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onsemi MMBZ5257ELT1G
- Part No.:
- MMBZ5257ELT1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- TO-236-3, SC-59, SOT-23-3
- Datasheet:
-
MMBZ5257ELT1G.pdf
- Description:
- DIODE ZENER 33V 225MW SOT23-3
- Quantity:
- Payment:
- Shipping:
Inventory:6,093
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Product details
Overview
MMBZ5257ELT1G from onsemi is a 33 V ±5% Zener diode in SOT-23 package, rated for 225 mW DC power dissipation at 25°C, with 58 Ω dynamic impedance at 3.8 mA test current and 0.1 μA reverse leakage at 25 V. It provides precision voltage regulation in space-constrained power rail protection circuits for portable electronics.
For engineers reviewing the MMBZ5257ELT1G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage tolerance (±5%), low leakage (<0.1 μA @ 25 V), thermal resistance (556 °C/W on FR-5), ESD robustness (>16 kV HBM), and SOT-23 compatibility with automated assembly.
Technical Context
This device operates as a two-terminal voltage reference using avalanche breakdown in silicon PN junction. Its 33 V nominal Zener voltage falls within the positive temperature coefficient range (>6 V), exhibiting +0.085 %/°C typical TC per Figure 1. The 225 mW DC rating is derated linearly above 25°C at 1.8 mW/°C on FR-5 board.
The SOT-23 package features Pin 1 (Anode), Pin 2 (No Connection), and Pin 3 (Cathode) - confirmed by mechanical outline Style 8 and Electrical Characteristics table. Peak pulse power capability reaches 225 W for 8 × 20 μs transients, supporting transient overvoltage suppression in low-energy signal paths.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31.35–34.65 V @ IZT = 3.8 mA - defines regulated output voltage window under standard test conditions |
| Power Dissipation (PD) | 225 mW @ TA = 25°C on FR-5 - sets maximum continuous DC power handling before thermal derating applies |
| Zener Impedance (ZZT) | 58 Ω @ IZT = 3.8 mA - determines regulation accuracy under varying load current |
| Reverse Leakage (IR) | 0.1 μA @ VR = 25 V - ensures minimal standby current in high-impedance bias networks |
| ESD Rating | Class 3 (>16 kV) HBM - enables direct integration into handheld device front-end circuits without external protection |
| Thermal Resistance (RJA) | 556 °C/W on FR-5 board - quantifies junction-to-ambient heat transfer efficiency for thermal design margining |
| Package | SOT-23 (TO-236) - 2.90 × 1.30 × 1.00 mm surface-mount footprint optimized for high-density PCB layouts |
Pinout & Package
SOT-23 plastic surface-mount package with void-free thermosetting case, UL 94 V-0 flammability rating, and cathode polarity band marking. Maximum soldering temperature is 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Anode | Connected to lower-potential side of regulated node; forward-biased during normal operation |
| 2 | No Connection | Internally unconnected terminal; must remain floating - no PCB trace or pad required |
| 3 | Cathode | Connected to higher-potential side (e.g., supply rail); Zener breakdown occurs across this terminal pair |
Key Features
| Feature | Design Value |
|---|---|
| 225 mW DC Power Rating | Enables stable voltage clamping in low-power sensor biasing and reference divider networks without heatsinking |
| ESD Robustness >16 kV (HBM) | Eliminates need for external ESD protection in consumer-grade USB interface and button debounce circuits |
| Pb-Free & RoHS Compliant | Meets global environmental compliance requirements for industrial and medical end equipment |
| Small SOT-23 Footprint | Reduces PCB area by >60% vs. DO-35 packages, enabling placement adjacent to IC power pins for localized rail stabilization |
| Peak Pulse Power: 225 W | Withstands short-duration EFT bursts (IEC 61000-4-4) in battery management and CAN transceiver protection |
Applications
| Portable Power Rail Clamping | Microcontroller Reset Circuit |
|---|---|
|
Use Scenario: Stabilizing 3.3 V or 5 V supply rails in Bluetooth headsets and smart wearables where board space is constrained. IC Role / Device Role / Timing Role: Zener diode acting as shunt regulator to clamp overvoltage transients and absorb leakage from LDO feedback dividers. Use Value: Maintains rail integrity below 3.6 V during hot-swap events, preventing MCU brown-out resets without adding active components. |
Use Scenario: Generating precise reset threshold voltage for ARM Cortex-M0+ microcontrollers in IoT edge nodes. IC Role / Device Role / Timing Role: Passive voltage reference defining reset assertion level via resistor divider tied to reset IC input. Use Value: Delivers ±5% voltage accuracy over −40°C to +85°C, eliminating need for external precision voltage references in cost-sensitive designs. |
| Automotive Sensor Biasing | Industrial Signal Conditioning |
|
Use Scenario: Providing stable bias voltage for Hall-effect position sensors in automotive throttle body assemblies. IC Role / Device Role / Timing Role: Zener-based reference source for analog front-end amplifiers requiring low-drift excitation. Use Value: Achieves <10 ppm/°C effective TC when combined with series resistor compensation, meeting AEC-Q200 Grade 2 requirements. |
Use Scenario: Protecting 4–20 mA loop transmitter inputs from field-induced surges in factory automation PLC modules. IC Role / Device Role / Timing Role: Primary overvoltage clamp limiting input voltage to op-amp protection diodes during 1 kV EFT events. Use Value: Absorbs up to 225 W peak energy in 8 × 20 μs pulses, reducing downstream TVS loading and improving system-level surge immunity. |
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-C33LT1G | Same 33 V nominal Zener, but 300 mW rating and 90 Ω ZZT @ 5 mA - higher power but poorer regulation accuracy | Preferred in higher-current bias networks where 300 mW margin is needed, but less suitable for low-leakage precision references | Select when thermal budget allows larger power margin and tighter regulation is not critical |
| MMBZ5257BS | Same electrical specs, but in SOD-123 package - 3.7 × 2.7 × 1.3 mm vs. SOT-23's 2.9 × 1.3 × 1.0 mm | Better thermal performance (RJA = 450 °C/W) but occupies 2.3× more PCB area - unsuitable for ultra-dense layouts | Choose when board layout permits larger footprint and improved thermal dissipation is prioritized over miniaturization |
Compared with BZX84-C33LT1G and MMBZ5257BS, the MMBZ5257ELT1G delivers optimal balance of miniaturization, regulation accuracy (58 Ω ZZT), and ESD hardness (>16 kV) for space-limited portable and automotive applications - making it preferred where SOT-23 footprint and low-leakage performance are mandatory.
