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Diodes Incorporated SMF4L40AQ-7
- Part No.:
- SMF4L40AQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L40AQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:4,719
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Product details
Overview
SMF4L40AQ-7 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for automotive-grade overvoltage protection in power rails and signal lines. It features a 40V working peak reverse voltage (VRWM), 44.4–49.1V breakdown voltage (VBR), 64.5V maximum clamping voltage (VC) at 6.2A surge current, and AEC-Q101 qualification for under-hood and battery-contact applications.
For engineers reviewing the SMF4L40AQ-7 datasheet, SMF4L40AQ-7 pinout, SMF4L40AQ-7 application, or SMF4L40AQ-7 equivalent, key selection criteria include clamping performance at 6.2A, unidirectional polarity with cathode band marking, DO-219AA package thermal resistance (RθJA = 96°C/W), and IEC61000-4-2 ±30kV ESD robustness.
Technical Context
This TVS operates as a fast-acting shunt clamp during transients, triggering when reverse voltage exceeds its 44.4V minimum breakdown threshold and limiting downstream voltage to ≤64.5V at 6.2A. Its <1.0ns response time ensures protection against ESD and ISO 7637-2 pulse 1/2a/3a surges before sensitive circuitry is damaged.
The device uses planar junction silicon construction in a low-inductance DO-219AA molded plastic package with matte tin-plated copper alloy leads. Thermal design is supported by RθJC = 18°C/W and RθJS = 70°C/W, enabling reliable operation from –55°C to +175°C ambient in high-vibration automotive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power | 400W (10/1000µs waveform); sustains single high-energy transients without failure |
| Working Peak Reverse Voltage | 40V; maximum continuous DC or RMS reverse voltage before leakage exceeds 0.5µA |
| Breakdown Voltage (VBR) | 44.4–49.1V @ 1mA; precise conduction onset ensures predictable clamping margin |
| Clamping Voltage (VC) | 64.5V @ 6.2A; limits protected circuit voltage during worst-case surge event |
| ESD Rating | ±30kV air / ±30kV contact per IEC61000-4-2; eliminates need for secondary ESD stages |
| AEC-Q101 Qualified | Validated for automotive use including temperature cycling, mechanical shock, and humidity testing |
| Package | DO-219AA; 2.8mm × 1.9mm footprint with 0.6mm lead length supports high-density PCB layouts |
Pinout & Package
Package: DO-219AA - surface-mount, low-profile (max height 0.75mm), cathode-band marked unidirectional configuration with two terminals: anode and cathode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line-side connection | Connected to protected line (e.g., 12V battery rail); conducts during forward surge events only if misapplied |
| Cathode | Output/Ground-side connection | Marked with band; ties to system ground or low-impedance return path to complete clamping loop |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q101 compliant with PPAP capability and IATF 16949 manufacturing control |
| Green packaging | Halogen- and antimony-free molding compound (Br+Cl <1500ppm, Sb <1000ppm), RoHS 3 compliant |
| Fast transient response | <1.0ns turn-on time from 0V to VBR ensures protection before IC latch-up or damage |
| Thermal reliability | RθJA = 96°C/W on 1"×1" FR-4 board enables stable operation up to +175°C junction temperature |
| Low leakage | 0.5µA max reverse leakage at 40V VRWM minimizes standby power loss in always-on systems |
Applications
| Automotive Power Rail Protection | USB-C Port ESD Clamping |
|---|---|
|
Use Scenario: 12V/24V battery feed lines exposed to load dump and jump-start transients in engine control units. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between battery input and DC-DC converter input stage. Use Value: Clamps ISO 7637-2 Pulse 1 (–150V/2Ω) to ≤64.5V, preventing regulator overvoltage shutdown and MCU brownout. |
Use Scenario: High-speed USB-C receptacle on infotainment head unit subject to user-hand ESD events. IC Role / Device Role / Timing Role: Primary ESD clamp on VBUS line upstream of USB PD controller and power switch. Use Value: Absorbs ±30kV contact discharge without degradation, maintaining VBUS regulation integrity during hot-plug cycles. |
| Industrial Sensor Interface Protection | Telematics LTE Antenna Feed Protection |
|
Use Scenario: 4–20mA analog sensor loop connected to CAN gateway in harsh factory environments. IC Role / Device Role / Timing Role: Bidirectional-capable variant used (SMF4L40CAQ-7), but unidirectional SMF4L40AQ-7 applied where polarity is fixed. Use Value: Limits induced lightning surges to <65V, preserving 24V loop supply stability and ADC reference accuracy. |
