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STMicroelectronics SM6HT39A
- Part No.:
- SM6HT39A
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6HT39A.pdf
- Description:
- TVS DIODE 33.3VWM 53.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:5,701
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Product details
Overview
SM6HT39A from STMicroelectronics is a unidirectional high-temperature Transil™ TVS diode in SMB (DO-214AA) package, designed for automotive surge protection. It features 39 V breakdown voltage (VBR), 53.9 V clamping voltage (VCL) at 11.1 A IPP, 600 W peak pulse power (10/1000 µs), and ≤5 µA leakage current at 150 °C - deployed in engine control units and powertrain modules.
For engineers reviewing the SM6HT39A datasheet, SM6HT39A pinout, SM6HT39A application, or SM6HT39A equivalent, key selection criteria include high-temperature leakage performance (≤5 µA @ 150 °C), clamping ratio (VCL/VBR = 1.38), unidirectional polarity, SMB footprint compatibility, and automotive-grade thermal robustness (Tj up to 175 °C).
Technical Context
This Transil device operates in voltage regulation mode during transient events, leveraging planar junction technology to maintain stable VBR and low thermal drift (αT = 10⁻⁴ /°C). Its unidirectional configuration provides reverse-biased clamping only, with cathode indicated by band marking.
Designed specifically for under-hood automotive environments, it sustains continuous operation from −65 °C to +175 °C junction temperature and delivers 6 W power dissipation on infinite heatsink at 50 °C ambient, supported by Rth(j-l) = 20 °C/W and Rth(j-a) = 100 °C/W (recommended PCB layout).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR | 39 V min @ IR = 1 mA - precise breakdown threshold ensures reliable triggering before system damage |
| VCL @ IPP | 53.9 V max @ 11.1 A (10/1000 µs) - limits downstream voltage stress during ISO 7637-2 pulses |
| IR @ 150°C | ≤5 µA - enables stable standby operation in high-temp engine compartments |
| PPP | 600 W (10/1000 µs) - meets automotive load dump and inductive switching surge requirements |
| Tj Range | −65 to +175 °C - qualified for under-hood placement without derating |
| Package | SMB (DO-214AA) - industry-standard SMD footprint compatible with automated assembly |
| VF @ 50 A | <3.5 V (pulse, tp ≤ 500 µs) - minimizes forward conduction loss during bidirectional surge events |
Pinout & Package
Package: SMB (JEDEC DO-214AA), surface-mount molded plastic case with solderable matte tin-plated leads, UL94V-0 flammability rating, and cathode indicated by band marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Surge return path | Connected to protected line (e.g., 12 V rail); conducts during reverse transients when cathode is held higher |
| Cathode (banded end) | Clamping reference / Surge sink | Connected to ground or lower-potential rail; defines clamping voltage relative to this node |
Key Features
| Feature | Design Value |
|---|---|
| High-temperature leakage control | ≤5 µA @ 150 °C - prevents false triggering and battery drain in hot engine bays |
| Low clamping factor | VCL/VBR = 1.38 - tight voltage margin preserves margin for downstream 40 V-rated ICs |
| Planar junction reliability | Stable VBR over lifetime and thermal cycling - critical for 15-year automotive service life |
| Automotive-grade thermal design | Rth(j-l) = 20 °C/W - enables direct PCB copper pour heat spreading without external heatsink |
Applications
| Engine Control Unit (ECU) | Body Control Module (BCM) |
|---|---|
Use Scenario: Protection of 12 V supply rail against ISO 7637-2 Pulse 5a (load dump) and Pulse 1 (inductive switch-off). IC Role / Device Role: Primary transient voltage suppressor on main power input, placed upstream of DC-DC converters and microcontrollers. Use Value: Clamps to 53.9 V within nanoseconds, preventing >40 V stress on 3.3 V/5 V logic rails and enabling compliance with AEC-Q101 stress testing. | Use Scenario: Safeguarding LIN bus transceiver power pins against battery reversal and jump-start surges. IC Role / Device Role: Unidirectional TVS on VCC line of LIN PHY, referenced to chassis ground. Use Value: Maintains ≤5 µA leakage at 150 °C ambient, avoiding quiescent current violation in always-on BCM sleep modes. |
| Transmission Control Module (TCM) | Electric Power Steering (EPS) |
