My Inquiry
My Account
STMicroelectronics SM50T27AY
- Part No.:
- SM50T27AY
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SM50T27AY.pdf
- Description:
- AUTOMOTIVE 5000 W, 23 V TVS IN S
- Quantity:
- Payment:
- Shipping:
Inventory:2,450
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SM50T27AY from STMicroelectronics is an AEC-Q101-qualified unidirectional automotive TVS diode in SMC package, designed to clamp transient overvoltages up to 37.8 V (10/1000 µs) with 135 A peak pulse current and 5000 W peak pulse power. It features 0.2 µA max leakage at 25 °C, 175 °C max operating junction temperature, and meets ISO 7637-2 Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V) requirements for 12 V battery systems.
For engineers reviewing the SM50T27AY datasheet, SM50T27AY pinout, SM50T27AY application, or SM50T27AY equivalent, key selection criteria include clamping voltage at 135 A (37.8 V), stand-off voltage (27 V), low dynamic resistance (26.5 mΩ), high-temperature reliability (Tj = 175 °C), and compliance with ISO 10605 (±30 kV ESD) and IEC 61000-4-4 Level 4 (4 kV EFT).
Technical Context
This unidirectional TVS diode uses planar silicon technology to achieve low leakage (0.2 µA at VRM = 27 V) and stable breakdown behavior across −55 °C to +175 °C junction temperature range. Its VBR min of 25.7 V and max of 28.4 V at 1 mA ensures precise overvoltage thresholding in automotive power rail protection.
The device delivers 5000 W peak pulse power under 10/1000 µs waveform and up to 49.2 kW under 8/20 µs surge, with clamping voltage tightly controlled by low dynamic resistance (26.5 mΩ) - critical for protecting downstream CAN transceivers, microcontrollers, and sensor interfaces during load dump and ISO 7637-2 transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VRM) | 27 V - Maximum continuous reverse operating voltage before conduction begins; sets minimum system rail margin for 24 V automotive applications. |
| Breakdown Voltage (VBR) | 25.7–28.4 V at 1 mA - Tight tolerance ensures predictable turn-on during transients without false triggering on normal ripple. |
| Clamping Voltage (VCL) | 37.8 V at 135 A (10/1000 µs) - Limits voltage seen by protected ICs to safe levels during ISO 7637-2 Pulse 1 and Pulse 3a events. |
| Peak Pulse Power (PPP) | 5000 W (10/1000 µs) - Sustains high-energy surges common in 12 V vehicle electrical systems without degradation. |
| Leakage Current (IRM) | 0.2 µA at 27 V, 25 °C - Minimizes standby power loss and avoids false resets in always-on ECUs and body control modules. |
| Dynamic Resistance (RD) | 26.5 mΩ - Low impedance enables rapid voltage clamping and reduces energy dissipation in the diode during fast transients. |
| Junction Temperature Range | −55 °C to +175 °C - Enables placement near hot engine compartments or power electronics without derating. |
Pinout & Package
SM50T27AY is housed in a JEDEC-registered SMC (DO-214AB) surface-mount package with matte tin-plated leads. The package measures 5.55–6.25 mm × 7.75–8.15 mm × 2.45 mm max height and supports IPC-7531 footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked side) | Transient current sink | Connected to protected line (e.g., 12 V rail); conducts surge current to ground when voltage exceeds VBR. |
| Anode | Reference node | Typically tied to system ground; forms low-inductance return path essential for effective ESD/EFT suppression. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive under-hood use including thermal cycling, humidity, and mechanical shock per JESD22 standards. |
| ISO 7637-2 compliance | Withstands Pulse 1 (−150 V), Pulse 2a (+112 V), Pulse 3a (−220 V), and Pulse 3b (+150 V) without failure or parameter shift. |
| IEC 61000-4-2 ESD immunity | Survives ±30 kV contact and air discharge - exceeds Level 4 for robustness in assembly and field environments. |
| Low dynamic resistance | 26.5 mΩ enables sub-40 V clamping at 135 A - protects 3.3 V/5 V logic rails downstream of DC-DC converters. |
| High-temperature operation | Rated for Tj up to +175 °C - eliminates need for thermal derating in proximity to power MOSFETs or ignition coils. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Line |
|---|---|
|
Use Scenario: Protects 12 V supply input of engine control units against load dump and alternator-induced surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and input filter capacitor to clamp transients before they reach LDOs and MCU power pins. Use Value: Clamps to 37.8 V at 135 A, preventing overvoltage damage to 40 V-rated input stages while maintaining <0.2 µA leakage to avoid battery drain. |
Use Scenario: Shields LIN transceiver data lines from ESD events during vehicle assembly and service operations. IC Role / Device Role / Timing Role: Bidirectional-capable layout (though SM50T27AY is unidirectional, used in rail-to-rail configurations) suppresses ±30 kV ESD per ISO 10605 without signal distortion. Use Value: Low capacitance (<100 pF typical at 0 V) preserves LIN signal integrity up to 20 kbps; 175 °C rating allows placement near door latch actuators. |
| Advanced Driver Assistance System (ADAS) Camera Power Rail | Electric Power Steering (EPS) Motor Driver Interface |
|
Use Scenario: Guards 5 V or 3.3 V camera module power inputs against coupled transients from nearby high-current solenoids. IC Role / Device Role / Timing Role: Secondary TVS stage after primary bulk protection, providing fine-clamp response for sensitive image sensors and ISP power domains. Use Value: 37.8 V clamping ensures downstream 5 V regulators remain within absolute maximum ratings; low leakage prevents dark current drift in CMOS image sensors. |
