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onsemi MMBZ5229B
- Part No.:
- MMBZ5229B
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5229B.pdf
- Description:
- DIODE ZENER 4.3V 350MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:8,218
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Product details
Overview
MMBZ5229B from Fairchild Semiconductor is a 4.3 V, ±5% tolerance Zener diode in SOT-23 package, rated for 350 mW power dissipation, with 22 Ω dynamic impedance at 20 mA test current and 1000 µA reverse leakage at 3.4 V, used for voltage regulation and reference in low-power analog circuits.
For engineers reviewing the MMBZ5229B datasheet, pinout, applications, or equivalent options, key selection factors include its precise 4.3 V nominal Zener voltage, low 22 Ω impedance, tight 5% tolerance, SOT-23 footprint compatibility, and suitability for overvoltage clamping and precision biasing in space-constrained designs.
Technical Context
The MMBZ5229B operates as a silicon planar Zener diode optimized for stable voltage reference and transient suppression in DC bias networks. It exhibits a nominal Zener voltage of 4.3 V at 20 mA, with dynamic impedance of 22 Ω and knee impedance of 20 Ω at 0.25 mA, ensuring predictable regulation across load variations.
Its thermal design supports operation up to +150°C junction temperature, with storage range from –55°C to +150°C. Forward voltage is capped at 0.9 V @ 10 mA, enabling bidirectional protection use when paired with complementary devices.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 4.3 V ±5% at IZ = 20 mA - defines stable regulation point for low-voltage reference rails |
| Dynamic Impedance (ZZ) | 22 Ω @ 20 mA - ensures minimal output voltage shift under varying load current |
| Knee Impedance (ZZK) | 20 Ω @ IZK = 0.25 mA - maintains regulation integrity even at very low bias currents |
| Reverse Leakage (IR) | 1000 µA @ VR = 3.4 V - quantifies off-state conduction affecting high-impedance node accuracy |
| Power Dissipation (PD) | 350 mW - sets maximum continuous thermal limit in SOT-23 package without derating |
| Forward Voltage (VF) | ≤0.9 V @ IF = 10 mA - enables use as bidirectional clamp when combined with series resistor |
Pinout & Package
SOT-23 surface-mount package with three terminals: Anode (Pin 1), Cathode (Pin 2), and No Connection (Pin 3). Pin 3 is internally unconnected and must remain floating per datasheet diagram.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Connected to lower-potential side of regulated node; forward conduction path when biased positively |
| Pin 2 | Cathode | Connected to higher-potential side; Zener breakdown occurs when cathode is ≥4.3 V above anode |
| Pin 3 | No Connection (NC) | Internally isolated; must not be soldered or tied to any net to avoid parametric deviation |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables accurate voltage setting without post-production trimming in cost-sensitive consumer and industrial controls |
| Low 22 Ω dynamic impedance | Minimizes regulation error under dynamic load steps typical in sensor bias and ADC reference circuits |
| SOT-23 footprint | Supports automated placement and reflow in high-density PCB layouts while maintaining thermal performance |
| 150°C max junction temperature | Permits reliable operation in enclosed enclosures or near heat-generating components without derating |
Applications
| Industrial Sensor Biasing | USB Port Overvoltage Clamp |
|---|---|
Use Scenario: Providing stable 4.3 V bias to bridge-based pressure sensors in factory automation modules. IC Role / Device Role / Timing Role: Zener reference diode establishing fixed excitation voltage for Wheatstone bridge output linearity. Use Value: Tight 5% tolerance and low 22 Ω impedance ensure <±10 mV drift over temperature and load, preserving measurement accuracy. | Use Scenario: Protecting 3.3 V USB data lines from ESD-induced transients exceeding 5 V during hot-plug events. IC Role / Device Role / Timing Role: Low-capacitance shunt clamp limiting voltage to safe level before reaching downstream PHY IC. Use Value: 4.3 V breakdown triggers clamping before damage threshold of 3.3 V logic, with 350 mW rating handling IEC 61000-4-2 Level 4 pulses. |
| Low-Power Microcontroller Reset Circuit | LED Current Regulation Reference |
Use Scenario: Generating clean reset signal for ARM Cortex-M0+ MCU operating at 3.3 V supply in battery-powered IoT nodes. IC Role / Device Role / Timing Role: Zener-based voltage monitor feeding comparator input to assert reset when supply drops below 3.7 V. Use Value: Predictable 4.3 V Zener point allows precise hysteresis design; 0.9 V forward drop enables dual-direction sensing if needed. | Use Scenario: Setting reference voltage for constant-current LED driver IC in architectural lighting control panels. IC Role / Device Role / Timing Role: Precision voltage reference source for current-sense amplifier feedback loop. Use Value: 22 Ω impedance ensures <1% current error across 10–100 mA LED loads, improving luminance consistency. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C4V3 | Same 4.3 V nominal, ±5% tolerance, but 400 mW PD and 30 Ω ZZ @ 5 mA | Higher power rating suits higher-energy transients; higher impedance reduces regulation precision at low currents | Select BZX84-C4V3 when surge energy exceeds 350 mW limits or when SOT-23-3 pinout compatibility is required |
| MMBZ5229BS | Same electrical specs but in SOD-323 package (smaller footprint, lower thermal mass) | SOD-323 reduces board area by ~30% but lowers thermal dissipation capability; requires tighter layout control | Select MMBZ5229BS only when PCB space is critical and peak power remains ≤250 mW average |
Compared with BZX84-C4V3 and MMBZ5229BS, the MMBZ5229B delivers optimal balance of regulation precision (22 Ω ZZ), thermal robustness (350 mW), and SOT-23 manufacturability-making it preferred for mid-volume industrial and automotive body electronics where stability and process yield matter.
