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STMicroelectronics SM15T22AY
- Part No.:
- SM15T22AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM15T22AY.pdf
- Description:
- TVS DIODE 18.8VWM 39.3VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:1,754
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Product details
Overview
SM15T22AY from STMicroelectronics is a unidirectional automotive-grade transient voltage suppressor (TVS) diode in SMC package, designed for ISO 7637-2 pulse protection in 12 V battery systems. It features a 22 V nominal breakdown voltage (VBR = 18.8–23.1 V), 30.6 V clamping voltage (VCL) at 49 A (10/1000 µs), 1500 W peak pulse power, and ≤0.2 µA leakage at 25 °C - deployed in engine control units, body electronics, and infotainment power rails.
For engineers reviewing the SM15T22AY datasheet, SM15T22AY pinout, SM15T22AY application, or SM15T22AY equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1 (−150 V), junction temperature derating to 1250 W at Tj = 150 °C, low dynamic resistance (RD = 0.153 Ω), and AEC-Q101 qualification for automotive reliability.
Technical Context
This TVS operates as a unidirectional avalanche clamp, triggered when reverse voltage exceeds its 22 V VBR threshold. Its planar silicon structure ensures stable leakage (<1 µA at 85 °C) and high thermal robustness up to Tj = 150 °C, enabling long-term operation in under-hood environments.
The device meets IEC 61000-4-2 (±30 kV contact/air), ISO 10605 (C = 330 pF/R = 330 Ω), and ISO 7637-2 (Pulse 1: −150 V; Pulse 2a: +112 V; Pulse 3a: −220 V; Pulse 3b: +150 V), with clamping validated across both 10/1000 µs and 8/20 µs surge waveforms.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VBR (min/typ/max) | 18.8 / 20.9 / 23.1 V - defines precise turn-on threshold for overvoltage clamping in 12 V automotive systems |
| VCL @ IPP = 49 A (10/1000 µs) | 30.6 V - maximum voltage seen by protected circuit during 1500 W transient, limiting stress on downstream ICs |
| IR @ VRM = 18 V | ≤0.2 µA at 25 °C - ultra-low leakage preserves battery standby current in always-on modules |
| RD (dynamic resistance) | 0.153 Ω - determines VCL rise slope under surge, critical for fast-clamp response |
| PPP (10/1000 µs) | 1500 W at Tamb = 25 °C; derates to 1250 W at Tj = 150 °C - defines sustained surge handling capability |
| Stand-off voltage (VRM) | 18 V - maximum continuous reverse operating voltage before leakage exceeds spec, compatible with 12 V nominal bus |
| AEC-Q101 qualified | Validated for automotive temperature cycling, humidity bias, and mechanical shock - required for ECU front-end protection |
Pinout & Package
SM15T22AY is housed in an SMC (DO-214AB) surface-mount package with two terminals: Cathode (marked side) and Anode. The package complies with JEDEC registered outline and IPC7531 footprint, featuring matte tin-plated leads rated for 260 °C soldering (10 s).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Surge current sink node | Connected to protected line (e.g., CAN_H, LIN, or 12 V rail); conducts avalanche current to ground during overvoltage |
| Anode | Reference/ground return | Typically tied to chassis or system ground; completes clamping path - polarity-critical for unidirectional operation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive temperature, humidity, and mechanical stress - enables use in engine bay and ADAS modules without requalification |
| ISO 7637-2 Pulse 1 (−150 V) compliance | Clamps transients from load dump and inductive switching in 12 V battery systems - protects MCU power supplies and communication interfaces |
| Low dynamic resistance (0.153 Ω) | Minimizes VCL overshoot during fast surges - ensures downstream ICs remain within absolute maximum ratings |
| 150 °C junction temperature rating | Supports placement near heat sources (e.g., power converters) without derating loss - extends lifetime in high-ambient environments |
| Matte tin lead finish (JESD 22-B102 E3) | Ensures reliable solderability and whisker resistance - critical for automated assembly and long-term field reliability |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus |
|---|---|
|
Use Scenario: Protection against load dump (ISO 7637-2 Pulse 1: −150 V) and alternator ripple on 12 V supply rail. IC Role / Device Role / Timing Role: Unidirectional TVS clamps negative transients while blocking forward conduction - placed between fuse and LDO input. Use Value: Limits voltage to ≤30.6 V during 49 A surge, preventing damage to 3.3 V/5 V regulators and microcontrollers. |
Use Scenario: ESD and burst protection on LIN physical layer (12 V biased bus) in door modules and seat controllers. IC Role / Device Role / Timing Role: Standby-mode clamp absorbing ±30 kV IEC 61000-4-2 discharges without latch-up or parametric shift. Use Value: Maintains <0.2 µA leakage at 25 °C, avoiding false wake-up of LIN transceivers during sleep mode. |
| Infotainment Head Unit USB Power | ADAS Camera Power Rail |
|
