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onsemi MMBZ5251BLT1
- Part No.:
- MMBZ5251BLT1
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5251BLT1.pdf
- Description:
- DIODE ZENER 22V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,724
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Product details
Overview
MMBZ5251BLT1 from onsemi is a 22 V Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board, with 5.6 mA test current, 29 Ω dynamic impedance at IZT, and 0.1 μA leakage current at 17 V reverse bias. It provides precision voltage regulation in space-constrained portable electronics.
For engineers reviewing the MMBZ5251BLT1 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 cases in voltage reference and overvoltage protection circuits.
Technical Context
This device operates as a two-terminal voltage reference diode with cathode-anode polarity, requiring no external biasing circuitry. Its Zener breakdown mechanism delivers stable 22 V regulation at 5.6 mA, with temperature coefficient optimized for nominal Zener voltages near 22 V.
The SOT-23 package supports automated placement and reflow soldering per JEDEC J-STD-020, with maximum soldering temperature of 260°C for 10 seconds. Thermal resistance is 556°C/W on FR-5 board, enabling predictable junction temperature rise under continuous DC operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 20.9–23.1 V at 5.6 mA - defines regulated output voltage tolerance band for reference design |
| Power Dissipation (PD) | 225 mW on FR-5 board @ 25°C - sets maximum continuous DC power handling before thermal derating |
| Zener Impedance (ZZT) | 29 Ω @ IZT = 5.6 mA - determines AC ripple rejection and regulation stability under load transients |
| Leakage Current (IR) | 0.1 μA @ VR = 17 V - ensures minimal standby current draw in battery-powered systems |
| Forward Voltage (VF) | 0.95 V max @ IF = 10 mA - enables bidirectional clamping when used with series resistor in protection circuits |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - qualifies for direct interface with exposed I/O lines in handheld devices |
| Operating Temperature | −65°C to +150°C - supports industrial and automotive under-hood applications without derating |
Pinout & Package
SOT-23 (TO-236) surface-mount package, 2.90 × 1.30 × 1.00 mm, void-free thermosetting plastic case with corrosion-resistant finish. Cathode indicated by polarity band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | DC current entry point during forward conduction; connected to ground or low-side reference in shunt regulator configuration |
| 2 | No Connection | Internally unconnected terminal - must remain floating; no PCB trace or pad required |
| 3 | Cathode | Regulated voltage node; connects to supply rail being stabilized or to input of downstream protection circuit |
Key Features
| Feature | Design Value |
|---|---|
| Pb-Free, Halogen-Free/BFR-Free | RoHS-compliant construction with UL 94 V-0 flammability rating - meets global environmental compliance requirements without performance trade-offs |
| Small-Signal Zener Regulation | 225 mW rating in 2.9 mm × 1.3 mm footprint - enables high-density layout on compact PCBs for portable and wearable electronics |
| Automated Assembly Optimized | SOT-23 package with standardized pitch and coplanarity - compatible with standard pick-and-place and reflow processes without custom tooling |
| High ESD Robustness | Class 3 (>16 kV HBM) - eliminates need for external TVS diodes in many consumer interface applications |
| Wide Operating Range | −65°C to +150°C junction temperature - supports deployment in extended-temperature environments without additional thermal management |
Applications
| Smartphone Power Rail Protection | USB Interface Voltage Clamping |
|---|---|
|
Use Scenario: Protects 3.3 V and 5 V USB data and power lines from ESD events and transient overvoltage during hot-plug insertion. IC Role / Device Role / Timing Role: Shunt clamping element placed between signal line and ground, conducting only during overvoltage conditions. Use Value: Leverages 0.1 μA leakage at 17 V and Class 3 ESD rating to suppress transients without loading normal operation or requiring active control logic. |
Use Scenario: Stabilizes reference voltage for ADCs and comparators in battery-powered IoT sensor nodes. IC Role / Device Role / Timing Role: Two-terminal passive voltage reference providing stable 22 V node for precision analog front-end biasing. Use Value: Achieves ±5% regulation accuracy (20.9–23.1 V) at 5.6 mA with 29 Ω dynamic impedance, minimizing drift across operating temperature range. |
| Automotive Body Control Module | Industrial PLC Input Conditioning |
|
Use Scenario: Regulates auxiliary 24 V supply rail in body control modules where space and thermal budget are constrained. IC Role / Device Role / Timing Role: Shunt regulator maintaining stable voltage for microcontroller I/O buffers and CAN transceiver biasing. Use Value: Operates reliably from −40°C to +125°C ambient with full 225 mW rating, eliminating need for larger TO-92 alternatives. |
Use Scenario: Provides overvoltage protection for 24 V digital input channels in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional clamp using forward conduction (0.95 V max) and reverse Zener action (22 V) to limit input swing. Use Value: Combines low forward drop and precise 22 V breakdown to protect FPGA or microcontroller GPIOs without external series resistors exceeding 10 kΩ. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMBZ5251BLT1G | Identical electrical specs; Pb-free suffix 'G' denotes RoHS-compliant plating and packaging - same Zener voltage, impedance, and leakage. | Same functional use; differs only in tape-and-reel packaging (3,000 vs. 10,000 units) and marking format. | Select MMBZ5251BLT1G for RoHS-compliant production runs requiring standard 3k/reel logistics. |
| SZMMBZ5251BLT1G | Identical Zener characteristics but AEC-Q101 qualified with PPAP capability - same 20.9–23.1 V, 29 Ω, 0.1 μA specs. | Required for automotive applications where qualification documentation and process traceability are mandatory. | Choose SZMMBZ5251BLT1G when designing for automotive ECUs or ADAS subsystems needing certified components. |
Compared with MMBZ5251BLT1, MMBZ5251BLT1G offers identical performance with formal RoHS compliance documentation, while SZMMBZ5251BLT1G adds automotive-grade qualification - neither requires PCB redesign, but selection depends on compliance and traceability requirements.