Availability
MMBZ5229B is available at Aetrix Electronics and suitable for industrial sensor biasing, USB port protection, and microcontroller reset circuits requiring stable component supply, consistent parametric performance, and long-term lifecycle support.
Supply support for MMBZ5229B 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016.
The MMBZ5229B belongs to Fairchild's MMBZ52xxB Zener diode family, engineered for precision voltage reference and transient suppression in compact, high-reliability applications across consumer, industrial, and automotive segments.
FAQ
What is the nominal Zener voltage of the MMBZ5229B and how tightly is it specified?
The MMBZ5229B has a nominal Zener voltage of 4.3 V with a guaranteed tolerance of ±5% at 20 mA test current. This means the actual measured VZ falls between 4.085 V and 4.515 V across production lots, supporting accurate voltage setting in reference and regulation circuits without calibration.
Can the MMBZ5229B be used in bidirectional ESD protection configurations?
Yes-the MMBZ5229B can serve in bidirectional clamping when paired with a series resistor and a second identical device in reverse orientation. Its 0.9 V forward voltage @ 10 mA and 4.3 V reverse breakdown enable symmetric clamping around 0 V, though dedicated TVS arrays offer lower capacitance for high-speed data lines.
What is the maximum power dissipation rating for the MMBZ5229B and under what conditions does it apply?
The MMBZ5229B is rated for 350 mW maximum power dissipation at TA = 25°C with no heatsinking. Derating is required above 25°C ambient-typically 2.33 mW/°C-down to zero at +150°C junction temperature. This rating assumes proper PCB copper area and airflow per Fairchild's SOT-23 thermal guidelines.
How does the MMBZ5229B's dynamic impedance compare to other 4.3 V Zeners in the same family?
Among the MMBZ5221B–MMBZ5257B series, the MMBZ5229B's 22 Ω dynamic impedance at 20 mA is among the lowest for sub-5 V devices-lower than MMBZ5228B (23 Ω) and significantly lower than MMBZ5227B (24 Ω), making it preferable for applications demanding minimal regulation error under load variation.
Is Pin 3 of the MMBZ5229B electrically connected, and what happens if it is grounded?
No-Pin 3 of the MMBZ5229B is designated NC (No Connection) and is internally unconnected. Grounding or routing Pin 3 to any net may cause unpredictable parametric shifts or increased leakage due to parasitic coupling; the datasheet explicitly requires Pin 3 to remain floating in all functional designs using the MMBZ5229B.
MMBZ5229B 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):
- 4.3 V
- Tolerance:
- ±5%
- Power - Max:
- 350 mW
- Impedance (Max) (Zzt):
- 22 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 1 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
MMBZ5229B FAQ
1.How can I place an order for MMBZ5229B through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5229B 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 MMBZ5229B reliable?
The price and inventory of MMBZ5229B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5229B is usually 5 days.
3.What payment methods are accepted for MMBZ5229B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5229B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5229B?
MMBZ5229B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5229B 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 MMBZ5229B?
For technical support, including MMBZ5229B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5229B requirements.
6.How does Aetrix verify that MMBZ5229B is sourced from the original manufacturer or authorized distributors?
All MMBZ5229B 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 MMBZ5229B meets industry standards.
7.What is the process for return or replacement of MMBZ5229B?
All MMBZ5229B units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5229B, 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 MMBZ5229B part is unused and in its original packaging.
Return procedure for MMBZ5229B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5229B Tags
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