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onsemi SZ1SMA5942BT3G
- Part No.:
- SZ1SMA5942BT3G
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SZ1SMA5942BT3G.pdf
- Description:
- DIODE ZENER 51V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,688
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Product details
Overview
SZ1SMA5942BT3G from onsemi is a 1.5 W surface-mount Zener diode with nominal Zener voltage of 51 V, ±5% tolerance, 7.3 Ω dynamic impedance at 70 mA test current, and AEC-Q101 qualification for automotive applications. It regulates voltage in power supply rails, overvoltage protection circuits, and reference sources where stable 51 V clamping is required.
For engineers reviewing the SZ1SMA5942BT3G datasheet, pinout, applications, or equivalent options, key selection criteria include Zener voltage accuracy, thermal derating above 75°C, low-profile SMA package compatibility, and automotive-grade reliability under temperature cycling and humidity stress.
Technical Context
This device operates as a precision voltage reference by maintaining a stable reverse breakdown voltage across its cathode-anode terminals when biased above VZ. Its 70 mA Zener test current (IZT) and 1100 Ω maximum impedance at knee current (IZK = 0.25 mA) define regulation fidelity under light and heavy load conditions.
The SMA package (Case 403D) supports top-slide or bottom-board mounting with flat handling surface and UL 94 V-0 flammability rating. Thermal resistance junction-to-lead is 50°C/W, enabling 1.5 W dissipation at TL = 75°C with linear derating above that point.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 48.45 V min / 51 V nom / 53.55 V max - defines tight ±5% regulation window for 51 V reference designs |
| Zener Test Current (IZT) | 70 mA - operating point where VZ and ZZT are guaranteed; sets minimum bias requirement |
| Zener Impedance (ZZT) | 7.3 Ω max @ IZT - ensures low voltage deviation under dynamic load changes |
| Power Dissipation (PD) | 1.5 W @ TL = 75°C - usable power limit with zero-lead-length thermal condition |
| Thermal Resistance (RJL) | 50°C/W - determines junction temperature rise per watt; critical for layout copper pad sizing |
| Leakage Current (IR) | 0.25 μA max @ VR = 38.8 V - confirms sharp knee and low standby loss below regulation threshold |
| AEC-Q101 Qualified | Yes - validated for automotive electronics including engine control, body modules, and ADAS sensors |
Pinout & Package
SMA package (Case 403D, Style 1), surface-mount, low-profile plastic case with molded cathode band. Cathode terminal marked by polarity notch/band; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Reverse-biased Zener terminal | Connected to higher-potential rail; clamps voltage when reverse voltage exceeds VZ |
| Anode | Reference/ground return path | Typically tied to system ground or lower-voltage node; completes Zener conduction path |
Key Features
| Feature | Design Value |
|---|---|
| ESD robustness | Class 3 (>16 kV HBM) - withstands handling and board-level ESD events without parameter shift |
| Automotive qualification | AEC-Q101 qualified - meets stress testing for temperature cycling, humidity, and mechanical shock in vehicle environments |
| Pb-free construction | RoHS-compliant, void-free molded plastic - supports lead-free reflow profiles up to 260°C for 10 s |
| Low-profile mounting | Flat handling surface - enables accurate pick-and-place placement and consistent solder joint formation |
| UL 94 V-0 rating | Flame-retardant housing - satisfies safety requirements for enclosed automotive and industrial enclosures |
Applications
| Automotive Engine Control Unit (ECU) Reference | Industrial Power Supply Overvoltage Clamp |
|---|---|
Use Scenario: Provides stable 51 V reference for analog-to-digital converter inputs monitoring battery voltage and alternator output in engine management systems. IC Role / Device Role / Timing Role: Precision Zener reference diode establishing fixed voltage threshold for fault detection circuitry. Use Value: ±5% VZ tolerance and <7.3 Ω ZZT ensure repeatable trip points across temperature and lifetime, reducing false alarms in emission-critical systems. | Use Scenario: Clamps transient overvoltage spikes on 48 V DC bus lines in factory automation PLCs during relay switching or motor braking. IC Role / Device Role / Timing Role: Standby-mode voltage clamp protecting downstream regulators and microcontrollers from destructive transients. Use Value: 1.5 W power rating and 50°C/W RJL allow sustained energy absorption without thermal runaway under repeated 100 ms surges. |
| Telecom Line Card Voltage Supervisor | Medical Imaging Power Rail Monitor |
Use Scenario: Monitors -48 V telecom distribution rail for undervoltage and overvoltage faults using comparator input referenced to 51 V Zener. IC Role / Device Role / Timing Role: Stable voltage reference source feeding comparator hysteresis network in centralized power supervision IC. Use Value: Low 0.25 μA leakage at 38.8 V ensures minimal loading on high-impedance sensing nodes, preserving measurement accuracy. | Use Scenario: Serves as calibration reference for X-ray generator high-voltage feedback loop requiring traceable 51 V setpoint stability over 10-year service life. IC Role / Device Role / Timing Role: Primary voltage reference element in closed-loop HV control circuit with long-term drift compensation. Use Value: AEC-Q101 qualification correlates with extended reliability testing (e.g., HTOL, uHAST), supporting MTBF > 100,000 hours in Class II medical equipment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| BZX84-C51LT1G | 300 mW SOT-23 package; 51 V ±5%; ZZT = 90 Ω @ 5 mA | Lower power, smaller footprint; unsuitable for >300 mW continuous dissipation | Select when board space is constrained and peak power remains <300 mW |
| 1N5357B | 5 W DO-15 through-hole; 51 V ±5%; ZZT = 1.5 Ω @ 150 mA | Higher power, legacy through-hole mounting; incompatible with SMT-only assembly | Select when thermal mass and higher surge capability justify through-hole layout |
Compared with BZX84-C51LT1G and 1N5357B, SZ1SMA5942BT3G delivers optimal balance of 1.5 W surface-mount power handling, automotive qualification, and 7.3 Ω low-impedance regulation-making it the preferred choice for mid-power automotive and industrial SMT designs requiring AEC-Q101 compliance.
