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Diodes Incorporated MMSZ5257B-7
- Part No.:
- MMSZ5257B-7
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
MMSZ5257B-7.pdf
- Description:
- DIODE ZENER 33V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:2,600
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Product details
Overview
MMSZ5257B-7 from Diodes Incorporated is a 33 V, 500 mW surface-mount Zener diode in SOD-123 package, rated for 3.8 mA test current with 58 Ω dynamic impedance at 1 kHz and 0.1 µA reverse leakage at 25 V, widely used for voltage regulation and reference in power supply feedback loops.
For engineers reviewing the MMSZ5257B-7 datasheet, MMSZ5257B-7 pinout, MMSZ5257B-7 application, or MMSZ5257B-7 equivalent, key selection criteria include nominal Zener voltage tolerance (±3.5%), thermal resistance (338 °C/W), AEC-Q101 qualification, RoHS/Green compliance, and SOD-123 footprint compatibility with automated assembly.
Technical Context
This Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load or line conditions. It delivers precise 33 V regulation with ±3.5% tolerance (31.35–34.65 V) at 3.8 mA test current and exhibits low dynamic impedance (58 Ω) for effective noise suppression in feedback networks.
Designed for high-reliability commercial and automotive applications, it features a matte tin-plated Alloy 42 leadframe, UL 94V-0 molding compound, moisture sensitivity level 1, and operates across –65 °C to +150 °C ambient temperature range without derating below +75 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 33 V nominal, 31.35–34.65 V range at 3.8 mA - ensures tight regulation in precision reference circuits |
| Power Dissipation | 370 mW @ TA = +25°C - defines maximum continuous DC power on standard FR-4 PCB |
| Zener Impedance (ZZT) | 58 Ω @ 1 kHz, 3.8 mA - determines AC ripple rejection capability in voltage references |
| Reverse Leakage (IR) | 0.1 µA @ VR = 25 V - minimizes quiescent current loss in low-power bias networks |
| Thermal Resistance (RθJA) | 338 °C/W - sets junction-to-ambient temperature rise per watt dissipated on standard layout |
| Operating Temperature | –65 °C to +150 °C - supports deployment in under-hood automotive and industrial environments |
Pinout & Package
Package: SOD-123 - compact 2-terminal surface-mount plastic case with cathode band marking, 1.55 mm width, 2.65 mm length, and 0.30 mm lead thickness; optimized for reflow soldering and high-density PCB layouts.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Reverse breakdown reference node | Connected to lower-potential side of regulated circuit; forms reference ground return path |
| Cathode | Zener voltage output terminal / Breakdown anode | Marked with band; supplies stable 33 V relative to anode when reverse biased above knee voltage |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| Lead-free & Green compliant | Halogen- and antimony-free molding compound (<900 ppm Br/Cl, <1000 ppm Sb); RoHS 2 compliant |
| Automated assembly compatible | SOD-123 footprint and matte tin plating ensure consistent solder wetting and placement yield |
| Low leakage at high VR | 0.1 µA @ 25 V enables use in battery-backed or ultra-low-power bias networks |
Applications
| Switch-Mode Power Supply Feedback | Industrial Sensor Reference |
|---|---|
Use Scenario: Regulates output voltage in isolated flyback converters via optocoupler-coupled feedback loop. IC Role / Device Role / Timing Role: Zener reference providing stable 33 V threshold to TL431 shunt regulator input. Use Value: Tight 31.35–34.65 V tolerance ensures ±1% output regulation accuracy over temperature and line variation. | Use Scenario: Supplies precision bias voltage to bridge-based pressure transducers in factory automation systems. IC Role / Device Role / Timing Role: Stable voltage reference for ratiometric ADC excitation and offset compensation. Use Value: Low 0.1 µA leakage prevents loading error in high-impedance sensor bridges. |
| Automotive Body Control Module | USB-C PD Voltage Clamp |
Use Scenario: Protects microcontroller I/O pins from load-dump transients in 12 V vehicle subsystems. IC Role / Device Role / Timing Role: Clamping diode limiting voltage spikes to 33 V during ISO 7637-2 pulse 5a events. Use Value: AEC-Q101 qualification guarantees operation at 150 °C junction temperature during sustained overvoltage. | Use Scenario: Limits CC logic line voltage to safe levels during USB-C power negotiation. IC Role / Device Role / Timing Role: Overvoltage clamp protecting USB-C controller GPIO from >33 V fault conditions. Use Value: 58 Ω Zener impedance ensures fast response to transient overvoltage without signal distortion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX584C33 | 33 V, ±5% tolerance, 300 mW rating, SOD-323 package | Lower power rating and wider voltage tolerance; smaller footprint | Select when board space is constrained and ±5% regulation is acceptable |
| MM3Z33VT1G | 33 V, ±5%, 200 mW, SOD-323, 100 nA leakage @ 25 V | Higher leakage spec (100 nA vs. 0.1 µA), lower power, same package size | Prefer for ultra-low-leakage biasing where 200 mW suffices and SOD-323 is preferred |
Compared with BZX584C33 and MM3Z33VT1G, MMSZ5257B-7 offers tighter voltage tolerance (±3.5%), higher power handling (370 mW), and AEC-Q101 qualification-making it optimal for automotive and industrial feedback regulation where stability and reliability are critical.
