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Vishay General Semiconductor - Diodes Division SMAJ20CAHM3/I
- Part No.:
- SMAJ20CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20CAHM3/I.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,213
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Product details
Overview
SMAJ20CAHM3/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 20 V standoff voltage (VWM), 22.2–24.5 V breakdown voltage (VBR) at 1 mA, clamps transients to ≤32.4 V at 12.3 A peak pulse current (IPPM), and delivers 400 W peak pulse power (10/1000 μs waveform). It is widely deployed in automotive ECUs, industrial sensor interfaces, and telecom power supplies.
For engineers reviewing the SMAJ20CAHM3/I datasheet, SMAJ20CAHM3/I pinout, SMAJ20CAHM3/I application, or SMAJ20CAHM3/I equivalent, this device is selected for its AEC-Q101 qualification, halogen-free RoHS-compliant construction (HM3 suffix), low clamping ratio (VC/VBR ≈ 1.42), and compatibility with automated SMT assembly on SMA (DO-214AC) footprint.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, enabling protection of AC-coupled or floating signal paths without polarity concerns. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 μA at VWM), while the 30 °C/W junction-to-lead thermal resistance supports reliable surge energy dissipation under repetitive transient conditions.
The device complies with ANSI/IEEE C62.35 for surge protector definitions and meets MSL Level 1 per J-STD-020 with 260 °C reflow peak. Its 120 °C/W junction-to-ambient thermal resistance reflects standard PCB mounting on 5.0 mm × 5.0 mm copper pads - critical for thermal design validation in high-reliability applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin. |
| VBR (min/max) | 22.2 V / 24.5 V at 1 mA - Confirmed breakdown threshold range; ensures predictable turn-on during transients. |
| VC @ IPPM | ≤32.4 V at 12.3 A - Clamped voltage under 10/1000 μs surge; determines protected circuit's maximum stress level. |
| PPPM | 400 W - Peak pulse power handling (10/1000 μs); defines single-event surge capability on standard layout. |
| IPPM | 12.3 A - Peak surge current corresponding to VC; used to size upstream fusing and trace routing. |
| TJ max. | +150 °C - Maximum junction temperature; sets thermal derating limits for ambient and power dissipation. |
| Package | SMA (DO-214AC) - Standard surface-mount outline with 5.28 mm × 4.50 mm body; compatible with JEDEC MS-013. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, UL 94 V-0 rated compound. Bidirectional configuration has no polarity marking - terminals are symmetrical and interchangeable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Transient conduction path | Both terminals function identically; conducts surge current in either direction when |V| > VBR. |
| Case | Non-electrical mechanical interface | No internal connection; serves only as thermal and mechanical interface to PCB copper pads. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for engine control and ADAS modules. |
| Halogen-free & RoHS-compliant (HM3) | Meets IEC 61249-2-21 and JEDEC JESD201 Class 2 whisker resistance - required for Tier-1 automotive supply chains. |
| 400 W peak pulse power (10/1000 μs) | Handles ISO 7637-2 Pulse 1/2a/5a surges without degradation when mounted per recommended pad layout. |
| Low clamping ratio (VC/VBR ≈ 1.42) | Minimizes voltage overshoot during clamping - critical for protecting 24 V logic interfaces and CAN transceivers. |
| MSL Level 1, 260 °C peak reflow | Enables single-pass lead-free reflow without moisture sensitivity concerns - eliminates bake requirements pre-assembly. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
|
Use Scenario: Protecting 24 V supply inputs in body control modules against load dump and inductive switching spikes per ISO 16750-2. IC Role / Device Role / Timing Role: Bidirectional clamping element placed directly at connector entry point before DC/DC converter input. Use Value: Limits transient voltage to ≤32.4 V, preventing damage to downstream PMICs and microcontrollers rated for 36 V absolute maximum. |
Use Scenario: Safeguarding analog outputs (e.g., 4–20 mA current loops) in factory automation sensors exposed to ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance (≈150 pF at 0 V) shunt protector across signal and return lines near connector. Use Value: Responds in <1 ps to clamp ±15 kV contact ESD (IEC 61000-4-2) without distorting low-bandwidth analog signals. |
| Telecom DC Power Interface | Consumer Device USB Port Protection |
|
Use Scenario: Securing -48 V DC feeding circuits in base station remote radio units against lightning-induced surges on long feeder cables. IC Role / Device Role / Timing Role: Primary surge suppression stage before hot-swap controller and intermediate bus converter. Use Value: Withstands 400 W pulses without parametric shift - maintains protection integrity after repeated 10/1000 μs transients up to 12.3 A. |
