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onsemi MMBZ5256BLT1
- Part No.:
- MMBZ5256BLT1
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5256BLT1.pdf
- Description:
- DIODE ZENER 30V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,774
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Product details
Overview
MMBZ5256BLT1 from onsemi is a 30 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board, with 4.2 mA test current, 49 Ω dynamic impedance at IZT, and 0.25 μA leakage at 23 V reverse bias - used for precision voltage reference and overvoltage protection in portable power rails.
For engineers reviewing the MMBZ5256BLT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, cathode-anode polarity mapping, ESD robustness (Class 3, >16 kV HBM), and direct alternatives for low-power regulation in space-constrained designs.
Technical Context
This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load and temperature conditions. Its 30 V nominal Zener voltage exhibits a positive temperature coefficient near zero crossing, minimizing drift in mid-voltage range applications.
The device features a no-connect terminal (Pin 2), enabling unambiguous anode-cathode orientation in automated placement. Thermal resistance of 556 °C/W (Junction-to-Ambient, FR-5) defines safe operating limits when derated above 25 °C at 1.8 mW/°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 28.5–31.5 V @ IZT = 4.2 mA - defines regulated output voltage tolerance band for feedback or clamping circuits. |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 board - sets maximum continuous power handling before thermal shutdown or degradation. |
| Zener Impedance (ZZT) | 49 Ω @ IZT = 4.2 mA - determines regulation stiffness; lower value improves line/load regulation performance. |
| Leakage Current (IR) | 0.25 μA @ VR = 23 V - ensures minimal standby current draw in battery-powered systems during non-regulation state. |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - guarantees robustness against electrostatic discharge during PCB handling and assembly. |
| Package | SOT-23 (TO-236), 2.90 × 1.30 × 1.00 mm - enables high-density mounting on compact PCBs with standard reflow profiles. |
| Junction Temp Range | −65 to +150 °C - supports operation in extended industrial and automotive ambient environments. |
Pinout & Package
SOT-23 plastic surface-mount package with void-free thermosetting case, corrosion-resistant finish, and UL 94 V-0 flammability rating. Cathode indicated by polarity band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential node; reverse-biased during Zener operation. |
| 2 | No Connection | Internally isolated; must remain unconnected on PCB to avoid parasitic coupling or shorting. |
| 3 | Cathode | Connected to higher-potential node; provides regulated voltage reference point. |
Key Features
| Feature | Design Value |
|---|---|
| 225 mW power rating on FR-5 board | Enables use in low-power portable devices without heatsinking or airflow. |
| ESD robustness >16 kV (HBM) | Eliminates need for external ESD protection in handheld and wearable designs. |
| Pb-free, halogen-free, RoHS-compliant | Meets global environmental compliance requirements for consumer and industrial shipments. |
| Small SOT-23 footprint | Reduces PCB area by >50% vs. DO-35 or SOD-123 packages, supporting miniaturized layouts. |
| Stable Zener voltage over −65 to +150 °C | Ensures reliable regulation across automotive under-hood and industrial control environments. |
Applications
| Portable Power Rail Protection | Low-Power Reference Generator |
|---|---|
|
Use Scenario: Clamping transient spikes on 3.3 V or 5 V supply lines in Bluetooth headsets and smartwatches. IC Role / Device Role / Timing Role: Zener diode acting as shunt regulator and overvoltage clamp. Use Value: Prevents damage to downstream LDOs and microcontrollers during ESD events or load-dump transients. |
Use Scenario: Providing stable 30 V reference for ADC biasing or DAC calibration in medical sensor modules. IC Role / Device Role / Timing Role: Precision voltage reference source with low temperature drift. Use Value: Enables <±0.5% full-scale accuracy in 12-bit analog signal chains without trimming. |
| Battery Management Monitoring | USB-C Port Overvoltage Clamp |
|
Use Scenario: Monitoring Li-ion cell stack voltage in 2S/3S battery packs using resistive divider + Zener clamp. IC Role / Device Role / Timing Role: Protective clamp limiting divider node voltage to safe levels for MCU GPIO input. Use Value: Extends system uptime by preventing brown-out resets during cell imbalance or charging surges. |
Use Scenario: Protecting USB-C CC logic pins from accidental 20 V PD negotiation voltage exposure. IC Role / Device Role / Timing Role: Fast-acting shunt limiter absorbing excess energy before IC damage occurs. Use Value: Achieves <100 ns response time and survives >1000 ESD strikes without parameter shift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C30LT1G | Same 30 V nominal Zener, but 350 mW rating and 70 Ω ZZT; SOT-23 package with identical pinout (Pin 1=Anode, Pin 2=NC, Pin 3=Cathode). | Higher power handling suits higher-current clamping; less precise regulation due to higher impedance. | Select when >225 mW dissipation is required and tighter voltage stability is secondary. |
| SZMMBZ5256BLT1G | Identical electrical specs and package, but AEC-Q101 qualified and PPAP-capable for automotive use. | Required for under-hood or ADAS subsystems where automotive-grade traceability and failure mode analysis are mandated. | Choose for automotive production programs needing certified reliability and change control documentation. |
Compared with MMBZ5256BLT1, BZX84-C30LT1G offers higher power margin at the cost of regulation accuracy, while SZMMBZ5256BLT1G delivers identical performance with automotive qualification - making the original ideal for cost-sensitive industrial and portable designs where AEC-Q101 is not required.
