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onsemi 1SMA5938BT3
- Part No.:
- 1SMA5938BT3
- Manufacturer:
- onsemi
- Category:
- Single Zener Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA5938BT3.pdf
- Description:
- DIODE ZENER 36V 1.5W SMA
- Quantity:
- Payment:
- Shipping:
Inventory:6,496
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Product details
Overview
1SMA5938BT3 from onsemi is a 1.5 W surface-mount Zener diode with nominal zener voltage of 36 V (±5%), maximum zener impedance of 10.4 Ω at 38 mA test current, and 0.25 μA reverse leakage at 27.4 V. It operates from −65 °C to +150 °C and is qualified to AEC−Q101 for automotive applications.
For engineers reviewing the 1SMA5938BT3 datasheet, pinout, applications, or equivalent options, this device serves as a precision voltage reference and overvoltage clamp in power supply regulation, ESD protection circuits, and voltage monitoring systems where stable 36 V breakdown and low dynamic impedance are required.
Technical Context
The 1SMA5938BT3 functions as a silicon planar Zener diode operating in reverse breakdown mode, delivering regulated voltage under controlled DC current. Its 36 V nominal zener voltage is specified at IZT = 38 mA, with thermal coefficient of approximately +30 mV/°C (inferred from Figure 6 for VZ ≈ 36 V range), and exhibits low leakage (0.25 μA @ VR = 27.4 V) and tight ±5% tolerance.
Designed for surface-mount assembly on FR-4 PCBs, it uses the SMA (DO-214AC) package with cathode band marking, supports top-slide or bottom-mount placement, and meets UL 94 V−0 flammability rating. Its 50 °C/W junction-to-lead thermal resistance enables reliable 1.5 W dissipation at TL = 75 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 34.2 V min / 36 V nom / 37.8 V max at IZT = 38 mA - defines precise clamping threshold for 36 V rail protection |
| Zener Impedance (ZZT) | 10.4 Ω max at IZT = 38 mA - ensures minimal voltage shift under load variation |
| Power Dissipation (PD) | 1.5 W @ TL = 75 °C - supports robust thermal management with 50 °C/W RJL |
| Reverse Leakage (IR) | 0.25 μA max @ VR = 27.4 V - guarantees low standby current in high-impedance bias networks |
| Operating Temp Range | −65 °C to +150 °C - validated for under-hood automotive and industrial environments |
| ESD Rating | Class 3 (>16 kV HBM) - provides inherent system-level ESD resilience without external suppressors |
Pinout & Package
The 1SMA5938BT3 is housed in the SMA (DO-214AC, Case 403D-02) plastic surface-mount package, measuring 4.06–4.57 mm in length (E), 2.29–2.92 mm in width (D), and 1.97–2.20 mm in height (A). Cathode is marked by a molded band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Reverse-biased anode connection point | Connected to higher-potential node during regulation; carries full zener current in clamp mode |
| Anode | Reverse-biased cathode connection point | Typically tied to ground or low-side reference; completes current path during breakdown |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 qualification | Validated for automotive powertrain and body electronics requiring zero-failure reliability |
| 16 kV HBM ESD rating | Reduces need for external TVS devices in I/O and sensor interface protection |
| Low-profile SMA package | Enables compact layout in space-constrained modules; replaces larger MELF diodes |
| Pb−Free (RoHS-compliant) | Meets global environmental compliance without sacrificing solderability or thermal performance |
Applications
| Automotive Power Supply Clamp | Industrial Sensor Reference |
|---|---|
Use Scenario: Clamping transient spikes on 36 V battery-fed ECUs in start-stop systems. IC Role / Device Role / Timing Role: Zener diode acting as shunt regulator and overvoltage protector. Use Value: Maintains 36 V rail integrity during load dump (ISO 7637-2 Pulse 5a), leveraging 1.5 W power handling and −65 °C to +150 °C operation. | Use Scenario: Providing stable 36 V reference for 4–20 mA transmitter calibration circuitry. IC Role / Device Role / Timing Role: Precision voltage reference element in analog front-end bias network. Use Value: Delivers ±5% tolerance and 10.4 Ω dynamic impedance to minimize reference drift across temperature and current variations. |
| LED Driver Overvoltage Protection | Programmable Power Supply Feedback |
Use Scenario: Safeguarding constant-current LED drivers against input surge events. IC Role / Device Role / Timing Role: Shunt clamp limiting input voltage to protect driver IC and LEDs. Use Value: Activates reliably at 34.2–37.8 V with <0.25 μA leakage, preventing false triggering while ensuring fast response. | Use Scenario: Setting output voltage threshold in adjustable DC-DC converter feedback loop. IC Role / Device Role / Timing Role: Zener-based voltage divider node defining regulation setpoint. Use Value: Enables accurate 36 V output setting with low ZZT to reduce regulation error under varying load conditions. |
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-C36LT1G | 36 V ±5%, 300 mW SOT-23 package, 90 Ω ZZT @ 5 mA - lower power, higher impedance | Suitable for low-current bias/reference only; not rated for 1.5 W clamping | Select when board space is critical and power dissipation ≤300 mW suffices |
| 1N5365B | 36 V ±5%, 5 W through-hole DO-15, 1.5 Ω ZZT @ 120 mA - higher power, lower impedance, axial lead | Requires through-hole assembly and larger PCB footprint; better for high-energy transients | Select when >1.5 W surge handling or legacy through-hole compatibility is required |
Compared with BZX84-C36LT1G and 1N5365B, the 1SMA5938BT3 uniquely balances 1.5 W surface-mount capability, 10.4 Ω low-impedance regulation at 38 mA, and AEC−Q101 qualification - making it optimal for automotive-grade SMT power rail clamping where space, reliability, and thermal performance intersect.
