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

onsemi MMBZ5223B

Name: MMBZ5223B
Brand: onsemi
SKU: MMBZ5223B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBZ5223B

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: MMBZ5223B.pdf

Description:: DIODE ZENER 2.7V 350MW SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MMBZ5223B from Fairchild Semiconductor is a 2.7 V, 350 mW surface-mount Zener diode in SOT-23 package, with 30 Ω dynamic impedance at 20 mA test current, 0.25 µA reverse leakage at 1.0 V, and maximum 0.9 V forward voltage at 10 mA - used for precision voltage reference and overvoltage protection in low-power sensor interfaces and portable power rails.

For engineers reviewing the MMBZ5223B datasheet, pinout, applications, or equivalent options, key selection criteria include its tight 5% tolerance, low Zener impedance, stable temperature coefficient, and compatibility with space-constrained PCB layouts requiring reliable clamping below 3 V.

Technical Context

The MMBZ5223B operates as a silicon planar Zener diode optimized for low-voltage regulation and transient suppression in DC bias networks. Its 2.7 V nominal breakdown voltage is specified at I_Z = 20 mA, with Zener impedance (Z_Z) of 30 Ω and knee impedance (Z_ZK) of 20 Ω at I_ZK = 1.0 mA.

It exhibits a typical temperature coefficient near zero for voltages below 5 V, enabling stable reference performance across –55°C to +150°C operating junction range. The device is rated for 350 mW steady-state power dissipation and supports forward conduction up to 10 mA with ≤0.9 V drop.

Key Specifications

Parameter	Value and Actual Design Meaning
V_Z Nominal	2.7 V ±5% - defines precise clamping threshold for 3 V rail stabilization and low-voltage reference generation
P_D	350 mW - sets maximum continuous power handling in compact SOT-23 footprint without derating below 25°C
Z_Z	30 Ω @ I_Z = 20 mA - ensures minimal voltage deviation under load variation in feedback or sensing circuits
I_R	0.25 µA @ V_R = 1.0 V - guarantees negligible leakage in high-impedance bias networks and battery-backed systems
V_F	≤0.9 V @ I_F = 10 mA - enables use as forward-biased clamp or level shifter in dual-direction protection schemes
T_J Max	+150°C - supports operation in thermally demanding environments including automotive cabin electronics and industrial controllers

Pinout & Package

SOT-23 plastic surface-mount package with three terminals: anode (Pin 1), cathode (Pin 2), and no-connect (Pin 3). Pin 3 is internally unconnected and must remain floating per datasheet connection diagram.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Anode	Connected to lower-potential node; forward conduction path when biased positive relative to cathode
Pin 2	Cathode	Connected to higher-potential node; Zener breakdown occurs when reverse voltage exceeds 2.7 V
Pin 3	No-connect	Internally isolated; must not be soldered or tied to any net to avoid parametric shift or failure

Key Features

Feature	Design Value
5% Zener voltage tolerance	Enables accurate voltage setting without external trimming in cost-sensitive consumer and IoT power monitors
Low 30 Ω dynamic impedance	Maintains <±20 mV regulation error across 5–25 mA load current changes in reference divider networks
0.25 µA max reverse leakage	Preserves battery life in always-on sensor nodes by minimizing standby current draw below 1 µA
SOT-23 footprint	Supports automated placement and reflow on high-density PCBs with 2.9 mm × 1.3 mm board area allocation

