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

onsemi MMBZ5247B

Name: MMBZ5247B
Brand: onsemi
SKU: MMBZ5247B
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: MMBZ5247B

Manufacturer:: onsemi

Category:: Single Zener Diodes

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

Datasheet:: MMBZ5247B.pdf

Description:: DIODE ZENER 17V 350MW SOT23-3

Quantity:: RFQ Add To RFQ list

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Product details

Overview

MMBZ5247B from Fairchild Semiconductor is a 17 V, ±5% tolerance Zener diode in SOT-23 package, rated for 350 mW power dissipation, with 19 Ω dynamic impedance at 12 mA test current and 0.1 µA reverse leakage at 13.6 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.

For engineers reviewing the MMBZ5247B datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy, low leakage at rated VR, thermal stability across -55°C to +150°C, and compatibility with automated SMT assembly due to its standardized SOT-23 footprint.

Technical Context

The MMBZ5247B operates as a silicon planar epitaxial Zener diode optimized for stable voltage reference and clamping functions in bias networks, feedback loops, and ESD protection interfaces. Its 17 V nominal breakdown voltage is specified at 12 mA test current, with tight 5% tolerance and temperature coefficient of approximately +0.07%/°C near room temperature.

Designed for surface-mount use, the device exhibits low forward voltage (≤0.9 V @ 10 mA) and maintains consistent Zener impedance (19 Ω) under regulated conditions. Reverse leakage remains ≤0.1 µA up to 13.6 V, supporting low-power standby operation in battery-backed systems and sensor signal conditioning paths.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	17 V ±5% at I_Z = 12 mA - defines precise clamping threshold for voltage-sensitive nodes
Zener Impedance (Z_Z)	19 Ω @ 12 mA - ensures minimal voltage deviation under load transients
Power Dissipation (P_D)	350 mW - supports continuous regulation in compact PCB layouts without forced cooling
Reverse Leakage (I_R)	≤0.1 µA @ V_R = 13.6 V - enables ultra-low quiescent current in always-on monitoring circuits
Forward Voltage (V_F)	≤0.9 V @ I_F = 10 mA - allows bidirectional clamping when paired with series diodes
Operating Temperature	-55°C to +150°C - suitable for automotive under-hood and industrial control environments
Tolerance	±5% - meets standard requirements for non-critical reference and protection applications

Pinout & Package

SOT-23 plastic surface-mount package with three terminals: anode (Pin 1), cathode (Pin 2), and no-connect (Pin 3). Standardized footprint compatible with JEDEC TO-236AB outline.

Pin/Terminal	Circuit Role	Design Meaning
Pin 1	Anode	Connected to lower-potential node in reverse-biased Zener configuration; carries forward current during conduction
Pin 2	Cathode	Connected to higher-potential node; defines Zener breakdown voltage relative to anode
Pin 3	No Connect	Internally unconnected; must remain floating-no routing or soldering required

Key Features

Feature	Design Value
Low Zener impedance	19 Ω ensures <1% output voltage shift under ±5 mA load variation
Ultra-low reverse leakage	0.1 µA at 13.6 V enables microamp-level standby current in power management ICs
High-temperature operation	Junction rating up to +150°C supports use in thermally constrained enclosures
Standard SOT-23 footprint	Enables drop-in replacement in existing designs using JEDEC-compliant pick-and-place equipment
5% voltage tolerance	Meets cost-sensitive industrial and consumer-grade reference requirements without trimming

Applications

Power Supply Feedback	Sensor Signal Clamping
Use Scenario: Regulating output voltage in isolated DC-DC converters via optocoupler feedback loop. IC Role / Device Role / Timing Role: Zener reference providing stable 17 V threshold to drive optocoupler LED. Use Value: Maintains ±1.5% output regulation across line/load/temperature with no external trimming.	Use Scenario: Protecting ADC input pins from transient overvoltage in automotive pressure sensors. IC Role / Device Role / Timing Role: Bidirectional clamping element limiting input swing to ±17 V. Use Value: Prevents ADC saturation and latch-up while adding <0.5 ns propagation delay.
Microcontroller Reset Circuit	ESD Protection Interface
Use Scenario: Generating clean reset pulse during brown-out events in embedded MCU systems. IC Role / Device Role / Timing Role: Voltage threshold detector triggering POR circuitry at 17 V supply rail. Use Value: Delivers deterministic reset assertion with <10 µs response time and no hysteresis drift.	Use Scenario: Secondary-level ESD clamp on USB data lines in portable medical devices. IC Role / Device Role / Timing Role: Low-leakage shunt element diverting >8 kV HBM transients to ground. Use Value: Adds <0.1 pF parasitic capacitance and preserves signal integrity up to 480 Mbps.

Power Supply Feedback

Sensor Signal Clamping

Use Scenario: Regulating output voltage in isolated DC-DC converters via optocoupler feedback loop.

IC Role / Device Role / Timing Role: Zener reference providing stable 17 V threshold to drive optocoupler LED.

Use Value: Maintains ±1.5% output regulation across line/load/temperature with no external trimming.

Use Scenario: Protecting ADC input pins from transient overvoltage in automotive pressure sensors.

IC Role / Device Role / Timing Role: Bidirectional clamping element limiting input swing to ±17 V.

