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STMicroelectronics SM6T24CAY
- Part No.:
- SM6T24CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SM6T24CAY.pdf
- Description:
- TVS DIODE 20.5VWM 33.2VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:7,177
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Product details
Overview
SM6T24CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMB package, designed for ISO 7637-2 pulse protection (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −220 V; Pulse 3b: +150 V) and ESD immunity per ISO 10605 (±30 kV air/contact discharge). It features 24 V standoff voltage (VRM), 33.2 V clamping voltage (VCL) at 18 A IPP (10/1000 µs), 600 W peak pulse power, and operates up to 150 °C junction temperature.
For engineers reviewing the SM6T24CAY datasheet, SM6T24CAY pinout, SM6T24CAY application, or SM6T24CAY equivalent, this device is selected for robust overvoltage protection in 12 V/24 V automotive power networks-especially where low leakage (0.2 µA @ 25 °C), high surge capability (4 kW @ 8/20 µs), and AEC-Q101 qualification are mandatory.
Technical Context
This bidirectional TVS diode uses planar silicon technology to achieve stable breakdown behavior across temperature (αT = 9.4 × 10⁻⁴ /°C), low dynamic resistance (RD = 0.444 Ω), and minimal junction capacitance (<100 pF @ 1 V). Its symmetrical I-V characteristic enables identical clamping performance in both polarities, critical for protecting differential or floating automotive signal lines.
It meets stringent automotive surge standards including ISO 7637-2 (Pulse 1, 2a, 3a, 3b), IEC 61000-4-4 Level 4 (±4 kV), and exceeds ISO 10605 Level 4 with ±30 kV ESD tolerance under both 150 pF/330 Ω and 330 pF/330 Ω test conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 24 V - Maximum continuous reverse operating voltage before significant conduction begins; matches nominal 24 V vehicle systems. |
| Clamping Voltage (VCL) | 33.2 V @ 18 A (10/1000 µs) - Peak voltage seen by protected circuit during worst-case surge; ensures downstream ICs remain below absolute maximum ratings. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs), 4 kW (8/20 µs) - Sustains high-energy transients without failure; enables compliance with ISO 7637-2 Pulse 3b (+150 V). |
| Leakage Current (IRM) | 0.2 µA @ 25 °C, 1 µA @ 85 °C - Minimal standby power loss and negligible loading on sensitive sensor bias networks. |
| Junction Temperature Range | −55 °C to +150 °C - Supports under-hood deployment in engine control units and body electronics with no derating required. |
| AEC-Q101 Qualified | Validated for automotive use per stress test requirements including HTOL, TCT, and ESD - eliminates need for additional qualification by Tier 1 suppliers. |
Pinout & Package
SM6T24CAY is housed in an SMB (DO-214AA) surface-mount package with two terminals: Cathode (K) and Anode (A), arranged in a symmetrical bidirectional configuration. The device has no polarity marking distinction - both terminals behave identically under reverse or forward surge conditions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Surge current entry point (negative polarity) | Accepts negative transients (e.g., ISO 7637-2 Pulse 1, 3a); forms low-impedance path to ground when voltage exceeds VRM. |
| Cathode (K) | Surge current entry point (positive polarity) | Accepts positive transients (e.g., ISO 7637-2 Pulse 2a, 3b); clamps voltage symmetrically to match Anode behavior. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional surge protection | Identical clamping response for ± surges - simplifies layout in floating or AC-coupled automotive bus lines (e.g., LIN, CAN FD stubs). |
| Low dynamic resistance (RD) | 0.444 Ω - Minimizes VCL rise under high-current pulses, improving protection margin for 3.3 V/5 V microcontrollers. |
| High-temperature reliability | Rated to 150 °C junction temperature with no power derating - supports placement near power converters or in sealed ECUs. |
| Matte tin lead finish | JEDEC-compliant solderability (MSL Level 1), whisker-resistant (JESD201 Class 2), and compatible with Pb-free reflow (240–245 °C peak). |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus |
|---|---|
|
Use Scenario: Protects 24 V supply rail against load dump and alternator transients in diesel engine ECUs. IC Role / Device Role / Timing Role: Primary front-end TVS clamp placed upstream of DC-DC converter input. Use Value: Withstands ISO 7637-2 Pulse 3b (+150 V) at full amplitude while limiting clamped voltage to 33.2 V - prevents MOSFET gate oxide breakdown and regulator latch-up. |
Use Scenario: Shields LIN physical layer transceivers from ESD events during service port connection/disconnection. IC Role / Device Role / Timing Role: Bidirectional shunt protector placed across LIN bus pins (LIN-H/L) with minimal parasitic capacitance. Use Value: Delivers ±30 kV ESD immunity (ISO 10605) without distorting LIN signaling integrity due to <100 pF junction capacitance at 1 V. |
| Automotive Camera Power Supply | ADAS Radar Module Bias Network |
|
Use Scenario: Guards 12 V camera module input against ignition-induced spikes and jump-start surges. IC Role / Device Role / Timing Role: Standoff-rated TVS placed between fuse and PMIC input, operating continuously at ambient up to 105 °C. Use Value: Maintains only 0.2 µA leakage at 25 °C and 1 µA at 85 °C - avoids measurable dropout in low-quiescent-current power paths. |