Availability
MMSZ5257B-7 is available at Aetrix Electronics and suitable for switch-mode power supplies, automotive body control modules, industrial sensor references, and USB-C PD voltage clamping requiring stable component supply and long-term lifecycle support.
Supply support for MMSZ5257B-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 MMSZ52xxB series belongs to Diodes' general-purpose Zener diode product line, engineered for cost-effective, high-yield voltage regulation and reference in consumer, industrial, and automotive power management circuits.
FAQ
What is the maximum reverse voltage before breakdown for MMSZ5257B-7?
The nominal Zener voltage is 33 V with a guaranteed range of 31.35 V to 34.65 V at 3.8 mA test current. Breakdown begins near the lower limit, and full regulation is established above 31.35 V. The device is not rated for continuous operation above 34.65 V in reverse bias without exceeding power limits.
Can MMSZ5257B-7 be used in place of a 30 V Zener diode?
No - MMSZ5257B-7 is specifically a 33 V Zener diode (M2 type code). Substituting it for a 30 V part (e.g., MMSZ5256B) introduces a 10% voltage error in regulation or reference circuits, potentially causing overvoltage stress or functional failure in feedback-controlled systems.
Does MMSZ5257B-7 require a heatsink in typical applications?
No - with a thermal resistance of 338 °C/W and a maximum power dissipation of 370 mW at +25°C ambient, junction temperature rise is ~125°C at full load. On standard FR-4 with 1-inch copper pad, it remains within the –65 °C to +150 °C operating range without external heatsinking under normal conditions.
Is MMSZ5257B-7 suitable for bidirectional ESD protection?
No - it is a unidirectional Zener diode optimized for reverse-bias voltage regulation. Its forward voltage is ~0.9 V at 10 mA, but it lacks symmetric clamping characteristics or specified ESD ratings (e.g., IEC 61000-4-2). Dedicated TVS diodes like PESD5V0S1BA should be used for bidirectional ESD protection.
MMSZ5257B-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Voltage - Zener (Nom) (Vz):
- 33 V
- Tolerance:
- ±5%
- Power - Max:
- 500 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:
- SOD-123
MMSZ5257B-7 FAQ
1.How can I place an order for MMSZ5257B-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for MMSZ5257B-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 MMSZ5257B-7 reliable?
The price and inventory of MMSZ5257B-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MMSZ5257B-7 is usually 5 days.
3.What payment methods are accepted for MMSZ5257B-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MMSZ5257B-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MMSZ5257B-7?
MMSZ5257B-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MMSZ5257B-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 MMSZ5257B-7?
For technical support, including MMSZ5257B-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MMSZ5257B-7 requirements.
6.How does Aetrix verify that MMSZ5257B-7 is sourced from the original manufacturer or authorized distributors?
All MMSZ5257B-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 MMSZ5257B-7 meets industry standards.
7.What is the process for return or replacement of MMSZ5257B-7?
All MMSZ5257B-7 units undergo pre-shipment inspection (PSI). If there is an issue with MMSZ5257B-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 MMSZ5257B-7 part is unused and in its original packaging.
Return procedure for MMSZ5257B-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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