Use Scenario: LTE antenna feed line in vehicle telematics module exposed to RF coupling and static discharge. IC Role / Device Role / Timing Role: Series-shunt TVS configuration with low capacitance (typ. 150pF at 1MHz) minimizing RF insertion loss. Use Value: Maintains VSWR <2.0 across 700MHz–2.7GHz while suppressing ESD-induced front-end LNA damage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A | Same 40V VRWM, but SMA package (larger footprint, higher RθJA = 110°C/W) | Less suitable for space-constrained automotive modules; lower thermal efficiency on dense PCBs | Select when legacy layout compatibility or higher surge margin (400W same rating) outweighs size constraints |
| TPSMD40A | DO-214AB package, 65V VC @ 6.2A (higher clamping), 100pF typical capacitance | Better for RF-sensitive lines due to lower capacitance; less effective clamping on 12V rails | Prefer for antenna or high-speed data lines where low Cj matters more than absolute VC minimization |
Compared with SMAJ40A and TPSMD40A, SMF4L40AQ-7 delivers superior thermal performance in minimal area (DO-219AA), tighter clamping (64.5V vs. ≥65V), and automotive-specific qualification-making it optimal for next-gen compact ECU and ADAS power domains.
Availability
SMF4L40AQ-7 is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and USB-C power delivery systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMF4L40AQ-7 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive power-line and interface protection where reliability, small size, and high surge immunity are mandatory.
FAQ
What is the maximum operating temperature for SMF4L40AQ-7?
The SMF4L40AQ-7 is rated for junction temperatures from –55°C to +175°C, with derated peak pulse power above +25°C ambient per Figure 1 in DS43393. Its RθJA of 96°C/W allows sustained operation at +125°C board temperature when mounted on standard FR-4 with 2 oz. copper.
Is SMF4L40AQ-7 bidirectional or unidirectional?
SMF4L40AQ-7 is unidirectional, indicated by the cathode band marking on the DO-219AA package. It conducts only during reverse overvoltage events and blocks forward current beyond VF ≈ 3V at 16A. For bidirectional protection, the functionally matched part is SMF4L40CAQ-7.
How does SMF4L40AQ-7 compare to standard SMAJ devices in surge handling?
Both deliver 400W peak pulse power, but SMF4L40AQ-7 achieves this in a 30% smaller DO-219AA package with lower thermal resistance (RθJA = 96°C/W vs. SMAJ's 110°C/W) and tighter clamping (64.5V vs. typically 67–69V), improving protection margin in thermally constrained automotive modules.
Can SMF4L40AQ-7 be used in non-automotive applications?
Yes-it is widely deployed in industrial power supplies, medical equipment, and telecom infrastructure where AEC-Q101 qualification provides assurance of robustness, long-term reliability, and resistance to thermal cycling, vibration, and humidity-even outside automotive end markets.
SMF4L40AQ-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-219AA
- Series:
- SMF4L
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 6.2A
- Power - Peak Pulse:
- 400W
- 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:
- DO-219AA
SMF4L40AQ-7 FAQ
1.How can I place an order for SMF4L40AQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L40AQ-7 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 SMF4L40AQ-7 reliable?
The price and inventory of SMF4L40AQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L40AQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L40AQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L40AQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L40AQ-7?
SMF4L40AQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L40AQ-7 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 SMF4L40AQ-7?
For technical support, including SMF4L40AQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L40AQ-7 requirements.
6.How does Aetrix verify that SMF4L40AQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L40AQ-7 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 SMF4L40AQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L40AQ-7?
All SMF4L40AQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L40AQ-7, 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 SMF4L40AQ-7 part is unused and in its original packaging.
Return procedure for SMF4L40AQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L40AQ-7 Tags
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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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Diodes Incorporated
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Diodes Incorporated
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