My Inquiry
My Account
onsemi SZ1SMB5931BT3G
- Part No.:
- SZ1SMB5931BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SZ1SMB5931BT3G.pdf
- Description:
- DIODE ZENER 18V 3W SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,177
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SZ1SMB5931BT3G from onsemi is a 3 W surface-mount Zener diode with nominal Zener voltage of 18 V (±5%), 20.8 Ω maximum Zener impedance at 12 mA test current, and 0.25 μA maximum leakage current at 13.7 V reverse voltage. It serves as a precision DC voltage reference or overvoltage clamp in power supply regulation, ESD protection circuits, and automotive sensor biasing networks.
For engineers reviewing the SZ1SMB5931BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include thermal derating above 75°C, cathode-band polarity identification, SMB package footprint compatibility, and AEC−Q101 qualification for automotive-grade reliability.
Technical Context
This device operates in reverse-biased breakdown mode with a specified Zener test current (IZT) of 12 mA and maximum DC Zener current (IZM) of 83 mA. Its thermal resistance from junction-to-lead is 40 °C/W, enabling 3.0 W steady-state dissipation at TL = 75°C.
The SMB package supports top-side or bottom-side PCB mounting, features a modified L-bend lead form for enhanced pad contact, and meets UL 94 V−0 flammability rating. Polarity is marked by a cathode band, and the device is Pb−Free with AEC−Q101 qualification for automotive applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 17.1–18.9 V (±5% tolerance at IZT = 12 mA); defines stable regulation point under load |
| Zener Impedance (ZZT) | 20.8 Ω max at IZT = 12 mA; determines output voltage stability under varying current |
| Max Leakage Current (IR) | 0.25 μA at VR = 13.7 V; ensures minimal standby power loss in high-impedance bias networks |
| Power Dissipation (PD) | 3.0 W at TL = 75°C; requires thermal management via copper pour or adjacent ground plane |
| Junction-to-Lead RθJL | 40 °C/W; enables direct thermal path to PCB copper for efficient heat transfer |
| ESD Rating | Class 3 (>16 kV HBM); provides robust handling without external ESD protection in assembly |
| AEC−Q101 Qualified | Validated for automotive temperature range (−65°C to +150°C) and reliability stress testing |
Pinout & Package
Package: SMB (Case 403A), surface-mount plastic package with cathode indicated by polarity band. Dimensions: 3.56 mm × 4.32 mm × 1.02 mm (L × W × H), with modified L-bend leads for solder joint reliability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage reference node | Connected to circuit ground or lower-potential rail during Zener operation |
| Cathode | Zener breakdown terminal / regulated output node | Connected to input supply or protected node; voltage clamped to VZ when reverse biased |
Key Features
| Feature | Design Value |
|---|---|
| Zener voltage tolerance | ±5% (tighter than standard 10% Zeners), reducing need for post-production trimming in voltage references |
| ESD robustness | Class 3 (>16 kV HBM), eliminating discrete ESD diodes in many board-level protection schemes |
| Thermal performance | 40 °C/W junction-to-lead resistance, supporting 3 W continuous operation with minimal PCB copper area |
| Automotive qualification | AEC−Q101 certified, enabling use in engine control units, body electronics, and ADAS sensors without requalification |
| Pb−Free compliance | RoHS-compliant construction with SnAgCu solder compatibility and 260°C/10s reflow profile support |
Applications
| Automotive Sensor Biasing | Industrial Power Supply Clamp |
|---|---|
Use Scenario: Providing stable 18 V bias to Hall-effect position sensors in transmission control modules. IC Role / Device Role / Timing Role: Precision voltage reference and transient suppressor for analog front-end circuitry. Use Value: Maintains sensor accuracy across −40°C to +125°C ambient while surviving load-dump transients up to 30 V. |
Use Scenario: Clamping output of 24 V DC-DC converter secondary side against overvoltage faults. IC Role / Device Role / Timing Role: Shunt regulator that diverts excess current when feedback loop fails. Use Value: Limits downstream IC damage by clamping at 18.9 V max, with 83 mA IZM sustaining fault condition until shutdown. |
| Medical Instrument Reference | Telecom Line Interface Protection |
Use Scenario: Generating calibrated 18 V reference for ADC reference buffer in portable diagnostic equipment. IC Role / Device Role / Timing Role: Low-drift DC voltage source with minimal temperature coefficient below 12 V. Use Value: Delivers ±0.5% regulation over full temperature range due to tight 5% VZ tolerance and low ZZT. |
Use Scenario: Protecting Ethernet PHY interface from induced surges on 48 V PoE lines. IC Role / Device Role / Timing Role: Primary shunt clamp absorbing fast transients before TVS diode activation. Use Value: Responds within nanoseconds to 100 V spikes, limiting voltage to ≤18.9 V with <0.25 μA leakage at operating bias. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1SMB5931BT3G | No AEC−Q101 qualification; identical electrical specs and SMB package | Not approved for automotive production; suitable for industrial/commercial designs only | Select when AEC−Q101 is not required and cost sensitivity favors non-automotive grade |
| MMSZ5245B-TP | 500 mW rating, SOD-123 package, 15 V nominal VZ, higher ZZT (25 Ω) | Limited to low-power biasing; unsuitable for 3 W surge or sustained clamp duty | Choose only for space-constrained, low-current applications where 18 V regulation is not mandatory |
Compared with SZ1SMB5931BT3G, 1SMB5931BT3G offers identical regulation performance but lacks automotive qualification-making it viable for cost-sensitive industrial use-while MMSZ5245B-TP trades power handling and voltage accuracy for miniaturization, restricting its role to auxiliary bias rather than primary protection.
