My Inquiry
My Account
Diodes Incorporated SMF4L40CAQ-7
- Part No.:
- SMF4L40CAQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L40CAQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:4,811
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF4L40CAQ-7 from Diodes Incorporated is a bi-directional transient voltage suppressor (TVS) diode designed for automotive-grade overvoltage protection in power rails and signal lines. It features a 40 V working peak reverse voltage (VRWM), 44.4–49.1 V breakdown voltage (VBR), 64.5 V maximum clamping voltage (VC) at 6.2 A surge current, and 400 W peak pulse power dissipation (10/1000 µs waveform). It is AEC-Q101 qualified and used in battery contact protection and CAN/LIN bus interfaces.
For engineers reviewing the SMF4L40CAQ-7 datasheet, SMF4L40CAQ-7 pinout, SMF4L40CAQ-7 application, or SMF4L40CAQ-7 equivalent, key selection criteria include clamping voltage margin vs. system rail, IEC 61000-4-2 ±30 kV ESD capability, DO-219AA package thermal performance, and AEC-Q101 qualification status for automotive deployment.
Technical Context
This bi-directional TVS operates symmetrically across both polarities, enabling robust protection of AC-coupled or differential signal paths without polarity dependency. Its sub-5 ns response time ensures suppression before sensitive downstream circuitry sustains damage during fast transients like ISO 7637-2 pulse 1/2a or ESD events.
The device uses planar junction silicon construction in a low-inductance DO-219AA surface-mount package, optimized for minimal parasitic inductance (<0.5 nH typical) and efficient heat transfer to PCB copper. Thermal resistance junction-to-solder point (RθJS) is 70 °C/W, supporting sustained operation up to +175 °C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 40 V - Maximum continuous reverse operating voltage before leakage exceeds 0.5 µA; sets upper limit for protected line voltage. |
| VBR (min/max) | 44.4 V / 49.1 V - Breakdown occurs within this range at 1 mA test current; defines turn-on threshold consistency. |
| VC @ IRSM | 64.5 V @ 6.2 A - Clamping voltage during 10/1000 µs surge; must remain below IC absolute maximum ratings. |
| PPK | 400 W - Peak pulse power handling per 10/1000 µs waveform; determines survivability against load dump or EFT. |
| ESD Rating | ±30 kV air / ±30 kV contact (IEC 61000-4-2) - Full-system ESD immunity without external shielding or filtering. |
| Operating Temp | −55 °C to +175 °C - Enables under-hood and battery-box placement in automotive applications. |
| AEC-Q101 | Qualified - Validated for automotive use with stress testing including HTGB, HTRB, and TCT. |
Pinout & Package
Package: DO-219AA - ultra-low-profile (max height 0.75 mm), molded green plastic case with matte tin-plated copper alloy leadframe; moisture sensitivity level 1 (J-STD-020); weight ≈ 0.016 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Cathode Band Absent) | Bi-directional terminal 1 | No cathode band indicates symmetrical bi-directional configuration; either terminal serves as anode or cathode depending on transient polarity. |
| Cathode (Cathode Band Absent) | Bi-directional terminal 2 | Identical electrical behavior to Anode; bidirectional clamping requires no orientation during placement. |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q101 qualified, PPAP-capable, manufactured in IATF 16949 certified facilities - meets OEM supply chain traceability and reliability requirements. |
| Low clamping ratio | VC/VRWM = 1.61 - tight margin between working voltage and clamping voltage improves system-level overvoltage margin. |
| Fast transient response | <5.0 ns (bi-directional) - suppresses ESD and EFT events before propagation into MCU or transceiver inputs. |
| Green packaging | Halogen- and antimony-free, RoHS 3 compliant (Br+Cl <1500 ppm, Sb <1000 ppm) - satisfies EU environmental compliance mandates. |
| Thermal efficiency | RθJS = 70 °C/W - enables high-power transient absorption without excessive junction temperature rise on standard 2 oz. FR-4 PCBs. |
Applications
| Automotive Power Rail Protection | CAN Bus Transient Suppression |
|---|---|
|
Use Scenario: Protecting 12 V battery-fed ECUs from load dump (ISO 16750-2) and jump-start surges. IC Role / Device Role / Timing Role: Primary clamping element placed directly at connector entry point to shunt >400 W transients away from DC-DC converters and microcontrollers. Use Value: Withstands 64.5 V clamping at 6.2 A while maintaining VRWM = 40 V, ensuring compatibility with 36 V max automotive transients and avoiding false triggering. |
Use Scenario: Shielding high-speed CAN FD physical layer (PHY) transceivers from ESD and coupled noise on vehicle harnesses. IC Role / Device Role / Timing Role: Bi-directional TVS placed across CANH–CANL differential pair to clamp common-mode transients without distorting signal integrity. Use Value: Sub-5 ns response preserves CAN bit timing; ±30 kV ESD rating eliminates need for secondary board-level protection layers. |
| Industrial Sensor Interface Protection | USB-C Port ESD Guard |
|
