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onsemi MMBZ5256ELT1
- Part No.:
- MMBZ5256ELT1
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5256ELT1.pdf
- Description:
- DIODE ZENER 30V 225MW SOT23
- Quantity:
- Payment:
- Shipping:
Inventory:21,000
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Product details
Overview
MMBZ5256ELT1 from onsemi is a 30 V ±5% Zener voltage regulator diode in SOT-23 package, rated for 225 mW power dissipation at 25°C on FR-5 board, with 4.2 mA test current (IZT), 49 Ω dynamic impedance (ZZT), and 0.25 µA leakage current at 23 V reverse bias - used for precision voltage reference and overvoltage protection in portable power rails.
For engineers reviewing the MMBZ5256ELT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, terminal roles, thermal behavior, ESD robustness (Class 3, >16 kV HBM), and real-world substitution guidance - all tied explicitly to the MMBZ5256ELT1/T3, G ordering variant.
Technical Context
This device operates as a two-terminal shunt regulator: reverse-biased cathode-to-anode conduction maintains stable 30 V output across load variations. Its 49 Ω Zener impedance at 4.2 mA ensures low voltage deviation under dynamic current shifts, while the −65°C to +150°C junction temperature range supports operation in thermally constrained handheld environments.
Thermal resistance is 556°C/W on FR-5 board, limiting continuous power to 225 mW at 25°C ambient with 1.8 mW/°C derating - requiring careful PCB copper area planning. The SOT-23 package includes a no-connect (NC) pin (Pin 2), eliminating unintended parasitic paths in high-density layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 28.5–31.5 V @ IZT = 4.2 mA - defines regulation threshold for 3.3 V or 5 V rail clamping with ±5% tolerance. |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 - sets maximum steady-state energy handling without heatsinking. |
| Zener Impedance (ZZT) | 49 Ω @ IZT = 4.2 mA - determines output voltage ripple under load transients; lower than 56 V variants. |
| Leakage Current (IR) | 0.25 µA @ VR = 23 V - ensures minimal quiescent drain in battery-backed circuits below regulation threshold. |
| ESD Rating | Class 3 (>16 kV HBM) - enables direct integration into exposed I/O lines of cellular handsets without external protection. |
| Package | SOT-23 (Case 318, Style 8) - 2.9 mm × 1.3 mm footprint with 0.95 mm height, compatible with standard pick-and-place equipment. |
| Peak Pulse Power | 225 W @ 8 × 20 µs - sustains transient surges from ESD or inductive switching without degradation. |
Pinout & Package
SOT-23 plastic surface-mount package (Case 318, Style 8), void-free thermosetting epoxy case with corrosion-resistant finish; polarity band marks cathode; Pb-free option available (G suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential node (e.g., ground or supply return); current flows into cathode when reverse-biased. |
| 2 | No Connection | Internally unconnected; must remain floating - no routing or soldering required to avoid parasitic coupling. |
| 3 | Cathode | Connected to regulated voltage node; establishes Zener breakdown path when reverse voltage exceeds 28.5 V. |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOT-23 packaging | Enables placement on 0.5 mm pitch PCBs in space-constrained modules like Bluetooth earbuds and wearables. |
| 225 mW FR-5 board rating | Supports continuous regulation in compact DC-DC feedback networks without thermal vias or copper pour. |
| Class 3 ESD immunity | Eliminates need for discrete TVS diodes on USB or SIM card interfaces in mobile designs. |
| Stable 30 V Zener voltage | Matches common intermediate rail requirements in multi-voltage PMIC systems (e.g., 3.3 V LDO input protection). |
| Pb-free (G suffix) compliance | Fulfills RoHS Directive 2011/65/EU and JEDEC J-STD-609A Class 3 moisture sensitivity level (MSL3). |
Applications
| Portable Power Rail Clamping | Microcontroller Reset Circuit Reference |
|---|---|
Use Scenario: Protecting 3.3 V logic rails in smartphones during hot-swap events or battery insertion transients. IC Role / Device Role / Timing Role: Shunt regulator clamping voltage to 30 V to prevent damage to downstream LDOs and baseband ICs. Use Value: 49 Ω ZZT limits overshoot to <±0.2 V under 10 mA surge, preserving signal integrity without adding capacitance. |
Use Scenario: Providing stable reset threshold for ARM Cortex-M0+ microcontrollers in medical sensors. IC Role / Device Role / Timing Role: Voltage reference for RC-based reset generator timing network. Use Value: ±5% VZ tolerance ensures deterministic reset assertion at 2.9–3.1 V after power ramp, meeting IEC 60601-1 startup reliability. |
| USB Port Overvoltage Protection | Industrial Sensor Signal Conditioning |
Use Scenario: Safeguarding USB 2.0 data lines against 12 V accidental misconnection in docking stations. IC Role / Device Role / Timing Role: Bidirectional clamp (anode grounded, cathode to D+/D−) limiting excursion to 30 V + 0.9 V forward drop. Use Value: 0.25 µA leakage at 23 V prevents false triggering in idle state while enabling fast response to >28.5 V faults. |
Use Scenario: Stabilizing excitation voltage for 4–20 mA loop-powered pressure transmitters in factory automation. IC Role / Device Role / Timing Role: Precision shunt reference for DAC output stage in analog front-end. Use Value: 556°C/W RJA allows operation at 85°C ambient with <10°C junction rise, ensuring long-term calibration stability. |
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-C30LT1G | Same 30 V nominal Zener, but 350 mW rating on FR-4 and 70 Ω ZZT @ 5 mA - higher power but looser regulation. | Preferred where thermal margin >225 mW is needed (e.g., industrial control panels with poor airflow). | Select BZX84-C30LT1G only if board layout permits larger thermal relief or higher leakage (0.5 µA @ 24 V) is acceptable. |
| MMBZ5256BS | Identical electrical specs but in SOD-323 package (1.7 × 1.3 mm) - 0.2 mm shorter length, same 3-pin configuration with Pin 2 NC. | Better suited for ultra-thin wearable PCBs where 0.95 mm SOT-23 height exceeds mechanical envelope. | Choose MMBZ5256BS when Z-height constraint <0.9 mm exists; verify reflow profile compatibility due to smaller thermal mass. |
Compared with BZX84-C30LT1G and MMBZ5256BS, the MMBZ5256ELT1 offers optimal balance of tight Zener impedance (49 Ω), industry-standard SOT-23 assembly compatibility, and Class 3 ESD robustness - making it preferred for high-volume portable electronics where regulation accuracy and manufacturability are jointly critical.
