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onsemi 1SMA5942BT3
- Part No.:
- 1SMA5942BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA5942BT3.pdf
- Description:
- DIODE ZENER 51V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:9,357
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Product details
Overview
1SMA5942BT3 from onsemi is a 1.5 W surface-mount Zener diode with nominal zener voltage of 51 V, ±5% tolerance, maximum zener impedance of 7.3 Ω at 70 mA test current, and 0.25 μA reverse leakage at 38.8 V. It operates from −65 °C to +150 °C and is used for precision voltage regulation and overvoltage protection in power supply feedback loops.
For engineers reviewing the 1SMA5942BT3 datasheet, pinout, applications, or equivalent options, key selection criteria include zener voltage accuracy, dynamic impedance at rated test current, thermal resistance (50 °C/W junction-to-lead), low-profile SMA package compatibility, and AEC-Q101 qualification status for automotive-grade reliability.
Technical Context
This device functions as a two-terminal voltage reference diode operating in reverse breakdown mode. Its zener voltage is specified at IZT = 70 mA with tight ±5% tolerance and temperature coefficient optimized for stable regulation across industrial temperature ranges.
It features low-profile SMA (DO-214AC) packaging with cathode band polarity marking, Pb-free construction (G suffix variant), and ESD rating >16 kV per HBM-enabling robust performance in automated SMT assembly and harsh electrical environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 48.45 V min / 51 V nom / 53.55 V max @ IZT = 70 mA - defines regulated output voltage window under standard test conditions |
| Zener Impedance (ZZT) | 7.3 Ω max @ IZT = 70 mA - determines load regulation error and ripple rejection capability |
| Max DC Power Dissipation | 1.5 W @ TL = 75 °C - sets thermal limit for PCB copper pad heatsinking design |
| Thermal Resistance (RJL) | 50 °C/W - enables thermal modeling of junction temperature rise above lead temperature |
| Reverse Leakage (IR) | 0.25 μA max @ VR = 38.8 V - ensures minimal quiescent current in standby regulation circuits |
| ESD Rating (HBM) | Class 3 (>16 kV) - supports handling without special ESD controls during manufacturing |
| Operating Temp Range | −65 °C to +150 °C - qualifies for under-hood automotive and industrial control applications |
Pinout & Package
SMA (DO-214AC) package: molded plastic case, flat handling surface, cathode indicated by band, 2.6 mm nominal width, 4.3 mm nominal length, 1.14 mm nominal height. Compliant with JEDEC DO-214AC outline and IPC-7351B footprint standard.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Reverse-biased terminal | Connected to regulated output node; voltage referenced to anode; polarity critical for correct biasing |
| Anode | Reference/ground terminal | Typically tied to system ground or feedback divider low-side; establishes reference potential for zener conduction |
Key Features
| Feature | Design Value |
|---|---|
| ±5% Zener voltage tolerance | Enables accurate voltage setpoint without external trimming in feedback networks |
| AEC-Q101 qualified (SZ prefix variant) | Validated for automotive powertrain and body electronics requiring zero-failure reliability |
| Low-profile SMA package | Reduces board space vs. axial leads and MELF; compatible with high-speed pick-and-place |
| 16 kV HBM ESD rating | Eliminates need for upstream ESD protection in many consumer and industrial designs |
| Pb-free (RoHS-compliant) construction | Meets global environmental compliance requirements without solderability compromise |
Applications
| Switch-Mode Power Supply Feedback | Automotive Engine Control Unit (ECU) |
|---|---|
Use Scenario: Regulating 5V auxiliary rail in isolated flyback converter via optocoupler feedback loop. IC Role / Device Role / Timing Role: Precision voltage reference establishing feedback threshold for TL431-like control. Use Value: Tight 51 V zener tolerance and low ZZT minimize output voltage drift across line/load/temperature. | Use Scenario: Overvoltage clamp protecting microcontroller I/O pins from load dump transients. IC Role / Device Role / Timing Role: Fast-acting shunt protector absorbing transient energy before downstream IC damage. Use Value: 1.5 W power rating and −65 °C to +150 °C operation ensure survivability in under-hood environments. |
| Industrial PLC Analog Input Protection | LED Driver Constant-Current Reference |
Use Scenario: Clamping 24 V sensor input lines against ESD and surge events per IEC 61000-4-2/4-4. IC Role / Device Role / Timing Role: Primary front-end transient suppressor placed before signal conditioning circuitry. Use Value: 16 kV HBM rating and low leakage (<0.25 μA) prevent false triggering and measurement offset. | Use Scenario: Setting reference voltage for LM3410X-based constant-current LED driver. IC Role / Device Role / Timing Role: Stable voltage reference defining current-sense threshold in feedback path. Use Value: Low dynamic impedance (7.3 Ω) maintains regulation accuracy despite LED forward voltage variation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4733A | 5.1 V nominal, 1 W rating, DO-41 through-hole package | Lower voltage, lower power, not surface-mount - unsuitable for space-constrained or automated SMT designs | Select only for legacy through-hole boards where 5.1 V regulation is required and rework is acceptable |
| BZX84-C51 | 51 V nominal, ±5%, 300 mW rating, SOT-23 package | Same voltage but significantly lower power dissipation - inadequate for >100 mA regulation loads | Choose only for low-current biasing or sensing; avoid in power supply feedback where 70 mA IZT is needed |
Compared with 1N4733A and BZX84-C51, the 1SMA5942BT3 delivers higher power handling (1.5 W), surface-mount compatibility, and automotive-grade reliability-making it the preferred choice for modern SMT power regulation and transient protection where 51 V reference stability and robustness are critical.
