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onsemi MMBZ5257BLT3G
- Part No.:
- MMBZ5257BLT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5257BLT3G.pdf
- Description:
- DIODE ZENER 33V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:4,339
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Product details
Overview
MMBZ5257BLT3G from onsemi is a 33 V ±5% Zener diode in SOT-23 package, rated for 225 mW power dissipation on FR-5 board, with 700 Ω dynamic impedance at 3.8 mA test current and 0.1 μA leakage at 25 V reverse bias. It serves as a precision voltage reference or overvoltage clamp in compact portable electronics.
For engineers reviewing the MMBZ5257BLT3G datasheet, pinout, applications, or equivalent options, key selection criteria include its 33 V nominal Zener voltage, low 0.1 μA leakage at VR = 25 V, ESD rating >16 kV HBM, SOT-23 footprint compatibility, and thermal resistance of 556 °C/W on FR-5 board.
Technical Context
This device operates in reverse breakdown to maintain stable voltage across its terminals under varying load or supply conditions. Its Zener voltage is specified at IZT = 3.8 mA with ±5% tolerance, and it exhibits a positive temperature coefficient near 33 V, typical for mid-voltage Zeners in this family.
The SOT-23 package features Pin 1 (Anode), Pin 2 (No Connection), and Pin 3 (Cathode), enabling unidirectional clamping or regulation. With 225 mW power rating and 556 °C/W junction-to-ambient thermal resistance on FR-5, it supports continuous operation up to +150 °C junction temperature when properly derated.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31.35–34.65 V @ IZT = 3.8 mA - defines regulated output voltage range under standard test conditions |
| Power Dissipation (PD) | 225 mW on FR-5 board @ TA = 25°C - sets maximum steady-state power handling without heatsinking |
| Zener Impedance (ZZT) | 700 Ω max @ IZT = 3.8 mA - indicates voltage regulation stability under small-signal AC variations |
| Leakage Current (IR) | 0.1 μA max @ VR = 25 V - ensures minimal standby current in clamping or reference circuits |
| ESD Rating | Class 3 (>16 kV) per Human Body Model - enables robust handling in automated assembly and end-use environments |
| Junction Temperature Range | −65 °C to +150 °C - supports operation in automotive, industrial, and extended-temperature portable applications |
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; polarity indicated by cathode band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential side in reverse-bias regulation; must be held ≤ VZ below cathode for conduction |
| 2 | No Connection | Internally isolated; no electrical function - must remain unconnected on PCB |
| 3 | Cathode | Connected to higher-potential side; defines reference node location in voltage-clamp or shunt-regulator topologies |
Key Features
| Feature | Design Value |
|---|---|
| Pb-Free, Halogen-Free/BFR-Free | Fully RoHS-compliant construction with UL 94 V-0 flammability rating for safety-critical PCBs |
| Automated Assembly Optimized | SOT-23 footprint and marking design support high-yield pick-and-place and reflow soldering |
| High-Density Packaging | Small 2.90 × 1.30 mm outline enables placement in space-constrained mobile and wearable designs |
| Stable Zener Voltage Tolerance | ±5% tolerance at 33 V ensures predictable clamping threshold without post-production trimming |
Applications
| USB Power Protection | Smartphone Battery Monitoring |
|---|---|
|
Use Scenario: Clamping transient surges on USB VBUS line during hot-plug events or ESD discharge. IC Role / Device Role / Timing Role: Shunt protection element placed between VBUS and ground, conducting only above 33 V threshold. Use Value: Prevents damage to downstream USB controller ICs by limiting peak voltage to ≤34.65 V with sub-μA leakage below threshold. |
Use Scenario: Providing stable reference voltage for ADC input in battery fuel-gauge circuitry. IC Role / Device Role / Timing Role: Precision shunt reference connected to microcontroller ADC reference pin or divider network. Use Value: Delivers 33 V reference with <±5% tolerance and <700 Ω dynamic impedance, minimizing ADC measurement error due to source impedance. |
| IoT Sensor Node Voltage Clamp | Wearable Device ESD Suppression |
|
Use Scenario: Protecting analog front-end inputs of environmental sensors from overvoltage during field deployment. IC Role / Device Role / Timing Role: Low-leakage Zener placed across sensor signal path to ground, activated only during fault conditions. Use Value: Maintains system accuracy with 0.1 μA leakage at 25 V, avoiding signal-path loading during normal operation. |
Use Scenario: Integrated ESD protection on exposed buttons, touch interfaces, or charging contacts in fitness trackers. IC Role / Device Role / Timing Role: First-line transient suppressor absorbing >16 kV HBM discharges before reaching sensitive ASICs. Use Value: Leverages Class 3 ESD rating and SOT-23 size to meet IEC 61000-4-2 Level 4 requirements without adding board area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C33LT1G | Same 33 V nominal Zener, but 300 mW rating on FR-4 and 30 Ω ZZT @ 5 mA - lower impedance, higher power | Preferred where tighter voltage regulation under variable load is required; not suitable for ultra-low-leakage designs | Select BZX84-C33LT1G when lower dynamic impedance and higher power margin are needed; verify thermal layout for 300 mW dissipation |
| SZMMBZ5257BLT3G | Identical electrical specs, but AEC-Q101 qualified and PPAP capable for automotive use | Required for under-hood or infotainment systems needing automotive-grade reliability and traceability | Choose SZMMBZ5257BLT3G for automotive applications; otherwise MMBZ5257BLT3G suffices for consumer/industrial use |
Compared with BZX84-C33LT1G, MMBZ5257BLT3G offers lower leakage (0.1 μA vs. 0.5 μA) and smaller thermal footprint, while SZMMBZ5257BLT3G adds automotive qualification without altering electrical behavior - making MMBZ5257BLT3G optimal for cost-sensitive, space-constrained non-automotive designs.
