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Vishay General Semiconductor - Diodes Division SMAJ20CAHM3_A/H
- Part No.:
- SMAJ20CAHM3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20CAHM3_A/H.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ20CAHM3_A/H 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 and power lines. It features 20 V standoff 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 (10/1000 μs waveform), commonly used to protect MOSFET gates, sensor interfaces, and automotive ECUs against ESD and load dump.
For engineers reviewing the SMAJ20CAHM3_A/H datasheet, SMAJ20CAHM3_A/H pinout, SMAJ20CAHM3_A/H application, or SMAJ20CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, halogen-free RoHS compliance, low thermal resistance (RθJL = 30 °C/W), 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 paths without polarity concerns. Its glass-passivated junction ensures stable breakdown characteristics and fast response time (<1 ns), while the SMA package supports high surge current handling (IPPM = 12.3 A) under repetitive 0.01% duty cycle conditions.
The device is rated for continuous operation from –55 °C to +150 °C junction temperature, with thermal resistance RθJA = 120 °C/W (on standard PCB pad layout) and RθJL = 30 °C/W - critical for thermal management in compact automotive and industrial modules where heatsinking is limited.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - maximum reverse working voltage before significant leakage; defines safe operating range for protected line |
| VBR min/max | 22.2 V / 24.5 V at 1 mA - guaranteed breakdown threshold ensures predictable clamping onset |
| VC @ IPPM | 32.4 V at 12.3 A - limits transient voltage seen by downstream ICs during 10/1000 μs surge |
| PPPM | 400 W - peak pulse power rating per JEDEC standard; sufficient for ISO 7637-2 Pulse 1/2a/3a and IEC 61000-4-5 Level 3 |
| IFSM | 40 A - non-repetitive forward surge current rating (8.3 ms half-sine); relevant for unidirectional variants only (not applicable here) |
| TJ max | +150 °C - enables use in under-hood automotive environments and industrial enclosures without derating |
| Package | SMA (DO-214AC) - industry-standard 2-pin SMD outline; compatible with IPC-7351B footprint and reflow profiles up to 260 °C peak |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102, qualified to MSL level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (positive half-cycle) | One terminal of symmetrical PN junction; conducts when voltage exceeds VBR in either polarity |
| Cathode | Transient current entry (negative half-cycle) | Second terminal of symmetrical structure; identical electrical behavior to Anode in bidirectional mode |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC signals, differential buses (e.g., CAN, RS-485), and floating power rails without external polarity logic |
| AEC-Q101 qualified | Validated for automotive applications including engine control, body electronics, and ADAS sensors per stress test requirements |
| Halogen-free & RoHS-compliant | Meets EU Directive 2011/65/EU and JEDEC J-STD-20E; supports green manufacturing and end-of-life recycling compliance |
| 400 W peak pulse power | Withstands repeated 10/1000 μs transients up to 12.3 A without degradation - sufficient for ISO 16750-2 load dump simulation |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ESD ±15 kV contact discharge), improving system-level immunity margin |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed microcontroller power inputs in vehicle body control modules against load dump surges (ISO 16750-2 Pulse 5a). IC Role / Device Role / Timing Role: Bidirectional TVS clamps transients above 32.4 V while passing normal 12–14 V supply; no DC blocking required. Use Value: Prevents latch-up or permanent damage to MCU LDO regulators and internal circuitry during alternator field collapse events. | Use Scenario: Safeguarding analog output lines (0–10 V, 4–20 mA) of pressure/temperature sensors in factory automation PLC I/O modules. IC Role / Device Role / Timing Role: Fast-response TVS absorbs induced switching noise from nearby contactors or VFDs without affecting signal fidelity. Use Value: Maintains measurement accuracy by limiting transient-induced offset errors and preventing ADC saturation or reset events. |
| Automotive CAN Bus Protection | Consumer USB Port ESD Protection |
Use Scenario: Placing across CAN_H/CAN_L differential pair in automotive infotainment head units to meet ISO 11898-2 EMC requirements. IC Role / Device Role / Timing Role: Symmetrical clamping maintains common-mode rejection ratio (CMRR) while suppressing ±30 kV ESD (IEC 61000-4-2) on both lines. Use Value: Ensures bus integrity during hot-plug events and prevents CAN controller lockup without adding series impedance or timing skew. | Use Scenario: Integrated into USB 2.0 Type-A port ESD protection network on smart home hub PCBs exposed to user-handling discharge. IC Role / Device Role / Timing Role: Low-capacitance (typ. 150 pF at 0 V) bidirectional TVS shunts ESD energy before it reaches USB transceiver PHY. Use Value: Passes USB-IF compliance testing (USB2.0 HS eye diagram) while achieving >±15 kV air/±8 kV contact IEC 61000-4-2 immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20CAHE3_A/H | RoHS-compliant but not halogen-free; same electrical specs and AEC-Q101 qualification | Preferred for commercial-grade automotive modules where halogen content is unrestricted | Select when cost sensitivity outweighs halogen-free requirement and full AEC-Q101 validation is mandatory |
| SMAJ20AHE3_A/H | Unidirectional variant; cathode band marked; VF = 3.5 V at 25 A (forward conduction) | Required only for DC-biased lines where reverse conduction must be blocked (e.g., 5 V rail input) | Choose only if circuit topology mandates polarity-aware clamping and reverse leakage must be minimized below 1 μA |
Compared with SMAJ20CAHM3_A/H, the HE3 variant trades halogen-free status for lower unit cost without sacrificing AEC-Q101 reliability, while the unidirectional SMAJ20AHE3_A/H adds forward voltage drop and polarity dependency - making it unsuitable for AC or floating signal protection unless explicitly required.
