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Diodes Incorporated SMF4L51A-7
- Part No.:
- SMF4L51A-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L51A-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:6,395
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Product details
Overview
SMF4L51A-7 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 51V working peak reverse voltage (VRWM), 56.7V minimum breakdown voltage (VBR), 82.4V maximum clamping voltage (VC) at 4.9A surge current, and sub-1ns response time - deployed in automotive battery interfaces, industrial power supplies, and USB-C port protection.
For engineers reviewing the SMF4L51A-7 datasheet, SMF4L51A-7 pinout, SMF4L51A-7 application, or SMF4L51A-7 equivalent, key selection criteria include clamping performance under IEC 61000-4-2 ±30kV ESD, DO-219AA package thermal resistance (RθJA = 96°C/W), unidirectional polarity marking, and compliance with AEC-Q200-referenced reliability standards.
Technical Context
This TVS operates as a voltage-clamped shunt protector: when transient voltage exceeds VBR (56.7V min), it avalanches into low-impedance conduction to divert surge current away from downstream circuitry. Its unidirectional configuration enables integration on positive-rail-only paths without reverse-bias leakage concerns.
The device sustains 400W peak pulse power (10/1000µs waveform) while maintaining <0.5µA reverse leakage at VRWM and delivering 82.4V clamping at 4.9A - critical for protecting 48V automotive subsystems and 24–60V industrial controllers against ISO 7637-2 pulses and EFT bursts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 51V - Maximum continuous DC operating voltage before clamping begins; sets safe margin above nominal 48V rail. |
| VBR (min) | 56.7V - Minimum breakdown voltage at 1mA test current; defines earliest avalanche onset for predictable protection threshold. |
| VC (max) | 82.4V - Maximum clamping voltage at 4.9A IPP; ensures protected ICs see no more than 82.4V during worst-case surge. |
| PPK | 400W - Peak pulse power handling (10/1000µs waveform); supports high-energy transients like load dump in automotive systems. |
| IR @ VRWM | <0.5µA - Reverse leakage current at rated VRWM; minimizes standby power loss in always-on circuits. |
| Response Time | <1.0ns - Time from 0V to VBR under unidirectional surge; fast enough to protect high-speed logic and analog front-ends. |
| ESD Rating | ±30kV contact/air per IEC 61000-4-2 - Enables single-device ESD hardening for connectors and ports without external RC networks. |
Pinout & Package
Package: DO-219AA - ultra-compact surface-mount plastic package (2.80mm × 1.90mm × 0.60mm height), matte tin-plated copper alloy lead frame, RoHS-compliant and halogen-free, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or negative rail; forms return path for clamped surge current. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 48V supply rail); cathode band marks polarity for unidirectional operation. |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse power rating | Enables protection against high-energy transients including ISO 7637-2 Pulse 5a (load dump) in 12V/24V/48V automotive systems. |
| 82.4V clamping at 4.9A | Provides defined overvoltage ceiling for downstream 65V-rated MOSFETs, gate drivers, and microcontrollers. |
| ±30kV IEC 61000-4-2 ESD immunity | Eliminates need for additional ESD diodes on board-level interfaces such as CAN FD, LIN, or sensor inputs. |
| DO-219AA footprint | Reduces PCB area by >40% vs. SMA/SMB packages while maintaining thermal performance via low RθJC (18°C/W). |
| Unidirectional polarity with cathode band | Prevents accidental reverse biasing in DC applications and avoids leakage-induced power drain in always-on monitoring circuits. |
Applications
| Automotive Battery Interface | Industrial 48V Power Supply |
|---|---|
Use Scenario: Protection of body control module (BCM) power input against load dump and jump-start surges. IC Role / Device Role / Timing Role: Shunt TVS placed between battery rail and DC-DC converter input to clamp transients before they reach regulation stage. Use Value: Limits voltage excursion to ≤82.4V during 120V/50ms load dump events, preserving 100V-input buck converters and preventing latch-up in MCU power domains. |
Use Scenario: Surge suppression on output rail of programmable 48V industrial power supply feeding PLC I/O modules. IC Role / Device Role / Timing Role: Primary overvoltage clamp on regulated 48V output, coordinated with OVP comparator and shutdown logic. Use Value: Maintains system uptime by absorbing repetitive 400W surges without degradation, meeting IEC 61000-4-4 Level 4 (4kV EFT) immunity requirements. |
| USB-C Power Delivery Port | Smart Sensor Node Input |
Use Scenario: Input protection for USB-C PD controller and CC logic on host devices supporting 20V/5A PPS. IC Role / Device Role / Timing Role: First-line TVS on VBUS line, upstream of e-marked cable detection and sink negotiation circuitry. Use Value: Clamps hot-plug transients and ESD events to <82.4V within 1ns, preventing damage to 20V-tolerant PD controllers and preserving USB-IF certification. |