Availability
SZ1SMA5942BT3G is available at Aetrix Electronics and suitable for automotive engine control units, industrial 48 V power clamping, and telecom line card supervision requiring stable component supply, full traceability, and long-lifecycle support.
Supply support for SZ1SMA5942BT3G 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 delivering energy-efficient silicon solutions for automotive, industrial, cloud, medical, and IoT applications.
SZ1SMA5942BT3G belongs to the 1SMA59xxBT3G/SZ1SMA59xxBT3G family-engineered specifically for surface-mount Zener regulation in automotive and high-reliability industrial systems where AEC-Q101 compliance and thermal robustness are mandatory.
FAQ
What is the Zener voltage tolerance for SZ1SMA5942BT3G?
The SZ1SMA5942BT3G has a ±5% Zener voltage tolerance, with specified limits of 48.45 V (minimum) and 53.55 V (maximum) at 70 mA test current and 25°C ambient. This tolerance is guaranteed at thermal equilibrium and applies across the full operating temperature range of −65°C to +150°C, as confirmed in the onsemi datasheet revision 11.
Is SZ1SMA5942BT3G suitable for automotive applications?
Yes, SZ1SMA5942BT3G is AEC-Q101 qualified and PPAP capable, with validation for temperature cycling, humidity, mechanical shock, and high-temperature operating life. The "SZ" prefix explicitly denotes automotive-grade manufacturing controls and site-specific change management, making SZ1SMA5942BT3G appropriate for engine control, body electronics, and ADAS subsystems.
What is the maximum power dissipation for SZ1SMA5942BT3G at 100°C lead temperature?
At 100°C lead temperature (TL), SZ1SMA5942BT3G derates linearly from 1.5 W at 75°C at 20 mW/°C. Therefore, power dissipation is reduced to 1.0 W (1.5 W − (100 − 75) × 0.02 W). This derating curve is defined in the Maximum Ratings table and must be applied in thermal design for reliable operation.
Does SZ1SMA5942BT3G have Pb-free construction?
Yes, SZ1SMA5942BT3G is Pb-free and RoHS-compliant, with void-free transfer-molded plastic packaging. It supports lead-free reflow soldering up to 260°C for 10 seconds, as documented in the Mechanical Characteristics section of the onsemi datasheet. The "G" suffix in the part number explicitly denotes Pb-free packaging.
What is the Zener impedance of SZ1SMA5942BT3G and why does it matter?
SZ1SMA5942BT3G has a maximum Zener impedance (ZZT) of 7.3 Ω at IZT = 70 mA. This low dynamic impedance ensures minimal output voltage variation under changing load currents-critical for precision reference and clamping applications where regulation stability directly impacts system accuracy and fault response time.
SZ1SMA5942BT3G 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):
- 51 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 70 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 38.8 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
SZ1SMA5942BT3G FAQ
1.How can I place an order for SZ1SMA5942BT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMA5942BT3G 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 SZ1SMA5942BT3G reliable?
The price and inventory of SZ1SMA5942BT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMA5942BT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMA5942BT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMA5942BT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMA5942BT3G?
SZ1SMA5942BT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMA5942BT3G 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 SZ1SMA5942BT3G?
For technical support, including SZ1SMA5942BT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMA5942BT3G requirements.
6.How does Aetrix verify that SZ1SMA5942BT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMA5942BT3G 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 SZ1SMA5942BT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMA5942BT3G?
All SZ1SMA5942BT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMA5942BT3G, 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 SZ1SMA5942BT3G part is unused and in its original packaging.
Return procedure for SZ1SMA5942BT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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