Availability
MMBZ5251BLT1 is available at Aetrix Electronics and suitable for smartphone power rail protection, USB interface clamping, and industrial PLC input conditioning requiring stable component supply and consistent parametric performance across production lots.
Supply support for MMBZ5251BLT1 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 manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The MMBZ52xxBLT1G series was designed specifically for compact, high-density voltage regulation and transient suppression in portable and battery-powered electronics - prioritizing small footprint, low leakage, and robust ESD immunity.
FAQ
What is the Zener voltage tolerance of MMBZ5251BLT1?
The MMBZ5251BLT1 has a Zener voltage range of 20.9 V to 23.1 V at 5.6 mA test current, representing a ±5% tolerance around the nominal 22 V rating. This tolerance is guaranteed across the full operating temperature range of −65°C to +150°C and is measured under pulse test conditions to avoid self-heating effects. The MMBZ5251BLT1 maintains this specification without requiring external compensation.
Does MMBZ5251BLT1 require a current-limiting resistor in shunt regulator applications?
Yes, MMBZ5251BLT1 must be used with an external series current-limiting resistor to set the operating Zener current within its specified 5.6 mA test point and stay within the 225 mW power limit. The resistor value is calculated based on input voltage, desired output voltage (22 V), and target current - for example, a 24 V supply requires ~357 Ω to deliver 5.6 mA. Without this resistor, excessive current can cause thermal runaway and permanent failure of the MMBZ5251BLT1.
Is MMBZ5251BLT1 suitable for automotive applications?
The base MMBZ5251BLT1 is not AEC-Q101 qualified. For automotive use, the SZMMBZ5251BLT1G variant must be selected - it shares identical electrical specifications (20.9–23.1 V, 29 Ω ZZT, 0.1 μA IR) but includes PPAP documentation, lot-level traceability, and process controls required for automotive ECUs. The MMBZ5251BLT1 itself is intended for industrial and consumer applications where qualification is not mandated.
What is the thermal resistance of MMBZ5251BLT1 on standard PCB material?
The MMBZ5251BLT1 has a junction-to-ambient thermal resistance (RJA) of 556°C/W when mounted on FR-5 board (1.0 × 0.75 × 0.62 in). This means each watt of dissipated power raises the junction temperature by 556°C above ambient - so at its full 225 mW rating, junction temperature rises approximately 125°C above ambient. Derating is required above 25°C ambient at 1.8 mW/°C to maintain reliability and avoid exceeding the +150°C maximum junction temperature.
Can MMBZ5251BLT1 be used for bidirectional ESD protection?
MMBZ5251BLT1 functions unidirectionally as a Zener diode - it conducts in reverse breakdown above 22 V and forward above ~0.95 V. For true bidirectional ESD protection, two MMBZ5251BLT1 devices must be connected in series opposition (anode-to-anode or cathode-to-cathode). A single MMBZ5251BLT1 alone cannot clamp both positive and negative transients without external configuration - its pinout (Pin 1 = anode, Pin 2 = NC, Pin 3 = cathode) supports only one-directional shunt regulation unless paired.
MMBZ5251BLT1 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):
- 22 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 29 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 17 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)
MMBZ5251BLT1 FAQ
1.How can I place an order for MMBZ5251BLT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5251BLT1 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 MMBZ5251BLT1 reliable?
The price and inventory of MMBZ5251BLT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5251BLT1 is usually 5 days.
3.What payment methods are accepted for MMBZ5251BLT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5251BLT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5251BLT1?
MMBZ5251BLT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5251BLT1 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 MMBZ5251BLT1?
For technical support, including MMBZ5251BLT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5251BLT1 requirements.
6.How does Aetrix verify that MMBZ5251BLT1 is sourced from the original manufacturer or authorized distributors?
All MMBZ5251BLT1 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 MMBZ5251BLT1 meets industry standards.
7.What is the process for return or replacement of MMBZ5251BLT1?
All MMBZ5251BLT1 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5251BLT1, 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 MMBZ5251BLT1 part is unused and in its original packaging.
Return procedure for MMBZ5251BLT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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