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Diodes Incorporated SMF4L33CAQ-7
- Part No.:
- SMF4L33CAQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L33CAQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:9,673
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Product details
Overview
SMF4L33CAQ-7 from Diodes Incorporated is a bi-directional transient voltage suppressor (TVS) diode designed for automotive-grade overvoltage protection in low-voltage signal and power lines. It features a 33 V working peak reverse voltage (VRWM), 36.7–40.6 V breakdown voltage (VBR), 53.3 V maximum clamping voltage (VC) at 7.5 A surge current, and 400 W peak pulse power rating per 10/1000 µs waveform - deployed in battery contact and ECU power rail protection.
For engineers reviewing the SMF4L33CAQ-7 datasheet, SMF4L33CAQ-7 pinout, SMF4L33CAQ-7 application, or SMF4L33CAQ-7 equivalent, this device is selected for AEC-Q101-compliant transient suppression where fast response (<5 ns), ±30 kV IEC61000-4-2 ESD robustness, and DO-219AA space-constrained packaging are required in automotive body electronics and infotainment subsystems.
Technical Context
This bi-directional TVS operates symmetrically across both polarities, enabling clamping of positive and negative transients without polarity dependency. Its silicon avalanche structure delivers sub-5 ns response from 0 V to VBR, with thermal resistance RθJA = 96 °C/W on standard FR-4 PCB layout.
The device sustains 40 A peak forward surge current (IFSM) under 8.3 ms half-sine stress and maintains <0.5 µA reverse leakage at VRWM, ensuring minimal standby power impact in always-on vehicle modules. It is rated for operation from –55 °C to +175 °C and qualified to AEC-Q101 with PPAP support.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33 V - Maximum continuous reverse operating voltage before clamping initiates; sets threshold for battery-supplied 12 V systems. |
| VBR (min/max) | 36.7 V / 40.6 V - Breakdown occurs within this range at 1 mA test current; defines guaranteed conduction onset under surge. |
| VC @ IRSM | 53.3 V at 7.5 A - Clamping voltage during worst-case transient; limits downstream IC stress to safe levels in 33 V-rated circuits. |
| PPK | 400 W - Peak pulse power handling per 10/1000 µs waveform; supports ISO 7637-2 Pulse 1/2/5a surge immunity compliance. |
| ESD Rating | ±30 kV air / ±30 kV contact per IEC61000-4-2 - Enables direct interface with exposed connectors without external ESD staging. |
| Operating Temp | –55 °C to +175 °C - Validated for under-hood and transmission control unit environments with high thermal cycling demand. |
| AEC-Q101 | Qualified - Meets automotive reliability stress testing including HTGB, HTRB, and temperature cycling for safety-critical applications. |
Pinout & Package
Package: DO-219AA - ultra-compact surface-mount molded plastic case (2.80 mm × 1.90 mm × 0.60 mm), halogen-free, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient return path (bi-directional) | Connects to protected line; conducts during negative surges and provides reference for clamping symmetry. |
| Cathode | Transient return path (bi-directional) | Connects to protected line; conducts during positive surges; no cathode band marking confirms bi-directional configuration. |
Key Features
| Feature | Design Value |
|---|---|
| Bi-directional clamping | Enables single-device protection of AC-coupled or floating signal lines (e.g., LIN bus, sensor differential pairs) without polarity concerns. |
| 400 W 10/1000 µs rating | Withstands repetitive load dump and alternator ripple events in 12 V automotive systems without degradation. |
| ±30 kV IEC61000-4-2 ESD | Eliminates need for upstream ESD diodes in USB-C, CAN FD, or display interface ports exposed to user handling. |
| DO-219AA footprint | Reduces PCB area by 40% vs. SMA; compatible with automated placement and reflow, supporting high-volume automotive module assembly. |
| AEC-Q101 qualification | Validates long-term reliability under thermal shock, humidity, and vibration - required for Tier-1 supplier BOM acceptance. |
Applications
| Automotive Body Control Module (BCM) | Infotainment Display Interface |
|---|---|
Use Scenario: Protects LIN bus transceivers and door actuator drivers from battery load dump and ESD events during service. IC Role / Device Role / Timing Role: Bi-directional TVS placed directly at connector entry point to clamp transients before reaching MCU GPIO or transceiver inputs. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V logic interfaces while maintaining signal integrity up to 20 kbps LIN data rate. |
Use Scenario: Shields MIPI DSI or LVDS video lines between head unit and TFT display from hot-plug ESD and cable-induced surges. IC Role / Device Role / Timing Role: Low-capacitance bi-directional TVS mounted adjacent to display connector to suppress ±30 kV contact discharge without distorting 1+ Gbps video signals. Use Value: Achieves <0.5 pF typical junction capacitance (per datasheet Fig. 5 at 33 V), minimizing signal rise-time degradation. |
| Engine Control Unit (ECU) Power Rail | Telematics Cellular Antenna Port |
