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Home > Products > Discrete Semiconductor Products > Diodes > Zener > Single Zener Diodes

onsemi SZ1SMA5931BT3G

Name: SZ1SMA5931BT3G
Brand: onsemi
SKU: SZ1SMA5931BT3G
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SZ1SMA5931BT3G

Manufacturer:: onsemi

Category:: Single Zener Diodes

Package:: DO-214AC, SMA

Datasheet:: SZ1SMA5931BT3G.pdf

Description:: DIODE ZENER 18V 1.5W SMA

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Inventory:20,118

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Product details

Overview

SZ1SMA5931BT3G from onsemi is a 1.5 W surface-mount Zener diode with nominal zener voltage of 18 V, maximum zener impedance of 20.8 Ω at 12 mA test current, and reverse leakage current ≤0.25 μA at 14.4 V, designed for precision voltage regulation in automotive power supplies and industrial sensor biasing circuits.

For engineers reviewing the SZ1SMA5931BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage tolerance (±5%), thermal resistance (250 °C/W), AEC−Q101 qualification status, and low-profile SMA package compatibility with automated SMT assembly.

Technical Context

This device operates as a two-terminal voltage reference using avalanche breakdown in silicon PN junction. It maintains stable reverse conduction above its specified V_Z threshold while dissipating up to 1.5 W at lead temperature ≤75°C, with derating to 0.5 W at ambient 25°C.

Its design supports both top-slide and bottom-board mounting configurations in the SMA package, features ESD robustness (>16 kV HBM), and meets UL 94 V−0 flammability rating - critical for under-hood automotive modules and industrial control units requiring long-term reliability under thermal cycling.

Key Specifications

Parameter	Value and Actual Design Meaning
Zener Voltage (V_Z)	17.1–18.9 V @ I_ZT = 12 mA; ±5% tolerance ensures predictable clamping level in overvoltage protection circuits
Max Power Dissipation	1.5 W @ T_L = 75°C; enables compact thermal design without heatsink in space-constrained PCB layouts
Zener Impedance (Z_ZT)	20.8 Ω max @ I_ZT; low dynamic impedance preserves regulation accuracy under varying load conditions
Reverse Leakage Current	≤0.25 μA @ V_R = 14.4 V; minimizes standby power loss in battery-backed systems
Thermal Resistance (R_JA)	250 °C/W; defines worst-case junction-to-ambient rise under FR-4 board conditions per onsemi footprint
ESD Rating	Class 3 (>16 kV HBM); protects against handling-induced electrostatic discharge during manufacturing
AEC−Q101 Qualified	Yes; validated for automotive-grade reliability including temperature cycling, humidity, and mechanical shock

Pinout & Package

The SZ1SMA5931BT3G uses the SMA (DO-214AC) surface-mount package (Case 403D), featuring a flat handling surface, void-free molded plastic case, and cathode indicated by a molded polarity notch or band. Maximum soldering temperature is 260°C for 10 seconds.

Pin/Terminal	Circuit Role	Design Meaning
Cathode (marked side)	High-side terminal for reverse-bias operation	Connected to regulated output node; must be held at higher potential than anode to enable zener conduction
Anode	Low-side terminal / reference ground path	Provides return path for zener current; ties to system ground or lower-potential rail in shunt regulator topology

Key Features

Feature	Design Value
AEC−Q101 qualification	Validated for automotive applications including engine control units and ADAS power domains
Pb−Free construction	Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 reflow profile requirements
Low-profile SMA package	Enables high-density placement on double-sided PCBs and compatibility with standard SMT pick-and-place equipment
ESD robustness >16 kV HBM	Reduces need for external ESD protection components in front-end power conditioning stages
Flat handling surface	Improves placement accuracy and reduces tombstoning risk during reflow soldering

