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Vishay General Semiconductor - Diodes Division SMAJ45CA-E3/5A
- Part No.:
- SMAJ45CA-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ45CA-E3/5A.pdf
- Description:
- TVS DIODE 45VWM 72.7VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ45CA-E3/5A from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal and power lines. It features a 45 V stand-off voltage (VWM), 50.0–55.3 V breakdown voltage (VBR) at 1 mA, 72.7 V maximum clamping voltage (VC) at 5.5 A peak pulse current, and 400 W peak pulse power (10/1000 μs waveform), protecting MOSFETs and ICs in automotive and industrial power supplies.
For engineers reviewing the SMAJ45CA-E3/5A datasheet, SMAJ45CA-E3/5A pinout, SMAJ45CA-E3/5A application, or SMAJ45CA-E3/5A equivalent, key selection criteria include bidirectional clamping capability, low clamping ratio (VC/VWM = 1.62), AEC-Q101 qualification eligibility, RoHS-compliant matte tin plating, and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode operates symmetrically in both directions due to its bidirectional CA construction, enabling protection of AC-coupled or differential signal lines without polarity concerns. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 μA at VWM), while the low incremental surge resistance supports fast energy dissipation during ESD or lightning-induced surges.
The device is rated for 150 °C maximum junction temperature and exhibits a thermal resistance of 120 °C/W (junction-to-ambient) on standard PCB pads. Its 10/1000 μs waveform rating applies up to 400 W below 78 V - precisely covering the SMAJ45CA-E3/5A's operating range - with derating above 25 °C per Figure 2 of the datasheet.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous reverse working voltage before clamping begins; defines safe operating margin for 48 V nominal systems. |
| VBR (min/max) | 50.0 V / 55.3 V at 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on during overvoltage events without premature conduction. |
| VC @ IPPM | 72.7 V at 5.5 A - Clamped voltage under 400 W transient; limits downstream stress to ≤1.62× VWM, critical for 3.3 V/5 V logic interface protection. |
| PPPM | 400 W (10/1000 μs) - Peak surge power handling capacity; sufficient for ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 3 transients. |
| IPPM | 5.5 A - Peak pulse current corresponding to VC; determines minimum trace width and PCB copper area required (0.2" × 0.2" pads specified). |
| TJmax | 150 °C - Maximum junction temperature; enables operation in under-hood automotive environments and industrial enclosures without forced cooling. |
| RθJA | 120 °C/W - Thermal resistance to ambient on standard layout; informs derating curves for sustained surge repetition or elevated ambient temperatures. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads compliant with J-STD-002 and JESD 22-B102. No polarity marking - bidirectional symmetry eliminates cathode/anode orientation concerns during placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Bidirectional transient conduction path | Both terminals function identically; connects across protected line and ground (or between differential lines) without polarity dependency. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables robust protection against automotive load dump (ISO 7637-2 Pulse 5a) and industrial switching surges without thermal runaway. |
| Low clamping ratio (VC/VWM = 1.62) | Minimizes overvoltage exposure to downstream ICs - e.g., keeps 3.3 V microcontroller I/O pins below absolute maximum rating during clamping. |
| AEC-Q101 qualification option (HE3/HM3 suffix) | Supports automotive-grade sourcing paths; HE3 variant meets stress testing requirements for engine control, body electronics, and ADAS subsystems. |
| MSL Level 1 (260 °C peak reflow) | Permits single-pass lead-free reflow without moisture sensitivity concerns - eliminates baking steps and reduces assembly cost. |
| Glass passivated junction | Ensures long-term parameter stability and low leakage (<1.0 μA) across temperature and humidity, critical for battery-powered sensor nodes. |
Applications
| Automotive Power Line Protection | Industrial Sensor Signal Conditioning |
|---|---|
|
Use Scenario: Protecting 48 V battery rail inputs in ADAS camera modules from load dump and alternator transients. IC Role / Device Role / Timing Role: Bidirectional clamping element placed between power input and DC/DC converter input stage. Use Value: Limits transient voltage to ≤72.7 V, preventing damage to 80 V-rated input capacitors and enabling use of lower-cost 60 V MOSFETs in front-end regulation. |
Use Scenario: Shielding analog output lines (e.g., 4–20 mA current loop) of pressure sensors in factory automation PLCs. IC Role / Device Role / Timing Role: Low-capacitance (<50 pF) shunt protector across signal and return lines to suppress EFT bursts (IEC 61000-4-4). Use Value: Maintains signal integrity with <1.0 μA leakage at 45 V, avoiding offset errors in precision 16-bit DAC outputs driving field devices. |
| Telecom Interface Surge Suppression | Consumer USB-C Power Delivery Protection |
|
Use Scenario: Safeguarding RS-485 transceivers in base station backhaul equipment exposed to lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: Primary-level TVS mounted at connector entry point, coordinated with secondary GDT or polymer PTC. Use Value: Responds in <1 ns to clamp 1 kV/100 Ω surge to <73 V within 100 ns, preserving transceiver latch-up immunity per TIA-485-A. |
Use Scenario: Securing VBUS lines in portable USB-C PD sink controllers against hot-plug and cable ESD events. IC Role / Device Role / Timing Role: Secondary-stage TVS after primary common-mode choke, absorbing residual differential-mode surges. Use Value: Withstands 30 kV contact ESD (IEC 61000-4-2) without degradation, maintaining 45 V hold-off for 20 V PD negotiation and 48 V extended power range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ45CA-M3/5A | Halogen-free, RoHS-compliant variant with identical electrical specs and SMA package; same thermal and surge ratings. | No functional difference; selected when halogen-free compliance is mandated by OEM environmental policy (e.g., EU auto Tier 1). | Choose SMAJ45CA-M3/5A if halogen-free materials are contractually required; otherwise, E3 and M3 are electrically interchangeable. |
| SMAJ43CA-E3/5A | Lower VWM (43 V), VBR (47.8–52.8 V), and VC (69.4 V); 5.8 A IPPM at 400 W - tighter clamping but reduced margin for 48 V nominal systems. | Better suited for 42 V battery systems or designs requiring lower let-through voltage; may false-trigger near 43 V steady-state conditions. | Select SMAJ43CA-E3/5A only when system max operating voltage is ≤43 V; SMAJ45CA-E3/5A provides safer margin for 48 V architectures. |
Compared with SMAJ45CA-M3/5A, the SMAJ45CA-E3/5A offers identical protection performance with standard RoHS compliance, while SMAJ43CA-E3/5A trades 2 V higher VWM margin for 3.3 V lower clamping - making SMAJ45CA-E3/5A optimal for 48 V automotive and industrial power rails where reliability trumps marginal clamping reduction.
