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onsemi MMBZ5255BLT1
- Part No.:
- MMBZ5255BLT1
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5255BLT1.pdf
- Description:
- DIODE ZENER 28V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,674
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Product details
Overview
MMBZ5255BLT1 from onsemi is a 28 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board, with 4.5 mA test current, 44 Ω dynamic impedance at IZT, and 0.1 μA leakage at 21 V reverse bias. It provides precision voltage regulation in space-constrained portable electronics.
For engineers reviewing the MMBZ5255BLT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, ESD robustness (Class 3, >16 kV HBM), and real-world use context for low-power voltage reference and overvoltage protection design.
Technical Context
This Zener diode operates in reverse breakdown to maintain stable voltage across its cathode-anode terminals under varying load conditions. Its 28 V nominal Zener voltage exhibits a positive temperature coefficient near zero crossing - typical for mid-voltage Zeners - enabling predictable drift in ambient temperature ranges from −65°C to +150°C.
The device features a no-connect (NC) terminal (Pin 2), isolating internal structure from external circuitry and simplifying layout routing. Its 225 mW FR-5 rating and 556°C/W junction-to-ambient thermal resistance define safe continuous operation limits when mounted on standard PCB substrates without heatsinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 26.6 V min / 28 V nom / 29.4 V max @ IZT = 4.5 mA - defines regulated output voltage tolerance band for reference or clamp design. |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 board - sets maximum steady-state power handling before thermal derating applies. |
| Zener Impedance (ZZT) | 44 Ω @ IZT = 4.5 mA - determines AC voltage variation under changing load current; lower value improves regulation fidelity. |
| Leakage Current (IR) | 0.1 μA @ VR = 21 V - ensures minimal parasitic current draw in standby or high-impedance sensing nodes. |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - supports robust handling and operation in handheld and consumer-grade assemblies. |
| Junction Temperature Range | −65°C to +150°C - enables deployment in automotive under-hood, industrial control, and extended-temperature embedded systems. |
Pinout & Package
SOT-23 (TO-236) surface-mount plastic package, 2.90 mm × 1.30 mm × 1.00 mm body size, void-free thermosetting case with corrosion-resistant finish. Cathode indicated by polarity band; RoHS-compliant, Pb-free, halogen-free/BFR-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential node in reverse-bias configuration; carries forward current during transient conduction or ESD events. |
| 2 | No Connection | Internally unconnected; must remain floating - no PCB trace or pad tie required, reducing routing complexity and crosstalk risk. |
| 3 | Cathode | Connected to higher-potential node; establishes regulated voltage reference point relative to anode in clamping or shunt-regulator topologies. |
Key Features
| Feature | Design Value |
|---|---|
| 225 mW FR-5 power rating | Enables compact voltage regulation without heatsink in 0.05–0.1 W signal-path applications like sensor biasing or ADC reference stabilization. |
| ESD Class 3 (>16 kV HBM) | Eliminates need for external TVS in low-energy I/O protection circuits, reducing BOM count in portable USB or button interface designs. |
| SOT-23 automated assembly compatibility | Supports high-throughput pick-and-place placement and reflow soldering on dense PCBs, including 0.5 mm pitch layouts. |
| −65°C to +150°C operating range | Validates use in automotive cabin modules, industrial PLC analog input stages, and outdoor IoT sensor nodes without derating penalties. |
Applications
| Portable Power Rail Clamping | Low-Power Sensor Reference |
|---|---|
Use Scenario: Protecting 3.3 V or 5 V supply rails in Bluetooth earbuds against ESD and battery overvoltage transients. IC Role / Device Role / Timing Role: Shunt regulator and transient voltage suppressor placed between rail and ground. Use Value: Limits voltage excursions to ≤29.4 V while drawing <0.1 μA at 21 V - preserving battery life and preventing IC latch-up. |
Use Scenario: Providing stable bias voltage for MEMS microphone preamplifiers or thermistor measurement bridges. IC Role / Device Role / Timing Role: Precision DC reference source in analog front-end signal chains. Use Value: Delivers 28 V ±5% regulation with 44 Ω dynamic impedance, minimizing noise coupling into high-gain amplifier inputs. |
| Industrial Analog Input Protection | Automotive Body Control Module Clamp |
Use Scenario: Safeguarding 24 V analog input channels in programmable logic controllers against field-wiring faults and inductive kickback. IC Role / Device Role / Timing Role: Overvoltage clamp referenced to system ground in signal conditioning stage. Use Value: Withstands 150°C junction temperature and maintains <0.1 μA leakage at 21 V - ensuring long-term reliability in uncooled enclosures. |
Use Scenario: Regulating auxiliary 12 V rail voltage in door module ECUs exposed to load-dump pulses up to 40 V. IC Role / Device Role / Timing Role: Secondary shunt regulator backing up primary LDO in low-quiescent-current subsystems. Use Value: Operates across −40°C to +125°C ambient with AEC-Q101-qualified variants available - meeting automotive qualification requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C27LT1G | 27 V nominal, ±5% tolerance, 300 mW rating on FR-4, 80 Ω ZZT @ 5 mA | Higher power rating but looser regulation accuracy and higher dynamic impedance | Preferred where higher surge energy absorption is needed and tighter voltage stability is not critical. |
| MMBZ5255BS | Same 28 V Zener voltage, SOD-123 package, 500 mW rating, 44 Ω ZZT, but larger footprint | Requires more PCB area but offers improved thermal performance and higher surge capability | Chosen when board layout allows larger package and higher reliability under repeated transient stress is prioritized. |
Compared with MMBZ5255BLT1, BZX84-C27LT1G trades regulation precision for higher power margin, while MMBZ5255BS retains identical electrical behavior but sacrifices miniaturization for enhanced thermal resilience - making MMBZ5255BLT1 optimal for ultra-dense, battery-powered designs demanding strict voltage tolerance and minimal footprint.