Availability
SMAJ20CAHM3_A/H is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor systems, and consumer USB interface designs requiring stable component supply, AEC-Q101 validation, and halogen-free compliance.
Supply support for SMAJ20CAHM3_A/H 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 is engineered specifically for robust transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where high-energy surges, thermal cycling, and long-term stability are critical design constraints.
FAQ
What does the "CA" suffix indicate in SMAJ20CAHM3_A/H?
The "CA" suffix denotes a bidirectional configuration, meaning SMAJ20CAHM3_A/H provides symmetrical clamping in both polarities - essential for protecting AC-coupled lines, differential buses like CAN or RS-485, and floating power domains without polarity concerns. Unlike unidirectional "A" variants, SMAJ20CAHM3_A/H has no cathode band marking and identical VBR and VC in either direction.
Is SMAJ20CAHM3_A/H qualified for automotive use?
Yes, SMAJ20CAHM3_A/H is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3_X", where "H" indicates AEC-Q101 qualification and "M3" denotes halogen-free RoHS compliance. This makes SMAJ20CAHM3_A/H suitable for under-hood and chassis-mounted automotive applications including body control modules, ADAS sensors, and infotainment systems.
What is the maximum clamping voltage of SMAJ20CAHM3_A/H at its rated peak pulse current?
The maximum clamping voltage (VC) of SMAJ20CAHM3_A/H is 32.4 V at 12.3 A peak pulse current (IPPM) under the standard 10/1000 μs waveform. This value is measured per JEDEC standards and guarantees that downstream components will not experience voltages exceeding 32.4 V during specified surge events - a key parameter for ensuring robustness of 3.3 V or 5 V logic interfaces.
How does the SMA package of SMAJ20CAHM3_A/H impact thermal performance?
The SMA (DO-214AC) package of SMAJ20CAHM3_A/H delivers RθJL = 30 °C/W (junction-to-lead) and RθJA = 120 °C/W (junction-to-ambient on 5.0 mm × 5.0 mm copper pads). This allows SMAJ20CAHM3_A/H to dissipate 400 W pulses without exceeding TJ = 150 °C when properly mounted, supporting reliable operation in space-constrained automotive and industrial PCB layouts where active cooling is unavailable.
Can SMAJ20CAHM3_A/H replace SMAJ20AHE3_A/H in a design?
No - SMAJ20CAHM3_A/H is bidirectional while SMAJ20AHE3_A/H is unidirectional with a cathode band marking and forward voltage drop (VF = 3.5 V at 25 A). Substituting SMAJ20CAHM3_A/H for SMAJ20AHE3_A/H may cause unintended conduction on DC-biased lines. Always verify circuit polarity and clamping symmetry requirements before interchange; SMAJ20CAHM3_A/H is not a drop-in replacement for unidirectional variants.
SMAJ20CAHM3_A/H 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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ20CAHM3_A/H FAQ
1.How can I place an order for SMAJ20CAHM3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20CAHM3_A/H 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 SMAJ20CAHM3_A/H reliable?
The price and inventory of SMAJ20CAHM3_A/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20CAHM3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ20CAHM3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20CAHM3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20CAHM3_A/H?
SMAJ20CAHM3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20CAHM3_A/H 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 SMAJ20CAHM3_A/H?
For technical support, including SMAJ20CAHM3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20CAHM3_A/H requirements.
6.How does Aetrix verify that SMAJ20CAHM3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ20CAHM3_A/H 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 SMAJ20CAHM3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ20CAHM3_A/H?
All SMAJ20CAHM3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20CAHM3_A/H, 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 SMAJ20CAHM3_A/H part is unused and in its original packaging.
Return procedure for SMAJ20CAHM3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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