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Vishay General Semiconductor - Diodes Division SMAJ20A-E3/5A
- Part No.:
- SMAJ20A-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20A-E3/5A.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ20A-E3/5A from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed to protect sensitive electronics against ESD, lightning-induced surges, and inductive switching transients. It features a 20 V stand-off voltage (VWM), 22.2–24.5 V breakdown voltage (VBR) at 1 mA, 32.4 V maximum clamping voltage (VC) at 12.3 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - ideal for DC power rail and signal line protection in automotive and industrial control systems.
For engineers reviewing the SMAJ20A-E3/5A datasheet, SMAJ20A-E3/5A pinout, SMAJ20A-E3/5A application, or SMAJ20A-E3/5A equivalent, key selection criteria include its unidirectional polarity, 1.0 μA max reverse leakage at VWM, 150 °C max junction temperature, RoHS-compliant matte tin-plated leads, and AEC-Q101 qualification eligibility via HE3/HM3 variants.
Technical Context
This TVS diode operates as a clamping device: under normal conditions it presents high impedance (>1 MΩ) with only 1.0 μA leakage at 20 V; during transient events exceeding VBR, it avalanches rapidly (<1 ns response time) to clamp voltage at ≤32.4 V while diverting up to 12.3 A surge current. Its glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repetitive surge stress.
The SMAJ20A-E3/5A is rated for 400 W peak pulse power (10/1000 μs) on 5.0 mm × 5.0 mm copper pads, derating linearly above 25 °C ambient per Fig. 2, with thermal resistance of 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead). Polarity is marked by a cathode band; no marking applies to bidirectional versions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 20 V - maximum continuous reverse operating voltage before significant leakage begins; defines safe DC operating margin. |
| VBR (Breakdown Voltage) | 22.2–24.5 V at 1 mA - guaranteed avalanche initiation range; ensures predictable clamping onset across production lots. |
| VC (Clamping Voltage) | 32.4 V at 12.3 A IPPM - maximum voltage seen by protected circuit during worst-case 10/1000 μs surge; determines IC survivability. |
| PPPM (Peak Pulse Power) | 400 W - surge energy handling capacity with standard 10/1000 μs waveform; sufficient for ISO 7637-2 Pulse 1/2a/5a compliance. |
| IPPM (Peak Pulse Current) | 12.3 A - maximum non-repetitive surge current the device can safely shunt without degradation. |
| TJmax | 150 °C - maximum junction temperature; supports operation in under-hood automotive environments and industrial enclosures. |
| Package | SMA (DO-214AC) - industry-standard surface-mount outline with 5.28 mm length, 4.50 mm width, and 2.29 mm height; compatible with automated pick-and-place. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated, MSL Level 1 (260 °C reflow peak), and JESD 201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal (unidirectional) | Connected to lower-potential side of protected line; current flows anode-to-cathode during forward surge or bias. |
| Cathode | Reverse-biased terminal (marked with band) | Connected to higher-potential side (e.g., VCC rail); avalanche conduction occurs when cathode-to-anode voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables robust protection against ISO 16750-2 and IEC 61000-4-5 Level 3 surges without external series impedance. |
| 32.4 V clamping at 12.3 A | Keeps downstream 24 V logic or microcontroller I/O pins below absolute maximum ratings during 100 A/m surge coupling. |
| Glass-passivated junction | Ensures stable VBR tolerance (±5 % typical), low leakage drift over temperature, and >1000 surge cycles endurance. |
| RoHS-compliant, matte tin plating | Guarantees solderability per J-STD-002/JESD 22-B102 and eliminates lead-free assembly compatibility issues. |
| AEC-Q101 qualification path | HE3/HM3 suffix variants support automotive applications requiring qualification per stress test requirements (HTOL, TCT, etc.). |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 24 V supply lines in body control modules against load dump (ISO 7637-2 Pulse 5a) and alternator transients. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed between battery rail and DC-DC input, absorbing >400 W surges within nanoseconds. Use Value: Limits voltage excursion to ≤32.4 V, preventing damage to upstream regulators and downstream MCU power domains. |
Use Scenario: Safeguarding analog sensor outputs (e.g., pressure, temperature) connected to PLC analog inputs in factory automation. IC Role / Device Role / Timing Role: Low-capacitance (≈150 pF) TVS mounted at connector entry point to shunt ESD (IEC 61000-4-2 ±8 kV contact) and cable discharge events. Use Value: Maintains signal integrity with <1.0 μA leakage at 20 V, avoiding offset errors in 16-bit ADC front-ends. |
| Consumer USB Power Delivery Line | Telecom Ethernet Port Surge Suppression |
|
Use Scenario: Secondary overvoltage protection on 5 V/9 V/15 V USB PD bus lines after primary buck converter output filter. IC Role / Device Role / Timing Role: Fast-response (sub-ns) clamping device triggered by hot-swap insertion transients or adapter fault conditions. Use Value: Clamps to 32.4 V before downstream USB controller ICs exceed 36 V absolute maximum rating. |
Use Scenario: Board-level protection for RJ45 Ethernet PHY interfaces exposed to lightning-induced common-mode surges (IEC 61000-4-5). IC Role / Device Role / Timing Role: Paired unidirectional TVS devices (one per line) referenced to chassis ground, handling differential and common-mode transients. Use Value: Withstands 12.3 A peak current per line while maintaining <100 ps response latency to preserve 100BASE-TX signal timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20A-M3/5A | Halogen-free, RoHS-compliant variant with identical electrical specs and SMA package; same thermal and surge performance. | No functional difference; selected where halogen-free BOM compliance is mandated (e.g., EU public infrastructure projects). | Direct material substitution when halogen-free certification is required; no layout or validation changes needed. |
| SMAJ20CA-E3/5A | Bidirectional version: symmetric VBR (22.2–24.5 V), same VC (32.4 V), but no polarity marking and double the ID limit (2.0 μA) for VWM ≤10 V - not applicable here. | Used in AC-coupled or floating signal lines (e.g., RS-485, CAN bus) where voltage polarity reverses; unsuitable for DC rail protection. | Select only for bidirectional signal paths; not a drop-in replacement for unidirectional DC applications like SMAJ20A-E3/5A. |
Compared with SMAJ20A-M3/5A, the SMAJ20A-E3/5A offers standard RoHS compliance without halogen restrictions, simplifying procurement for commercial-grade designs; versus SMAJ20CA-E3/5A, the unidirectional configuration provides tighter leakage control and avoids unnecessary bidirectional conduction in DC power domains.
