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Diodes Incorporated MMBZ5251BW-7
- Part No.:
- MMBZ5251BW-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SC-70, SOT-323
- Datasheet:
-
MMBZ5251BW-7.pdf
- Description:
- DIODE ZENER 22V 350MW SOT323
- Quantity:
- Payment:
- Shipping:
Inventory:7,127
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Product details
Overview
MMBZ5251BW-7 from Diodes Incorporated is a 22 V, 200 mW surface-mount Zener diode in SOT323 package, rated for ±5% Zener voltage tolerance (20.9–23.1 V), with 5.6 mA test current, 29 Ω dynamic impedance at 1 kHz, and ≤0.1 μA reverse leakage at 17 V. It serves as a precision voltage reference or overvoltage clamp in low-power analog signal conditioning circuits.
For engineers reviewing the MMBZ5251BW-7 datasheet, MMBZ5251BW-7 pinout, MMBZ5251BW-7 application, or MMBZ5251BW-7 equivalent, key selection criteria include Zener voltage accuracy, low dynamic impedance at nominal test current, thermal derating behavior up to +150°C, and AEC-Q101 qualification for automotive-grade reliability.
Technical Context
This Zener diode operates in reverse breakdown mode with tightly controlled voltage regulation across its specified test current range. Its 29 Ω Zener impedance at 5.6 mA ensures stable reference performance under moderate load variation, while the 625 °C/W junction-to-ambient thermal resistance defines power handling limits on standard FR4 PCBs.
The device uses alloy-42 leadframe with matte tin plating and green molding compound compliant with AEC-Q101, RoHS, and halogen/antimony-free requirements. Polarity is unidirectional, with cathode marked by a band on the SOT323 package top view.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 22 V nominal, 20.9–23.1 V range at 5.6 mA - enables precise 22 V rail clamping or reference generation |
| Power Dissipation (PD) | 200 mW at 25°C - limits continuous dissipation without heatsinking on standard PCB layout |
| Zener Impedance (ZZT) | 29 Ω at 5.6 mA, 1 kHz - determines output voltage deviation under dynamic load changes |
| Reverse Leakage (IR) | ≤0.1 μA at 17 V - ensures minimal quiescent current in high-impedance bias networks |
| Thermal Resistance (RθJA) | 625 °C/W - defines temperature rise per milliwatt on FR4 with recommended pad layout |
| Operating Temperature | −65°C to +150°C - supports under-hood automotive and industrial ambient environments |
| AEC-Q101 Qualified | Yes - validated for automotive electronics applications requiring high-reliability stress testing |
Pinout & Package
Package: SOT323 - ultra-small plastic surface-mount case (2.10 mm × 1.30 mm × 0.90 mm), molded with UL 94V-0 green compound, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower-potential node when used in shunt regulation |
| Cathode | Reverse-biased Zener terminal / voltage reference output | Connected to regulated node; voltage develops across cathode-to-anode during breakdown |
| Case / Exposed Pad | Non-electrical mechanical termination | No internal connection; serves only structural and thermal interface role |
Key Features
| Feature | Design Value |
|---|---|
| Automated assembly compatibility | SOT323 footprint optimized for pick-and-place and reflow soldering per J-STD-020D Level 1 |
| AEC-Q101 qualification | Validated for automotive electronics including temperature cycling, HTRB, and ESD robustness |
| Green compound construction | Halogen- and antimony-free molding compound (<900 ppm Br/Cl, <1000 ppm Sb) |
| Lead-free terminations | Matte tin plating over Alloy 42 leadframe, MIL-STD-202 solderable |
Applications
| Automotive Sensor Signal Conditioning | Industrial PLC Input Protection |
|---|---|
Use Scenario: Clamping 5 V sensor supply rails against transients in engine control modules. IC Role / Device Role / Timing Role: Shunt Zener regulator providing overvoltage protection for analog front-end ICs. Use Value: 22 V standoff prevents damage to downstream op-amps during load dump events while maintaining low leakage at nominal bias. | Use Scenario: Stabilizing reference voltage for 24 V digital input isolation circuits. IC Role / Device Role / Timing Role: Precision voltage reference for optocoupler biasing and threshold detection. Use Value: Tight 5% tolerance and 29 Ω impedance ensure repeatable turn-on thresholds across temperature and production lots. |
| Consumer Power Adapter Feedback | Medical Diagnostic Equipment Biasing |