Use Scenario: Safeguarding 4–20 mA loop-powered sensors connected to PLC analog input modules exposed to field wiring transients. IC Role / Device Role / Timing Role: Standoff-rated TVS mounted at terminal block to absorb induced surges before reaching precision ADC front-end. Use Value: 40 V VRWM aligns with industrial 24 V nominal systems; 64.5 V VC ensures downstream op-amps remain within absolute max ratings during 1 kV EFT bursts. |
Use Scenario: Providing primary ESD protection on USB-C CC and VBUS pins in portable automotive accessories and infotainment dongles. IC Role / Device Role / Timing Role: Bi-directional clamping device placed immediately after connector to intercept ±30 kV air/contact discharge before USB PD controller ICs. Use Value: DO-219AA footprint minimizes board space; low capacitance (typ. 120 pF at 1 MHz) avoids USB 2.0 signal degradation. |
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 |
|---|---|---|---|
| SMAJ40CA | DO-214AC package; higher RθJA (100 °C/W); 64.5 V VC same, but 1.0 W steady-state power rating vs. 1.0 W for SMF4L40CAQ-7. | Larger footprint (4.5 × 2.7 mm vs. 2.0 × 1.2 mm); less suitable for dense automotive modules. | Choose SMAJ40CA only if legacy layout reuse is required; SMF4L40CAQ-7 offers superior thermal density and space savings. |
| TPSMD40CA | DO-214AB package; identical 40 V VRWM and 64.5 V VC; slightly lower PPK (300 W vs. 400 W); AEC-Q101 not claimed. | Not AEC-Q101 qualified; lacks PPAP support and IATF 16949 manufacturing evidence. | Select TPSMD40CA for cost-sensitive non-automotive industrial use; avoid where automotive qualification is mandatory. |
Compared with SMAJ40CA and TPSMD40CA, SMF4L40CAQ-7 delivers the highest power density (400 W in DO-219AA), full AEC-Q101 compliance, and smallest PCB footprint-making it optimal for next-generation automotive ECUs where space, thermal headroom, and qualification rigor are critical.
Availability
SMF4L40CAQ-7 is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and USB-C accessory designs requiring stable component supply and long-term lifecycle assurance.
Supply support for SMF4L40CAQ-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 SMF4L series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive power and data-line protection with emphasis on low clamping, fast response, and green packaging compliance.
FAQ
Is SMF4L40CAQ-7 unidirectional or bidirectional?
SMF4L40CAQ-7 is a bi-directional TVS diode, confirmed by its part number suffix "CAQ" (C = bi-directional, A = automotive grade, Q = green/RoHS) and absence of cathode band marking. Its symmetrical VBR and VC specifications across both polarities enable protection of AC-coupled or differential lines such as CAN, LIN, or USB without orientation constraints.
What is the maximum surge current rating for SMF4L40CAQ-7?
The maximum peak pulse current (IRSM) for SMF4L40CAQ-7 is 6.2 A under the standardized 10/1000 µs double-exponential waveform, corresponding to its 400 W peak pulse power rating. This value is measured at clamping voltage VC = 64.5 V and is validated per IEC 61000-4-5 Ed. 3 Annex C test conditions.
Does SMF4L40CAQ-7 require a heatsink for 400 W pulse handling?
No external heatsink is required. The DO-219AA package achieves sufficient thermal dissipation via PCB copper land (2 oz. FR-4, 1" × 1" pad) with RθJS = 70 °C/W. At 6.2 A surge, junction temperature rise remains within safe limits (≤125 °C above ambient) for single-event transients, as verified in Diodes' thermal simulation and JEDEC JESD51-14 characterization.
How does SMF4L40CAQ-7 differ from SMF4L40AQ?
SMF4L40AQ is the unidirectional variant (no "C" in suffix), marked with a cathode band and specified only for reverse-biased operation. SMF4L40CAQ-7 adds symmetrical forward/reverse clamping, enabling use on bidirectional signal pairs. Electrical differences include doubled IR limit (1.0 µA vs. 0.5 µA) for bi-directional devices per datasheet Note 12.
SMF4L40CAQ-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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 6.2A
- 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
SMF4L40CAQ-7 FAQ
1.How can I place an order for SMF4L40CAQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L40CAQ-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 SMF4L40CAQ-7 reliable?
The price and inventory of SMF4L40CAQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L40CAQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L40CAQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L40CAQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L40CAQ-7?
SMF4L40CAQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L40CAQ-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 SMF4L40CAQ-7?
For technical support, including SMF4L40CAQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L40CAQ-7 requirements.
6.How does Aetrix verify that SMF4L40CAQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L40CAQ-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 SMF4L40CAQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L40CAQ-7?
All SMF4L40CAQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L40CAQ-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 SMF4L40CAQ-7 part is unused and in its original packaging.
Return procedure for SMF4L40CAQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L40CAQ-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…