Use Scenario: Surge suppression on 5 V USB VBUS derived from vehicle 12 V via DC-DC converter. IC Role / Device Role / Timing Role: Fast-response clamp (tRESP < 1 ns) shunting 8/20 µs transients before they reach USB controller ICs. Use Value: Delivers 39.3 A peak current at 39.3 V clamping (8/20 µs), meeting USB-IF surge immunity requirements. |
Use Scenario: Front-end protection for 12 V camera power in parking assist systems exposed to ignition noise and cable discharge. IC Role / Device Role / Timing Role: High-Tj (150 °C) capable TVS mounted adjacent to image sensor power entry point. Use Value: Sustains 1250 W clamping at full junction temperature - avoids thermal runaway during repeated pulse 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 |
|---|---|---|---|
| SMAJ22A | Same 22 V VBR, but lower PPP = 400 W (10/1000 µs); RD = 0.35 Ω; no AEC-Q101 qualification | Limited to non-automotive industrial or consumer use; insufficient for ISO 7637-2 Pulse 1 | Select only for cost-sensitive non-automotive designs where 1500 W surge immunity is not required. |
| SMBJ22A | Higher PPP = 600 W; VCL = 35.5 V @ 16.9 A; AEC-Q101 qualified; SMC-compatible footprint but larger RD = 0.21 Ω | Meets basic automotive ESD but fails ISO 7637-2 Pulse 1 due to lower energy rating | Acceptable for cabin modules with lower surge exposure; avoid in powertrain or exterior-facing systems. |
Compared with SMAJ22A and SMBJ22A, SM15T22AY delivers 2.5× higher peak power (1500 W vs. 600 W), 20% lower clamping voltage at rated current, and full ISO 7637-2 Pulse 1 compliance - making it the only option qualified for under-hood ECU front-end protection.
Availability
SM15T22AY is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment head units, and ADAS camera systems requiring stable component supply across automotive production lifecycles.
Supply support for SM15T22AY 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.
The SM15TxxAY series belongs to ST's automotive-grade TVS portfolio, engineered specifically to meet stringent ISO 7637-2 and AEC-Q101 requirements for front-end power rail protection in harsh vehicular environments.
FAQ
What is the maximum clamping voltage of SM15T22AY under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 30.6 V at 49 A for a 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature per αT = 9.2 × 10−4/°C, reaching ~32.1 V at Tj = 125 °C.
Is SM15T22AY suitable for bidirectional signal line protection?
No - SM15T22AY is unidirectional and must be used with cathode toward the protected line. For bidirectional protection (e.g., CAN, LIN), ST offers the SM15T22CAY variant, which has symmetrical clamping in both polarities and identical VBR and VCL specs.
How does SM15T22AY perform under ISO 7637-2 Pulse 3a (−220 V)?
It clamps Pulse 3a transients to ≤30.6 V at peak currents up to 49 A (10/1000 µs), satisfying the standard's requirement for suppression below the protected IC's absolute maximum rating. Its 1500 W rating exceeds the 1.2 kJ energy of Pulse 3a when properly heatsinked.
What is the recommended PCB footprint for SM15T22AY?
The official footprint uses 5.11 mm × 8.19 mm pad spacing with 3.14 mm pad width (per DS6928 Figure 18). Copper area ≥2 cm² per pad reduces Rth(j-a) to <60 °C/W, critical for sustaining 1250 W at Tj = 150 °C during repetitive surges.
SM15T22AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- SM15TY, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18.8V
- Voltage - Breakdown (Min):
- 20.9V
- Voltage - Clamping (Max) @ Ipp:
- 39.3V
- Current - Peak Pulse (10/1000µs):
- 254A (8/20µs)
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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:
- SMC
SM15T22AY FAQ
1.How can I place an order for SM15T22AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM15T22AY 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 SM15T22AY reliable?
The price and inventory of SM15T22AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM15T22AY is usually 5 days.
3.What payment methods are accepted for SM15T22AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM15T22AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM15T22AY?
SM15T22AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM15T22AY 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 SM15T22AY?
For technical support, including SM15T22AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM15T22AY requirements.
6.How does Aetrix verify that SM15T22AY is sourced from the original manufacturer or authorized distributors?
All SM15T22AY 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 SM15T22AY meets industry standards.
7.What is the process for return or replacement of SM15T22AY?
All SM15T22AY units undergo pre-shipment inspection (PSI). If there is an issue with SM15T22AY, 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 SM15T22AY part is unused and in its original packaging.
Return procedure for SM15T22AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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