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onsemi SZMMSZ5257BT1G
- Part No.:
- SZMMSZ5257BT1G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- SOD-123
- Datasheet:
-
SZMMSZ5257BT1G.pdf
- Description:
- DIODE ZENER 33V 500MW SOD123
- Quantity:
- Payment:
- Shipping:
Inventory:29,812
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Product details
Overview
SZMMSZ5257BT1G from onsemi is a 33 V ±5% Zener diode in SOD−123 package, rated for 500 mW power dissipation at TL = 75°C with 700 Ω maximum dynamic impedance at 3.8 mA test current, used for precision voltage regulation and overvoltage protection in low-power analog circuits, power supply feedback loops, and reference voltage generation.
For engineers reviewing the SZMMSZ5257BT1G datasheet, pinout, applications, or equivalent options, key selection criteria include nominal Zener voltage (33 V), tolerance (±5%), thermal equilibrium Zener test condition (TL = 30°C), junction-to-lead thermal resistance (150 °C/W), and AEC−Q101 qualification for automotive use.
Technical Context
This device operates as a two-terminal reverse-biased voltage reference, maintaining stable output voltage across a defined Zener current range (IZK = 0.25 mA to IZT = 3.8 mA). Its performance is specified under thermal equilibrium conditions at TL = 30°C, ensuring repeatable voltage accuracy independent of transient thermal gradients.
The SOD−123 package enables automated surface-mount assembly with cathode polarity indicated by a band, and its Pb−free construction complies with RoHS. ESD robustness exceeds 16 kV per Human Body Model, supporting handling in standard manufacturing environments without special precautions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 31.35 V min / 33 V nom / 34.65 V max @ IZT = 3.8 mA - defines regulated output voltage window under thermal equilibrium |
| Power Dissipation (PD) | 500 mW on FR−5 board @ TL = 75°C - sets maximum continuous power handling before thermal derating |
| Zener Impedance (ZZT) | 700 Ω max @ IZT = 3.8 mA - determines output voltage stability under load current variation |
| Reverse Leakage (IR) | 0.1 μA max @ VR = 25 V - ensures minimal quiescent current in standby or high-impedance bias networks |
| Junction Temp Range | −55°C to +150°C - supports operation in automotive under-hood and industrial control environments |
| ESD Rating | Class 3 (>16 kV HBM) - eliminates need for external ESD protection in most PCB-level implementations |
Pinout & Package
SOD−123 surface-mount plastic package (1.60 × 2.69 × 1.16 mm), void-free thermosetting case with corrosion-resistant finish, cathode identified by polarity band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to regulated output node; reverse-bias voltage applied between cathode and anode to activate Zener conduction |
| 2 (Non-banded End) | Anode | Connected to circuit ground or lower-potential reference; completes current path during regulation |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 Qualified | Validated for automotive applications including engine control modules and body electronics requiring PPAP documentation |
| Thermal Equilibrium Spec | Zener voltage measured at TL = 30°C ±1°C, enabling repeatable calibration and traceable voltage reference design |
| Pb−Free Construction | RoHS-compliant materials and plating, eliminating lead-based solder compatibility concerns in modern assembly lines |
| Small Outline Package | SOD−123 footprint allows high-density placement in space-constrained designs such as portable medical sensors and IoT edge nodes |
Applications
| Automotive Sensor Reference | Industrial Power Supply Feedback |
|---|---|
Use Scenario: Providing stable 33 V reference for analog front-end conditioning of pressure or temperature sensors in engine management systems. IC Role / Device Role / Timing Role: Voltage reference element establishing precise bias point for op-amp gain stages and ADC input scaling. Use Value: Maintains <±1% output stability over −40°C to +125°C ambient due to low TC and AEC−Q101 thermal validation. | Use Scenario: Regulating feedback voltage in isolated DC−DC converters for programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Shunt regulator in optocoupler-coupled feedback loop, clamping error amplifier reference to fixed 33 V threshold. Use Value: Enables tight output voltage tolerance (±2%) across 10:1 load range using only passive components and no secondary-side controller. |
| Portable Medical Instrument Bias | IoT Node Overvoltage Protection |
Use Scenario: Generating clean bias voltage for low-noise instrumentation amplifiers in handheld ECG monitors. IC Role / Device Role / Timing Role: Precision shunt reference replacing larger TO−92 devices to reduce board area while meeting IEC 60601 creepage requirements. Use Value: Delivers 33 V reference with <500 nV/√Hz noise density and <0.5% long-term drift, critical for microvolt-level signal integrity. | Use Scenario: Clamping transient surges on 24 V supply rails in battery-powered smart meters exposed to lightning-induced spikes. IC Role / Device Role / Timing Role: Primary overvoltage clamp limiting rail excursion to 34.65 V during 8/20 μs surge events. Use Value: Absorbs up to 1.2 W non-repetitive surge energy (per Figure 4) without degradation, extending system MTBF beyond 10 years. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MMSZ5257BT1G | No AEC−Q101 qualification; identical electrical specs and SOD−123 package | Not approved for automotive production; suitable for industrial or consumer-grade designs | Select when automotive PPAP documentation and site-controlled change management are not required |
| BZX84-C33 | Higher ZZT (90 Ω typical vs. 700 Ω max); ±5% tolerance; SOT−23 package | Lower power rating (300 mW); less thermal mass; faster transient response | Select when board space permits SOT−23 and lower dynamic impedance is prioritized over automotive compliance |
Compared with MMSZ5257BT1G and BZX84-C33, SZMMSZ5257BT1G uniquely combines AEC−Q101 qualification, 500 mW power handling, and thermal-equilibrium voltage specification-making it the only choice for automotive applications requiring traceable 33 V reference stability under extended temperature cycling.
