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onsemi MMBZ5242BLT3
- Part No.:
- MMBZ5242BLT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5242BLT3.pdf
- Description:
- DIODE ZENER 12V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,213
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Product details
Overview
MMBZ5242BLT3 from onsemi is a 12 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board, with 30 Ω dynamic impedance at 20 mA test current and 1 μA reverse leakage at 9.1 V, used for precision voltage regulation in portable power rails and ESD-protected signal conditioning circuits.
For engineers reviewing the MMBZ5242BLT3 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, thermal derating behavior, cathode-anode polarity mapping, and direct alternatives for low-power voltage reference and overvoltage clamp design.
Technical Context
This device operates as a two-terminal silicon Zener diode with sharp reverse breakdown at nominal 12 V, designed for stable voltage reference and transient suppression in space-constrained PCBs. Its 225 mW rating applies to FR-5 substrates at 25°C, derating linearly by 1.8 mW/°C above ambient.
The SOT-23 package features Pin 1 (Anode), Pin 2 (No Connection), and Pin 3 (Cathode), with polarity indicated by a band adjacent to Pin 3. It achieves Class 3 ESD robustness (>16 kV HBM) and complies with RoHS, Pb-free, and halogen-free requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 11.4 V min / 12.0 V nom / 12.6 V max @ IZT = 20 mA - defines tight 5% tolerance band for stable reference under load |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 board - sets maximum continuous DC power before thermal shutdown risk |
| Zener Impedance (ZZT) | 30 Ω max @ IZT = 20 mA - ensures minimal output voltage shift under varying load current |
| Reverse Leakage (IR) | 1 μA max @ VR = 9.1 V - guarantees low standby current in battery-powered clamping applications |
| Thermal Resistance (RJA) | 556 °C/W on FR-5 board - determines junction temperature rise per milliwatt of dissipated power |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - enables direct placement on I/O lines without external ESD protection |
| Junction Temp Range | −65°C to +150°C - supports operation in automotive under-hood and industrial ambient environments |
Pinout & Package
SOT-23 (TO-236) surface-mount package: 2.90 mm × 1.30 mm × 1.00 mm body, 1.90 mm lead pitch, void-free thermosetting plastic case with corrosion-resistant finish and UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connected to lower-potential node in reverse-bias configuration; must be held at voltage ≤ VZ − 0.7 V during forward conduction |
| Pin 2 | No Connection | Internally unconnected; must remain floating - no PCB trace or pad required |
| Pin 3 | Cathode | Connected to higher-potential node; polarity band on package aligns with this terminal for visual orientation |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOT-23 footprint | Enables placement on 0.5 mm pitch traces and high-density PCBs where board area is constrained |
| 225 mW FR-5 power rating | Supports sustained regulation in compact DC-DC feedback paths without heatsinking |
| 12 V ±5% Zener tolerance | Meets precision biasing requirements for analog comparators and reference buffers |
| Class 3 ESD immunity | Eliminates need for discrete TVS diodes on low-speed sensor or control I/O lines |
| Pb-free, halogen-free, RoHS-compliant | Meets global environmental compliance mandates for consumer and industrial end equipment |
Applications
| USB Port Overvoltage Clamp | Microcontroller Reset Circuit |
|---|---|
|
Use Scenario: Clamps USB VBUS transients up to ±15 V during hot-plug events while maintaining 5 V rail integrity. IC Role / Device Role / Timing Role: Two-terminal shunt regulator placed between VBUS and GND, conducting only when voltage exceeds 12.6 V. Use Value: Prevents damage to downstream USB PHY ICs by limiting peak voltage to 12.6 V with <1 μA leakage below 9.1 V. |
Use Scenario: Generates clean 12 V reference for reset supervisor ICs monitoring 3.3 V or 5 V logic supplies. IC Role / Device Role / Timing Role: Stable voltage reference source feeding comparator input in voltage-monitoring ICs like MAX809. Use Value: Delivers 12.0 V ±0.6 V reference with 30 Ω dynamic impedance, minimizing error due to supply ripple. |
| Portable Device Battery Protection | Industrial Sensor Signal Conditioning |
|
Use Scenario: Limits charging voltage to safe threshold in Li-ion battery management circuits using linear regulators. IC Role / Device Role / Timing Role: Shunt element across battery sense line, activated only during overvoltage fault conditions. Use Value: Activates at 11.4 V minimum to prevent cell overcharge, with 1 μA leakage preserving battery shelf life. |
Use Scenario: Stabilizes excitation voltage for bridge-based pressure sensors operating from 12 V supply rails. IC Role / Device Role / Timing Role: Precision voltage reference for Wheatstone bridge biasing in 4–20 mA transmitter modules. Use Value: Maintains 12.0 V ±0.6 V across −40°C to +85°C ambient, supporting <0.1% full-scale error in analog sensing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C12LT1G | Same 12 V nominal Zener, but 350 mW rating on FR-4 and 25 Ω ZZT @ 5 mA - lower test current, higher power capability | Preferred for higher-current regulation where board layout allows larger thermal mass; not drop-in due to different IZT condition | Select when >20 mA Zener current or >300 mW dissipation is required; verify thermal layout compatibility |
| 1N4742A | Through-hole DO-41 package, 1 W rating, 22 Ω ZZT @ 21 mA - higher power, larger footprint, same VZ tolerance | Suitable for prototyping or legacy designs requiring axial-leaded components; incompatible with automated SMT assembly | Choose for manual assembly, high-reliability test fixtures, or where thermal margin exceeds SOT-23 limits |
Compared with MMBZ5242BLT3, BZX84-C12LT1G offers higher power handling but requires revalidation of Zener current sourcing, while 1N4742A provides mechanical robustness and thermal headroom at the cost of board area and SMT compatibility.
