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Diodes Incorporated SMF4L45AQ-7
- Part No.:
- SMF4L45AQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L45AQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:6,231
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Product details
Overview
SMF4L45AQ-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 45V working peak reverse voltage (VRWM), 50V minimum breakdown voltage (VBR), 72.7V maximum clamping voltage (VC) at 5.5A surge current, and AEC-Q101 qualification for under-hood and battery-contact applications.
For engineers reviewing the SMF4L45AQ-7 datasheet, SMF4L45AQ-7 pinout, SMF4L45AQ-7 application, or SMF4L45AQ-7 equivalent, key selection criteria include clamping performance at 10/1000µs waveform, IEC61000-4-2 ±30kV ESD robustness, DO-219AA package thermal resistance (RθJA = 96°C/W), and unidirectional polarity marking with cathode band.
Technical Context
This TVS operates as a fast-acting shunt protector that remains high-impedance below VRWM (45V) and clamps transients above VBR (50V min) to ≤72.7V at 5.5A. Its sub-1ns response time ensures suppression before downstream IC damage occurs in automotive power management circuits.
The device uses silicon avalanche junction technology in a planar construction, optimized for low capacitance (<100pF at 1MHz) and stable leakage (<0.5μA at VRWM). Thermal design leverages the DO-219AA package's 70°C/W junction-to-solder-point resistance for reliable operation up to +175°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 45V - Maximum continuous reverse operating voltage before clamping begins; sets safe margin above 36V automotive nominal systems. |
| VBR (min) | 50V - Minimum breakdown voltage at 1mA test current; defines onset of avalanche conduction during overvoltage events. |
| VC (max) | 72.7V - Maximum clamped voltage at 5.5A IPP; determines peak stress imposed on protected circuitry during 10/1000µs surge. |
| PPK | 400W - Peak pulse power rating per 10/1000µs waveform; enables robust protection against ISO 7637-2 pulse 1, 2a, and 5a transients. |
| IR (max) | 0.5μA - Maximum reverse leakage at VRWM; ensures minimal standby power loss in always-on vehicle modules. |
| TJ Range | −55°C to +175°C - Extended junction temperature range supports engine bay, battery terminal, and ADAS ECU placement. |
| AEC-Q101 | Qualified - Validated for automotive use per stress test requirements including HTOL, TCT, and ESD; PPAP-capable with IATF 16949 manufacturing. |
Pinout & Package
Package: DO-219AA - Surface-mount, flat lead, green molded plastic case (UL 94V-0), 0.016g weight, moisture sensitivity level 1. Cathode band denotes unidirectional polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or low-impedance return path; forms shunt path during overvoltage event. |
| Cathode | High-side connection point | Connected to protected line (e.g., 45V rail); cathode band identifies this terminal visually. |
Key Features
| Feature | Design Value |
|---|---|
| IEC61000-4-2 ESD Protection | ±30kV air discharge, ±30kV contact discharge - eliminates need for external ESD diodes in infotainment and body control modules. |
| Fast Response Time | <1.0ns (unidirectional) - triggers before most microcontroller I/O pins can be damaged by EFT or lightning-induced surges. |
| Lead-Free & Halogen-Free | RoHS 3 compliant, Br+Cl <1500ppm, Sb <1000ppm - meets global automotive environmental mandates without compromising surge capability. |
| Thermal Performance | RθJS = 70°C/W - enables direct mounting to copper pour for effective heat dissipation in space-constrained PCB layouts. |
| Stable Clamping Ratio | VC/VBR = 1.45 - tight ratio ensures predictable voltage limiting across production lot and temperature range (−55°C to +175°C). |
Applications
| Battery Management System (BMS) Voltage Monitoring | Automotive Infotainment Power Rail |
|---|---|
Use Scenario: Protects analog front-end inputs of BMS cell voltage monitors from load dump and jump-start transients. IC Role / Device Role / Timing Role: Shunt TVS placed between sense line and ground, clamping spikes before they reach precision ADC inputs. Use Value: Maintains measurement accuracy by limiting input voltage to ≤72.7V during 400W surges, preventing ADC saturation or latch-up. |
Use Scenario: Safeguards 5V/12V power inputs to head unit SoCs and display drivers against ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main DC-DC converter output, coordinated with upstream fuse and downstream ceramic capacitors. Use Value: Enables compliance with CISPR 25 Class 5 radiated emissions by suppressing high-frequency ringing induced by transient clamping. |
| Engine Control Unit (ECU) Sensor Interface | ADAS Camera Module Power Input |
Use Scenario: Shields LIN/CAN transceiver supply pins and analog sensor inputs (e.g., MAP, O2) from ignition noise and alternator ripple. IC Role / Device Role / Timing Role: Localized TVS at connector entry point, placed immediately before ESD protection diode array and LDO regulator. Use Value: Prevents false triggering of fault diagnostics by holding sensor reference voltage within ±5% tolerance during 100ns-fast transients. |
