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Vishay General Semiconductor - Diodes Division SMAJ20CAHE3_A/I
- Part No.:
- SMAJ20CAHE3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20CAHE3_A/I.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,891
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Product details
Overview
SMAJ20CAHE3_A/I from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal or power lines. 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 (IPPM), and 400 W peak pulse power (10/1000 μs waveform), targeting protection of MOSFETs, ICs, and sensor interfaces in automotive and industrial systems.
For engineers reviewing the SMAJ20CAHE3_A/I datasheet, SMAJ20CAHE3_A/I pinout, SMAJ20CAHE3_A/I application, or SMAJ20CAHE3_A/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, 150 °C max junction temperature, low incremental surge resistance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates symmetrically in both directions due to its bidirectional construction, enabling suppression of positive and negative transients without polarity sensitivity. Its glass-passivated junction ensures stable breakdown characteristics and fast response time (<1 ns), while the SMA package supports high thermal dissipation via low RθJL (30 °C/W) and meets MSL level 1 reflow requirements (260 °C peak).
The device delivers 400 W peak pulse power up to 78 V and derates to 300 W above that threshold, with clamping performance validated under standardized 10/1000 μs surge waveforms. It exhibits a temperature coefficient of VBR at +0.094 %/°C and maintains ≤1.0 μA reverse leakage at VWM - critical for low-power sensor line protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - maximum continuous reverse operating voltage before clamping begins; defines safe signal line operating margin. |
| VBR min/max | 22.2 V / 24.5 V at 1 mA - guaranteed breakdown range ensuring predictable turn-on during overvoltage events. |
| VC @ IPPM | 32.4 V at 12.3 A - clamped voltage seen by protected circuit during 10/1000 μs transient; limits stress on downstream components. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - peak surge energy handling capacity per JEDEC standard waveform; determines survivability against ESD/lightning surges. |
| ID @ VWM | ≤1.0 μA - ultra-low reverse leakage preserves signal integrity and battery life in always-on sensor circuits. |
| TJ max | +150 °C - enables operation in under-hood automotive and high-temperature industrial environments. |
| AEC-Q101 | Qualified - certified for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per AEC specification. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking; terminals are matte tin-plated for J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient return path (bidirectional) | Provides symmetrical conduction path for both positive and negative surges; connects to ground or common reference plane. |
| Cathode | Transient return path (bidirectional) | Functionally identical to anode in CA devices; no cathode band marking distinguishes it from unidirectional variants. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity concerns - e.g., CAN bus, RS-485, or differential sensors. |
| 400 W peak pulse power (10/1000 μs) | Withstands high-energy transients from inductive switching (e.g., solenoid drivers) while maintaining sub-33 V clamping voltage. |
| AEC-Q101 qualification | Validated for automotive applications including engine control units, body electronics, and ADAS sensor interfaces requiring long-term field reliability. |
| Low profile SMA package | 0.208" × 0.157" footprint with 0.078" height enables dense PCB layouts and compatibility with standard SMT pick-and-place equipment. |
| MSL Level 1 (260 °C) | Supports lead-free reflow without moisture-induced damage, eliminating bake requirements prior to assembly. |
Applications
| Automotive Sensor Protection | Industrial I/O Interface |
|---|---|
Use Scenario: Protecting analog output lines of pressure or temperature sensors in engine control modules exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed between sensor output and microcontroller ADC input. Use Value: Limits transient voltage to ≤32.4 V, preventing ADC saturation and latch-up while maintaining <1 μA leakage for accurate DC measurement. |
Use Scenario: Shielding 24 V digital input channels on PLC modules from relay coil flyback and EFT bursts. IC Role / Device Role / Timing Role: Primary overvoltage suppressor across input terminal and common rail. Use Value: Absorbs 400 W surge energy within nanoseconds, holding clamped voltage below 33 V to ensure optocoupler and Schmitt trigger integrity. |
| Telecom Line Interface | Consumer Power Adapter Feedback Loop |
Use Scenario: Safeguarding RS-485 transceiver pins in base station backhaul equipment subjected to lightning-induced surges. IC Role / Device Role / Timing Role: Differential-line TVS pair (one per line) referenced to ground. Use Value: Symmetrical clamping prevents data corruption during ±1 kV EFT events while adding <1 pF capacitance per line - negligible at 10 Mbps. |
Use Scenario: Securing optocoupler feedback path in isolated AC/DC adapters against primary-side switching noise coupling. IC Role / Device Role / Timing Role: Clamp across optocoupler LED anode-cathode to limit reverse voltage during startup transients. Use Value: Prevents LED breakdown with 20 V standoff and 32.4 V clamping, ensuring stable regulation loop behavior under 10/1000 μs surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20CA-M3/61 | Halogen-free, RoHS-compliant, commercial grade (non-AEC-Q101 qualified); same electrical specs and SMA package. | Lacks automotive qualification; suitable for industrial/commercial designs where AEC compliance is not mandated. | Select when cost-sensitive non-automotive applications require identical clamping performance without automotive certification overhead. |
| SMBJ20CAHE3_A/I | Same VWM/VBR/VC ratings but in larger SMB (DO-214AA) package; higher 600 W PPPM rating (10/1000 μs); RθJA = 85 °C/W vs. 120 °C/W. | Better thermal performance and surge margin; requires larger PCB area and may not fit space-constrained layouts. | Choose when system-level surge immunity exceeds 400 W requirement or board layout allows SMB footprint for enhanced reliability margin. |
Compared with SMAJ20CAHE3_A/I, SMAJ20CA-M3/61 offers identical protection performance without AEC-Q101 validation, while SMBJ20CAHE3_A/I provides higher surge power handling and lower thermal resistance at the cost of increased board area - enabling trade-offs between qualification, robustness, and miniaturization.
