zener impedance (10 Ω @ 1 kHz) and minimal capacitance (~8 pF), enabling stable regulation in noise-sensitive signal conditioning paths.

Designed for surface-mount assembly on FR4 PCBs using recommended pad layout AP02001, it delivers consistent performance across –65 °C to +150 °C operating temperature range and supports automated reflow soldering per J-STD-020D Level 1 moisture sensitivity.

Key Specifications

Pinout & Package

Package: SOT323 - ultra-small plastic surface-mount case (2.10 mm × 1.30 mm × 0.90 mm), matte tin-plated terminals, halogen- and antimony-free "Green" molding compound rated UL 94V-0.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C9V1 and MMSZ5239ET1G, MMBZ5239BW-7 offers the smallest footprint (SOT323), AEC-Q101 qualification, and optimal balance of low leakage (3.0 μA), low impedance (10 Ω), and tight voltage tolerance - making it the preferred choice for space-constrained, automotive-grade voltage reference designs.

Availability

MMBZ5239BW-7 is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor signal chains, USB-C PD monitoring, and medical wearable battery management requiring stable component supply and long-term lifecycle support.

Supply support for MMBZ5239BW-7 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, specializing in high-reliability, energy-efficient components for automotive, industrial, and consumer markets.

The MMBZ52xxBW series belongs to Diodes' AEC-Q101-qualified Zener diode product line, engineered specifically for precision voltage regulation and overvoltage protection in harsh-environment automotive and industrial control systems.

FAQ

What is the maximum reverse voltage (V_R) at which leakage remains ≤3.0 μA?

The datasheet specifies that reverse leakage current is ≤3.0 μA at V_R = 7.0 V. This is a guaranteed limit - not a breakdown point. The device begins regulating near 8.65 V (V_{Z min}) and reaches full conduction at 9.1 V nominal. Operation above 9.56 V risks exceeding power rating unless current is strictly limited.

Is MMBZ5239BW-7 compatible with lead-free reflow profiles?

Yes. The device uses matte tin-plated terminals qualified to MIL-STD-202, Method 208 and supports standard Pb-free reflow profiles (peak 260 °C, 10–15 sec). Its Level 1 moisture sensitivity eliminates pre-bake requirements, enabling direct placement into high-volume SMT lines without process modification.

How does the SOT323 package affect thermal performance compared to SOD-123?

SOT323 has higher thermal resistance (R_θJA = 625 °C/W) than SOD-123 (~300 °C/W) due to smaller copper pad area and thinner leadframe. To maintain 200 mW rating, PCB layout must follow Diodes' AP02001 recommended pads - minimum 12 mm² copper pour per terminal - otherwise derating below 25 °C ambient is required.

Can MMBZ5239BW-7 be used in series for higher voltage reference?

No. Zener diodes in series exhibit mismatched temperature coefficients and dynamic impedances, causing unstable combined voltage. For >9.1 V references, use a single higher-voltage Zener (e.g., MMBZ5242BW for 12 V) or a dedicated voltage reference IC with trimmed TC and low drift.