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onsemi MMBZ5259BLT3G
- Part No.:
- MMBZ5259BLT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5259BLT3G.pdf
- Description:
- DIODE ZENER 39V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,342
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Product details
Overview
MMBZ5259BLT3G from onsemi is a 39 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board at 25°C, with 80 Ω dynamic impedance at 3.2 mA test current and 0.1 μA leakage at 30 V reverse bias - used for precision voltage clamping and reference in portable power rails.
For engineers reviewing the MMBZ5259BLT3G datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, thermal derating behavior, cathode-anode polarity mapping, and automotive-grade alternatives compliant with AEC-Q101 requirements.
Technical Context
This device operates as a two-terminal voltage reference diode with sharp reverse breakdown at nominal 39 V, exhibiting a positive temperature coefficient of +4.5 mV/°C typical across −55°C to +150°C. Its 80 Ω Zener impedance at IZT = 3.2 mA ensures stable regulation under moderate load transients.
The SOT-23 (TO-236) package features a defined anode–no-connect–cathode pinout (Pin 1: Anode, Pin 2: NC, Pin 3: Cathode), enabling unambiguous orientation during automated placement. It supports Pb-free reflow per JEDEC J-STD-020, with max soldering temperature of 260°C for 10 seconds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 37.05 V min / 39 V nom / 40.95 V max @ IZT = 3.2 mA - defines tight 5% tolerance band for stable reference generation. |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 board - sets maximum continuous clamping energy before thermal derating begins. |
| Zener Impedance (ZZT) | 80 Ω max @ IZT = 3.2 mA - determines output voltage deviation under varying load current. |
| Leakage Current (IR) | 0.1 μA max @ VR = 30 V - ensures minimal standby current draw in battery-powered systems. |
| Thermal Resistance (RJA) | 556 °C/W on FR-5 board - quantifies junction-to-ambient temperature rise per milliwatt dissipated. |
| ESD Rating | Class 3 (>16 kV) HBM - enables robust handling in high-static manufacturing environments without added protection circuitry. |
| Operating Temperature | −65°C to +150°C - supports operation in extended industrial and automotive under-hood applications. |
Pinout & Package
SOT-23 (TO-236) surface-mount plastic package, dimensions 2.90 × 1.30 × 1.00 mm, void-free thermosetting case with corrosion-resistant finish and UL 94 V-0 flammability rating. Polarity indicated by cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 | Anode | Forward-biased terminal; connects to lower-potential node in clamping configuration. |
| Pin 2 | No Connection | Internally isolated; must remain unconnected on PCB to avoid parasitic coupling or mechanical stress. |
| Pin 3 | Cathode | Reverse-biased terminal; connects to higher-potential rail for Zener breakdown operation. |
Key Features
| Feature | Design Value |
|---|---|
| 225 mW power rating on FR-5 board | Enables compact overvoltage protection in space-constrained mobile PCBs without heatsinking. |
| ESD rating >16 kV (HBM) | Eliminates need for external ESD suppressors in handheld device front-end circuits. |
| Pb-free, halogen-free, RoHS-compliant | Meets global environmental compliance mandates without performance trade-offs. |
| AEC-Q101 qualified (SZ variant only) | Validated for automotive electronics where reliability under thermal cycling and vibration is critical. |
| Small SOT-23 footprint | Supports high-density layout in multi-rail PMIC subsystems and sensor interface boards. |
Applications
| USB Power Rail Clamping | Li-ion Battery Protection Circuit |
|---|---|
Use Scenario: Clamp transient surges on 5 V USB input lines during hot-plug events or ESD strikes. IC Role / Device Role / Timing Role: Two-terminal shunt regulator absorbing excess energy above 39 V threshold. Use Value: Prevents damage to downstream USB controller ICs by limiting peak voltage to ≤40.95 V with <0.1 μA leakage below 30 V. |
Use Scenario: Provide precise overvoltage detection reference in 3-cell Li-ion pack monitoring ICs. IC Role / Device Role / Timing Role: Stable voltage reference feeding comparator input for cell-balancing decision logic. Use Value: Enables accurate 39 V trip point with ±5% tolerance and <80 Ω dynamic impedance, minimizing false triggers during load transients. |
| Automotive Infotainment Power Sequencing | Industrial Sensor Signal Conditioning |
Use Scenario: Regulate auxiliary 3.3 V supply rail derived from 12 V vehicle battery via LDO pre-regulator. IC Role / Device Role / Timing Role: Zener reference stabilizing feedback divider network of automotive-grade LDO. Use Value: Maintains regulation accuracy across −40°C to +125°C ambient with +4.5 mV/°C TC, ensuring consistent sequencing timing. |
Use Scenario: Protect analog front-end inputs of 24-bit ADCs from overvoltage during field wiring faults. IC Role / Device Role / Timing Role: Fast-response shunt clamp limiting input to 40.95 V before ADC input stage saturation. Use Value: Limits fault energy with 225 mW rating and 556 °C/W RJA, preventing thermal runaway during sustained overvoltage events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C39LT1G | Same 39 V nominal Zener, but 300 mW rating on FR-4 board and 60 Ω ZZT @ 5 mA - lower impedance but higher power footprint. | Preferred in non-space-constrained industrial controls where tighter regulation at higher currents is needed. | Select when system requires lower dynamic impedance and can accommodate larger thermal mass or board area. |
| SZMMBZ5259BLT3G | Identical electrical specs, but AEC-Q101 qualified and PPAP-capable with SZ prefix - same SOT-23 package and marking. | Mandatory for automotive OEM designs requiring certified component traceability and process control. | Choose for automotive applications; otherwise, MMBZ5259BLT3G suffices for commercial/industrial use. |
Compared with BZX84-C39LT1G, MMBZ5259BLT3G offers superior space efficiency and ESD robustness (16 kV vs. 8 kV HBM), while SZMMBZ5259BLT3G adds automotive qualification without altering electrical behavior - making MMBZ5259BLT3G optimal for cost-sensitive, high-density consumer electronics.