Availability
SMAJ20CAHE3_A/I is available at Aetrix Electronics and suitable for automotive sensor protection, industrial PLC I/O hardening, and telecom line interface applications requiring stable component supply, AEC-Q101 qualification, and consistent TVS clamping performance across production batches.
Supply support for SMAJ20CAHE3_A/I 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, TVS devices, and power MOSFETs with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for robust transient suppression in harsh environments - particularly targeting automotive, industrial, and telecom systems where fast-response, bidirectional clamping and AEC-Q101 compliance are mandatory design requirements.
FAQ
What does the "CA" suffix indicate in SMAJ20CAHE3_A/I?
The "CA" suffix denotes a bidirectional configuration, meaning SMAJ20CAHE3_A/I clamps voltage transients equally in both polarities - unlike unidirectional "A" variants that only protect against reverse-biased surges. This makes SMAJ20CAHE3_A/I ideal for AC-coupled or floating signal paths such as RS-485, CAN, or differential sensor outputs where polarity is undefined or alternating.
Is SMAJ20CAHE3_A/I suitable for automotive applications?
Yes, SMAJ20CAHE3_A/I is AEC-Q101 qualified, confirming its suitability for automotive use cases including engine control units, body electronics, and ADAS sensor interfaces. Its 150 °C maximum junction temperature, MSL Level 1 reflow compatibility, and validated performance under temperature cycling and HTRB testing meet stringent automotive reliability requirements.
How does the clamping voltage VC of SMAJ20CAHE3_A/I compare to its stand-off voltage VWM?
SMAJ20CAHE3_A/I has a 20 V stand-off voltage (VWM) and a maximum clamping voltage (VC) of 32.4 V at 12.3 A - representing a 62 % overvoltage margin. This ensures protected circuits remain within safe operating limits during transients, as VC defines the highest voltage imposed on downstream components during worst-case surge conditions.
What is the thermal resistance profile of SMAJ20CAHE3_A/I, and how does it affect PCB layout?
SMAJ20CAHE3_A/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and junction-to-lead (RθJL) of 30 °C/W. To maintain reliability, it must be mounted on minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal - underscoring the need for adequate copper pour in PCB layout to dissipate 3.3 W steady-state power and manage transient thermal spikes.
Can SMAJ20CAHE3_A/I replace SMAJ20AHE3_A/I in a design?
No - SMAJ20CAHE3_A/I is bidirectional, while SMAJ20AHE3_A/I is unidirectional with a cathode band marking and forward voltage drop (~3.5 V at 25 A). Substituting them requires verifying circuit polarity, grounding scheme, and whether reverse conduction during negative transients is acceptable; direct replacement is not recommended without schematic and layout review.
SMAJ20CAHE3_A/I 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):
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ20CAHE3_A/I FAQ
1.How can I place an order for SMAJ20CAHE3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20CAHE3_A/I 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 SMAJ20CAHE3_A/I reliable?
The price and inventory of SMAJ20CAHE3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20CAHE3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ20CAHE3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20CAHE3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20CAHE3_A/I?
SMAJ20CAHE3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20CAHE3_A/I 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 SMAJ20CAHE3_A/I?
For technical support, including SMAJ20CAHE3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20CAHE3_A/I requirements.
6.How does Aetrix verify that SMAJ20CAHE3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ20CAHE3_A/I 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 SMAJ20CAHE3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ20CAHE3_A/I?
All SMAJ20CAHE3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20CAHE3_A/I, 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 SMAJ20CAHE3_A/I part is unused and in its original packaging.
Return procedure for SMAJ20CAHE3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ20CAHE3_A/I Tags
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