Availability
1SMA5938BT3 is available at Aetrix Electronics and suitable for automotive power management, industrial sensor conditioning, and LED driver protection requiring stable component supply and AEC−Q101 compliance.
Supply support for 1SMA5938BT3 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 focused on energy-efficient electronics, delivering silicon solutions for automotive, industrial, cloud, and IoT applications.
The 1SMA59xxBT3 series was designed specifically for high-reliability surface-mount voltage regulation and transient suppression in automotive and industrial power systems, emphasizing AEC−Q101 compliance, low-profile packaging, and robust thermal performance.
FAQ
What is the zener voltage tolerance of the 1SMA5938BT3?
The 1SMA5938BT3 has a zener voltage tolerance of ±5%, with a nominal value of 36 V and guaranteed limits of 34.2 V (min) and 37.8 V (max) at IZT = 38 mA. This tolerance is explicitly stated in the datasheet's note 3 and confirmed in the Electrical Characteristics table for the SZ/1SMA5938BT3, G device row.
Is the 1SMA5938BT3 suitable for automotive applications?
Yes, the 1SMA5938BT3 is AEC−Q101 qualified and PPAP capable, as clearly designated by the "SZ" prefix and "G" suffix in its ordering part number SZ/1SMA5938BT3, G. Its −65 °C to +150 °C operating range, 16 kV HBM ESD rating, and Pb−Free construction meet core automotive reliability requirements.
What is the maximum DC zener current (IZM) for the 1SMA5938BT3?
The maximum DC zener current IZM for the 1SMA5938BT3 is 42 A, derived from the power dissipation limit (1.5 W) and minimum zener voltage (34.2 V): IZM = PD / VZ(min) ≈ 1.5 W / 34.2 V ≈ 43.9 mA - rounded down to 42 mA per the datasheet's Electrical Characteristics table for this device.
Does the 1SMA5938BT3 have a Pb−Free package option?
Yes, the "G" suffix in the part number (SZ/1SMA5938BT3, G) explicitly indicates a Pb−Free (RoHS-compliant) package. The datasheet confirms Pb−Free availability for the entire SZ1SMA59xxBT3G series and specifies compatible soldering profiles including 260 °C for 10 seconds.
What is the thermal resistance junction-to-lead (RJL) for the 1SMA5938BT3?
The thermal resistance junction-to-lead (RJL) for the 1SMA5938BT3 is 50 °C/W, as listed in the Maximum Ratings table under "Thermal Resistance, Junction−to−Lead". This value enables 1.5 W power dissipation at a lead temperature (TL) of 75 °C, supporting thermally demanding SMT layouts with adequate copper pad area.
1SMA5938BT3 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):
- 36 V
- Tolerance:
- ±5%
- Power - Max:
- 1.5 W
- Impedance (Max) (Zzt):
- 38 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 27.4 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
1SMA5938BT3 FAQ
1.How can I place an order for 1SMA5938BT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA5938BT3 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 1SMA5938BT3 reliable?
The price and inventory of 1SMA5938BT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA5938BT3 is usually 5 days.
3.What payment methods are accepted for 1SMA5938BT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA5938BT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA5938BT3?
1SMA5938BT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA5938BT3 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 1SMA5938BT3?
For technical support, including 1SMA5938BT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA5938BT3 requirements.
6.How does Aetrix verify that 1SMA5938BT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA5938BT3 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 1SMA5938BT3 meets industry standards.
7.What is the process for return or replacement of 1SMA5938BT3?
All 1SMA5938BT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA5938BT3, 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 1SMA5938BT3 part is unused and in its original packaging.
Return procedure for 1SMA5938BT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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