Availability
1SMA5942BT3 is available at Aetrix Electronics and suitable for switch-mode power supplies, automotive engine control units, industrial PLC analog inputs, and LED driver reference circuits requiring stable component supply and long-term manufacturability.
Supply support for 1SMA5942BT3 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 manufacturer specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The 1SMA59xxBT3 series is part of onsemi's high-reliability Zener regulator portfolio designed specifically for precision voltage reference and overvoltage protection in automotive and industrial power systems.
FAQ
What is the nominal zener voltage and tolerance of the 1SMA5942BT3?
The 1SMA5942BT3 has a nominal zener voltage of 51 V with a guaranteed tolerance of ±5%, meaning the actual breakdown voltage falls between 48.45 V and 53.55 V when tested at IZT = 70 mA and TA = 25 °C. This tight tolerance enables accurate voltage setting in feedback and reference circuits without calibration.
Does the 1SMA5942BT3 meet automotive qualification standards?
The SZ1SMA5942BT3G variant is AEC-Q101 qualified and PPAP capable, confirming its suitability for automotive applications. While the base 1SMA5942BT3 part number does not carry the "SZ" prefix, it shares identical electrical and mechanical specifications and is manufactured on the same qualified process-making it appropriate for non-automotive industrial use with identical reliability.
What is the maximum DC zener current (IZM) for the 1SMA5942BT3?
The maximum DC zener current IZM for the 1SMA5942BT3 is 29 mA, calculated from PD = 1.5 W and VZ = 51 V (IZM = PD/VZ). However, the device is characterized at IZT = 70 mA for specification purposes, indicating it can sustain higher pulsed or short-duration currents within thermal limits defined by RJL = 50 °C/W.
How does the 1SMA5942BT3 compare to the 1N4733A in terms of package and power rating?
The 1SMA5942BT3 uses an SMA (DO-214AC) surface-mount package with 1.5 W power dissipation, while the 1N4733A uses a DO-41 through-hole package rated at 1 W. The 1SMA5942BT3 offers superior thermal performance (RJL = 50 °C/W vs. ~100 °C/W typical for DO-41), smaller footprint, and automated assembly compatibility-making it a direct upgrade path for new SMT designs requiring 51 V regulation.
Is the 1SMA5942BT3 RoHS compliant and lead-free?
Yes-the "G" suffix in the ordering code (e.g., 1SMA5942BT3G) explicitly denotes Pb-free (RoHS-compliant) construction. The 1SMA5942BT3 itself is available in both standard and Pb-free versions; all devices meet JEDEC J-STD-020 moisture sensitivity level 1 and support standard reflow profiles up to 260 °C for 10 seconds.
1SMA5942BT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 1SMA59xxBT3G
- Package/Case:
- DO-214AC, SMA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA5942BT3 FAQ
1.How can I place an order for 1SMA5942BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA5942BT3 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 1SMA5942BT3 reliable?
The price and inventory of 1SMA5942BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA5942BT3 is usually 5 days.
3.What payment methods are accepted for 1SMA5942BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA5942BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA5942BT3?
1SMA5942BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA5942BT3 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 1SMA5942BT3?
For technical support, including 1SMA5942BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA5942BT3 requirements.
6.How does Aetrix verify that 1SMA5942BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA5942BT3 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 1SMA5942BT3 meets industry standards.
7.What is the process for return or replacement of 1SMA5942BT3?
All 1SMA5942BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA5942BT3, 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 1SMA5942BT3 part is unused and in its original packaging.
Return procedure for 1SMA5942BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA5942BT3 Tags
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