Availability
MMBZ5242BLT3 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 long-term lifecycle support.
Supply support for MMBZ5242BLT3 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 is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MMBZ52xxBLT3 series targets space-constrained, low-power voltage regulation and ESD protection in handheld and high-density PCBs, emphasizing miniaturization, reliability, and environmental compliance.
FAQ
What is the exact Zener voltage tolerance of MMBZ5242BLT3?
The MMBZ5242BLT3 has a guaranteed Zener voltage range of 11.4 V (minimum) to 12.6 V (maximum) at 20 mA test current, representing a ±5% tolerance around the nominal 12.0 V value. This specification is measured under controlled pulse conditions at 25°C ambient and is validated per onsemi's production test flow for the MMBZ52xxBLT3G series.
Does MMBZ5242BLT3 have a functional Pin 2 connection?
No, Pin 2 of the MMBZ5242BLT3 is internally unconnected (NC) and must remain electrically floating on the PCB. The device uses only Pin 1 (Anode) and Pin 3 (Cathode) for operation. This is confirmed in the marking diagram and mechanical outline documentation for Style 8 SOT-23 packages used by the MMBZ52xxBLT3G series.
What is the maximum allowable reverse leakage current for MMBZ5242BLT3?
The MMBZ5242BLT3 specifies a maximum reverse leakage current (IR) of 1 μA when biased at 9.1 V - which is 75% of its nominal Zener voltage. This parameter is tested per the Electrical Characteristics table on page 3 of the official onsemi datasheet and reflects worst-case leakage under specified conditions.
Can MMBZ5242BLT3 be used in automotive applications?
The standard MMBZ5242BLT3 is not AEC-Q101 qualified; however, the SZMMBZ5242BLT3G variant - with identical electrical specs and SOT-23 packaging - is explicitly qualified for automotive use and PPAP-capable. For automotive-grade deployment, engineers must specify the SZ-prefix part, not the base MMBZ5242BLT3.
How does thermal derating affect MMBZ5242BLT3's power handling above 25°C?
MMBZ5242BLT3's 225 mW power rating on FR-5 board decreases linearly by 1.8 mW per °C above 25°C ambient, reaching zero dissipation at approximately 158°C. This derating slope is defined in the Maximum Ratings table and must be applied when calculating safe operating area in enclosed or high-ambient environments.
MMBZ5242BLT3 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):
- 12 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 30 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 9.1 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
MMBZ5242BLT3 FAQ
1.How can I place an order for MMBZ5242BLT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5242BLT3 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 MMBZ5242BLT3 reliable?
The price and inventory of MMBZ5242BLT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5242BLT3 is usually 5 days.
3.What payment methods are accepted for MMBZ5242BLT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5242BLT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5242BLT3?
MMBZ5242BLT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5242BLT3 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 MMBZ5242BLT3?
For technical support, including MMBZ5242BLT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5242BLT3 requirements.
6.How does Aetrix verify that MMBZ5242BLT3 is sourced from the original manufacturer or authorized distributors?
All MMBZ5242BLT3 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 MMBZ5242BLT3 meets industry standards.
7.What is the process for return or replacement of MMBZ5242BLT3?
All MMBZ5242BLT3 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5242BLT3, 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 MMBZ5242BLT3 part is unused and in its original packaging.
Return procedure for MMBZ5242BLT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5242BLT3 Tags
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