Use Scenario: Guards 5 V/3.3 V regulator inputs against ISO 7637-2 Pulse 5a (load dump) transients up to 60 V peak. IC Role / Device Role / Timing Role: Primary clamping device placed after input fuse and before DC-DC converter, sized to absorb 400 W surge energy. Use Value: Limits voltage seen by LDOs to ≤53.3 V, preventing overvoltage shutdown and enabling single-stage protection architecture. |
Use Scenario: Protects LTE/GNSS front-end LNA inputs from ESD during SIM card insertion or antenna handling in connected car modules. IC Role / Device Role / Timing Role: Bi-directional TVS integrated into RF matching network PCB layout near SMA connector, co-located with DC blocking cap. Use Value: Maintains RF insertion loss <0.3 dB up to 3 GHz due to ultra-low parasitic inductance of DO-219AA package and symmetrical layout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bi-directional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33CA | DO-214AC package; 600 W PPK; higher VC = 53.3 V same, but larger footprint (4.5 mm × 2.7 mm) and RθJA = 50 °C/W. | Used in industrial power supplies where board space is less constrained and thermal mass supports higher steady-state dissipation. | Select when higher surge margin is needed and DO-219AA size is not mandatory; avoid in AEC-Q101-restricted automotive designs. |
| TPSMD33C | Texas Instruments part; DO-214AB; 400 W PPK; VC = 53.3 V; but only AEC-Q200 qualified (not Q101), and no PPAP documentation available. | Deployed in non-safety-critical consumer telematics modules where automotive qualification depth is relaxed. | Acceptable for cost-sensitive aftermarket units; reject for OEM ECU or ADAS-related BOMs requiring full AEC-Q101 traceability. |
Compared with SMAJ33CA and TPSMD33C, SMF4L33CAQ-7 uniquely combines AEC-Q101 qualification, DO-219AA miniaturization, and full PPAP support - making it the only option for space-constrained, production-grade automotive electronics requiring zero-defect reliability and audit-ready compliance.
Availability
SMF4L33CAQ-7 is available at Aetrix Electronics and suitable for automotive body electronics, infotainment interface protection, and engine control unit power rail stabilization requiring stable component supply across multi-year vehicle production cycles.
Supply support for SMF4L33CAQ-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 the Americas.
The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive transient suppression where compact size, high ESD robustness, and thermal resilience in under-hood environments are critical.
FAQ
Is SMF4L33CAQ-7 unidirectional or bidirectional?
SMF4L33CAQ-7 is a bi-directional TVS diode, confirmed by its part number suffix "CAQ" (C = bi-directional), absence of cathode band marking, and symmetric electrical characteristics in both polarities - enabling clamping of positive and negative transients on the same line without polarity orientation constraints.
What is the maximum clamping voltage at rated surge current?
The maximum clamping voltage (VC) is 53.3 V at 7.5 A peak reverse surge current (IRSM), measured per the 10/1000 µs waveform defined in IEC 61000-4-5. This value is guaranteed across the full operating temperature range and ensures downstream 33 V-rated components remain within safe operating limits during transient events.
Does SMF4L33CAQ-7 require derating at elevated ambient temperatures?
Yes - peak pulse power must be derated linearly above +25°C ambient, per Figure 1 in DS43393 Rev. 3-2. At +125°C, the device retains ~65% of its 400 W rating (≈260 W); at +150°C, it retains ~45% (≈180 W). Derating ensures junction temperature remains below 175°C under worst-case surge conditions.
Can SMF4L33CAQ-7 replace SMAJ33CA in an existing design?
Direct replacement requires PCB pad redesign due to DO-219AA (2.8 mm × 1.9 mm) vs. DO-214AC (4.5 mm × 2.7 mm) footprint mismatch. Electrical parameters align closely (same VRWM, VBR, VC), but thermal performance differs: DO-219AA has higher RθJA (96 °C/W vs. 50 °C/W), necessitating layout review for sustained surge duty cycles.
SMF4L33CAQ-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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 7.5A
- 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
SMF4L33CAQ-7 FAQ
1.How can I place an order for SMF4L33CAQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L33CAQ-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 SMF4L33CAQ-7 reliable?
The price and inventory of SMF4L33CAQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L33CAQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L33CAQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L33CAQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L33CAQ-7?
SMF4L33CAQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L33CAQ-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 SMF4L33CAQ-7?
For technical support, including SMF4L33CAQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L33CAQ-7 requirements.
6.How does Aetrix verify that SMF4L33CAQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L33CAQ-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 SMF4L33CAQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L33CAQ-7?
All SMF4L33CAQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L33CAQ-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 SMF4L33CAQ-7 part is unused and in its original packaging.
Return procedure for SMF4L33CAQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L33CAQ-7 Tags
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