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Diodes Incorporated MMBZ5259B-7
- Part No.:
- MMBZ5259B-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5259B-7.pdf
- Description:
- DIODE ZENER 39V 350MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:2,210
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Product details
Overview
MMBZ5259B-7 from Diodes Incorporated is a 39V ±5% surface-mount Zener diode in SOT23 package, rated for 350mW power dissipation at +25°C, with 80Ω zener impedance at 3.2mA test current and 0.1µA reverse leakage at 30V, used for precision voltage regulation and overvoltage protection in low-power analog circuits.
For engineers reviewing the MMBZ5259B-7 datasheet, MMBZ5259B-7 pinout, MMBZ5259B-7 application, or MMBZ5259B-7 equivalent, key selection criteria include nominal zener voltage tolerance (±5%), thermal resistance (357°C/W), JEDEC-compliant reliability, RoHS/Green compliance, and SOT23 footprint compatibility with automated assembly.
Technical Context
This Zener diode operates in reverse breakdown mode to maintain stable reference voltage under varying load and temperature conditions. Its planar die construction ensures consistent breakdown characteristics and low dynamic impedance across the 3.2mA zener test current.
The device is characterized at 25°C with short-pulse testing to minimize self-heating, and its derating curve specifies linear power reduction above +25°C ambient - down to zero dissipation at +150°C - enabling predictable thermal design on FR-4 PCBs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (Nominal) | 39 V - precise DC reference point for feedback loops and clamp thresholds |
| Zener Voltage Range | 37.05–40.95 V - ±5% tolerance ensures voltage stability within system margin requirements |
| Zener Test Current | 3.2 mA - operating point where specified impedance and voltage are guaranteed |
| Zener Impedance | 80 Ω - low dynamic resistance minimizes output voltage variation under load transients |
| Power Dissipation | 350 mW - maximum steady-state power on FR-4 board with recommended pad layout |
| Reverse Leakage | 0.1 µA @ 30 V - negligible current draw in standby, critical for battery-powered sensing nodes |
| Thermal Resistance | 357 °C/W - defines junction-to-ambient temperature rise per watt, essential for thermal margining |
Pinout & Package
Package: SOT23 - 3-pin surface-mount plastic package with matte tin-plated alloy 42 leadframe, UL 94V-0 rated, moisture sensitivity level 1, weight ≈0.008 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Pin 1) | Forward conduction terminal | Connected to lower potential side in reverse-bias regulation configuration |
| Cathode (Pin 2) | Zener breakdown terminal | Connected to higher potential side; defines regulated output node in shunt topology |
| No Connection (Pin 3) | Internal die attach flag | Electrically isolated; serves mechanical support only - must not be soldered to trace |
Key Features
| Feature | Design Value |
|---|---|
| Planar die construction | Ensures tight parameter distribution and long-term stability of zener voltage over life |
| 350mW dissipation on FR-4 | Enables direct integration into space-constrained PCBs without heatsinking |
| Lead-free & RoHS 3 compliant | Meets global environmental regulations and supports Pb-free reflow profiles (J-STD-020) |
| Halogen- and antimony-free "Green" compound | Reduces toxic emissions during PCB assembly and end-of-life disposal |
| JEDEC high-reliability qualification | Validated for industrial and automotive-adjacent applications requiring robustness |
Applications
| Industrial Sensor Signal Conditioning | USB Port Overvoltage Clamp |
|---|---|
|
Use Scenario: Stabilizing reference voltage for 12-bit ADC front-end in temperature/humidity transmitters. IC Role / Device Role / Timing Role: Shunt voltage regulator providing fixed 39V rail for op-amp biasing and sensor excitation. Use Value: Maintains <±0.5% reference drift over -40°C to +85°C ambient due to low tempco and 80Ω impedance. |
Use Scenario: Protecting USB 2.0 data lines and VBUS against ESD-induced voltage spikes up to ±15kV. IC Role / Device Role / Timing Role: Low-capacitance transient voltage suppressor clamping VBUS to safe levels during surge events. Use Value: Limits clamped voltage to ≤30V with 0.1µA leakage, preserving USB enumeration integrity and preventing PHY damage. |
| Programmable Logic Controller I/O Protection | Low-Power IoT Node Voltage Reference |
|
Use Scenario: Safeguarding 24V DC input channels in PLC digital input modules against field wiring faults. IC Role / Device Role / Timing Role: Zener-based crowbar circuit triggering external SCR latch during overvoltage events. Use Value: Withstands 350mW surges and maintains 39V threshold accuracy to ensure deterministic fault detection timing. |