Availability
SMAJ20A-E3/5A is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, consumer USB PD systems, and telecom port protection requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ20A-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 qualification.
The SMAJ series was engineered for high-energy transient suppression in space-constrained surface-mount applications, targeting automotive, industrial, and communications systems where fast response, repeatable clamping, and AEC-Q101 readiness are critical.
FAQ
What is the maximum clamping voltage of the SMAJ20A-E3/5A under a 10/1000 μs surge?
The SMAJ20A-E3/5A has a maximum clamping voltage (VC) of 32.4 V at 12.3 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is measured per JEDEC standards and guarantees that protected circuits will not experience voltages exceeding 32.4 V during standardized surge events - a critical parameter for ensuring compatibility with 3.3 V, 5 V, and 24 V system components. The SMAJ20A-E3/5A maintains this clamping performance across its full operating temperature range.
Is the SMAJ20A-E3/5A suitable for automotive applications?
Yes - the SMAJ20A-E3/5A is manufactured by Vishay General Semiconductor and supports automotive qualification via the HE3/HM3 suffix variants (e.g., SMAJ20AHE3_A/I), which are AEC-Q101 qualified. While the base SMAJ20A-E3/5A is commercial-grade, its 150 °C junction rating, 400 W surge capability, and robust construction make it widely deployed in non-safety-critical automotive subsystems such as infotainment power rails and sensor interfaces. For certified applications, specify the HE3 variant.
What does the "E3/5A" suffix mean in SMAJ20A-E3/5A?
The "E3" suffix denotes RoHS-compliant, commercial-grade construction with matte tin-plated leads; "5A" specifies the packaging format: 7500 units per 13-inch plastic tape-and-reel. This differs from "E3/61", which uses 7-inch reels with 1800 units. Both share identical electrical and thermal specifications - the suffix solely indicates environmental compliance and logistics configuration. The SMAJ20A-E3/5A is fully compatible with standard SMT assembly processes including reflow up to 260 °C peak.
How does the SMAJ20A-E3/5A compare to SMAJ15A or SMAJ24A in terms of voltage rating?
The SMAJ20A-E3/5A has a 20 V stand-off voltage (VWM) and 22.2–24.5 V breakdown range, positioning it between SMAJ15A (15 V VWM) and SMAJ24A (24 V VWM). Its 32.4 V clamping voltage is lower than SMAJ24A's 38.9 V but higher than SMAJ15A's 24.4 V - making SMAJ20A-E3/5A optimal for 24 V nominal systems where margin above VWM must balance surge headroom and IC voltage limits. All three share identical package, power rating, and thermal behavior.
Does the SMAJ20A-E3/5A require a heatsink for 400 W surge handling?
No - the 400 W peak pulse power rating of the SMAJ20A-E3/5A is specified with mounting on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal, per Figure 1 in the datasheet. This pad layout provides sufficient thermal mass for single-event surge dissipation without external heatsinking. Continuous power dissipation is limited to 3.3 W (PD), so sustained DC power handling requires board-level thermal design - but transient suppression relies entirely on the PCB copper area, not added heatsinks.
SMAJ20A-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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 12.3A
- 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)
SMAJ20A-E3/5A FAQ
1.How can I place an order for SMAJ20A-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20A-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 SMAJ20A-E3/5A reliable?
The price and inventory of SMAJ20A-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 SMAJ20A-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ20A-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20A-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20A-E3/5A?
SMAJ20A-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20A-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 SMAJ20A-E3/5A?
For technical support, including SMAJ20A-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20A-E3/5A requirements.
6.How does Aetrix verify that SMAJ20A-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ20A-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 SMAJ20A-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ20A-E3/5A?
All SMAJ20A-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20A-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 SMAJ20A-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ20A-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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