Applications

Automotive Engine Control Unit (ECU) Reference	Industrial Sensor Signal Conditioning
Use Scenario: Providing stable 18 V reference for analog-to-digital converter (ADC) biasing in diesel ECU power management subsystems. IC Role / Device Role / Timing Role: Shunt voltage regulator maintaining precise DC reference despite battery voltage fluctuations (9–16 V). Use Value: Ensures <±0.5% ADC full-scale accuracy across −40°C to +125°C operating range due to tight V_Z tolerance and low tempco.	Use Scenario: Biasing bridge-type pressure transducers in factory automation PLC input modules. IC Role / Device Role / Timing Role: Precision voltage clamp limiting excitation voltage to 18 V to prevent transducer overvoltage damage. Use Value: Prevents sensor drift and calibration loss by holding excitation within ±0.1 V of nominal value under transient load changes.
Telecom Power Supply Overvoltage Protection	Medical Diagnostic Equipment Power Sequencing
Use Scenario: Secondary-side overvoltage clamp in isolated 48 V telecom DC/DC converters. IC Role / Device Role / Timing Role: Fast-acting crowbar element triggering shutdown when output exceeds 18.9 V. Use Value: Limits fault energy to <1.5 J during surge events, meeting IEC 62368-1 transient immunity requirements.	Use Scenario: Voltage supervision for FPGA configuration rails in portable ultrasound imaging devices. IC Role / Device Role / Timing Role: Standby-mode reference source enabling accurate brown-out detection at 17.1 V threshold. Use Value: Guarantees safe power-down sequencing with <10 μs response time and zero false triggers from EMI noise.

Automotive Engine Control Unit (ECU) Reference

Industrial Sensor Signal Conditioning

Use Scenario: Providing stable 18 V reference for analog-to-digital converter (ADC) biasing in diesel ECU power management subsystems.

IC Role / Device Role / Timing Role: Shunt voltage regulator maintaining precise DC reference despite battery voltage fluctuations (9–16 V).

Use Value: Ensures <±0.5% ADC full-scale accuracy across −40°C to +125°C operating range due to tight V_Z tolerance and low tempco.

Use Scenario: Biasing bridge-type pressure transducers in factory automation PLC input modules.

IC Role / Device Role / Timing Role: Precision voltage clamp limiting excitation voltage to 18 V to prevent transducer overvoltage damage.

Use Value: Prevents sensor drift and calibration loss by holding excitation within ±0.1 V of nominal value under transient load changes.

Telecom Power Supply Overvoltage Protection

Medical Diagnostic Equipment Power Sequencing

Use Scenario: Secondary-side overvoltage clamp in isolated 48 V telecom DC/DC converters.

IC Role / Device Role / Timing Role: Fast-acting crowbar element triggering shutdown when output exceeds 18.9 V.

Use Value: Limits fault energy to <1.5 J during surge events, meeting IEC 62368-1 transient immunity requirements.

Use Scenario: Voltage supervision for FPGA configuration rails in portable ultrasound imaging devices.

IC Role / Device Role / Timing Role: Standby-mode reference source enabling accurate brown-out detection at 17.1 V threshold.

Use Value: Guarantees safe power-down sequencing with <10 μs response time and zero false triggers from EMI noise.

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-C18LT1G	300 mW rating, SOT-23 package, 25 Ω Z_ZT, ±5% tolerance	Lower power handling limits use to low-current biasing only; unsuitable for >50 mA regulation loads	Select when board space is constrained and power dissipation remains below 300 mW
MMSZ5245B-TP	500 mW rating, SOD-123 package, 23 Ω Z_ZT, ±5% tolerance, no AEC−Q101 qualification	Lacks automotive qualification and ESD robustness; intended for commercial-grade consumer electronics	Choose for cost-sensitive non-automotive designs where AEC−Q101 compliance is not required

Compared with BZX84-C18LT1G and MMSZ5245B-TP, the SZ1SMA5931BT3G delivers 3× higher power capability, superior thermal performance (250 °C/W vs ≥350 °C/W), and automotive-grade reliability - making it the only option suitable for under-hood voltage reference and industrial power monitoring where sustained 1.5 W dissipation is required.

