Diodes Incorporated MMBZ5250BW-7

Overview

MMBZ5250BW-7 from Diodes Incorporated is a 20 V, 200 mW surface-mount Zener diode in SOT323 package, with nominal zener voltage 20.0 V (min 19.0 V, max 21.0 V), test current 6.2 mA, and zener impedance 25 Ω at 1 kHz. It provides precision voltage regulation in low-power biasing and reference circuits, such as power supply feedback networks and analog sensor excitation.

For engineers reviewing the MMBZ5250BW-7 datasheet, MMBZ5250BW-7 pinout, MMBZ5250BW-7 application, or MMBZ5250BW-7 equivalent, key selection criteria include zener voltage tolerance (±5%), low leakage (<0.1 µA at 15 V), thermal resistance (625 °C/W), and AEC-Q101 qualification for automotive-grade reliability.

Technical Context

This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load or input conditions. Its 20 V nominal zener voltage is specified at 6.2 mA test current, with dynamic impedance of 25 Ω measured at 1 kHz - critical for minimizing output ripple in reference paths.

The device uses a planar epitaxial construction and is packaged in a lead-free, halogen-free SOT323 case rated for -65 °C to +150 °C operation. Its 200 mW power dissipation is derated linearly above +25 °C ambient per the published curve, with junction-to-ambient thermal resistance fixed at 625 °C/W on FR4 board with recommended pad layout.

Key Specifications

Pinout & Package

Package: SOT323 - ultra-small plastic surface-mount case (2.10 mm × 1.30 mm × 0.90 mm), matte tin-plated alloy 42 leads, moisture sensitivity level 1, weight ≈ 0.006 g.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZX84-C20LT1G and MMSZ5250ET1G, MMBZ5250BW-7 offers tighter leakage (<0.1 µA), AEC-Q101 compliance, and smallest footprint - making it optimal for space-constrained automotive and portable medical designs requiring long-term voltage stability.

Availability

MMBZ5250BW-7 is available at Aetrix Electronics and suitable for automotive engine control units, industrial sensor transmitters, and portable medical diagnostic instruments requiring stable component supply and long-lifecycle support.

Supply support for MMBZ5250BW-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, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.

The MMBZ52xxBW series belongs to Diodes' precision Zener diode product line, engineered specifically for high-reliability voltage reference and regulation in automotive, industrial, and consumer power management systems.

FAQ

What is the maximum reverse voltage (V_R) that can be applied before significant leakage occurs?

The datasheet specifies maximum reverse leakage current I_R ≤ 0.1 µA at V_R = 15 V. At 19 V (just below nominal zener voltage), leakage remains below 1 µA. Operation above 15 V in non-breakdown mode is not recommended - the device is designed to operate in controlled reverse breakdown at or above 19.0 V with appropriate current limiting.

Is MMBZ5250BW-7 compatible with lead-free reflow soldering profiles?

Yes - the device is fully RoHS-compliant with matte tin finish on alloy 42 leads and qualified for standard lead-free reflow profiles (J-STD-020D Level 1). Its SOT323 package withstands peak temperatures up to 260 °C for 30 seconds, and moisture sensitivity level 1 eliminates bake requirements prior to assembly.

How does the zener impedance affect regulation performance in a feedback loop?

With Z_ZT = 25 Ω at 6.2 mA, the MMBZ5250BW-7 introduces minimal AC impedance into the reference path. In a switching regulator feedback network, this keeps loop gain variation under ±3% across load steps - directly improving transient response and output voltage stability compared to higher-impedance alternatives (>50 Ω).

Can this Zener diode replace a 20 V TL431-based shunt regulator?

No - the MMBZ5250BW-7 is a passive two-terminal Zener, lacking the active feedback, adjustable threshold, and 100 mA sink capability of the TL431. It serves only as a fixed-voltage reference or simple shunt limiter (<10 mA). For programmable or high-current regulation, a TL431 or similar IC remains necessary; this diode complements such circuits as a precision voltage clamp or bias source.