Availability
MMBZ5257BLT3G is available at Aetrix Electronics and suitable for USB power protection, smartphone battery monitoring, IoT sensor node voltage clamp, and wearable device ESD suppression requiring stable component supply and consistent SOT-23 packaging.
Supply support for MMBZ5257BLT3G 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 supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The MMBZ52xxBLT3G series is part of onsemi's precision Zener voltage regulator portfolio, designed specifically for compact, high-density portable electronics requiring reliable voltage reference or overvoltage protection in SOT-23 form factor.
FAQ
What is the nominal Zener voltage of MMBZ5257BLT3G and how tightly is it specified?
The nominal Zener voltage of MMBZ5257BLT3G is 33 V, with a guaranteed range of 31.35 V to 34.65 V at IZT = 3.8 mA. This ±5% tolerance is confirmed in the Electrical Characteristics table on page 3 of the official onsemi datasheet, ensuring predictable clamping behavior in production designs using MMBZ5257BLT3G.
Does MMBZ5257BLT3G have a no-connect pin, and how is it configured in the SOT-23 package?
Yes, MMBZ5257BLT3G has Pin 2 designated as "No Connection" - it is internally isolated and must remain unconnected on the PCB. The active terminals are Pin 1 (Anode) and Pin 3 (Cathode), per Style 8 mechanical outline in the datasheet, which applies directly to MMBZ5257BLT3G.
What is the maximum leakage current specification for MMBZ5257BLT3G and at what reverse voltage is it measured?
The maximum reverse leakage current for MMBZ5257BLT3G is 0.1 μA, measured at VR = 25 V and TA = 25°C. This value is explicitly listed in the Electrical Characteristics table for MMBZ5257BLT1G/T3G on page 3, confirming low standby power impact when used as a reference or clamp with MMBZ5257BLT3G.
Is MMBZ5257BLT3G RoHS compliant and what flammability rating does its package carry?
Yes, MMBZ5257BLT3G is Pb-free, halogen-free/BFR-free, and RoHS compliant, as stated in the Features section. Its SOT-23 thermosetting plastic case carries a UL 94 V-0 flammability rating, verified in the Mechanical Characteristics section - critical for safety certification in consumer and medical devices using MMBZ5257BLT3G.
How does the thermal resistance of MMBZ5257BLT3G compare between FR-5 board and alumina substrate?
MMBZ5257BLT3G has RJA = 556 °C/W on FR-5 board and RJA = 417 °C/W on alumina substrate (0.4 × 0.3 × 0.024 in), per Maximum Ratings table. This 25% lower thermal resistance on alumina allows ~33% higher power dissipation before reaching TJ = 150°C - a key consideration when selecting board material for MMBZ5257BLT3G in thermally demanding layouts.
MMBZ5257BLT3G 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):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 225 mW
- Impedance (Max) (Zzt):
- 58 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 25 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)
MMBZ5257BLT3G FAQ
1.How can I place an order for MMBZ5257BLT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5257BLT3G 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 MMBZ5257BLT3G reliable?
The price and inventory of MMBZ5257BLT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5257BLT3G is usually 5 days.
3.What payment methods are accepted for MMBZ5257BLT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5257BLT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5257BLT3G?
MMBZ5257BLT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5257BLT3G 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 MMBZ5257BLT3G?
For technical support, including MMBZ5257BLT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5257BLT3G requirements.
6.How does Aetrix verify that MMBZ5257BLT3G is sourced from the original manufacturer or authorized distributors?
All MMBZ5257BLT3G 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 MMBZ5257BLT3G meets industry standards.
7.What is the process for return or replacement of MMBZ5257BLT3G?
All MMBZ5257BLT3G units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5257BLT3G, 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 MMBZ5257BLT3G part is unused and in its original packaging.
Return procedure for MMBZ5257BLT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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