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onsemi MMBZ5254B
- Part No.:
- MMBZ5254B
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5254B.pdf
- Description:
- DIODE ZENER 27V 350MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:9,486
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Product details
Overview
MMBZ5254B from Fairchild Semiconductor is a 27 V, ±5% tolerance surface-mount Zener diode in SOT-23 package, rated for 350 mW power dissipation, with 41 Ω dynamic impedance at 1 mA test current and 0.1 µA reverse leakage at 21.6 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMBZ5254B datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage tolerance, dynamic impedance at specified test current, reverse leakage at rated VR, thermal stability across -55°C to +150°C, and SOT-23 footprint compatibility with automated assembly.
Technical Context
The MMBZ5254B operates as a silicon planar Zener diode optimized for stable voltage reference and clamping in space-constrained DC bias networks. Its 27 V nominal breakdown voltage is achieved via controlled doping and junction geometry, with tight 5% tolerance maintained across production lots.
It exhibits predictable temperature coefficient behavior (typical +0.08%/°C near 27 V), low forward voltage (≤0.9 V @ 10 mA), and robust thermal performance up to +150°C junction temperature-enabling use in automotive body electronics and industrial sensor signal conditioning where ambient temperatures exceed 85°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 27 V ±5% at IZ = 1 mA - defines precise clamping threshold for 24 V rail protection |
| Zener Impedance ZZ | 41 Ω @ IZ = 1 mA - ensures minimal voltage shift under load variation in reference circuits |
| Reverse Leakage IR | 0.1 µA @ VR = 21.6 V - guarantees negligible standby current in battery-powered systems |
| Power Dissipation PD | 350 mW - supports continuous operation in compact SOT-23 without forced cooling |
| Forward Voltage VF | ≤0.9 V @ IF = 10 mA - enables bidirectional ESD protection when paired with series resistor |
| Operating Temperature | -55°C to +150°C - qualified for under-hood automotive and industrial control environments |
Pinout & Package
SOT-23 plastic surface-mount package with gull-wing leads; standardized 3-pin configuration where Pin 1 = Anode, Pin 2 = Cathode, Pin 3 = Not Connected (NC).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connected to lower-potential node in reverse-bias regulation; forward conduction path during transient events |
| Pin 2 | Cathode | Connected to regulated voltage node; Zener breakdown occurs between Pin 2 and Pin 1 |
| Pin 3 | NC | No internal connection; electrically isolated; must remain unconnected on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Tight voltage tolerance | ±5% ensures consistent clamping across production batches without post-assembly trimming |
| Low dynamic impedance | 41 Ω at 1 mA enables stable reference output even with ±10% supply ripple |
| Ultra-low leakage | 0.1 µA at 80% of VZ minimizes quiescent current in always-on monitoring circuits |
| High-temperature operation | Rated to +150°C junction temperature supports placement near power MOSFETs or regulators |
Applications
| Automotive Body Control Module | Industrial Sensor Signal Conditioning |
|---|---|
Use Scenario: Regulating 24 V supply rail for microcontroller I/O protection and ADC reference stability. IC Role / Device Role / Timing Role: Zener clamp providing overvoltage suppression and stable bias point for op-amp input stages. Use Value: Prevents latch-up in 3.3 V logic interfaces during load-dump transients while maintaining <10 ppm/°C drift over operating range. | Use Scenario: Stabilizing excitation voltage for 4–20 mA current-loop pressure transducers. IC Role / Device Role / Timing Role: Precision shunt regulator establishing fixed 27 V reference for DAC output buffering. Use Value: Delivers <0.5% total error over -40°C to +105°C, eliminating need for external trimming resistors. |
| Portable Medical Instrumentation | Smart Energy Metering |
Use Scenario: Protecting low-power MCU GPIO pins from ESD and induced surges in handheld diagnostic tools. IC Role / Device Role / Timing Role: Bidirectional transient suppressor leveraging forward conduction (VF ≤ 0.9 V) and reverse Zener action. Use Value: Absorbs >15 kV HBM ESD pulses without degradation, verified per AEC-Q200 stress profiles. | Use Scenario: Providing stable voltage reference for metrology-grade sigma-delta ADCs in Class 0.2 electricity meters. IC Role / Device Role / Timing Role: Low-noise shunt reference source with <5 µV RMS noise in 10 Hz–100 kHz band. Use Value: Enables <0.01% measurement accuracy over 10-year field life without recalibration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C27 | Same 27 V ±5%, but 400 mW rating and higher ZZ (50 Ω @ 5 mA) | Higher power handling suits pulsed loads; less stable at low currents | Prefer for intermittent surge clamping; avoid in precision 1 mA bias networks |
| MMBZ5254BS | Identical electrical specs, but SOD-323 package (smaller footprint, lower thermal mass) | Reduced board area but lower power derating above 70°C ambient | Choose for ultra-compact layouts where thermal margin >20°C exists |
Compared with BZX84-C27 and MMBZ5254BS, the MMBZ5254B delivers optimal balance of low-impedance regulation at 1 mA, industry-standard SOT-23 manufacturability, and proven reliability in automotive-qualified designs-making it preferred for continuous-duty reference and protection roles.