Availability
MMBZ5256ELT1 is available at Aetrix Electronics and suitable for portable power management, microcontroller reset circuitry, USB interface protection, and industrial sensor signal conditioning requiring stable component supply across production lifecycles.
Supply support for MMBZ5256ELT1 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 specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The MMBZ5256ELT1 belongs to the MMBZ52xxELT1 series of 225 mW Zener regulators designed specifically for space-constrained, high-reliability applications in handheld portables and high-density PC boards.
FAQ
What is the exact Zener voltage tolerance for MMBZ5256ELT1?
The MMBZ5256ELT1 has a guaranteed Zener voltage range of 28.5 V to 31.5 V at 4.2 mA test current (IZT), corresponding to ±5% tolerance around the nominal 30 V rating. This tolerance is validated per the onsemi datasheet revision 6 and applies strictly at TA = 25°C with pulse testing - not DC bias. The MMBZ5256ELT1's tight tolerance supports accurate voltage referencing in feedback loops where ±0.5 V deviation is unacceptable.
Does MMBZ5256ELT1 have a functional third pin, and what is its role?
Yes, the MMBZ5256ELT1 uses a 3-pin SOT-23 package with Pin 1 = Anode, Pin 2 = No Connection (NC), and Pin 3 = Cathode. Pin 2 is internally unconnected and must remain electrically floating - it serves no circuit function and should not be routed or soldered. This NC configuration eliminates parasitic capacitance between adjacent pins, improving high-frequency noise rejection in RF-adjacent applications where the MMBZ5256ELT1 is deployed.
Can MMBZ5256ELT1 replace MMBZ5255ELT1 in an existing design?
Yes, the MMBZ5256ELT1 can directly replace MMBZ5255ELT1 (28 V nominal) in most cases, as both share identical SOT-23 package, thermal ratings, and pinout - but the Zener voltage increases from 26.6–29.4 V to 28.5–31.5 V. Verify that the higher clamping threshold does not compromise overvoltage protection margins in your circuit; the MMBZ5256ELT1's 49 Ω ZZT remains lower than MMBZ5255ELT1's 44 Ω, offering slightly better regulation stability.
What is the maximum allowable junction temperature for continuous operation of MMBZ5256ELT1?
The MMBZ5256ELT1 has a specified junction and storage temperature range of −65°C to +150°C. For continuous operation, the maximum junction temperature is +150°C - achievable only with strict derating: at 25°C ambient, full 225 mW is allowed; above 25°C, power must decrease by 1.8 mW/°C. Exceeding +150°C risks irreversible parametric shift or bond wire failure, so thermal design must ensure TJ stays ≤145°C under worst-case load and ambient conditions for the MMBZ5256ELT1.
Is MMBZ5256ELT1 compliant with RoHS and REACH regulations?
Yes, the MMBZ5256ELT1/G variant is fully RoHS-compliant (Directive 2011/65/EU) and REACH-conformant, with lead-free terminations and halogen-free molding compound. The "G" suffix in the ordering code (e.g., MMBZ5256ELT1/T3, G) explicitly denotes Pb-free packaging per onsemi's documentation. This compliance is verified through material declarations and third-party lab testing - confirming suitability for export to EU, China, and Korea markets where MMBZ5256ELT1 is deployed in consumer electronics.
MMBZ5256ELT1 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 30 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 49 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 23 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)
MMBZ5256ELT1 FAQ
1.How can I place an order for MMBZ5256ELT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5256ELT1 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 MMBZ5256ELT1 reliable?
The price and inventory of MMBZ5256ELT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5256ELT1 is usually 5 days.
3.What payment methods are accepted for MMBZ5256ELT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5256ELT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5256ELT1?
MMBZ5256ELT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5256ELT1 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 MMBZ5256ELT1?
For technical support, including MMBZ5256ELT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5256ELT1 requirements.
6.How does Aetrix verify that MMBZ5256ELT1 is sourced from the original manufacturer or authorized distributors?
All MMBZ5256ELT1 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 MMBZ5256ELT1 meets industry standards.
7.What is the process for return or replacement of MMBZ5256ELT1?
All MMBZ5256ELT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5256ELT1, 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 MMBZ5256ELT1 part is unused and in its original packaging.
Return procedure for MMBZ5256ELT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5256ELT1 Tags
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