Availability
SMAJ45CA-E3/5A is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interfaces, telecom infrastructure surge protection, and consumer USB-C PD systems requiring stable component supply and full traceability.
Supply support for SMAJ45CA-E3/5A 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, MOSFETs, and protection devices with emphasis on reliability, power efficiency, and automotive-grade validation.
The SMAJ series was engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where failure tolerance, AEC-Q101 readiness, and repeatable clamping performance are mandatory.
FAQ
What is the clamping voltage of SMAJ45CA-E3/5A at its rated peak pulse current?
The SMAJ45CA-E3/5A has a maximum clamping voltage (VC) of 72.7 V at its peak pulse current (IPPM) of 5.5 A, measured under the standardized 10/1000 μs waveform. This value is confirmed in the Electrical Characteristics table of Vishay's Document Number 88390 and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ45CA-E3/5A maintains this clamping performance across its qualified operating temperature range.
Is SMAJ45CA-E3/5A suitable for automotive applications?
Yes - while the base SMAJ45CA-E3/5A is commercial-grade, it shares identical electrical and mechanical specifications with the AEC-Q101-qualified SMAJ45CAHE3 variant. Its 150 °C junction rating, MSL Level 1 reflow compatibility, and glass-passivated junction meet core automotive stress requirements. For production automotive use, specify SMAJ45CAHE3_X (e.g., SMAJ45CAHE3_A) to ensure certified qualification; the SMAJ45CA-E3/5A serves as a drop-in evaluation or non-automotive qualified alternative.
How does the bidirectional design of SMAJ45CA-E3/5A affect its circuit implementation?
The bidirectional CA configuration of SMAJ45CA-E3/5A means it conducts identically in both polarities, eliminating the need for polarity-aware placement - no cathode band marking is present. This allows direct placement across AC signal pairs (e.g., RS-485 A/B), ungrounded power rails, or floating sensor outputs without risk of reverse bias damage. Unlike unidirectional variants, the SMAJ45CA-E3/5A provides symmetrical clamping regardless of transient polarity, simplifying layout and reducing BOM count in differential protection schemes.
What PCB pad layout is recommended for optimal thermal and surge performance of SMAJ45CA-E3/5A?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad for each terminal of the SMAJ45CA-E3/5A to achieve its rated 400 W peak pulse power and 120 °C/W thermal resistance. These pads must be directly connected to internal ground/power planes via multiple thermal vias to dissipate surge energy. Deviating from this layout - such as using smaller pads or isolated traces - reduces both surge current handling and thermal derating capability, potentially causing parametric shift or failure during repetitive transients.
Does SMAJ45CA-E3/5A have a defined junction capacitance, and how does it impact high-speed signal lines?
Yes - the SMAJ45CA-E3/5A exhibits typical junction capacitance of ~50 pF at VWM = 45 V, measured at 1 MHz with 50 mVp-p signal (Figure 4, Document 88390). While not optimized for RF or >100 Mbps data lines, this capacitance is acceptable for CAN, RS-485, and analog sensor outputs where bandwidth is <10 MHz. For high-speed interfaces, designers should verify signal integrity via simulation or measurement, as the SMAJ45CA-E3/5A's capacitance may attenuate edge rates or induce jitter if placed directly on GHz-range traces.
SMAJ45CA-E3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.7V
- Current - Peak Pulse (10/1000µs):
- 5.5A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ45CA-E3/5A FAQ
1.How can I place an order for SMAJ45CA-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ45CA-E3/5A 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 SMAJ45CA-E3/5A reliable?
The price and inventory of SMAJ45CA-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ45CA-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ45CA-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ45CA-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ45CA-E3/5A?
SMAJ45CA-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ45CA-E3/5A 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 SMAJ45CA-E3/5A?
For technical support, including SMAJ45CA-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ45CA-E3/5A requirements.
6.How does Aetrix verify that SMAJ45CA-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ45CA-E3/5A 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 SMAJ45CA-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ45CA-E3/5A?
All SMAJ45CA-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ45CA-E3/5A, 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 SMAJ45CA-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ45CA-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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