Use Scenario: Secondary-side voltage sensing in isolated flyback converters for USB-C chargers. IC Role / Device Role / Timing Role: Zener-based feedback element for TL431-like regulation without external bias. Use Value: Low 0.1 μA leakage at 17 V minimizes standby power loss while enabling accurate 22 V setpoint. | Use Scenario: Providing stable bias for low-noise amplifiers in portable ultrasound front-ends. IC Role / Device Role / Timing Role: Low-drift voltage reference for ADC driver stages requiring clean DC offset. Use Value: AEC-Q101 qualification and −65°C to +150°C operation support sterilization cycles and extended field use. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C22LT1G | Same 22 V nominal, but 350 mW rating and SOT23 package; 40 Ω ZZT at 5 mA | Higher power handling, larger footprint - suitable where board space allows and >200 mW margin needed | Select when thermal headroom or legacy SOT23 compatibility is required |
| MMSZ5251ET1G | 22 V nominal, 500 mW, SOD-123 package; 30 Ω ZZT at 20 mA - higher test current shifts operating point | Higher power and different thermal profile - better for sustained dissipation, less suited for low-current biasing | Choose for designs needing >200 mW capability and SOD-123 assembly infrastructure |
Compared with BZX84-C22LT1G and MMSZ5251ET1G, MMBZ5251BW-7 offers the smallest footprint (SOT323), lowest leakage (0.1 μA), and AEC-Q101 qualification - making it optimal for space-constrained, low-power, automotive-grade voltage references.
Availability
MMBZ5251BW-7 is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC input stages, consumer power adapter feedback loops, and medical diagnostic equipment biasing requiring stable component supply and long-term lifecycle assurance.
Supply support for MMBZ5251BW-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The MMBZ52xxBW series belongs to Diodes' AEC-Q101-qualified Zener diode portfolio, engineered specifically for automotive and industrial applications demanding high reliability, tight voltage tolerance, and green material compliance.
FAQ
What is the maximum reverse voltage (VR) before significant leakage occurs?
The MMBZ5251BW-7 exhibits ≤0.1 μA reverse leakage at 17 V, which is 77% of its nominal Zener voltage. Significant conduction begins near 20.9 V (minimum VZ), with full regulation established at 5.6 mA. Operation below 17 V ensures negligible current draw in standby conditions.
Can this Zener diode be used in parallel for higher power handling?
No - due to manufacturing tolerances in Zener voltage (±5%), paralleling units causes current hogging, where the lowest-VZ unit conducts most of the current and risks thermal runaway. For higher power, select a single higher-rated part like MMSZ5251ET1G (500 mW) instead.
Is the SOT323 package compatible with standard reflow profiles?
Yes - the SOT323 package is qualified for lead-free reflow per J-STD-020D Level 1. Recommended peak temperature is 260°C for ≤10 seconds, with ramp rates ≤3°C/s. The matte tin terminations ensure reliable wetting without voiding on ENIG or OSP PCB finishes.
How does the 625 °C/W thermal resistance impact real-world PCB layout?
At 200 mW dissipation, the junction-to-ambient temperature rise is 125°C above ambient - meaning operation at 25°C ambient reaches 150°C junction. To stay within safe limits, reduce power or increase copper area: doubling thermal pad size typically lowers RθJA by ~150°C/W per the AP02001 recommended layout.
MMBZ5251BW-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SC-70, SOT-323
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 22 V
- Tolerance:
- ±5%
- Power - Max:
- 350 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:
- -65°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-323
MMBZ5251BW-7 FAQ
1.How can I place an order for MMBZ5251BW-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5251BW-7 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 MMBZ5251BW-7 reliable?
The price and inventory of MMBZ5251BW-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5251BW-7 is usually 5 days.
3.What payment methods are accepted for MMBZ5251BW-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5251BW-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5251BW-7?
MMBZ5251BW-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5251BW-7 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 MMBZ5251BW-7?
For technical support, including MMBZ5251BW-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5251BW-7 requirements.
6.How does Aetrix verify that MMBZ5251BW-7 is sourced from the original manufacturer or authorized distributors?
All MMBZ5251BW-7 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 MMBZ5251BW-7 meets industry standards.
7.What is the process for return or replacement of MMBZ5251BW-7?
All MMBZ5251BW-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5251BW-7, 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 MMBZ5251BW-7 part is unused and in its original packaging.
Return procedure for MMBZ5251BW-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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