Use Scenario: Protection of analog input of industrial temperature/humidity sensor node powered from 24V field bus. IC Role / Device Role / Timing Role: Rail-to-rail TVS on sensor supply line, placed adjacent to LDO input to prevent overvoltage propagation. Use Value: Blocks induced lightning surges (per IEC 61000-4-5) up to 400W while adding only 0.5µA leakage - extending 10-year battery life in wireless nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51A | Same 51V VRWM, but SMA package (larger footprint, RθJA = 100°C/W), 400W rating, unidirectional. | Less suitable for space-constrained automotive modules; higher thermal resistance limits sustained surge duty cycle. | Select when legacy PCB layout prohibits DO-219AA rework and thermal derating is acceptable. |
| SMF4L51CA | Bidirectional variant (no cathode band), identical VRWM/VBR/VC specs, same DO-219AA package. | Required for AC-coupled or dual-polarity signal lines (e.g., RS-485, CAN bus), not for DC rail protection. | Choose only when protecting symmetric differential signals or floating rails where reverse conduction must be supported. |
Compared with SMAJ51A and SMF4L51CA, SMF4L51A-7 delivers superior board-area efficiency and lower thermal resistance in unidirectional DC applications - making it optimal for next-gen automotive ECUs and compact industrial power modules where size and thermal headroom are critical.
Availability
SMF4L51A-7 is available at Aetrix Electronics and suitable for automotive battery management, industrial 48V power distribution, and USB-C PD port protection requiring stable component supply across multi-year production cycles.
Supply support for SMF4L51A-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 protection, power management, and signal integrity solutions for automotive, industrial, and computing markets.
The SMF4L series belongs to Diodes' high-power TVS portfolio engineered specifically for AEC-Q200-aligned automotive and harsh-environment industrial applications - emphasizing low clamping, fast response, and green packaging.
FAQ
What is the maximum clamping voltage of SMF4L51A-7 at its rated peak pulse current?
The maximum clamping voltage (VC) is 82.4V at 4.9A peak pulse current (IPP), measured using the standard 10/1000µs double-exponential waveform. This value is guaranteed across the full operating temperature range (−55°C to +175°C) and defines the upper voltage limit imposed on protected circuitry during surge events.
Is SMF4L51A-7 suitable for automotive applications requiring AEC-Q200 qualification?
Yes - SMF4L51A-7 is manufactured in IATF 16949-certified facilities and qualified to JEDEC standards referenced in AEC-Q200 for high-reliability operation. While the standard part number does not carry a Q-suffix, it meets the stress-test requirements and failure mechanisms criteria for Grade 1 (−40°C to +125°C) and Grade 0 (−55°C to +175°C) applications.
How does the DO-219AA package of SMF4L51A-7 compare thermally to SMA or SMB packages?
The DO-219AA package delivers RθJA = 96°C/W (on 1"×1" FR-4 with 2 oz. Cu), significantly better than SMA (RθJA ≈ 100°C/W) and comparable to SMB. Its low RθJC = 18°C/W enables efficient heat transfer from die to PCB, supporting higher surge repetition rates in thermally constrained layouts like automotive junction boxes.
Can SMF4L51A-7 replace SMF4L51CA in a bidirectional signal line?
No - SMF4L51A-7 is unidirectional (cathode-banded) and blocks reverse current beyond VRWM; using it on AC or bidirectional lines (e.g., CAN, RS-485) would cause forward conduction and potential damage. SMF4L51CA is the correct bidirectional variant with symmetrical clamping in both directions and no polarity marking.
SMF4L51A-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):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- 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
SMF4L51A-7 FAQ
1.How can I place an order for SMF4L51A-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L51A-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 SMF4L51A-7 reliable?
The price and inventory of SMF4L51A-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L51A-7 is usually 5 days.
3.What payment methods are accepted for SMF4L51A-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L51A-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L51A-7?
SMF4L51A-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L51A-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 SMF4L51A-7?
For technical support, including SMF4L51A-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L51A-7 requirements.
6.How does Aetrix verify that SMF4L51A-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L51A-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 SMF4L51A-7 meets industry standards.
7.What is the process for return or replacement of SMF4L51A-7?
All SMF4L51A-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L51A-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 SMF4L51A-7 part is unused and in its original packaging.
Return procedure for SMF4L51A-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L51A-7 Tags
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Diodes Incorporated
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