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Diodes Incorporated SMF4L33CA-7
- Part No.:
- SMF4L33CA-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L33CA-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:3,904
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Product details
Overview
SMF4L33CA-7 from Diodes Incorporated is a bi-directional transient voltage suppressor (TVS) diode in DO-219AA package, designed for high-energy ESD and surge protection on power rails and signal lines. It features a 33V working peak reverse voltage (VRWM), 36.7V minimum breakdown voltage (VBR), 53.3V maximum clamping voltage (VC) at 7.5A peak pulse current, and 400W peak pulse power dissipation (10/1000µs waveform). It is used in automotive battery contact protection and industrial power management circuits.
For engineers reviewing the SMF4L33CA-7 datasheet, SMF4L33CA-7 pinout, SMF4L33CA-7 application, or SMF4L33CA-7 equivalent, key selection criteria include clamping voltage under 53.3V at 7.5A, bi-directional polarity for AC-coupled or floating lines, IEC61000-4-2 ±30kV ESD robustness, and DO-219AA footprint compatibility with space-constrained PCB layouts.
Technical Context
This bi-directional TVS operates symmetrically across both polarities, enabling protection of differential or ungrounded signal paths without polarity constraints. Its silicon avalanche structure delivers sub-5ns response time from 0V to VBR min, ensuring suppression before downstream IC damage occurs during fast transients like ESD or inductive switching spikes.
Thermal design is supported by low junction-to-solder-point thermal resistance (RθJS = 70°C/W) and DC power dissipation rating of 1.0W, allowing sustained operation under repetitive low-energy surges. The device is qualified per JEDEC reliability standards and supports automotive-grade variants via Q-suffix derivatives.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33V - Maximum continuous reverse operating voltage before leakage exceeds 0.5μA |
| VBR (min) | 36.7V @ 1mA - Ensures reliable conduction onset above normal system voltage |
| VC (max) | 53.3V @ 7.5A - Clamps transient energy to safe levels for 3.3V–24V logic and power ICs |
| PPK | 400W (10/1000µs) - Handles high-energy surges common in automotive load-dump and ISO 7637-2 pulses |
| ESD Rating | ±30kV air / ±30kV contact (IEC61000-4-2) - Meets stringent end-equipment immunity requirements |
| Package | DO-219AA - Surface-mount, 2.8mm × 1.9mm footprint with 0.6mm height for ultra-thin designs |
| Polarity | Bi-directional - Protects AC signals, differential buses (e.g., CAN, RS-485), or floating power domains |
Pinout & Package
DO-219AA is a two-terminal surface-mount package with no cathode band marking for bi-directional devices. Terminals are symmetrical; either end connects to protected line and ground respectively. The molded plastic body meets UL 94V-0 flammability rating and uses matte tin-plated copper alloy leads solderable per MIL-STD-202.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Transient current path | Either terminal conducts avalanche current bidirectionally during overvoltage events |
| Case (plastic body) | Non-conductive isolation | No electrical connection; provides mechanical mounting and thermal path to PCB copper |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse power | Enables single-device protection against ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 2a (load dump initiation) in 12V automotive systems |
| Sub-5ns response time | Activates before most microcontrollers and transceivers experience latch-up or gate oxide damage during ESD events |
| Bi-directional symmetry | Eliminates orientation concerns during placement and supports protection of differential interfaces without additional components |
| RoHS-compliant & halogen-free | Meets automotive OEM environmental requirements (e.g., GMW3172, Ford WSS-M99P9999-A1) and enables use in green manufacturing |
Applications
| Automotive Battery Protection | Industrial Power Rail Clamp |
|---|---|
Use Scenario: Protection of 12V battery feed lines in infotainment head units against load-dump transients up to 35V for 400ms. IC Role / Device Role / Timing Role: Bi-directional TVS clamps positive and negative excursions simultaneously, absorbing energy before it reaches PMIC input stages. Use Value: Prevents permanent failure of buck converters and LDOs rated for ≤40V absolute maximum input, extending field reliability beyond 10-year vehicle life. | Use Scenario: Surge suppression on 24V PLC I/O module power inputs exposed to inductive kickback from solenoid drivers. IC Role / Device Role / Timing Role: Fast-acting clamp limits voltage overshoot to ≤53.3V during 10/1000µs transients, preserving isolation barrier integrity. Use Value: Reduces need for upstream fusing or redundant clamping, lowering BOM count while maintaining IEC 61000-4-5 Level 3 (1kV/2Ω) compliance. |
| USB-C Port ESD Guard | RS-485 Transceiver Line Protection |