Availability
MMBZ5259BLT3G is available at Aetrix Electronics and suitable for USB power protection, Li-ion battery management, automotive infotainment subsystems, and industrial sensor interfaces requiring stable component supply and full traceability.
Supply support for MMBZ5259BLT3G 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 (Semiconductor Components Industries, LLC) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MMBZ52xxBLT3G series belongs to onsemi's precision Zener voltage regulator product line, engineered for low-power, high-reliability voltage clamping and reference in portable and space-constrained electronic systems.
FAQ
What is the exact Zener voltage tolerance of MMBZ5259BLT3G?
The MMBZ5259BLT3G has a guaranteed Zener voltage range of 37.05 V (min) to 40.95 V (max) at test current IZT = 3.2 mA, corresponding to a ±5% tolerance around the nominal 39 V value. This tolerance is validated per onsemi's production testing and remains stable across the full operating temperature range of −65°C to +150°C.
Does MMBZ5259BLT3G have a no-connect pin, and how should it be handled on the PCB?
Yes, MMBZ5259BLT3G uses Pin 2 as a no-connect terminal per its SOT-23 Style 8 pinout. This pin is internally isolated and must remain unconnected on the PCB layout. Routing traces to or placing copper under Pin 2 may introduce parasitic capacitance or mechanical stress, potentially degrading ESD performance or causing solder joint reliability issues.
Can MMBZ5259BLT3G replace MMBZ5259BLT1G in existing designs?
Yes, MMBZ5259BLT3G is functionally identical to MMBZ5259BLT1G in electrical and thermal specifications, differing only in packaging quantity (10,000 vs. 3,000 per tape-and-reel). Both share the same SOT-23 package, pinout, marking, and RoHS compliance - allowing direct substitution without layout or firmware changes.
What is the thermal derating behavior of MMBZ5259BLT3G above 25°C ambient?
MMBZ5259BLT3G derates linearly at 1.8 mW/°C above 25°C ambient when mounted on FR-5 board. At 85°C ambient, its usable power drops to 225 mW − (60°C × 1.8 mW/°C) = 117 mW. This derating ensures safe junction temperature operation within the −65°C to +150°C range, assuming standard 1 oz copper land patterns.
Is MMBZ5259BLT3G suitable for automotive applications?
MMBZ5259BLT3G itself is not AEC-Q101 qualified; however, its automotive-grade counterpart SZMMBZ5259BLT3G shares identical electrical characteristics and SOT-23 packaging while meeting AEC-Q101 stress testing and PPAP requirements. For automotive use, specify SZMMBZ5259BLT3G - not MMBZ5259BLT3G - to ensure compliance.
MMBZ5259BLT3G 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):
- 39 V
- Tolerance:
- ±5%
- Power - Max:
- 225 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 (TO-236)
MMBZ5259BLT3G FAQ
1.How can I place an order for MMBZ5259BLT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5259BLT3G 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 MMBZ5259BLT3G reliable?
The price and inventory of MMBZ5259BLT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5259BLT3G is usually 5 days.
3.What payment methods are accepted for MMBZ5259BLT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5259BLT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5259BLT3G?
MMBZ5259BLT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5259BLT3G 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 MMBZ5259BLT3G?
For technical support, including MMBZ5259BLT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5259BLT3G requirements.
6.How does Aetrix verify that MMBZ5259BLT3G is sourced from the original manufacturer or authorized distributors?
All MMBZ5259BLT3G 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 MMBZ5259BLT3G meets industry standards.
7.What is the process for return or replacement of MMBZ5259BLT3G?
All MMBZ5259BLT3G units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5259BLT3G, 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 MMBZ5259BLT3G part is unused and in its original packaging.
Return procedure for MMBZ5259BLT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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