My Inquiry
My Account
Diodes Incorporated SMF4L28AQ-7
- Part No.:
- SMF4L28AQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L28AQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:1,959
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF4L28AQ-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 28V working peak reverse voltage (VRWM), 31.1–34.4V breakdown voltage (VBR), 45.4V maximum clamping voltage (VC) at 8.8A surge current, and AEC-Q101 qualification for under-hood and battery-contact applications.
For engineers reviewing the SMF4L28AQ-7 datasheet, SMF4L28AQ-7 pinout, SMF4L28AQ-7 application, or SMF4L28AQ-7 equivalent, key selection criteria include clamping performance under IEC 61000-4-2 ±30kV ESD stress, DO-219AA package thermal resistance (RθJA = 96°C/W), and unidirectional polarity marking for correct PCB orientation in 12V/24V automotive systems.
Technical Context
This TVS diode operates as a fast-acting shunt protector, triggering when transient voltage exceeds its VBR threshold to clamp downstream circuitry within safe limits. Its sub-1ns response time ensures suppression before sensitive ICs experience overstress, and its 400W peak pulse power rating (10/1000µs waveform) supports robust surge handling per ISO 7637-2 Pulse 1/2/5a.
The device uses planar junction silicon construction in a low-inductance DO-219AA package with matte tin-plated copper alloy leads. Thermal design is enabled by RθJC = 18°C/W and RθJS = 70°C/W, supporting reliable operation up to +175°C junction temperature in high-ambient automotive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 28V - Maximum continuous reverse operating voltage before leakage exceeds 0.5μA; sets upper limit for protected line voltage. |
| VBR (min/max) | 31.1V / 34.4V - Breakdown occurs within this range at 1mA test current; defines turn-on threshold tolerance. |
| VC @ IRSM | 45.4V at 8.8A - Clamped voltage during worst-case surge; determines maximum stress on downstream components. |
| IPP (max) | 8.8A - Peak pulse current it can safely divert without degradation; derived from 400W rating and VC. |
| ESD Rating | ±30kV contact & air per IEC 61000-4-2 - Validates immunity to human-body-model electrostatic discharge events. |
| Operating Temp | −55°C to +175°C - Enables use in engine control units, battery management systems, and other high-temp automotive zones. |
| Package | DO-219AA - Surface-mount, low-profile (1.90mm × 2.80mm), halogen-free, RoHS-compliant plastic case with cathode band marking. |
Pinout & Package
SMF4L28AQ-7 is a two-terminal unidirectional TVS diode in the DO-219AA package. The cathode is marked by a visible band on the top surface; the anode is the opposite end. No internal pins-terminals are the molded leadframe extensions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink | Connected to protected line; conducts surge current to ground when V > VBR. |
| Anode (unmarked end) | Reference node | Typically tied to system ground or lower-potential rail; completes clamping path. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive use including temperature cycling, humidity bias, and mechanical shock per JESD22 standards. |
| 400W peak pulse power | Handles ISO 7637-2 Pulse 5a (load dump) transients in 12V/24V vehicle electrical systems without failure. |
| Fast response time | <1.0ns rise-to-clamp delay ensures protection of high-speed CAN, LIN, and sensor interfaces. |
| Low clamping ratio | VC/VRWM = 1.62 - Tight voltage margin between operating and clamping levels improves system margin. |
| Green, RoHS-compliant | Halogen- and antimony-free molding compound (<900ppm Br+Cl, <1000ppm Sb); meets EU Directive 2015/863/EU. |
Applications
| Automotive Power Rail Protection | Battery Contact ESD Suppression |
|---|---|
|
Use Scenario: Protecting 12V/24V supply inputs in engine control modules (ECMs) and body control modules (BCMs) against load dump and jump-start transients. IC Role / Device Role / Timing Role: Shunt-type transient suppressor placed between power rail and chassis ground; activates within nanoseconds upon overvoltage detection. Use Value: Limits voltage to ≤45.4V during 8.8A surges, preventing damage to PMICs, microcontrollers, and analog front-ends rated for ≤48V absolute maximum. |
Use Scenario: Shielding battery connector pins in EV charging ports and 12V auxiliary battery terminals from human-handling ESD events. IC Role / Device Role / Timing Role: Unidirectional TVS mounted directly at connector interface; cathode tied to battery positive, anode to chassis ground. Use Value: Withstands ±30kV contact discharge per IEC 61000-4-2, eliminating latch-up or gate oxide rupture in connected BMS ICs and monitoring circuits. |
| Infotainment System USB Lines | ADAS Camera Power Input |
|
