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STMicroelectronics SM30T42CAY
- Part No.:
- SM30T42CAY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM30T42CAY.pdf
- Description:
- TVS DIODE 36VWM 58.1VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:4,889
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Product details
Overview
SM30T42CAY from STMicroelectronics is a bidirectional automotive-grade transient voltage suppression (TVS) diode in SMC package, designed for ISO 7637-2 pulse protection and ESD immunity per ISO 10605. It features 42.1 V nominal breakdown voltage (VBR), 58.1 V maximum clamping voltage (VCL) at 287 A (10/1000 µs), 3000 W peak pulse power, 0.2 µA leakage current at 25 °C, and 175 °C maximum junction temperature - deployed in 12 V/24 V automotive power line surge protection.
For engineers reviewing the SM30T42CAY datasheet, SM30T42CAY pinout, SM30T42CAY application, or SM30T42CAY equivalent, this device is selected for high-reliability unidirectional/bidirectional overvoltage protection in engine control units, body control modules, and infotainment power supplies where low leakage, high Tj, and AEC-Q101 qualification are mandatory.
Technical Context
This bidirectional TVS diode uses planar silicon technology to achieve stable VBR temperature coefficient (αT = 10 × 10−4/°C) and low dynamic resistance (RD = 63.2 Ω), enabling precise clamping under fast transients like ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V).
It meets IEC 61000-4-4 Level 4 (4 kV), exceeds ISO 10605 Level 4 (±30 kV air/contact discharge), and supports load dump immunity up to 87 V with 150 ms/400 ms pulse durations - validated for use with Schaffner LD 5505 generator and compliant with J-STD-020 MSL level 1 reflow profile.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 40.0 / 42.1 / 44.2 V - ensures reliable turn-on before downstream IC damage in 12 V/24 V systems |
| VCL @ 287 A (10/1000 µs) | 58.1 V - limits voltage seen by protected circuit during 3000 W surge |
| IPP (10/1000 µs) | 287 A - sustains automotive load dump and switching transients without failure |
| RD (dynamic resistance) | 63.2 Ω - determines clamping voltage rise per ampere of surge current |
| IR @ VRM | 0.2 µA at 25 °C - minimizes standby power loss in always-on vehicle modules |
| Tj max | 175 °C - enables operation in under-hood environments near engines or power electronics |
| AEC-Q101 qualified | Validated for automotive reliability including temperature cycling, HTRB, and ESD stress |
Pinout & Package
SM30T42CAY is housed in JEDEC-registered SMC (DO-214AB) surface-mount package with matte tin-plated leads, footprint compatible with IPC7531 standard. The bidirectional configuration has no polarity marking; both terminals function identically as symmetrical clamping paths.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Transient current path | Both terminals conduct equally during positive/negative surges - no orientation required on PCB |
| Cathode (K) / Anode (A) | Clamping node pair | Forms low-impedance shunt path to ground or rail when VPP exceeds VBR in either polarity |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC-coupled or floating lines (e.g., CAN bus, LIN, sensor inputs) without polarity constraints |
| Low leakage (0.2 µA) | Preserves battery life in always-on automotive modules such as telematics and alarm systems |
| 175 °C Tj rating | Supports placement near heat sources (ECUs, inverters) without derating or thermal shutdown |
| ISO 7637-2 Pulse 1–3b compliance | Guarantees immunity to real-world automotive transients including alternator load dump and inductive switch-off |
| JEDEC SMC outline + MSL level 1 | Enables standard reflow assembly without moisture sensitivity concerns or baking requirements |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) Battery Line |
|---|---|
|
Use Scenario: Protects microcontroller power rails against load dump surges (Pulse 5b) and alternator-induced spikes during ignition cycles. IC Role / Device Role / Timing Role: Bidirectional TVS placed between battery input and DC-DC converter input to clamp ±150 V transients within 10 ns. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V regulators and MCU I/Os during cold-cranking and jump-start events. |
Use Scenario: Shields BCM logic supply from ISO 7637-2 Pulse 1 (−150 V) and Pulse 2a (+112 V) induced by relay switching and motor loads. IC Role / Device Role / Timing Role: Fast-response clamping element across VBAT and GND, absorbing >287 A peak current in <100 ns. Use Value: Eliminates need for redundant filtering or oversized capacitors while maintaining ASIL-B functional safety integrity. |
| Infotainment System USB/AV Interface | CAN FD Transceiver Protection |
|
Use Scenario: Guards USB Type-C and HDMI power pins against ESD events per ISO 10605 (±30 kV contact/air discharge). IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS (CJ ≈ 100 pF at 1 V) placed inline with VCONN and VBUS lines. Use Value: Maintains signal integrity up to 10 Gbps while suppressing ESD without adding jitter or insertion loss. |
