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STMicroelectronics SMA6T39CAY
- Part No.:
- SMA6T39CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6T39CAY.pdf
- Description:
- TVS DIODE 33.3VWM 69.7VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,156
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Product details
Overview
SMA6T39CAY from STMicroelectronics is a bidirectional 600 W transient voltage suppression diode designed for automotive circuit protection against ISO 7637-2 pulses (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −220 V; Pulse 3b: +150 V) and ESD per ISO 10605 (±30 kV air/contact discharge). It features a 39 V breakdown voltage (VBR = 33.3–41.0 V), 53.9 V max clamping voltage (VCL) at 11.1 A (10/1000 µs), and operates up to Tj = 150 °C in SMA (DO-214AC) package.
For engineers reviewing the SMA6T39CAY datasheet, SMA6T39CAY pinout, SMA6T39CAY application, or SMA6T39CAY equivalent, key selection criteria include bidirectional surge clamping performance under ISO 7637-2 Pulse 1/2a/3a/3b, low leakage (<0.2 µA @ 25 °C), AEC-Q101 qualification, and compatibility with high-reliability automotive power line and signal line protection layouts.
Technical Context
This device implements planar silicon avalanche junction technology optimized for fast response (<1 ns) to transients while maintaining low dynamic resistance (RD = 1.16 Ω) and stable VBR temperature coefficient (αT = 10.0 × 10−4/°C). Its bidirectional structure enables symmetrical clamping on both polarities without external polarity biasing.
Designed specifically for 12 V and 24 V automotive battery networks, it meets IEC 61000-4-4 Level 4 (4 kV), exceeds ISO 10605 Level 4 (±30 kV), and supports operation across full automotive ambient range (−40 °C to +125 °C) with junction temperature up to +150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 33.3 / 37.1 / 41.0 V - ensures reliable turn-on before downstream IC damage at rated system voltage |
| VCL @ 11.1 A (10/1000 µs) | 53.9 V - limits peak voltage seen by protected load during worst-case ISO 7637-2 Pulse 1 |
| IPP (10/1000 µs) | 11.1 A - defines maximum surge current handled at 600 W peak power rating |
| RD (dynamic resistance) | 1.16 Ω - determines voltage overshoot above VBR during transient conduction |
| IR @ VRM (25 °C) | 0.2 µA - minimizes standby power loss and avoids false triggering in high-impedance circuits |
| Tj max | +150 °C - enables placement near hot engine control units without derating |
| AEC-Q101 qualified | Yes - validated for automotive underhood reliability including temperature cycling, HTRB, and mechanical shock |
Pinout & Package
Package: SMA (DO-214AC), JEDEC-registered surface-mount outline with matte tin-plated leads; footprint compatible with IPC7531 standard; thermal resistance Rth(j-a) = ~4.5 °C/W on 1 cm² FR4 copper.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Reference terminal for unidirectional types; symmetric node for bidirectional types | In SMA6T39CAY (bidirectional), both terminals are functionally identical - no polarity sensitivity in layout |
| Anode (unmarked end) | Reference terminal for unidirectional types; symmetric node for bidirectional types | Enables PCB trace routing flexibility - no orientation constraint required during placement |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Provides symmetrical overvoltage protection on AC-coupled or floating lines without polarity awareness |
| Low leakage current | 0.2 µA @ 25 °C ensures minimal impact on sensor bias networks and low-power wake-up circuits |
| High surge robustness | Withstands 4 kW (8/20 µs) and 600 W (10/1000 µs) surges - covers both lightning-induced and load-dump energy profiles |
| AEC-Q101 qualification | Validated for automotive underhood use including HTSL, TC, and mechanical vibration per JESD22 standards |
| Stable VBR tempco | αT = 10.0 × 10−4/°C ensures predictable clamping across −40 °C to +150 °C junction range |
Applications
| Power Line Protection | Signal Line Protection |
|---|---|
Use Scenario: 12 V battery rail in engine control unit exposed to ISO 7637-2 Pulse 1 (−150 V) and Pulse 3b (+150 V). IC Role / Device Role / Timing Role: Primary clamping element placed between battery input and DC-DC converter input stage. Use Value: Limits transient voltage to ≤53.9 V, preventing latch-up or gate oxide rupture in downstream PMICs. | Use Scenario: CAN FD bus lines (CANH/CANL) subjected to ESD events per ISO 10605 (±30 kV contact discharge). IC Role / Device Role / Timing Role: Bidirectional shunt protector placed differential across CANH–CANL pair, referenced to ground. Use Value: Clamps ESD pulse within <1 ns while adding <1 pF capacitance - preserves signal integrity up to 5 Mbps. |
| Body Control Module | ADAS Camera Power Input |