Availability

SZ1SMA5931BT3G is available at Aetrix Electronics and suitable for automotive engine control units, industrial sensor signal conditioning, telecom power supply overvoltage protection, and medical diagnostic equipment power sequencing requiring stable component supply and long-term lifecycle support.

Supply support for SZ1SMA5931BT3G 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 power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.

The SZ1SMA59xxBT3G series was developed specifically for AEC−Q101-compliant automotive voltage regulation and industrial power management, emphasizing robustness, tight tolerances, and surface-mount manufacturability.

FAQ

What is the zener voltage tolerance for SZ1SMA5931BT3G?

The SZ1SMA5931BT3G has a zener voltage tolerance of ±5%, with a guaranteed range of 17.1 V to 18.9 V at 12 mA test current (I_ZT). This tolerance is confirmed in the Electrical Characteristics table on page 2 of the official onsemi datasheet and applies across the full operating temperature range of −65°C to +150°C.

Is SZ1SMA5931BT3G qualified for automotive applications?

Yes, SZ1SMA5931BT3G is AEC−Q101 qualified and PPAP capable, as explicitly stated in the Features section of the onsemi datasheet. The "SZ" prefix denotes automotive-grade qualification, including validation for temperature cycling, mechanical shock, and humidity testing per AEC standards.

What is the maximum power dissipation of SZ1SMA5931BT3G at ambient temperature?

SZ1SMA5931BT3G has a maximum DC power dissipation of 0.5 W at T_A = 25°C, derating linearly at 4.0 mW/°C above that temperature. This value is defined in the Maximum Ratings table and assumes use of the onsemi-recommended FR-4 footprint per datasheet footnote 2.

What package type does SZ1SMA5931BT3G use?

SZ1SMA5931BT3G uses the SMA (DO-214AC) surface-mount package, also designated Case 403D in onsemi documentation. It features a flat handling surface, Pb−free construction, and cathode identification via molded polarity notch or band - all verified in the Mechanical Characteristics and Package Outline sections of the datasheet.

Does SZ1SMA5931BT3G have ESD protection built-in?

Yes, SZ1SMA5931BT3G has an ESD rating of Class 3 (>16 kV) per Human Body Model (HBM), as specified in the Features section of the onsemi datasheet. This level of ESD robustness eliminates the need for additional discrete ESD protection in many front-end power regulation circuits.

SZ1SMA5931BT3G Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: SZ1SMA59xxBT3G

Package/Case:: DO-214AC, SMA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Voltage - Zener (Nom) (Vz):: 18 V

Tolerance:: ±5%

Power - Max:: 1.5 W

Impedance (Max) (Zzt):: 12 Ohms

Current - Reverse Leakage @ Vr:: 500 nA @ 13.7 V

Voltage - Forward (Vf) (Max) @ If:: 1.2 V @ 200 mA

Operating Temperature:: -65°C ~ 150°C

Grade:: Automotive

Qualification:: AEC-Q101

Mounting Type:: Surface Mount

Supplier Device Package:: SMA

SZ1SMA5931BT3G FAQ

1.How can I place an order for SZ1SMA5931BT3G through Aetrix?

Please submit a Request for Quotation (RFQ) for SZ1SMA5931BT3G 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 SZ1SMA5931BT3G reliable?

The price and inventory of SZ1SMA5931BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMA5931BT3G is usually 5 days.

3.What payment methods are accepted for SZ1SMA5931BT3G?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMA5931BT3G transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SZ1SMA5931BT3G?

SZ1SMA5931BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SZ1SMA5931BT3G 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 SZ1SMA5931BT3G?

For technical support, including SZ1SMA5931BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMA5931BT3G requirements.

6.How does Aetrix verify that SZ1SMA5931BT3G is sourced from the original manufacturer or authorized distributors?

All SZ1SMA5931BT3G 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 SZ1SMA5931BT3G meets industry standards.

7.What is the process for return or replacement of SZ1SMA5931BT3G?

All SZ1SMA5931BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMA5931BT3G, 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 SZ1SMA5931BT3G part is unused and in its original packaging.

Return procedure for SZ1SMA5931BT3G:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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