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onsemi MMSZ5255BT3
- Part No.:
- MMSZ5255BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ5255BT3.pdf
- Description:
- DIODE ZENER 28V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:7,643
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Product details
Overview
MMSZ5255BT3 from ON Semiconductor is a 28 V ±5% Zener diode in SOD−123 package, rated for 500 mW power dissipation on FR−5 board at 75°C, with 44 Ω dynamic impedance at 4.5 mA test current and 0.1 µA reverse leakage at 21 V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMSZ5255BT3 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, SOD−123 terminal mapping, and validated alternative parts for voltage reference design, ESD-protected biasing, and compact regulator feedback networks.
Technical Context
This device operates as a two-terminal silicon Zener diode with sharp reverse breakdown at nominal 28 V, specified under thermal equilibrium conditions (TL = 30°C ±1°C). Its 44 Ω Zener impedance at IZT = 4.5 mA and 600 Ω at IZK = 0.25 mA supports stable regulation across moderate load variations.
The SOD−123 package enables automated placement and reflow soldering with 260°C/10s max solder temperature, while its Class 3 ESD rating (>16 kV HBM) ensures robustness in handling and end-use environments without external protection circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 26.6 V min / 28 V nominal / 29.4 V max @ IZT = 4.5 mA - defines regulated output range under standard test conditions |
| Power Dissipation (PD) | 500 mW @ TL = 75°C - maximum steady-state power before thermal derating begins |
| Zener Impedance (ZZT) | 44 Ω @ IZT = 4.5 mA - indicates regulation stiffness; lower value improves line/load regulation |
| Reverse Leakage (IR) | 0.1 µA @ VR = 21 V - confirms low standby current in pre-breakdown region |
| Thermal Resistance (RJA) | 340 °C/W - determines junction temperature rise above ambient for given power |
| ESD Rating | Class 3 (>16 kV HBM) - eliminates need for external ESD protection in most PCB-level handling scenarios |
| Operating Temperature | −55°C to +150°C - supports automotive under-hood and industrial control applications |
Pinout & Package
SOD−123 surface-mount plastic package (Case 425, Style 1), cathode indicated by polarity band; dimensions: 2.84 mm × 1.35 mm × 0.94 mm (L × W × H), 260°C max solder temperature for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to regulated output node; reverse-biased during Zener operation |
| 2 (Non-banded End) | Anode | Connected to ground or lower-potential reference; completes current path during regulation |
Key Features
| Feature | Design Value |
|---|---|
| 500 mW Power Rating | Enables use in medium-current bias networks without heatsinking on standard FR−5 PCB |
| ±5% Zener Tolerance | Supports cost-sensitive designs where tight voltage accuracy is not required |
| Low 0.1 µA Leakage at 21 V | Minimizes quiescent current in battery-powered sensor front-ends and sleep-mode circuits |
| Pb-Free Construction | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 reflow profiles |
| Automated Assembly Optimized | Flat leads and defined footprint reduce placement misalignment and tombstoning risk |
Applications
| Industrial Sensor Signal Conditioning | USB Port Overvoltage Clamp |
|---|---|
Use Scenario: Stabilizing reference voltage for 12-bit ADC input stages in temperature transmitters operating from 24 V loop power. IC Role / Device Role / Timing Role: Zener diode providing 28 V shunt regulation to set upper rail for op-amp biasing and ADC reference divider. Use Value: Maintains <±1% output stability over −40°C to +85°C due to known TC curve and low ZZT, reducing calibration drift. | Use Scenario: Protecting USB 2.0 data lines and VBUS against transient surges from hot-plug events or ESD discharge. IC Role / Device Role / Timing Role: Bidirectional clamping device (anode-to-ground, cathode-to-line) limiting voltage excursions to safe levels. Use Value: Leverages 16 kV HBM ESD rating and fast response to suppress >8 kV contact discharge without adding capacitance that degrades signal integrity. |
| Programmable Logic Controller Input Protection | Low-Power IoT Node Voltage Reference |
Use Scenario: Safeguarding 24 V digital input channels against field-wiring faults and inductive kickback in factory automation systems. IC Role / Device Role / Timing Role: Shunt regulator absorbing fault energy while holding input voltage below 30 V to protect downstream optocoupler drivers. Use Value: Withstands 500 mW continuous dissipation and handles non-repetitive surge up to 100 W (1 ms pulse), meeting IEC 61000-4-4 Level 3 requirements. | Use Scenario: Generating stable 28 V reference for ultra-low-power microcontroller reset supervision and brown-out detection. IC Role / Device Role / Timing Role: Precision Zener establishing threshold voltage for comparator-based reset logic in battery-operated edge devices. Use Value: Delivers 0.1 µA leakage at 21 V, extending coin-cell battery life beyond 10 years in always-on monitoring applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584C27LT1G | 27 V ±1%, 300 mW, SOD-323 package, 20 Ω ZZT @ 5 mA | Tighter tolerance and lower ZZT, but lower power rating and smaller package limits thermal margin | Select when higher accuracy and lower impedance are prioritized over power handling and board-level ruggedness |
| MMSZ5255ET3G | Same 28 V ±5% spec, but 2% tolerance variant (E suffix), identical SOD−123 package and 500 mW rating | Offers improved voltage consistency across production lots for critical analog references | Choose when tighter initial tolerance justifies minor cost increase and same thermal performance is required |
Compared with MMSZ5255BT3, BZX584C27LT1G trades power capability for higher precision in space-constrained layouts, while MMSZ5255ET3G retains identical thermal and mechanical behavior but delivers tighter lot-to-lot Zener voltage control for high-reliability analog subsystems.