Use Scenario: Adding secondary-level surge immunity to USB Type-C VBUS lines in portable monitors and docking stations. IC Role / Device Role / Timing Role: Secondary TVS placed downstream of primary fuse and common-mode choke to catch residual transients. Use Value: Halogen-free HM3 construction satisfies regional environmental compliance (e.g., China RoHS II), while SMA package enables compact layout near connector. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20CAHE3/I | Same electrical specs and AEC-Q101 qualification, but RoHS-compliant without halogen-free designation (E3 vs HM3). | Acceptable where halogen-free is not mandated (e.g., non-automotive industrial use), but lacks JEDEC JESD201 Class 2 whisker resistance. | Select SMAJ20CAHE3/I only if halogen content restrictions do not apply and cost optimization is prioritized. |
| SMBJ20CAHM3/I | Same VWM, VBR, and VC, but SMB (DO-214AA) package - 30 % larger footprint and 50 % higher PPPM (600 W). | Better suited for higher-energy surge environments (e.g., outdoor telecom enclosures), but requires PCB layout change. | Choose SMBJ20CAHM3/I when system-level surge testing exceeds 400 W requirements and board space permits larger package. |
Compared with SMAJ20CAHE3/I, the SMAJ20CAHM3/I adds halogen-free compliance and whisker resistance for automotive use; compared with SMBJ20CAHM3/I, it trades surge margin for space-constrained layouts where 400 W is sufficient and SMA footprint is fixed.
Availability
SMAJ20CAHM3/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and telecom power supply designs requiring stable component supply with full AEC-Q101 traceability and halogen-free compliance.
Supply support for SMAJ20CAHM3/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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and application-specific performance.
The SMAJ series is engineered for high-speed transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where robustness, consistency, and regulatory compliance are mandatory.
FAQ
What does the "HM3" suffix mean in SMAJ20CAHM3/I?
The "HM3" suffix in SMAJ20CAHM3/I indicates halogen-free, RoHS-compliant construction meeting JEDEC JESD201 Class 2 whisker resistance requirements. It also confirms compliance with Vishay's material categorization standard for environmentally restricted substances, making SMAJ20CAHM3/I suitable for automotive applications requiring strict chemical content control.
Is SMAJ20CAHM3/I unidirectional or bidirectional?
SMAJ20CAHM3/I is a bidirectional TVS diode, as confirmed by the "CA" suffix in its part number. It provides symmetrical clamping for both positive and negative transients, with identical VBR, VC, and IPPM specifications in either polarity - ideal for protecting AC-coupled or floating signal paths without polarity constraints.
What is the maximum clamping voltage of SMAJ20CAHM3/I under surge conditions?
The maximum clamping voltage (VC) of SMAJ20CAHM3/I is 32.4 V at 12.3 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is guaranteed per the Vishay datasheet (Document Number: 88390, Rev. 09-Jan-2024) and defines the upper voltage limit imposed on protected circuitry during standardized surge events.
Does SMAJ20CAHM3/I meet AEC-Q101 qualification?
Yes, SMAJ20CAHM3/I is AEC-Q101 qualified, as explicitly stated in the Vishay ordering information table and thermal characteristics notes. The "HM3" suffix denotes halogen-free, RoHS-compliant, and AEC-Q101-qualified construction - validated for automotive applications including engine control, infotainment, and ADAS subsystems.
What is the thermal resistance from junction to ambient for SMAJ20CAHM3/I?
The typical junction-to-ambient thermal resistance (RθJA) of SMAJ20CAHM3/I is 120 °C/W, measured with the device mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes standard FR-4 PCB construction and is essential for calculating steady-state temperature rise under continuous power dissipation or evaluating thermal margin during repetitive surge events.
SMAJ20CAHM3/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:
- Discontinued at Digi-Key
- 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/I FAQ
1.How can I place an order for SMAJ20CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20CAHM3/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 SMAJ20CAHM3/I reliable?
The price and inventory of SMAJ20CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ20CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ20CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20CAHM3/I?
SMAJ20CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20CAHM3/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 SMAJ20CAHM3/I?
For technical support, including SMAJ20CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20CAHM3/I requirements.
6.How does Aetrix verify that SMAJ20CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ20CAHM3/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 SMAJ20CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ20CAHM3/I?
All SMAJ20CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20CAHM3/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 SMAJ20CAHM3/I part is unused and in its original packaging.
Return procedure for SMAJ20CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ20CAHM3/I Tags
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