Use Scenario: Safeguarding USB 2.0 VBUS and D+/D− lines in head units and telematics control units against hot-plug and cable-induced surges. IC Role / Device Role / Timing Role: Discrete TVS array (single-device per line) placed upstream of USB transceivers; unidirectional configuration avoids DC blocking. Use Value: Clamps transients to ≤45.4V while maintaining <0.5μA leakage at 28V, preserving signal integrity and avoiding false disconnect detection. |
Use Scenario: Protecting 5V/12V power inputs to radar and camera modules in advanced driver-assistance systems exposed to ignition noise and alternator ripple. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power feed; paired with ceramic capacitors to form low-impedance transient filter. Use Value: Delivers 400W surge capacity with RθJA = 96°C/W, enabling stable operation at +105°C ambient without derating in compact camera housings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A | Same VRWM (28V), but SMA package (larger footprint, higher RθJA = 110°C/W); 400W rating, 45.4V VC. | Less suitable for space-constrained automotive PCBs; requires larger pad layout and more board area. | Choose if legacy SMA footprint compatibility is required and thermal margin allows higher junction temperature rise. |
| 1.5SMC28A | Higher VRWM tolerance (28V vs. 28V), same VC (45.4V), but SMC package (3.9mm × 2.5mm); 1500W rating, 45.4V VC. | Over-specified for most 400W needs; larger size and higher cost; not AEC-Q101 qualified. | Select only when legacy SMC assembly infrastructure exists and automotive qualification is not mandatory. |
Compared with SMAJ28A and 1.5SMC28A, SMF4L28AQ-7 offers superior board-space efficiency via DO-219AA, guaranteed AEC-Q101 compliance, and optimized thermal performance for high-density automotive modules-making it the preferred choice where qualification, size, and thermal reliability are jointly critical.
Availability
SMF4L28AQ-7 is available at Aetrix Electronics and suitable for automotive electronics, battery management systems, and infotainment power rail protection requiring stable component supply across extended production lifecycles.
Supply support for SMF4L28AQ-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 consumer markets.
The SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for robust transient suppression in harsh automotive environments-including under-hood, battery, and ADAS subsystems.
FAQ
What is the polarity configuration of SMF4L28AQ-7?
SMF4L28AQ-7 is a unidirectional TVS diode, identified by a cathode band on the DO-219AA package. It conducts only when the cathode is at a higher potential than the anode-ideal for protecting positive power rails referenced to ground. Its reverse leakage remains below 0.5μA at 28V VRWM.
Does SMF4L28AQ-7 meet automotive qualification requirements?
Yes-SMF4L28AQ-7 is AEC-Q101 qualified, PPAP capable, and manufactured in IATF 16949 certified facilities. It passes stress tests including temperature cycling, high-temperature operating life, and ESD per JESD22-A114, making it suitable for safety-critical automotive applications.
How does the DO-219AA package improve thermal performance over SMA or SMC?
The DO-219AA package delivers RθJA = 96°C/W (vs. 110°C/W for SMAJ28A and ~125°C/W for 1.5SMC28A), due to its optimized copper leadframe geometry and low-profile mold compound. This enables higher sustained power dissipation in compact layouts without exceeding +175°C junction temperature.
Can SMF4L28AQ-7 be used in bidirectional signal-line protection?
No-SMF4L28AQ-7 is unidirectional only. For bidirectional protection (e.g., RS-485, CAN bus), use the companion part SMF4L28CAQ-7, which has identical VRWM and clamping but symmetrical breakdown in both directions and no cathode band marking.
SMF4L28AQ-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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 8.8A
- 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
SMF4L28AQ-7 FAQ
1.How can I place an order for SMF4L28AQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L28AQ-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 SMF4L28AQ-7 reliable?
The price and inventory of SMF4L28AQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L28AQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L28AQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L28AQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L28AQ-7?
SMF4L28AQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L28AQ-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 SMF4L28AQ-7?
For technical support, including SMF4L28AQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L28AQ-7 requirements.
6.How does Aetrix verify that SMF4L28AQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L28AQ-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 SMF4L28AQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L28AQ-7?
All SMF4L28AQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L28AQ-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 SMF4L28AQ-7 part is unused and in its original packaging.
Return procedure for SMF4L28AQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L28AQ-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…
