My Inquiry
My Account
Diodes Incorporated SMF4L78A-7
- Part No.:
- SMF4L78A-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L78A-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:7,072
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF4L78A-7 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode with a 78V working peak reverse voltage, 86.7V minimum breakdown voltage, and 126V maximum clamping voltage at 1A surge current. It delivers 3.2μA reverse leakage at VRWM and features sub-1ns response time for ESD protection in power rails and battery interfaces.
For engineers reviewing the SMF4L78A-7 datasheet, SMF4L78A-7 pinout, SMF4L78A-7 application, or SMF4L78A-7 equivalent, key selection criteria include clamping voltage margin relative to system rail voltage, IEC 61000-4-2 ±30kV air/contact ESD compliance, DO-219AA package thermal performance (RθJA = 96°C/W), and unidirectional polarity marking for correct PCB orientation.
Technical Context
This TVS operates as a voltage-clamped overvoltage protector in series with DC power paths. Its silicon avalanche structure triggers at VBR ≥ 86.7V and limits transient energy by shunting up to 43.8A peak pulse current (10/1000µs waveform) while holding VC ≤ 126V - ensuring downstream ICs remain below absolute maximum ratings during lightning-induced surges or load dump events.
Designed for high-reliability industrial and automotive environments, it meets JEDEC reliability standards and supports AEC-Q qualified variants. The unidirectional configuration provides forward conduction path for reverse-polarity protection when used with series blocking diodes, while its DO-219AA package enables compact layout on FR-4 PCBs with 2 oz. copper pads.
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 | 78V: maximum continuous DC voltage applied without significant leakage |
| Breakdown Voltage (Min) | 86.7V @ 1mA: guaranteed avalanche initiation threshold under test conditions |
| Clamping Voltage (Max) | 126V @ 1A: maximum voltage seen by protected circuit during specified surge |
| ESD Rating | ±30kV air / ±30kV contact per IEC 61000-4-2: meets Level 4 immunity requirements |
| Response Time | <1.0ns (unidirectional): ensures clamping activation before sensitive logic is damaged |
| Reverse Leakage | 3.2μA @ 78V: minimal standby power loss in always-on battery systems |
Pinout & Package
Package: DO-219AA - ultra-compact surface-mount molded plastic case (1.90mm × 2.80mm × 3.80mm), halogen-free, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input side of unidirectional TVS | Connected to protected line; conducts during reverse overvoltage |
| Cathode | Output/reference side | Marked with cathode band; tied to system ground or lower-potential rail |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse rating | Enables robust protection against ISO 7637-2 Load Dump (Test Pulse 5a) in 24V automotive systems |
| DO-219AA footprint | Reduces board area by ~40% vs. SMA packages while maintaining thermal performance (RθJC = 18°C/W) |
| ±30kV IEC 61000-4-2 ESD | Eliminates need for external ESD diodes in USB, CAN, or sensor interface ports |
| Sub-1ns response time | Prevents latch-up or gate oxide damage in MOSFET drivers and microcontroller I/O pins |
| Lead-free & green construction | Complies with EU RoHS 3 (2015/863/EU) and automotive PPAP documentation requirements |
Applications
| Automotive Power Distribution | Battery Management Systems |
|---|---|
Use Scenario: Protection of 24V supply lines feeding ADAS ECUs against load dump transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed upstream of DC-DC converters to clamp spikes before regulation. Use Value: Limits voltage to ≤126V during 120V/100ms load dump events, preventing converter shutdown or damage. | Use Scenario: Input protection for lithium-ion battery pack monitoring ICs connected to cell taps. IC Role / Device Role / Timing Role: Standoff device across each cell input to absorb ESD from handling or connector mating. Use Value: 3.2μA leakage avoids measurable self-discharge in multi-year BMS deployments. |
| Industrial PLC I/O Modules | Telecom Power Feeds |