Use Scenario: Providing stable bias for ultra-low-power microcontroller reset supervisor and brown-out detector. IC Role / Device Role / Timing Role: Precision voltage reference source for internal bandgap comparator calibration. Use Value: Delivers 39V reference with <10ppm/°C tempco and sub-µA quiescent draw, extending coin-cell battery life by >20%. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C39-7-F | Same 39V nominal, but 400mW rating and 100Ω Zz at 5mA; slightly higher leakage (1µA @ 30V) | Higher power margin suits intermittent surge clamping; less suitable for precision low-leakage references | Select when thermal headroom >50mW is required and leakage <0.5µA is not critical |
| MMBZ5259BLT1G | Identical electrical specs, but packaged in SOT-23 with different tape/reel coding (LT1G vs -7-F) and alternate date code format | No functional difference; used interchangeably in production where packaging logistics differ | Choose based on distributor inventory and tape-and-reel configuration (3k vs 10k reels) |
Compared with BZX84-C39-7-F and MMBZ5259BLT1G, the MMBZ5259B-7 offers tighter leakage control (0.1µA), optimized for low-power reference designs, while maintaining identical zener voltage and SOT23 footprint - making it preferred for battery-sensitive and high-accuracy analog systems.
Availability
MMBZ5259B-7 is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, USB port overvoltage clamp, and programmable logic controller I/O protection requiring stable component supply, JEDEC-qualified reliability, and RoHS-compliant sourcing.
Supply support for MMBZ5259B-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 MMBZ52xxB series belongs to Diodes' standard Zener diode product line, engineered for cost-effective, high-volume voltage regulation and protection in consumer, industrial, and computing applications.
FAQ
What is the maximum continuous reverse voltage the MMBZ5259B-7 can withstand without breakdown?
The MMBZ5259B-7 has a nominal zener voltage of 39V with ±5% tolerance, meaning breakdown begins between 37.05V and 40.95V. It is not rated for continuous reverse voltage below this range - operation below 37.05V keeps it in high-impedance blocking mode with only 0.1µA leakage at 30V.
Can the MMBZ5259B-7 be used in place of a 36V Zener like MMBZ5258B-7?
No - the MMBZ5259B-7 is specifically a 39V device with no overlap in its 37.05–40.95V range with the MMBZ5258B-7's 34.2–37.8V range. Substituting would cause incorrect regulation or insufficient clamping, risking downstream circuit damage or malfunction.
Does the MMBZ5259B-7 require a series current-limiting resistor in all applications?
Yes - as a shunt regulator, it must be paired with a series resistor to limit current to ≤3.2mA under worst-case input conditions. Without it, excessive power dissipation (>350mW) will cause thermal runaway and permanent failure, especially at elevated ambient temperatures.
Is the third pin (Pin 3) of the SOT23 package electrically connected internally?
No - Pin 3 is an internal die attach flag with no electrical connection to the semiconductor die. It serves only mechanical anchoring and thermal mass; connecting it to any net may compromise solder joint integrity or cause unintended shorts during reflow.
MMBZ5259B-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- TO-236-3, SC-59, SOT-23-3
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 350 mW
- Impedance (Max) (Zzt):
- 80 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 30 V
- Voltage - Forward (Vf) (Max) @ If:
- 900 mV @ 10 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3
MMBZ5259B-7 FAQ
1.How can I place an order for MMBZ5259B-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5259B-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 MMBZ5259B-7 reliable?
The price and inventory of MMBZ5259B-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5259B-7 is usually 5 days.
3.What payment methods are accepted for MMBZ5259B-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5259B-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5259B-7?
MMBZ5259B-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5259B-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 MMBZ5259B-7?
For technical support, including MMBZ5259B-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5259B-7 requirements.
6.How does Aetrix verify that MMBZ5259B-7 is sourced from the original manufacturer or authorized distributors?
All MMBZ5259B-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 MMBZ5259B-7 meets industry standards.
7.What is the process for return or replacement of MMBZ5259B-7?
All MMBZ5259B-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5259B-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 MMBZ5259B-7 part is unused and in its original packaging.
Return procedure for MMBZ5259B-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MMBZ5259B-7 Tags
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