Use Scenario: Secondary ESD protection on USB-C VBUS line after primary front-end filtering, handling ±30kV contact discharge per IEC61000-4-2. IC Role / Device Role / Timing Role: Bi-directional clamping absorbs fast-rising ESD pulses before they couple into USB PD controller or Type-C CC logic. Use Value: Maintains <1pF junction capacitance (per datasheet Fig.3), avoiding signal integrity degradation on 10Gbps SuperSpeed+ lanes. | Use Scenario: Protection of half-duplex RS-485 transceiver A/B differential pair in factory automation gateways subjected to cable-induced surges. IC Role / Device Role / Timing Role: Symmetric clamping ensures equal voltage limiting on both lines, preserving common-mode rejection during 4kV EFT bursts. Use Value: Enables direct connection to unshielded 100m cable runs without external GDT or MOV staging, simplifying layout and reducing cost. |
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; higher RθJA (110°C/W); 53.3V VC same, but 1.5× larger footprint (4.3×2.6mm) | Less suitable for ultra-dense automotive modules where board area is constrained | Select when legacy SMA footprint compatibility is required and thermal margin allows higher junction temperature rise |
| TPSMD33C | DO-214AB package; lower PPK (300W); 53.3V VC; 10% higher IR leakage (5μA vs. 0.5μA) | Marginally adequate for non-automotive consumer applications with lower surge severity | Choose only for cost-sensitive, non-automotive designs where 400W rating is not mandated by system-level test plans |
Compared with SMAJ33CA and TPSMD33C, SMF4L33CA-7 delivers superior power density (400W in 2.8×1.9mm), tighter leakage control (0.5μA), and automotive-qualified reliability-making it optimal for next-generation ADAS domain controllers and compact industrial edge nodes.
Availability
SMF4L33CA-7 is available at Aetrix Electronics and suitable for automotive battery protection, industrial power rail clamping, USB-C port ESD guard, and RS-485 transceiver line protection requiring stable component supply across multi-year production cycles.
Supply support for SMF4L33CA-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 centers across Asia and manufacturing in ASE, J-Devices, and its own facilities.
The SMF4L series belongs to Diodes' high-reliability TVS portfolio, engineered specifically for automotive and industrial environments demanding AEC-Q200 alignment, low clamping voltage, and minimal PCB footprint.
FAQ
What is the maximum clamping voltage of SMF4L33CA-7 at its rated peak pulse current?
The maximum clamping voltage (VC) is 53.3V at 7.5A peak pulse current (10/1000µs waveform), measured per standard TVS test conditions. This value ensures protected downstream components see no more than 53.3V during worst-case surge events, supporting robust design margins for 3.3V–24V logic and power ICs.
Is SMF4L33CA-7 suitable for automotive applications requiring AEC-Q200 qualification?
SMF4L33CA-7 itself is not AEC-Q200 qualified; however, Diodes offers automotive-grade equivalents with Q-suffix (e.g., SMF4L33CAQ-7) that meet AEC-Q200 stress testing, PPAP capability, and IATF 16949 manufacturing certification. These variants share identical electrical specs and DO-219AA packaging.
How does the bi-directional configuration affect PCB layout compared to uni-directional TVS diodes?
Bi-directional configuration eliminates cathode band marking and orientation dependency-either terminal connects to the protected line and the other to ground. This simplifies pick-and-place programming, reduces assembly errors, and enables symmetric routing on differential pairs without polarity-aware trace routing or silkscreen indicators.
What is the thermal resistance from junction to solder point (RθJS) for SMF4L33CA-7, and why does it matter?
RθJS is 70°C/W, representing the thermal path from die junction to the PCB solder joint. This parameter directly impacts steady-state temperature rise under repetitive low-energy surges. With a 1.0W DC power rating, a 70°C/W RθJS limits junction temperature rise to 70°C above ambient-critical for long-term reliability in enclosed automotive enclosures operating up to +105°C ambient.
SMF4L33CA-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:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AA
SMF4L33CA-7 FAQ
1.How can I place an order for SMF4L33CA-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L33CA-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 SMF4L33CA-7 reliable?
The price and inventory of SMF4L33CA-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L33CA-7 is usually 5 days.
3.What payment methods are accepted for SMF4L33CA-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L33CA-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L33CA-7?
SMF4L33CA-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L33CA-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 SMF4L33CA-7?
For technical support, including SMF4L33CA-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L33CA-7 requirements.
6.How does Aetrix verify that SMF4L33CA-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L33CA-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 SMF4L33CA-7 meets industry standards.
7.What is the process for return or replacement of SMF4L33CA-7?
All SMF4L33CA-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L33CA-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 SMF4L33CA-7 part is unused and in its original packaging.
Return procedure for SMF4L33CA-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L33CA-7 Tags
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ESD9B5.0ST5G
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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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