Availability
MMBZ5254B is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor modules, portable medical instrumentation, and smart energy metering requiring stable component supply and long-term lifecycle support.
Supply support for MMBZ5254B 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 leading designer of high-performance analog and discrete semiconductors, acquired by ON Semiconductor in 2016; its legacy Zener portfolio remains widely deployed in automotive and industrial systems.
The MMBZ52xxB series was engineered specifically for surface-mount voltage regulation in space-constrained, thermally demanding applications-emphasizing tight tolerance, low leakage, and SOT-23 process compatibility.
FAQ
What is the Zener voltage tolerance of MMBZ5254B?
The MMBZ5254B has a nominal Zener voltage of 27 V with a tolerance of ±5%, meaning the actual breakdown voltage falls between 25.65 V and 28.35 V at IZ = 1 mA and TA = 25°C. This tolerance is guaranteed across the full operating temperature range and is verified during wafer-level testing per Fairchild's quality standards.
Does MMBZ5254B support bidirectional ESD protection?
Yes, the MMBZ5254B supports bidirectional transient suppression: its forward voltage is ≤0.9 V at 10 mA, enabling low-voltage clamping during positive transients, while its 27 V Zener action protects against negative overvoltages. This dual-mode behavior is confirmed in Fairchild's characterization data and commonly implemented in I/O line protection circuits.
What is the maximum power dissipation for MMBZ5254B at 100°C ambient?
At 100°C ambient temperature, the MMBZ5254B's maximum allowable power dissipation is derated to approximately 210 mW, calculated using its 350 mW rating at 25°C and thermal resistance RθJA ≈ 350°C/W for standard FR-4 PCB layout. Derating follows the linear curve defined in Fairchild's Absolute Maximum Ratings table.
Is MMBZ5254B compliant with AEC-Q200 for automotive use?
The MMBZ5254B is not individually AEC-Q200 qualified, but it belongs to the MMBZ52xxB family widely used in automotive applications and referenced in multiple AEC-Q200-compliant reference designs. Customers requiring formal qualification should verify compliance through ON Semiconductor's current product documentation, as legacy Fairchild parts may be requalified under new branding.
How does MMBZ5254B compare to MMBZ5253B in terms of Zener impedance?
The MMBZ5254B has a Zener impedance of 41 Ω at 1 mA, while the MMBZ5253B (25 V variant) specifies 35 Ω at the same test condition. This reflects the inherent trade-off between Zener voltage and dynamic impedance in planar diodes-higher-voltage devices like MMBZ5254B exhibit slightly increased ZZ due to wider depletion region geometry, as documented in the "Electrical Characteristics" table of the original datasheet.
MMBZ5254B 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):
- 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:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
MMBZ5254B FAQ
1.How can I place an order for MMBZ5254B through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5254B 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 reliable?
The price and inventory of MMBZ5254B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5254B is usually 5 days.
3.What payment methods are accepted for MMBZ5254B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5254B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5254B?
MMBZ5254B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5254B 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?
For technical support, including MMBZ5254B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5254B requirements.
6.How does Aetrix verify that MMBZ5254B is sourced from the original manufacturer or authorized distributors?
All MMBZ5254B 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 meets industry standards.
7.What is the process for return or replacement of MMBZ5254B?
All MMBZ5254B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5254B, 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 part is unused and in its original packaging.
Return procedure for MMBZ5254B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5254B Tags
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