Applications

USB Port ESD Clamp	Low-Voltage Microcontroller Reset Circuit
Use Scenario: Protecting USB D+ and D− lines from ±8 kV contact ESD per IEC 61000-4-2. IC Role / Device Role / Timing Role: Bidirectional transient voltage suppressor placed between signal line and ground, leveraging Zener action in both polarities. Use Value: Clamps transients to ≤3.5 V peak using 2.7 V Zener voltage and low Z_Z, preventing damage to 3.3 V USB PHY inputs.	Use Scenario: Generating a clean, temperature-stable reset signal for ARM Cortex-M0+ MCUs during brown-out conditions. IC Role / Device Role / Timing Role: Precision voltage reference feeding comparator input in discrete reset generator circuit. Use Value: Delivers 2.7 V reference with <±0.15 V drift over –40°C to +85°C, ensuring deterministic reset assertion at 2.85 V supply threshold.
Li-ion Battery Cell Monitor Reference	Industrial Sensor Signal Conditioning
Use Scenario: Providing stable reference for ADC measurement of individual 3.7 V Li-ion cell voltage in 4S BMS modules. IC Role / Device Role / Timing Role: Low-drift Zener reference source for ratiometric voltage divider scaling. Use Value: Maintains reference accuracy within ±0.135 V over full temperature range, enabling <1% cell voltage measurement error without calibration.	Use Scenario: Biasing op-amp input stage in 4–20 mA loop transmitter with 24 V supply and 3.3 V microcontroller interface. IC Role / Device Role / Timing Role: Voltage clamp limiting op-amp common-mode input to safe range during fault conditions. Use Value: Prevents op-amp saturation and latch-up by clamping inputs to ≤2.7 V above ground, compatible with rail-to-rail input amplifiers.

USB Port ESD Clamp

Low-Voltage Microcontroller Reset Circuit

Use Scenario: Protecting USB D+ and D− lines from ±8 kV contact ESD per IEC 61000-4-2.

IC Role / Device Role / Timing Role: Bidirectional transient voltage suppressor placed between signal line and ground, leveraging Zener action in both polarities.

Use Value: Clamps transients to ≤3.5 V peak using 2.7 V Zener voltage and low Z_Z, preventing damage to 3.3 V USB PHY inputs.

Use Scenario: Generating a clean, temperature-stable reset signal for ARM Cortex-M0+ MCUs during brown-out conditions.

IC Role / Device Role / Timing Role: Precision voltage reference feeding comparator input in discrete reset generator circuit.

Use Value: Delivers 2.7 V reference with <±0.15 V drift over –40°C to +85°C, ensuring deterministic reset assertion at 2.85 V supply threshold.

Li-ion Battery Cell Monitor Reference

Industrial Sensor Signal Conditioning

Use Scenario: Providing stable reference for ADC measurement of individual 3.7 V Li-ion cell voltage in 4S BMS modules.

IC Role / Device Role / Timing Role: Low-drift Zener reference source for ratiometric voltage divider scaling.

Use Value: Maintains reference accuracy within ±0.135 V over full temperature range, enabling <1% cell voltage measurement error without calibration.

Use Scenario: Biasing op-amp input stage in 4–20 mA loop transmitter with 24 V supply and 3.3 V microcontroller interface.

IC Role / Device Role / Timing Role: Voltage clamp limiting op-amp common-mode input to safe range during fault conditions.

Use Value: Prevents op-amp saturation and latch-up by clamping inputs to ≤2.7 V above ground, compatible with rail-to-rail input amplifiers.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C2V7	Same 2.7 V nominal, 5% tolerance, but 400 mW P_D and 60 Ω Z_Z @ 5 mA	Higher power rating allows greater surge handling; higher Z_Z reduces regulation precision at low currents	Select for higher-energy transient suppression where tighter regulation is secondary to robustness
MMBZ5223BS	Identical electrical specs but in SOD-323 package (smaller footprint, lower thermal mass)	Reduced thermal time constant limits sustained power handling; unsuitable for >100 ms pulse applications	Select only when board area is constrained and average power remains <150 mW

Compared with BZX84-C2V7 and MMBZ5223BS, the MMBZ5223B offers optimal balance of regulation precision (30 Ω Z_Z), thermal capability (350 mW), and SOT-23 manufacturability - making it preferred for production-grade 2.7 V reference and clamping in volume consumer and industrial designs.