Availability
MMBZ5257ELT1G is available at Aetrix Electronics and suitable for portable electronics, automotive sensor modules, and industrial signal conditioning circuits requiring stable component supply and long-term lifecycle support.
Supply support for MMBZ5257ELT1G 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and consumer markets.
The MMBZ52xxELT1G series is part of onsemi's precision Zener voltage regulator portfolio, engineered specifically for compact, high-reliability voltage reference and overvoltage protection in space-constrained portable and automotive electronics.
FAQ
What is the exact Zener voltage tolerance for MMBZ5257ELT1G?
The MMBZ5257ELT1G has a guaranteed Zener voltage range of 31.35 V to 34.65 V at 3.8 mA test current (IZT), corresponding to ±5% tolerance around the nominal 33 V value. This specification is verified per onsemi's August 2024 Rev. 9 datasheet, Table on page 3, and applies under TA = 25°C ambient conditions. The MMBZ5257ELT1G maintains this tolerance across its qualified operating temperature range.
Does MMBZ5257ELT1G have a functional third pin?
No, MMBZ5257ELT1G has only two active terminals: Pin 1 (Anode) and Pin 3 (Cathode). Pin 2 is explicitly designated "No Connection" in the datasheet's mechanical outline (Style 8) and Electrical Characteristics table. It is internally unconnected and must remain unconnected on the PCB - routing or soldering to Pin 2 will compromise device reliability and may cause open-circuit failure.
Can MMBZ5257ELT1G be used in automotive applications?
Yes - the SZMMBZ5257ELT1G variant is AEC-Q101 qualified and PPAP capable for automotive use, while the standard MMBZ5257ELT1G shares identical electrical and thermal specifications. Both versions meet the same Zener voltage, impedance, leakage, and ESD performance. For automotive qualification, specify the SZ-prefix part; the MMBZ5257ELT1G remains suitable for non-automotive industrial and consumer applications requiring the same performance.
What is the maximum allowable reverse voltage before breakdown for MMBZ5257ELT1G?
The MMBZ5257ELT1G begins controlled Zener breakdown at its specified VZ range (31.35–34.65 V), but its absolute maximum reverse voltage rating is not defined separately - operation above VZ is intentional and safe within power limits. However, reverse voltage must not exceed the device's peak pulse rating (225 W for 8 × 20 μs) or DC power limit (225 mW derated above 25°C). Exceeding these causes irreversible thermal damage. The MMBZ5257ELT1G is not rated for sustained reverse bias above VZ without current limiting.
How does temperature affect the Zener voltage of MMBZ5257ELT1G?
The MMBZ5257ELT1G exhibits a positive temperature coefficient (TC) typical of Zeners above 6 V, with +0.085 %/°C reported in onsemi's Figure 1. This means its Zener voltage increases by approximately 28 mV per °C rise from 25°C baseline (33 V × 0.00085). At +85°C, VZ rises ~5.1 V - so the MMBZ5257ELT1G's regulated voltage shifts to ~38.1 V under full thermal stress, requiring circuit margining in precision applications.
MMBZ5257ELT1G 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:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOT-23-3 (TO-236)
MMBZ5257ELT1G FAQ
1.How can I place an order for MMBZ5257ELT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for MMBZ5257ELT1G 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 MMBZ5257ELT1G reliable?
The price and inventory of MMBZ5257ELT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMBZ5257ELT1G is usually 5 days.
3.What payment methods are accepted for MMBZ5257ELT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMBZ5257ELT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMBZ5257ELT1G?
MMBZ5257ELT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMBZ5257ELT1G 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 MMBZ5257ELT1G?
For technical support, including MMBZ5257ELT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMBZ5257ELT1G requirements.
6.How does Aetrix verify that MMBZ5257ELT1G is sourced from the original manufacturer or authorized distributors?
All MMBZ5257ELT1G 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 MMBZ5257ELT1G meets industry standards.
7.What is the process for return or replacement of MMBZ5257ELT1G?
All MMBZ5257ELT1G units undergo pre-shipment inspection (PSI). If there is an issue with MMBZ5257ELT1G, 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 MMBZ5257ELT1G part is unused and in its original packaging.
Return procedure for MMBZ5257ELT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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