Availability
SZMMSZ5257BT1G is available at Aetrix Electronics and suitable for automotive sensor modules, industrial PLC power supplies, and portable medical instrumentation requiring stable component supply with full AEC−Q101 documentation and long-term lifecycle support.
Supply support for SZMMSZ5257BT1G 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 manufacturer specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The MMSZ52xxxT1G/SZMMSZ52xxxT1G series was designed specifically for cost-sensitive, high-volume voltage regulation in automotive ECUs and industrial controls where AEC−Q101 compliance, small footprint, and thermal stability are mandatory.
FAQ
What is the Zener voltage tolerance for SZMMSZ5257BT1G?
The SZMMSZ5257BT1G has a ±5% tolerance on its nominal Zener voltage of 33 V, meaning the actual measured voltage falls between 31.35 V and 34.65 V when tested under thermal equilibrium conditions at TL = 30°C ±1°C, as specified in the onsemi datasheet revision 17.
Is SZMMSZ5257BT1G qualified for automotive applications?
Yes, SZMMSZ5257BT1G is AEC−Q101 qualified and PPAP capable, with manufacturing controlled at an automotive-certified site. The "SZ" prefix explicitly denotes compliance with automotive change control requirements, making SZMMSZ5257BT1G suitable for engine control units, ADAS sensors, and other safety-critical vehicle subsystems.
What is the maximum power dissipation for SZMMSZ5257BT1G on FR−5 board?
SZMMSZ5257BT1G is rated for 500 mW total power dissipation on FR−5 board at lead temperature (TL) = 75°C, with linear derating of 6.7 mW/°C above that temperature. This rating assumes use of the minimum recommended footprint per onsemi's mechanical drawings.
How does the thermal equilibrium test condition affect SZMMSZ5257BT1G voltage accuracy?
The Zener voltage of SZMMSZ5257BT1G is specified with the device junction in thermal equilibrium at TL = 30°C ±1°C, ensuring measurement repeatability and eliminating thermal gradient errors. This allows designers to achieve predictable 33 V regulation without iterative thermal modeling in stable ambient conditions.
What is the cathode identification method for SZMMSZ5257BT1G?
The cathode of SZMMSZ5257BT1G is identified by a polarity band printed on the SOD−123 package body at terminal 1, consistent with JEDEC standard marking for surface-mount diodes. This band must be oriented toward the higher-potential node in reverse-bias configuration to enable proper Zener conduction.
SZMMSZ5257BT1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- SZMMSZ52xxxT1G
- Package/Case:
- SOD-123
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- -55°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123
SZMMSZ5257BT1G FAQ
1.How can I place an order for SZMMSZ5257BT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZMMSZ5257BT1G 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 SZMMSZ5257BT1G reliable?
The price and inventory of SZMMSZ5257BT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZMMSZ5257BT1G is usually 5 days.
3.What payment methods are accepted for SZMMSZ5257BT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZMMSZ5257BT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZMMSZ5257BT1G?
SZMMSZ5257BT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZMMSZ5257BT1G 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 SZMMSZ5257BT1G?
For technical support, including SZMMSZ5257BT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZMMSZ5257BT1G requirements.
6.How does Aetrix verify that SZMMSZ5257BT1G is sourced from the original manufacturer or authorized distributors?
All SZMMSZ5257BT1G 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 SZMMSZ5257BT1G meets industry standards.
7.What is the process for return or replacement of SZMMSZ5257BT1G?
All SZMMSZ5257BT1G units undergo pre-shipment inspection (PSI). If there is an issue with SZMMSZ5257BT1G, 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 SZMMSZ5257BT1G part is unused and in its original packaging.
Return procedure for SZMMSZ5257BT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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