Availability

MMBZ5223B is available at Aetrix Electronics and suitable for USB port protection, microcontroller reset generation, Li-ion battery monitoring, and industrial sensor signal conditioning requiring stable component supply and consistent parametric performance across production lots.

Supply support for MMBZ5223B 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 analog and power semiconductor manufacturer acquired by ON Semiconductor in 2016; known for high-reliability discrete devices and broad portfolio of Zener, TVS, and MOSFET products.

The MMBZ52xxB series was designed specifically for space-constrained, low-power voltage regulation and protection in portable electronics, instrumentation, and automotive body-control modules - emphasizing tight tolerance, low leakage, and SMT compatibility.

FAQ

What is the maximum reverse voltage rating for MMBZ5223B before breakdown?

The MMBZ5223B has a nominal Zener voltage (V_Z) of 2.7 V at 20 mA test current, with a guaranteed breakdown range of 2.565 V to 2.835 V (±5%). It is not rated for continuous reverse operation above this range; exceeding V_Z triggers controlled avalanche conduction. The absolute maximum reverse voltage is defined by its power limit: at 25°C, 350 mW dissipation corresponds to ~13 mA at 2.7 V.

Can MMBZ5223B be used in forward-bias mode like a standard diode?

Yes, the MMBZ5223B functions as a standard silicon diode in forward bias, with a maximum forward voltage (V_F) of 0.9 V at 10 mA. This allows dual-use configurations - for example, as a bidirectional clamp where forward conduction protects against negative transients and Zener action handles positive overvoltage - provided current limits and thermal design are observed.

Is MMBZ5223B RoHS compliant and halogen-free?

Yes, MMBZ5223B manufactured under Fairchild's Rev. A2 specification (2004) meets RoHS Directive 2002/95/EC requirements and is halogen-free per J-STD-709 definition. Lead-free soldering compatibility is confirmed for reflow profiles up to 260°C peak, and the SOT-23 package uses matte tin plating on copper leadframe.

How does temperature affect the Zener voltage of MMBZ5223B?

The MMBZ5223B exhibits a near-zero temperature coefficient around 2.7 V, with typical V_Z drift of ±0.002%/°C. Over –55°C to +150°C, total variation remains within ±20 mV - significantly tighter than higher-voltage Zeners. This stability makes it suitable for uncalibrated references in wide-temperature industrial sensors and automotive modules.

What is the role of Pin 3 (NC) in the SOT-23 package of MMBZ5223B?

Pin 3 in the MMBZ5223B SOT-23 package is a no-connect terminal - internally unconnected and electrically isolated. It must not be soldered to any trace or plane. Leaving Pin 3 floating avoids parasitic coupling, prevents unintended current paths, and ensures specified Zener voltage and impedance parameters remain valid per the original Fairchild datasheet.

MMBZ5223B Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: -

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

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Voltage - Zener (Nom) (Vz):: 2.7 V

Tolerance:: ±5%

Power - Max:: 350 mW

Impedance (Max) (Zzt):: 30 Ohms

Current - Reverse Leakage @ Vr:: 75 µA @ 1 V

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

Operating Temperature:: -55°C ~ 150°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-3

MMBZ5223B FAQ

1.How can I place an order for MMBZ5223B through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBZ5223B 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 MMBZ5223B reliable?

The price and inventory of MMBZ5223B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5223B is usually 5 days.

3.What payment methods are accepted for MMBZ5223B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5223B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBZ5223B?

MMBZ5223B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBZ5223B 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 MMBZ5223B?

For technical support, including MMBZ5223B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5223B requirements.

6.How does Aetrix verify that MMBZ5223B is sourced from the original manufacturer or authorized distributors?

All MMBZ5223B 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 MMBZ5223B meets industry standards.

7.What is the process for return or replacement of MMBZ5223B?

All MMBZ5223B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5223B, 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 MMBZ5223B part is unused and in its original packaging.

Return procedure for MMBZ5223B:

1.Submit a request within 90 days.

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

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