Use Scenario: Protects 3.3V/5V camera module power input from hot-swap surges and cable ESD during rear-view camera installation. IC Role / Device Role / Timing Role: First-line defense on power entry, sized to absorb 30kV contact ESD without degradation over 10,000 insertion cycles. Use Value: Extends field lifetime by eliminating infant mortality failures caused by repeated electrostatic discharge at vehicle service points. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ45A | Same VRWM (45V), but SMA package (RθJA = 110°C/W), lower PPK (400W same), higher VC (73V) | Larger footprint (SMA vs DO-219AA), less suitable for dense ADAS PCBs requiring thermal efficiency | Prefer SMF4L45AQ-7 when board space or thermal resistance is constrained; SMAJ45A acceptable for non-automotive industrial use. |
| TPSMD45A | DO-214AB package, identical VRWM/VC, but not AEC-Q101 qualified and higher IR (1.0μA) | Lacks automotive qualification and fails PPAP documentation requirements for Tier 1 OEMs | Select SMF4L45AQ-7 for automotive production; TPSMD45A only for cost-sensitive consumer or industrial prototypes. |
Compared with SMAJ45A and TPSMD45A, SMF4L45AQ-7 delivers superior thermal performance (RθJA = 96°C/W), guaranteed AEC-Q101 compliance, and tighter leakage control (0.5μA), making it the sole choice for safety-critical automotive power rail protection where long-term reliability and qualification traceability are mandatory.
Availability
SMF4L45AQ-7 is available at Aetrix Electronics and suitable for automotive battery management, infotainment power conditioning, and ADAS camera module protection requiring stable component supply across multi-year vehicle production cycles.
Supply support for SMF4L45AQ-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, specializing in high-reliability components for automotive, industrial, and computing markets with IATF 16949-certified facilities.
The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive power line and interface protection where compact size, low clamping voltage, and extended temperature operation are critical.
FAQ
What is the polarity configuration of SMF4L45AQ-7?
SMF4L45AQ-7 is a unidirectional TVS diode, identified by a visible cathode band on the DO-219AA package. It conducts only during reverse-biased overvoltage events, with anode tied to ground and cathode connected to the protected line. This configuration provides lower leakage and tighter clamping than bidirectional variants at the same VRWM.
Does SMF4L45AQ-7 meet automotive ESD standards?
Yes - SMF4L45AQ-7 is certified to IEC61000-4-2 Level 4 for both air discharge (±30kV) and contact discharge (±30kV). Its low capacitance (<100pF) and sub-1ns response ensure effective suppression of ESD events without signal integrity degradation on high-speed automotive interfaces like LVDS or FPD-Link.
How does the DO-219AA package improve thermal performance over SMA?
The DO-219AA package reduces thermal resistance by 14°C/W versus SMA (RθJA = 96°C/W vs 110°C/W) due to its shorter internal leadframe path and larger copper exposure area. This allows sustained 400W pulse handling at higher ambient temperatures and improves long-term reliability in engine compartment applications.
Can SMF4L45AQ-7 replace older SMF4L45A parts in existing designs?
Yes - SMF4L45AQ-7 is a direct replacement for SMF4L45A with identical electrical specs, DO-219AA mechanical outline, and enhanced process controls. The "Q" suffix denotes AEC-Q101 qualification and PPAP capability; no layout or firmware changes are required for drop-in migration in automotive production.
SMF4L45AQ-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):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.7V
- Current - Peak Pulse (10/1000µs):
- 5.5A
- 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
SMF4L45AQ-7 FAQ
1.How can I place an order for SMF4L45AQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L45AQ-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 SMF4L45AQ-7 reliable?
The price and inventory of SMF4L45AQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L45AQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L45AQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L45AQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L45AQ-7?
SMF4L45AQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L45AQ-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 SMF4L45AQ-7?
For technical support, including SMF4L45AQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L45AQ-7 requirements.
6.How does Aetrix verify that SMF4L45AQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L45AQ-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 SMF4L45AQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L45AQ-7?
All SMF4L45AQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L45AQ-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 SMF4L45AQ-7 part is unused and in its original packaging.
Return procedure for SMF4L45AQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L45AQ-7 Tags
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