Use Scenario: Protects gate driver IC supply and feedback sensing lines in EPS motor control circuits exposed to PWM-induced switching noise. IC Role / Device Role / Timing Role: Placed across VDD/GND of isolated gate drivers to absorb coupling spikes from 400 V traction inverter back-EMF. Use Value: 26.5 mΩ RD minimizes clamping delay, limiting voltage overshoot to <40 V - preserving gate oxide integrity of 650 V SiC MOSFET drivers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar automotive transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ27A | Lower PPP (400 W), higher VCL (45.7 V at 8.8 A), SMC package, no AEC-Q101 qualification | Limited to non-safety-critical 12 V accessories; insufficient for ISO 7637-2 Pulse 1 or load dump | Select only for cost-sensitive consumer-grade modules where automotive qualification is not required. |
| TPSMD27A | Same 27 V VRM, but 6000 W PPP (8/20 µs), 38.9 V VCL at 154 A, AEC-Q101 qualified, same SMC footprint | Higher surge capability suits 24 V commercial truck systems; slightly higher clamping may affect margin for 36 V-rated ICs | Prefer for heavy-duty vehicle platforms requiring >48 kW surge handling; verify layout thermal relief for 175 °C operation. |
Compared with SMAJ27A, SM50T27AY provides 12.5× higher peak power rating and automotive qualification, enabling direct replacement in safety-critical ECUs; versus TPSMD27A, it trades 1.1 V higher clamping for lower dynamic resistance (26.5 mΩ vs. 27.0 mΩ) and tighter VBR tolerance - advantageous for precision rail monitoring.
Availability
SM50T27AY is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera power supplies, and electric power steering interface protection requiring stable component supply across automotive production lifecycles.
Supply support for SM50T27AY 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 intelligent power, analog, MEMS, and microcontroller solutions for automotive, industrial, and consumer markets.
SM50T27AY belongs to the SM50TY series of high-power automotive TVS diodes, engineered specifically for ISO 7637-2 and ISO 16750-2 compliance in harsh-temperature vehicle subsystems - emphasizing long-term reliability under repeated surge stress.
FAQ
What is the maximum clamping voltage of SM50T27AY under a 10/1000 µs surge?
The maximum clamping voltage (VCL) of SM50T27AY is 37.8 V at 135 A under the 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature at a coefficient of 10⁻⁴/°C, reaching approximately 40.2 V at Tj = 175 °C using the formula VCL(Tj) = VCL(25°C) × [1 + αT × (Tj − 25)].
Is SM50T27AY suitable for bidirectional signal line protection?
No - SM50T27AY is a unidirectional TVS diode intended for DC power rail protection (e.g., 12 V battery input). For bidirectional data lines like CAN or LIN, ST offers the complementary SM50T27CAY variant, which features symmetrical breakdown in both polarities and identical surge ratings.
How does SM50T27AY compare to standard SMAJ-series TVS diodes in automotive use?
SM50T27AY delivers 12.5× higher peak pulse power (5000 W vs. 400 W), AEC-Q101 qualification, 175 °C junction rating (vs. 150 °C), and tighter VBR tolerance (±5%) - making it suitable for modern automotive power domains where SMAJ devices would fail under ISO 7637-2 Pulse 1 or load dump conditions.
What PCB layout practices maximize thermal performance for SM50T27AY?
To optimize thermal dissipation, use ≥2 cm² of 70 µm copper area under each lead (per Figure 12), connect both terminals to internal ground/power planes via multiple thermal vias, and avoid narrow traces. The recommended footprint (Figure 24) specifies 5.11 mm × 8.19 mm pad dimensions with 3.14 mm spacing to maintain mechanical stability during reflow.
SM50T27AY Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 23V (Max)
- Voltage - Breakdown (Min):
- 25.7V
- Voltage - Clamping (Max) @ Ipp:
- 37.8V
- Current - Peak Pulse (10/1000µs):
- 135A
- Power - Peak Pulse:
- 5000W (5kW)
- 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
SM50T27AY FAQ
1.How can I place an order for SM50T27AY through Aetrix?
Please submit a Request for Quotation (RFQ) for SM50T27AY 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 SM50T27AY reliable?
The price and inventory of SM50T27AY are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SM50T27AY is usually 5 days.
3.What payment methods are accepted for SM50T27AY?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SM50T27AY transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SM50T27AY?
SM50T27AY orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SM50T27AY 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 SM50T27AY?
For technical support, including SM50T27AY datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SM50T27AY requirements.
6.How does Aetrix verify that SM50T27AY is sourced from the original manufacturer or authorized distributors?
All SM50T27AY 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 SM50T27AY meets industry standards.
7.What is the process for return or replacement of SM50T27AY?
All SM50T27AY units undergo pre-shipment inspection (PSI). If there is an issue with SM50T27AY, 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 SM50T27AY part is unused and in its original packaging.
Return procedure for SM50T27AY:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SM50T27AY Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