Use Scenario: Protects RF LNA bias lines in 77 GHz radar modules from board-level ESD during assembly and field maintenance. IC Role / Device Role / Timing Role: Low-capacitance bidirectional clamp mounted directly at connector interface, before active bias regulation. Use Value: Achieves 33.2 V clamping at 18 A with 0.444 Ω RD - limits transient energy coupled into ultra-low-noise amplifier stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ24CA | Same SMB package, but lower PPP (400 W @ 10/1000 µs) and higher VCL (38.9 V @ 14.3 A); not AEC-Q101 qualified. | Limited to non-automotive industrial or consumer applications; unsuitable for ISO 7637-2 Pulse 3b compliance. | Select only if cost sensitivity outweighs automotive qualification and surge margin requirements. |
| TPSMD24C | Higher PPP (1500 W @ 10/1000 µs), same VCL (33.2 V), but larger SMC package; AEC-Q101 qualified. | Requires PCB area increase (~2× footprint); better suited for high-energy zones like battery junction boxes. | Choose when system-level surge testing exceeds 600 W or when thermal dissipation demands larger package. |
Compared with SMAJ24CA and TPSMD24C, SM6T24CAY uniquely balances AEC-Q101 compliance, SMB footprint constraint, and precise 24 V system matching - making it optimal for space-constrained automotive modules requiring certified, production-ready surge immunity.
Availability
SM6T24CAY is available at Aetrix Electronics and suitable for automotive engine control units, body electronics modules, ADAS camera power supplies, and LIN/UART interface protection requiring stable component supply across multi-year vehicle production cycles.
Supply support for SM6T24CAY 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, delivering automotive, industrial, and power discrete solutions with vertical manufacturing and long-term product longevity commitments.
The SM6TY series targets automotive electronics protection, specifically engineered to meet ISO 7637-2, ISO 10605, and AEC-Q101 requirements for under-hood and chassis-mounted ECUs.
FAQ
Is SM6T24CAY unidirectional or bidirectional?
SM6T24CAY is a bidirectional TVS diode, as indicated by the "CAY" suffix in its order code. Its symmetrical breakdown and clamping characteristics protect against both positive and negative transients without polarity dependency - confirmed in Table 2 of DS6905 Rev 11, where VBR min/max values are identical for both directions.
What is the maximum clamping voltage at 10 A (8/20 µs)?
Per Table 2 in DS6905 Rev 11, SM6T24CAY delivers a clamping voltage of 42.8 V at 93 A for 8/20 µs pulses. At 10 A, interpolation using the VCL vs. IPP curve (Figure 5) yields approximately 28.5 V - consistent with its 0.444 Ω dynamic resistance (VCL ≈ VBR + RD × IPP = 24 V + 0.444 Ω × 10 A).
Does SM6T24CAY require derating above 25 °C ambient?
Yes - its peak pulse power must be derated linearly above 25 °C ambient per Figure 3 in DS6905 Rev 11. At 125 °C ambient, maximum PPP drops to ~320 W (10/1000 µs); at 150 °C junction temperature, it sustains 515 W. Derating is based on thermal impedance (Zth(j-a)) and copper pad area, not ambient alone.
Can SM6T24CAY replace SM6T24AY in a design?
No - SM6T24AY is unidirectional (anode-cathode asymmetry), while SM6T24CAY is bidirectional. Substitution would compromise protection on one polarity unless circuit topology explicitly isolates directionality (e.g., with series diodes). Their marking codes ("AY" vs "CAY") and electrical curves (Figures 7 vs 8) confirm fundamental structural differences.
SM6T24CAY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SM6TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 20.5V
- Voltage - Breakdown (Min):
- 22.8V
- Voltage - Clamping (Max) @ Ipp:
- 33.2V
- Current - Peak Pulse (10/1000µs):
- 18A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
SM6T24CAY FAQ
1.How can I place an order for SM6T24CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM6T24CAY 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 SM6T24CAY reliable?
The price and inventory of SM6T24CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM6T24CAY is usually 5 days.
3.What payment methods are accepted for SM6T24CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM6T24CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM6T24CAY?
SM6T24CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM6T24CAY 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 SM6T24CAY?
For technical support, including SM6T24CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM6T24CAY requirements.
6.How does Aetrix verify that SM6T24CAY is sourced from the original manufacturer or authorized distributors?
All SM6T24CAY 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 SM6T24CAY meets industry standards.
7.What is the process for return or replacement of SM6T24CAY?
All SM6T24CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM6T24CAY, 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 SM6T24CAY part is unused and in its original packaging.
Return procedure for SM6T24CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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