Availability
MMBZ5256BLT1 is available at Aetrix Electronics and suitable for portable electronics, battery management systems, and USB interface protection requiring stable component supply with rapid lead times and consistent lot-to-lot parametric performance.
Supply support for MMBZ5256BLT1 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 silicon solutions for automotive, industrial, cloud, medical, and IoT applications.
The MMBZ52xxBLT1G series targets space-constrained, low-power voltage regulation and protection - designed specifically for handheld portables, high-density PC boards, and battery-powered edge devices.
FAQ
What is the Zener voltage tolerance of MMBZ5256BLT1?
The MMBZ5256BLT1 has a Zener voltage range of 28.5 V to 31.5 V at IZT = 4.2 mA, corresponding to ±5% tolerance around the nominal 30 V rating. This tolerance is guaranteed across the full operating temperature range of −65 °C to +150 °C and is validated per onsemi's production test flow.
Does MMBZ5256BLT1 have a built-in ESD protection structure?
Yes, MMBZ5256BLT1 is rated Class 3 (>16 kV) per Human Body Model (HBM), meaning it incorporates internal junction-level ESD protection sufficient for handling in standard manufacturing environments without external suppressors - confirmed in the "Features" section of the official datasheet.
Can MMBZ5256BLT1 be used in place of MMBZ5256BLT1G?
No - MMBZ5256BLT1 is obsolete and superseded by MMBZ5256BLT1G, which adds Pb-free and halogen-free compliance. The "G" suffix denotes RoHS-compliant packaging; MMBZ5256BLT1 lacks this certification and is no longer manufactured or supported by onsemi.
What is the thermal derating slope for MMBZ5256BLT1 on FR-5 board?
MMBZ5256BLT1 derates linearly at 1.8 mW/°C above 25 °C ambient temperature when mounted on FR-5 board, based on its 556 °C/W junction-to-ambient thermal resistance. At 75 °C ambient, maximum allowable power drops to 135 mW (225 mW − (50 × 1.8)).
Is Pin 2 of MMBZ5256BLT1 electrically connected internally?
No - Pin 2 of MMBZ5256BLT1 is a no-connect (NC) terminal, explicitly defined in the mechanical outline (Style 8) and electrical characteristics table. It must remain unconnected on the PCB to prevent unintended current paths or measurement errors.
MMBZ5256BLT1 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):
- 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)
MMBZ5256BLT1 FAQ
1.How can I place an order for MMBZ5256BLT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5256BLT1 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 MMBZ5256BLT1 reliable?
The price and inventory of MMBZ5256BLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5256BLT1 is usually 5 days.
3.What payment methods are accepted for MMBZ5256BLT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5256BLT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5256BLT1?
MMBZ5256BLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5256BLT1 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 MMBZ5256BLT1?
For technical support, including MMBZ5256BLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5256BLT1 requirements.
6.How does Aetrix verify that MMBZ5256BLT1 is sourced from the original manufacturer or authorized distributors?
All MMBZ5256BLT1 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 MMBZ5256BLT1 meets industry standards.
7.What is the process for return or replacement of MMBZ5256BLT1?
All MMBZ5256BLT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5256BLT1, 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 MMBZ5256BLT1 part is unused and in its original packaging.
Return procedure for MMBZ5256BLT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5256BLT1 Tags
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