Availability
MMBZ5255BLT1 is available at Aetrix Electronics and suitable for portable electronics, industrial sensor interfaces, and automotive body control modules requiring stable component supply with full traceability and lifecycle management.
Supply support for MMBZ5255BLT1 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MMBZ52xxBLT1G series is part of onsemi's precision Zener voltage regulator portfolio, engineered specifically for space-constrained, low-power applications requiring stable reference voltages and robust ESD immunity in portable and embedded systems.
FAQ
What is the Zener voltage tolerance of MMBZ5255BLT1?
The MMBZ5255BLT1 has a Zener voltage range of 26.6 V (minimum) to 29.4 V (maximum) at 4.5 mA test current, corresponding to a ±5% tolerance around the nominal 28 V rating. This tolerance is fully specified in the Electrical Characteristics table of the official onsemi datasheet and validated across production lots for consistent performance in voltage-reference and clamping applications.
Does MMBZ5255BLT1 have a functional third pin?
No, Pin 2 of the MMBZ5255BLT1 is explicitly designated as "No Connection" in the onsemi datasheet and mechanical outline. It is internally unconnected and must remain electrically floating in the PCB layout - no trace, via, or copper pour should be attached to it, as doing so may compromise device reliability or ESD performance.
What is the maximum allowable power dissipation for MMBZ5255BLT1 at 70°C ambient?
At 70°C ambient temperature, the MMBZ5255BLT1's power dissipation must be derated linearly from its 225 mW rating at 25°C using the 1.8 mW/°C derating factor. This yields 225 mW − (1.8 mW/°C × 45°C) = 144 mW maximum continuous power dissipation - a critical limit for thermal design validation in enclosed or high-temperature environments.
Is MMBZ5255BLT1 suitable for automotive applications?
The standard MMBZ5255BLT1 is not AEC-Q101 qualified; however, the functionally identical SZMMBZ5255BLT1G variant is explicitly certified for automotive use and PPAP-capable. For body control, infotainment, or lighting modules requiring automotive qualification, engineers must specify the SZ-prefix version - the MMBZ5255BLT1 itself is intended for industrial and consumer applications.
How does the ESD rating of MMBZ5255BLT1 impact system-level protection design?
The MMBZ5255BLT1's Class 3 ESD rating (>16 kV HBM) means it can absorb multiple high-voltage electrostatic discharges without degradation, allowing it to serve as both a voltage reference and first-line ESD clamp in I/O paths. This eliminates the need for separate TVS diodes in low-energy interfaces like pushbutton inputs or UART lines, reducing component count and board area in cost-sensitive designs.
MMBZ5255BLT1 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):
- 28 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 44 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 (TO-236)
MMBZ5255BLT1 FAQ
1.How can I place an order for MMBZ5255BLT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5255BLT1 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 MMBZ5255BLT1 reliable?
The price and inventory of MMBZ5255BLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5255BLT1 is usually 5 days.
3.What payment methods are accepted for MMBZ5255BLT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5255BLT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5255BLT1?
MMBZ5255BLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5255BLT1 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 MMBZ5255BLT1?
For technical support, including MMBZ5255BLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5255BLT1 requirements.
6.How does Aetrix verify that MMBZ5255BLT1 is sourced from the original manufacturer or authorized distributors?
All MMBZ5255BLT1 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 MMBZ5255BLT1 meets industry standards.
7.What is the process for return or replacement of MMBZ5255BLT1?
All MMBZ5255BLT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5255BLT1, 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 MMBZ5255BLT1 part is unused and in its original packaging.
Return procedure for MMBZ5255BLT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5255BLT1 Tags
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BZT52C5V6T-7
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BZX84C3V3LT1G
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