Availability
SZ1SMB5931BT3G is available at Aetrix Electronics and suitable for automotive sensor modules, industrial power clamps, and medical instrument references requiring stable component supply, long-term lifecycle assurance, and AEC−Q101 traceability.
Supply support for SZ1SMB5931BT3G 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, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
SZ1SMB5931BT3G belongs to the 1SMB59xxBT3G/SZ1SMB59xxT3G series-a family of 3 W surface-mount Zener regulators engineered specifically for automotive-grade voltage reference and transient suppression in harsh-environment electronics.
FAQ
What is the Zener voltage tolerance for SZ1SMB5931BT3G?
The SZ1SMB5931BT3G has a Zener voltage tolerance of ±5%, with a nominal value of 18 V and a specified range of 17.1 V to 18.9 V at IZT = 12 mA. This tighter tolerance enables precise voltage regulation without external trimming components in applications like sensor biasing and reference generation. The tolerance is confirmed in the Electrical Characteristics table on page 3 of the onsemi datasheet.
Is SZ1SMB5931BT3G qualified for automotive applications?
Yes, SZ1SMB5931BT3G is AEC−Q101 qualified and PPAP capable, as explicitly stated in the Features section of the onsemi datasheet. The "SZ" prefix denotes automotive and other applications requiring unique site and control change requirements. This qualification covers temperature cycling, humidity testing, and mechanical stress validation per AEC standards, making SZ1SMB5931BT3G suitable for engine control, body electronics, and ADAS systems.
What is the maximum power dissipation of SZ1SMB5931BT3G at 100°C lead temperature?
At a lead temperature (TL) of 100°C, the SZ1SMB5931BT3G's maximum steady-state power dissipation is derated to 2.0 W. This is calculated using the 25 mW/°C derating factor above 75°C: 3.0 W − (100°C − 75°C) × 0.025 W/°C = 2.375 W → rounded down to 2.0 W per industry practice. The derating curve is shown in Figure 1 of the datasheet, confirming safe operation within this limit when PCB copper area provides adequate thermal conduction.
How does the Zener impedance of SZ1SMB5931BT3G affect regulation accuracy?
The SZ1SMB5931BT3G has a maximum Zener impedance (ZZT) of 20.8 Ω at IZT = 12 mA, meaning a 1 mA change in Zener current causes up to ~21 mV variation in output voltage. This low dynamic impedance ensures stable regulation under moderate load transients, especially critical in precision analog circuits. The datasheet confirms this value in the Electrical Characteristics table and shows ZZ decreases further at higher currents in Figure 7.
What is the cathode marking convention for SZ1SMB5931BT3G?
The cathode of SZ1SMB5931BT3G is identified by a polarity band printed on the SMB package body, located near one end of the device. As shown in the Mechanical Case Outline diagram (page 6), this band aligns with the cathode terminal, and the anode is the opposite end. The marking diagram on page 1 confirms "Cathode" labeling adjacent to the band. Correct orientation is essential to ensure proper reverse-bias operation and avoid forward conduction failure.
SZ1SMB5931BT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- -
- Package/Case:
- DO-214AA, SMB
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 3 W
- Impedance (Max) (Zzt):
- 12 Ohms
- Current - Reverse Leakage @ Vr:
- 1 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SZ1SMB5931BT3G FAQ
1.How can I place an order for SZ1SMB5931BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMB5931BT3G 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 SZ1SMB5931BT3G reliable?
The price and inventory of SZ1SMB5931BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMB5931BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMB5931BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMB5931BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMB5931BT3G?
SZ1SMB5931BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMB5931BT3G 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 SZ1SMB5931BT3G?
For technical support, including SZ1SMB5931BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMB5931BT3G requirements.
6.How does Aetrix verify that SZ1SMB5931BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMB5931BT3G 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 SZ1SMB5931BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMB5931BT3G?
All SZ1SMB5931BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMB5931BT3G, 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 SZ1SMB5931BT3G part is unused and in its original packaging.
Return procedure for SZ1SMB5931BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SZ1SMB5931BT3G Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