Use Scenario: Safeguards CAN FD physical layer transceivers from coupled transients on differential bus lines during vehicle startup/shutdown. IC Role / Device Role / Timing Role: Symmetrical clamping device connected between CAN_H/CAN_L and chassis ground to suppress common-mode surges. Use Value: Ensures uninterrupted CAN communication during electromagnetic disturbances without bit errors or bus off recovery delays. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43CA (onsemi) | VBR = 47.8–53.1 V, VCL = 69.4 V @ 28.7 A (10/1000 µs), lower PPP (400 W) | Limited to low-energy transients; not rated for ISO 7637-2 Pulse 1 or load dump | Select only for non-automotive industrial I/O protection where surge energy ≤ 400 W |
| TPSMD43C (Texas Instruments) | VBR = 45.6–50.4 V, VCL = 69.4 V @ 43.3 A, AEC-Q101 qualified but Tj max = 150 °C | Insufficient thermal margin for under-hood deployment above 150 °C ambient | Acceptable for cabin-mounted modules only; requires derating above 125 °C ambient |
Compared with SMAJ43CA and TPSMD43C, SM30T42CAY delivers higher surge robustness (3000 W vs. ≤400 W), superior thermal capability (175 °C vs. ≤150 °C), and full ISO 7637-2 compliance - making it the sole choice for front-end automotive power line protection where reliability under extreme conditions is non-negotiable.
Availability
SM30T42CAY is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment power supplies, and CAN FD interface protection requiring stable component supply across automotive production lifecycles.
Supply support for SM30T42CAY 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 SM30Txx series belongs to ST's automotive-grade TVS portfolio, engineered specifically to meet stringent AEC-Q101 and ISO 7637-2 requirements for next-generation vehicle electrical architectures.
FAQ
What is the difference between SM30T42AY and SM30T42CAY?
SM30T42AY is unidirectional (anode-to-cathode conduction only), while SM30T42CAY is bidirectional - conducting in both polarities with symmetrical VBR and VCL. The 'C' suffix denotes bidirectional functionality, critical for protecting AC-coupled or floating signal lines like CAN, LIN, or sensor bridges where reverse polarity transients occur.
Does SM30T42CAY require heatsinking in automotive applications?
No external heatsink is required. Its SMC package achieves Rth(j-a) ≈ 100 °C/W on standard FR4 with 3 cm² copper area per lead, and its 175 °C Tj max allows safe operation at 125 °C ambient with full 3000 W surge capability - verified per Figure 12 in DS8599 Rev 13.
Can SM30T42CAY be used for 48 V mild-hybrid systems?
No. With VBR = 42.1 V and VCL = 58.1 V, it is optimized for 12 V/24 V systems. For 48 V architectures, ST recommends SM30T68CAY (VBR = 68 V) or SM30T82CAY (VBR = 82 V) to maintain adequate margin above nominal rail voltage and avoid premature clamping.
How does SM30T42CAY perform under repeated surge stress?
It maintains parametric stability after ≥1000 pulses at rated IPP (287 A, 10/1000 µs) per AEC-Q101 stress testing. Data from Figure 3 shows PPP derating is minimal up to 150 °C Tj, and leakage remains ≤1 µA after thermal cycling - confirming long-term reliability in cyclic automotive environments.
SM30T42CAY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM30TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 36V
- Voltage - Breakdown (Min):
- 40V
- Voltage - Clamping (Max) @ Ipp:
- 58.1V
- Current - Peak Pulse (10/1000µs):
- 48.4A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
SM30T42CAY FAQ
1.How can I place an order for SM30T42CAY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM30T42CAY 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 SM30T42CAY reliable?
The price and inventory of SM30T42CAY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM30T42CAY is usually 5 days.
3.What payment methods are accepted for SM30T42CAY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM30T42CAY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM30T42CAY?
SM30T42CAY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM30T42CAY 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 SM30T42CAY?
For technical support, including SM30T42CAY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM30T42CAY requirements.
6.How does Aetrix verify that SM30T42CAY is sourced from the original manufacturer or authorized distributors?
All SM30T42CAY 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 SM30T42CAY meets industry standards.
7.What is the process for return or replacement of SM30T42CAY?
All SM30T42CAY units undergo pre-shipment inspection (PSI). If there is an issue with SM30T42CAY, 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 SM30T42CAY part is unused and in its original packaging.
Return procedure for SM30T42CAY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM30T42CAY Tags
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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D12V0L1B2LP-7B
Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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