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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

Diodes Incorporated MMBZ5254B-7-F

Name: MMBZ5254B-7-F
Brand: Diodes Incorporated
SKU: MMBZ5254B-7-F
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBZ5254B-7-F

Manufacturer:: Diodes Incorporated

Category:: Single Zener Diodes

Package:: TO-236-3, SC-59, SOT-23-3

Datasheet:: MMBZ5254B-7-F.pdf

Description:: DIODE ZENER 27V 350MW SOT23-3

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Inventory:87,685

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Product details

Overview

MMBZ5254B-7-F from Diodes Incorporated is a 27 V, 350 mW surface-mount Zener diode in SOT23 package, with nominal Zener voltage tolerance ±3.7%, dynamic impedance 41 Ω at 5 mA test current, and reverse leakage ≤0.1 µA at 21 V, used for precision voltage regulation and overvoltage protection in low-power analog sensor interfaces.

For engineers reviewing the MMBZ5254B-7-F datasheet, MMBZ5254B-7-F pinout, MMBZ5254B-7-F application, or MMBZ5254B-7-F equivalent, key selection criteria include Zener voltage accuracy at low test current (5 mA), thermal resistance (357 °C/W on FR-4), moisture sensitivity level (MSL 1), and RoHS-compliant green molding compound.

Technical Context

This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its planar die construction ensures consistent breakdown characteristics and low leakage across production lots.

Designed for automated SMT assembly, it delivers specified Zener voltage (25.65–28.35 V) with tight distribution and supports operation from –65 °C to +150 °C ambient, with power derating beginning above +25 °C per Figure 1.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	27 V nominal, 25.65–28.35 V range at I_ZT = 5 mA - defines regulated output voltage tolerance in reference circuits
Power Dissipation (P_D)	350 mW on FR-4 PCB - sets maximum continuous power handling without heatsinking
Zener Impedance (Z_ZT)	41 Ω at I_ZT = 5 mA - determines regulation stiffness and output voltage variation under load changes
Reverse Leakage (I_R)	≤0.1 µA at V_R = 21 V - ensures minimal error current in high-impedance bias/reference networks
Thermal Resistance (R_θJA)	357 °C/W - quantifies junction-to-ambient temperature rise per watt dissipated on standard FR-4 layout
Operating Temperature	–65 °C to +150 °C - enables use in extended industrial and automotive under-hood environments

Pinout & Package

Package: SOT23 - 3-pin surface-mount plastic package with matte tin-plated alloy 42 leadframe, UL 94V-0 rated, 0.008 g weight, MSL Level 1.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Pin 1)	Forward conduction terminal / cathode reference ground	Connected to circuit ground or lower-potential node when used as shunt regulator
Cathode (Pin 2)	Zener breakdown terminal / regulated output node	Connected to input supply via series resistor; provides stable 27 V reference to load
No-Connect (Pin 3)	Internal die attach flag / mechanical support	Not electrically connected; serves structural role in SOT23 mold compound anchoring

Key Features

Feature	Design Value
Planar die construction	Ensures repeatable Zener voltage distribution and low parameter drift over time and temperature
350 mW dissipation on FR-4	Enables direct integration into standard PCB layouts without thermal vias or copper pours
MSL Level 1 rating	Allows unlimited floor life and reflow without baking-reduces manufacturing overhead
Halogen- and antimony-free "Green" compound	Meets IPC-1752A material declaration requirements for environmental compliance reporting
Lead-free and RoHS 3 compliant	Supports global market access including EU, China, Korea, and Turkey without exemptions

Applications

Industrial Sensor Signal Conditioning

USB-C Power Delivery Reference Clamp

Use Scenario: Stabilizing excitation voltage for 4–20 mA loop-powered pressure transmitters operating in factory-floor environments.

IC Role / Device Role / Timing Role: Shunt Zener reference providing 27 V rail clamp and precision bias for op-amp instrumentation stages.

Use Value: Maintains <±1% output stability over –40 °C to +85 °C due to low tempco and 41 Ω Z_ZT, reducing calibration drift.

Use Scenario: Overvoltage protection for USB-C CC line monitoring circuitry during hot-plug events with transient surges up to 20 V.

IC Role / Device Role / Timing Role: Fast-acting clamping diode limiting CC pin voltage to safe levels before controller IC damage occurs.

Use Value: Sub-µA leakage at 21 V prevents false detection while 27 V Zener threshold avoids interference with normal 5 V CC signaling.

Automotive Cabin Control Panel ESD Protection

Medical Wearable Battery Monitoring Reference

Use Scenario: Protecting touch-button microcontroller inputs against ISO 10605 ESD pulses in vehicle dashboard assemblies.

IC Role / Device Role / Timing Role: Low-capacitance Zener clamp absorbing 15 kV air discharge energy without latch-up.