Use Scenario: LIN bus transceiver power supply in door module exposed to load dump and alternator ripple. IC Role / Device Role / Timing Role: Standoff protector mounted directly at LIN transceiver VCC pin, with low IR preserving quiescent current budget. Use Value: Maintains <0.2 µA leakage at 25 °C and <1 µA at 85 °C - critical for sleep-mode current compliance. | Use Scenario: 5 V power rail feeding CMOS image sensor in rear-view camera exposed to cable discharge events. IC Role / Device Role / Timing Role: Secondary clamp after primary filter, placed adjacent to sensor's VDD pin to minimize loop inductance. Use Value: Delivers 53.9 V clamping at 11.1 A with RD = 1.16 Ω - reduces overshoot to <1.3 V above VBR. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6T39AY | Unidirectional; same VBR, VCL, and PPP; requires correct polarity placement | Suitable only where circuit topology enforces known polarity (e.g., regulated 5 V output rail) | Select when protecting single-polarity rails with space-constrained layouts requiring lowest possible capacitance |
| SMB6T39CAY | Same electrical specs but SMB (DO-214AA) package; 20% larger footprint; Rth(j-a) ≈ 3.8 °C/W | Better thermal dissipation for sustained surge duty cycles; less suitable for ultra-dense PCBs | Select when board layout allows larger pad area and higher average power handling is prioritized over miniaturization |
Compared with SMA6T39AY, SMA6T39CAY eliminates polarity dependency for differential or floating nodes; compared with SMB6T39CAY, it trades 0.7 °C/W higher thermal resistance for 30% smaller PCB area - optimal for compact ADAS and body electronics modules.
Availability
SMA6T39CAY is available at Aetrix Electronics and suitable for automotive power line protection, CAN/LIN bus safeguarding, body control module design, and ADAS camera power conditioning requiring stable component supply across extended temperature and surge stress conditions.
Supply support for SMA6T39CAY 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, specializing in automotive, industrial, and power management solutions with vertical manufacturing and AEC-Q100/Q101 validation infrastructure.
The SMA6TY series belongs to ST's Transil™ automotive TVS portfolio, engineered specifically to meet stringent ISO 7637-2 and ISO 10605 immunity requirements in engine bay and chassis-mounted ECUs.
FAQ
What is the difference between SMA6T39AY and SMA6T39CAY?
SMA6T39AY is unidirectional and must be oriented with cathode toward the protected line's positive side; SMA6T39CAY is bidirectional and functions identically regardless of terminal orientation. Both share identical VBR, VCL, and surge ratings, but CAY type simplifies layout for differential or AC-coupled signals like CAN or LIN bus lines.
Does SMA6T39CAY require a heatsink for 600 W pulse handling?
No heatsink is required for single-pulse 600 W (10/1000 µs) events because energy dissipation is brief (1 ms) and junction temperature rise remains within safe limits. Thermal design focuses on PCB copper area: ≥1 cm² per lead reduces Rth(j-a) to ~4.5 °C/W, sufficient for automotive ambient extremes.
Can SMA6T39CAY protect against ISO 7637-2 Pulse 2b?
No - Pulse 2b (inductive switch-off spike on alternator output) is not applicable to SMA6T39CAY, as its VRWM (33.3 V) is below typical 14 V nominal battery voltage plus alternator regulation margin (~15–16 V). This part is intended for loads downstream of main battery filtering, not direct alternator output protection.
Is the 30 kV ESD rating verified per ISO 10605 test setup C = 330 pF / R = 330 Ω?
Yes - the datasheet explicitly states "ISO 10605, C = 330 pF, R = 330 Ω exceeds level 4: – 30 kV (air discharge) – 30 kV (contact discharge)", confirming full compliance with that exact test configuration, not just the lower-energy C = 150 pF variant.
SMA6T39CAY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMA6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 33.3V
- Voltage - Breakdown (Min):
- 37.1V
- Voltage - Clamping (Max) @ Ipp:
- 69.7V
- Current - Peak Pulse (10/1000µs):
- 57A (8/20µs)
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA6T39CAY FAQ
1.How can I place an order for SMA6T39CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6T39CAY 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 SMA6T39CAY reliable?
The price and inventory of SMA6T39CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6T39CAY is usually 5 days.
3.What payment methods are accepted for SMA6T39CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6T39CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6T39CAY?
SMA6T39CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6T39CAY 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 SMA6T39CAY?
For technical support, including SMA6T39CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6T39CAY requirements.
6.How does Aetrix verify that SMA6T39CAY is sourced from the original manufacturer or authorized distributors?
All SMA6T39CAY 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 SMA6T39CAY meets industry standards.
7.What is the process for return or replacement of SMA6T39CAY?
All SMA6T39CAY units undergo pre-shipment inspection (PSI). If there is an issue with SMA6T39CAY, 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 SMA6T39CAY part is unused and in its original packaging.
Return procedure for SMA6T39CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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