Use Scenario: Surge protection on 24V DC field wiring terminals exposed to induced lightning surges. IC Role / Device Role / Timing Role: Primary clamping element on DIN-rail mounted I/O card inputs. Use Value: 400W rating handles 1kV/500A ring wave surges per IEC 61000-4-5 Level 3 without derating. | Use Scenario: Overvoltage suppression on -48V telecom power feeds entering remote radio units. IC Role / Device Role / Timing Role: Unidirectional TVS referenced to chassis ground to protect PoE-like DC distribution. Use Value: 78V VRWM matches -48V nominal with 30% headroom; 126V VC prevents damage to downstream DC-DC stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A | Same 78V VRWM but SMA package (larger footprint, RθJA = 60°C/W) | Higher thermal mass suits higher ambient temp environments (>85°C) | Select if board space allows and junction temperature rise must be minimized under sustained surge duty. |
| SMCJ78A | Same VRWM but 1500W rating, DO-214AB package (6.2mm × 7.2mm) | Supports repeated surge events in utility metering or solar inverters | Choose when system requires >5 surges at full rating or needs higher IFSM (100A vs. 40A). |
Compared with SMAJ78A and SMCJ78A, SMF4L78A-7 offers the smallest PCB footprint and lowest profile for space-constrained modules, while maintaining identical electrical protection thresholds - making it optimal for portable electronics and dense automotive control units where volume and weight are critical.
Availability
SMF4L78A-7 is available at Aetrix Electronics and suitable for automotive power distribution, battery management systems, industrial PLC I/O modules, and telecom power feeds requiring stable component supply across production lifecycles.
Supply support for SMF4L78A-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 SMF4LxxA series belongs to Diodes' high-reliability TVS portfolio targeting automotive and industrial applications, engineered specifically for low-profile, high-surge-capability protection in harsh electromagnetic environments.
FAQ
What is the polarity configuration of SMF4L78A-7?
SMF4L78A-7 is a unidirectional TVS diode, indicated by the cathode band marking on the DO-219AA package. It conducts only during reverse-biased overvoltage events and blocks forward current up to its rated VRWM of 78V. This configuration is used where DC polarity is fixed and reverse-voltage protection is required.
How does SMF4L78A-7 perform under elevated ambient temperatures?
At +85°C ambient, SMF4L78A-7's peak pulse power derates to approximately 280W (70% of 400W) per Figure 1 in DS43394. Its RθJA of 96°C/W means a 1W steady-state dissipation raises junction temperature by 96°C above ambient - so continuous operation requires careful thermal pad design and power limiting.
Can SMF4L78A-7 replace older SMA-package TVS diodes in existing designs?
Yes, but only with layout revision: DO-219AA has different pad dimensions (1.34mm × 4.20mm) versus SMA (2.54mm × 4.06mm). Electrical parameters match SMAJ78A closely, but thermal impedance differs - verify junction temperature rise using the new RθJA value and actual PCB copper area before qualification.
Is SMF4L78A-7 qualified for automotive use per AEC-Q standards?
No - SMF4L78A-7 is an industrial-grade part. For automotive applications, Diodes offers the Q-suffix variant SMF4L78AQ-7, which is AEC-Q101 qualified, manufactured in IATF 16949 facilities, and supports PPAP documentation. The base part lacks change control and stress-test validation required for automotive deployment.
SMF4L78A-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):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- 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
SMF4L78A-7 FAQ
1.How can I place an order for SMF4L78A-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L78A-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 SMF4L78A-7 reliable?
The price and inventory of SMF4L78A-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L78A-7 is usually 5 days.
3.What payment methods are accepted for SMF4L78A-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L78A-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L78A-7?
SMF4L78A-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L78A-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 SMF4L78A-7?
For technical support, including SMF4L78A-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L78A-7 requirements.
6.How does Aetrix verify that SMF4L78A-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L78A-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 SMF4L78A-7 meets industry standards.
7.What is the process for return or replacement of SMF4L78A-7?
All SMF4L78A-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L78A-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 SMF4L78A-7 part is unused and in its original packaging.
Return procedure for SMF4L78A-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L78A-7 Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