Use Value: 0.1 µA leakage preserves MCU wake-up current budget; SOT23 footprint fits tight button trace routing.

Use Scenario: Providing stable reference for lithium-ion cell voltage measurement in compact ECG patch devices.

IC Role / Device Role / Timing Role: Precision shunt reference enabling 12-bit ADC full-scale accuracy across battery discharge curve.

Use Value: Tight 25.65–28.35 V tolerance eliminates need for post-calibration trimming in volume production.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C27LT1G	Zener voltage 27 V ±5%, Z_ZT = 50 Ω at 5 mA, P_D = 300 mW, same SOT23 package	Higher impedance reduces regulation accuracy in low-current references; lower power rating limits sustained clamp duty	Select when cost sensitivity outweighs regulation precision and thermal margin requirements
MMBZ5254BS-7-F	Same electrical specs but SOT23-3 (standard) vs. SOT23 (Diodes' proprietary variant); identical marking and thermal performance	No functional difference; dual-sourced for supply chain resilience without design change	Choose for second-source assurance with zero redesign effort or qualification overhead

Compared with BZX84-C27LT1G and MMBZ5254BS-7-F, MMBZ5254B-7-F offers tighter voltage tolerance (±3.7% vs. ±5%), lower Zener impedance (41 Ω vs. 50 Ω), and higher power rating (350 mW vs. 300 mW), making it preferred for high-stability reference and repetitive surge-clamp roles.

Availability

MMBZ5254B-7-F is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB-C power delivery reference clamping, and automotive cabin control panel ESD protection requiring stable component supply across multi-year production cycles.

Supply support for MMBZ5254B-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.

This device belongs to the MMBZ52xxB family of 350 mW Zener diodes engineered for high-reliability voltage regulation in space-constrained, thermally demanding applications such as automotive infotainment, industrial PLC I/O modules, and portable medical electronics.

FAQ

What is the maximum reverse voltage (V_R) at which leakage remains ≤0.1 µA?

The MMBZ5254B-7-F guarantees reverse leakage current ≤0.1 µA at V_R = 21 V, as specified in the Electrical Characteristics table. This value is measured under DC conditions at +25 °C ambient and defines the upper limit of applied reverse voltage before significant leakage begins to affect high-impedance reference nodes.

Can this Zener diode be used in parallel for higher power handling?

No-MMBZ5254B-7-F must not be paralleled due to inherent Zener voltage mismatch between units, which causes current hogging and thermal runaway. For higher power needs, select a single higher-rated Zener (e.g., 1 W through-hole part) or implement active regulation instead.

Is the SOT23 package lead-free and RoHS-compliant?

Yes-the MMBZ5254B-7-F uses matte tin finish over alloy 42 leadframe, contains no intentionally added lead, and meets EU RoHS 2015/863/EU (RoHS 3), JEDEC J-STD-020 MSL Level 1, and Diodes' halogen/antimony-free "Green" specifications (<900 ppm Br, <900 ppm Cl, <1000 ppm Sb).

What is the recommended pad layout for optimal thermal performance?

Diodes specifies a SOT23 pad layout with X = 0.8 mm, Y = 0.9 mm, X1 = 1.35 mm, Y1 = 2.9 mm, and C = 2.0 mm (center-to-center). This layout achieves the rated 357 °C/W R_θJA on FR-4; deviations increase thermal resistance and reduce safe operating area.

MMBZ5254B-7-F Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: TO-236-3, SC-59, SOT-23-3

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 27 V

Tolerance:: ±5%

Power - Max:: 350 mW

Impedance (Max) (Zzt):: 41 Ohms

Current - Reverse Leakage @ Vr:: 100 nA @ 21 V

Voltage - Forward (Vf) (Max) @ If:: 900 mV @ 10 mA

Operating Temperature:: -65°C ~ 150°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

MMBZ5254B-7-F FAQ

1.How can I place an order for MMBZ5254B-7-F through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBZ5254B-7-F on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for MMBZ5254B-7-F reliable?

The price and inventory of MMBZ5254B-7-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5254B-7-F is usually 5 days.

3.What payment methods are accepted for MMBZ5254B-7-F?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5254B-7-F transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBZ5254B-7-F?

MMBZ5254B-7-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBZ5254B-7-F order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for MMBZ5254B-7-F?

For technical support, including MMBZ5254B-7-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5254B-7-F requirements.

6.How does Aetrix verify that MMBZ5254B-7-F is sourced from the original manufacturer or authorized distributors?

All MMBZ5254B-7-F products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MMBZ5254B-7-F meets industry standards.

7.What is the process for return or replacement of MMBZ5254B-7-F?

All MMBZ5254B-7-F units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5254B-7-F, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The MMBZ5254B-7-F part is unused and in its original packaging.

Return procedure for MMBZ5254B-7-F:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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