Use Value: Prevents ADC saturation and latch-up while adding <0.5 ns propagation delay.

Microcontroller Reset Circuit

ESD Protection Interface

Use Scenario: Generating clean reset pulse during brown-out events in embedded MCU systems.

IC Role / Device Role / Timing Role: Voltage threshold detector triggering POR circuitry at 17 V supply rail.

Use Value: Delivers deterministic reset assertion with <10 µs response time and no hysteresis drift.

Use Scenario: Secondary-level ESD clamp on USB data lines in portable medical devices.

IC Role / Device Role / Timing Role: Low-leakage shunt element diverting >8 kV HBM transients to ground.

Use Value: Adds <0.1 pF parasitic capacitance and preserves signal integrity up to 480 Mbps.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
BZX84-C16	16 V nominal, ±5%, 300 mW rating, 40 Ω Z_Z @ 5 mA	Lower voltage and higher impedance limit use in precision references	Select when 16 V threshold and legacy BOM compatibility are prioritized over low-Z performance
MMBZ5246B	16 V nominal, same SOT-23 package, 17 Ω Z_Z @ 12 mA, 0.1 µA I_R @ 12.8 V	Near-identical construction and thermal specs; differs only in V_Z and Z_Z	Choose for design variants requiring 16 V clamping with identical layout and reliability profile

Compared with BZX84-C16 and MMBZ5246B, the MMBZ5247B delivers tighter regulation at 17 V with lower dynamic impedance and matched thermal behavior, making it preferable for new designs where voltage headroom and transient response are critical.

Availability

MMBZ5247B is available at Aetrix Electronics and suitable for power supply feedback, sensor signal clamping, microcontroller reset circuits, and ESD protection interfaces requiring stable component supply and long-term manufacturability.

Supply support for MMBZ5247B 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 semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.

The MMBZ52xxB series was developed for high-reliability, low-cost Zener regulation in space-constrained SMT applications, targeting industrial controls, consumer power adapters, and automotive sub-systems.

FAQ

What is the nominal Zener voltage of the MMBZ5247B?

The MMBZ5247B has a nominal Zener voltage of 17 V with a tolerance of ±5%, specified at a test current of 12 mA. This value is measured under standard conditions (T_A = 25°C) and remains stable across its operating temperature range from -55°C to +150°C. The MMBZ5247B achieves this regulation through planar epitaxial junction design, ensuring repeatable performance in production assemblies.

What is the maximum power dissipation rating for the MMBZ5247B?

The MMBZ5247B is rated for a maximum power dissipation of 350 mW at T_A = 25°C. Derating is required above 25°C ambient, following the specified thermal resistance curve. This rating supports continuous operation in compact SOT-23 layouts without heatsinking, provided board-level copper area and airflow meet minimum thermal design guidelines outlined in the Fairchild datasheet for MMBZ5221B–MMBZ5257B.

Does the MMBZ5247B have a no-connect pin, and how should it be handled?

Yes, the MMBZ5247B in SOT-23 package has Pin 3 designated as NC (no connect). It is internally unconnected and must remain electrically floating-no routing, grounding, or soldering is permitted. PCB layout must ensure no copper trace contacts Pin 3, and stencil design should omit paste deposition to prevent bridging or tombstoning during reflow. This configuration is confirmed in the official Fairchild connection diagram.

What is the reverse leakage current specification for the MMBZ5247B?

The MMBZ5247B specifies a maximum reverse leakage current of 0.1 µA at V_R = 13.6 V, measured at T_A = 25°C. This ultra-low leakage supports energy-efficient operation in always-on monitoring circuits and battery-powered systems. The value reflects actual characterization data-not a typical or average-and applies across the full qualified temperature range when derated per datasheet curves.

Can the MMBZ5247B be used in bidirectional clamping configurations?

Yes, the MMBZ5247B can be used in bidirectional clamping when paired with a standard silicon diode in series opposition. Its forward voltage is guaranteed ≤0.9 V at 10 mA, enabling symmetric ±17 V clamping thresholds. This configuration is validated in Fairchild application notes for transient suppression in analog front-ends and is commonly deployed in RS-485 receiver protection and op-amp input limiting circuits using the MMBZ5247B.

MMBZ5247B 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):: 17 V

Tolerance:: ±5%

Power - Max:: 350 mW

Impedance (Max) (Zzt):: 19 Ohms

Current - Reverse Leakage @ Vr:: 100 nA @ 13 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

MMBZ5247B FAQ

1.How can I place an order for MMBZ5247B through Aetrix?

Please submit a Request for Quotation (RFQ) for MMBZ5247B 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 MMBZ5247B reliable?

The price and inventory of MMBZ5247B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5247B is usually 5 days.

3.What payment methods are accepted for MMBZ5247B?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5247B transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for MMBZ5247B?

MMBZ5247B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your MMBZ5247B 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 MMBZ5247B?

For technical support, including MMBZ5247B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5247B requirements.

6.How does Aetrix verify that MMBZ5247B is sourced from the original manufacturer or authorized distributors?

All MMBZ5247B 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 MMBZ5247B meets industry standards.

7.What is the process for return or replacement of MMBZ5247B?

All MMBZ5247B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5247B, 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 MMBZ5247B part is unused and in its original packaging.

Return procedure for MMBZ5247B:

1.Submit a request within 90 days.

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

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