Use Scenario: Input protection for solenoid driver ICs exposed to back-EMF from 24 V transmission valve coils. IC Role / Device Role: Clamp diode across coil supply, absorbing 600 W inductive spikes during PWM switching. Use Value: Withstands 175 °C junction temperature and delivers consistent VBR over 10,000 thermal cycles per AEC-Q100 Grade 0. | Use Scenario: Protection of motor gate driver supply against battery transients during EPS motor stall events. IC Role / Device Role: Secondary TVS on 12 V auxiliary rail feeding MOSFET drivers and position sensors. Use Value: Low clamping ratio (1.38) ensures gate oxide integrity of 40 V-rated drivers during 100 V load dump events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ39A | VBR = 39.0–43.1 V; VCL = 60.0 V @ 10.5 A; IR = 5 µA @ 25 °C only | Lacks specified leakage performance above 125 °C - unsuitable for sustained under-hood use | Select only for non-automotive, ambient-temperature applications where cost is prioritized over thermal stability |
| 1.5SMC39A | Same VBR/VCL specs but in larger SMC package; Rth(j-a) = 15 °C/W vs. 100 °C/W | Requires more PCB area and different thermal layout; not drop-in for SMB footprints | Choose when higher continuous power handling (1.5 kW PPP) is needed and board space permits SMC rework |
Compared with SMAJ39A and 1.5SMC39A, SM6HT39A uniquely guarantees ≤5 µA leakage at 150 °C and fits SMB layouts while maintaining automotive thermal qualification - making it the only validated choice for engine bay ECU power rail protection.
Availability
SM6HT39A is available at Aetrix Electronics and suitable for engine control units, transmission control modules, body control modules, and electric power steering systems requiring stable component supply across extended automotive lifecycles.
Supply support for SM6HT39A 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing silicon solutions for automotive, industrial, and consumer markets since 1987.
The SM6HT series belongs to ST's automotive-qualified Transil™ TVS portfolio, engineered specifically to meet AEC-Q101 requirements and address high-temperature surge immunity in engine compartment electronics.
FAQ
Is SM6HT39A AEC-Q101 qualified?
Yes. SM6HT39A is explicitly designed and tested to AEC-Q101 standards for discrete semiconductors, including stress tests for temperature cycling, high-temperature operating life, and surge robustness - confirmed in ST's official qualification reports and product change notices dated March 2007.
What is the maximum continuous power dissipation at 100 °C ambient?
At Tamb = 100 °C, continuous power dissipation is derated to approximately 2.4 W, calculated using P = (Tj_max − Tamb) / Rth(j-a) = (175 − 100) / 100 = 0.75 W - however, the datasheet specifies 6 W at Tamb = 50 °C with infinite heatsink, and real-world PCB layout determines actual capability.
Can SM6HT39A be used in bidirectional configurations?
No. SM6HT39A is unidirectional only, with cathode marked by a band. Bidirectional protection requires two devices in series opposing or a dedicated bidirectional part like SM6HT39AY; using SM6HT39A in reverse bias beyond VRM risks permanent breakdown.
Does the "HT" in SM6HT39A indicate high-temperature packaging or process?
"HT" denotes both: high-temperature planar junction process and optimized packaging materials (UL94V-0 epoxy, solderable leads rated to 260 °C), enabling full specification compliance from −65 °C to +175 °C junction temperature - verified via accelerated life testing and thermal impedance characterization.
SM6HT39A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6HT, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33.3V
- Voltage - Breakdown (Min):
- 37.1V
- Voltage - Clamping (Max) @ Ipp:
- 53.9V
- Current - Peak Pulse (10/1000µs):
- 11.1A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6HT39A FAQ
1.How can I place an order for SM6HT39A through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6HT39A 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 SM6HT39A reliable?
The price and inventory of SM6HT39A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6HT39A is usually 5 days.
3.What payment methods are accepted for SM6HT39A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6HT39A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6HT39A?
SM6HT39A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6HT39A 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 SM6HT39A?
For technical support, including SM6HT39A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6HT39A requirements.
6.How does Aetrix verify that SM6HT39A is sourced from the original manufacturer or authorized distributors?
All SM6HT39A 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 SM6HT39A meets industry standards.
7.What is the process for return or replacement of SM6HT39A?
All SM6HT39A units undergo pre-shipment inspection (PSI). If there is an issue with SM6HT39A, 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 SM6HT39A part is unused and in its original packaging.
Return procedure for SM6HT39A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM6HT39A Tags
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