Availability
MMSZ5255BT3 is available at Aetrix Electronics and suitable for industrial sensor conditioning, USB port protection, PLC input safeguarding, and low-power IoT node voltage referencing requiring stable component supply across long production lifecycles.
Supply support for MMSZ5255BT3 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
ON Semiconductor is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud computing, medical, and IoT applications.
The MMSZ52xxxT1G series was designed specifically for general-purpose, medium-current Zener regulation in high-density surface-mount applications-emphasizing manufacturability, thermal reliability, and ESD robustness in cost-sensitive designs.
FAQ
What is the nominal Zener voltage and tolerance of the MMSZ5255BT3?
The MMSZ5255BT3 has a nominal Zener voltage of 28 V with a ±5% tolerance, meaning its actual breakdown voltage falls between 26.6 V and 29.4 V when tested at IZT = 4.5 mA under thermal equilibrium conditions (TL = 30°C ±1°C). This tolerance is confirmed in the "5% TOLERANCE FG ELECTRICAL CHARACTERISTICS" table on page 3 of the ON Semiconductor datasheet.
What is the maximum power dissipation and thermal derating behavior of the MMSZ5255BT3?
The MMSZ5255BT3 is rated for 500 mW total power dissipation on FR−5 board at lead temperature (TL) = 75°C, with linear derating of 6.7 mW/°C above that temperature. Its thermal resistance from junction-to-ambient is 340 °C/W, so at 25°C ambient and full 500 mW load, junction temperature reaches approximately 190°C-exceeding absolute max; thus practical use requires board-level thermal management or reduced power.
How is the MMSZ5255BT3 marked and oriented on the PCB?
The MMSZ5255BT3 uses a single cathode band to identify Pin 1 (cathode); the unmarked end is the anode. Per the marking diagram in the datasheet, it carries the code "K5" laser-marked on the case. Orientation follows standard SOD−123 layout: banded end toward regulated output, non-banded end toward ground or lower potential-critical for correct reverse-bias operation.
Does the MMSZ5255BT3 meet automotive qualification standards?
The MMSZ5255BT3 itself is not AEC−Q101 qualified; however, the SZMMSZ5255BT3 variant (with SZ prefix) is explicitly stated as AEC−Q101 qualified and PPAP capable. The base MMSZ5255BT3 is intended for general-purpose industrial and consumer applications, while automotive-grade compliance requires the SZ-prefixed version with controlled site and change management.
What is the reverse leakage current specification for the MMSZ5255BT3 and at what voltage is it measured?
The MMSZ5255BT3 specifies a maximum reverse leakage current (IR) of 0.1 µA at VR = 21 V, as listed in the "5% TOLERANCE FG ELECTRICAL CHARACTERISTICS" table. This parameter reflects the diode's ability to block current well below its Zener knee, making it suitable for low-quiescent-current bias networks where standby power must be minimized.
MMSZ5255BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 28 V
- Tolerance:
- ±5%
- Power - Max:
- 500 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:
- SOD-123
MMSZ5255BT3 FAQ
1.How can I place an order for MMSZ5255BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ5255BT3 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 MMSZ5255BT3 reliable?
The price and inventory of MMSZ5255BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSZ5255BT3 is usually 5 days.
3.What payment methods are accepted for MMSZ5255BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ5255BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ5255BT3?
MMSZ5255BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ5255BT3 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 MMSZ5255BT3?
For technical support, including MMSZ5255BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ5255BT3 requirements.
6.How does Aetrix verify that MMSZ5255BT3 is sourced from the original manufacturer or authorized distributors?
All MMSZ5255BT3 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 MMSZ5255BT3 meets industry standards.
7.What is the process for return or replacement of MMSZ5255BT3?
All MMSZ5255BT3 units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ5255BT3, 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 MMSZ5255BT3 part is unused and in its original packaging.
Return procedure for MMSZ5255BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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