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Vishay General Semiconductor - Diodes Division SMAJ20AHM3_A/I
- Part No.:
- SMAJ20AHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ20AHM3_A/I.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ20AHM3_A/I from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal 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). It is used to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial power supplies.
For engineers reviewing the SMAJ20AHM3_A/I datasheet, SMAJ20AHM3_A/I pinout, SMAJ20AHM3_A/I application, or SMAJ20AHM3_A/I equivalent, key selection criteria include unidirectional polarity, 20 V stand-off rating, 32.4 V clamping performance under 12.3 A surge, AEC-Q101 qualification status, and halogen-free RoHS-compliant construction per HM3 suffix.
Technical Context
This TVS diode operates as a fast-acting shunt protector: under normal conditions it presents high impedance (>1 MΩ leakage at 20 V), but triggers into low-impedance conduction when reverse voltage exceeds VBR (~23.4 V typical), limiting transient energy by clamping to ≤32.4 V. Its glass-passivated junction enables sub-nanosecond response time and stable surge handling.
The device is rated for 40 A non-repetitive forward surge (IFSM, 8.3 ms half-sine) and 150 °C max junction temperature. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), requiring minimum 5.0 mm × 5.0 mm copper pads for full 400 W pulse rating per JEDEC standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before significant leakage; defines safe working range for protected line. |
| VBR (min/max) | 22.2 V / 24.5 V at 1 mA - Confirmed breakdown threshold; ensures reliable triggering above system nominal voltage. |
| VC @ IPPM | 32.4 V at 12.3 A - Clamped voltage during 10/1000 μs surge; determines maximum stress imposed on downstream ICs. |
| PPPM | 400 W (≤78 V) - Peak pulse power handling with standard waveform; validates protection level against IEC 61000-4-5 surges. |
| ID @ VWM | 1.0 μA - Reverse leakage at 20 V; negligible loading on 3.3 V/5 V/12 V rails during normal operation. |
| TJ max. | +150 °C - Maximum junction temperature; supports under-hood automotive and industrial ambient environments. |
| Package | SMA (DO-214AC) - Standard surface-mount outline with cathode band marking; compatible with automated pick-and-place. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, MSL Level 1 (JEDEC J-STD-020), 260 °C reflow peak. Cathode indicated by band on body; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink node | Connected to protected line; conducts surge current to ground when VREV > VBR. |
| Anode (unbanded end) | Reference/return path | Typically tied to system ground or low-impedance return; completes clamping path during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TCT, ESD, and surge robustness. |
| Halogen-free & RoHS-compliant (HM3) | Meets environmental compliance mandates for Tier-1 automotive and industrial OEMs without compromising surge performance. |
| 400 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 Level 4 (4 kV) surges on 50 Ω source impedance when properly mounted. |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes overvoltage overshoot during clamping-critical for protecting 24 V-rated logic and gate drivers. |
| Glass-passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter drift in harsh environments. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Guarding |
|---|---|
|
Use Scenario: 12 V/24 V battery-fed ECUs exposed to load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional shunt clamp placed between power rail and chassis ground to limit transients to <33 V. Use Value: Prevents latch-up or gate oxide damage in microcontrollers and CAN transceivers during 120 V/200 ms load dump events. |
Use Scenario: Analog output lines (e.g., 4–20 mA, 0–10 V) from pressure/temperature sensors in factory automation. IC Role / Device Role / Timing Role: Low-capacitance (<100 pF) TVS placed differential or common-mode across signal pair to suppress EFT/burst noise. Use Value: Maintains signal integrity below ±0.1% error while surviving 4 kV contact ESD (IEC 61000-4-2) without degradation. |
| DC-DC Converter Input Stage | MOSFET Gate Driver Protection |
|
Use Scenario: Input stage of 24 V → 5 V buck converter subjected to back-EMF from relay coils and motor commutation. IC Role / Device Role / Timing Role: Primary overvoltage clamp upstream of input capacitor and controller IC. Use Value: Limits input rail spikes to ≤32.4 V, preventing overvoltage shutdown or internal LDO failure in PMICs. |
Use Scenario: High-side N-channel MOSFET gate drive circuit in half-bridge motor driver with inductive flyback. IC Role / Device Role / Timing Role: Clamp placed between gate and source to suppress Miller-induced voltage spikes during switching transitions. Use Value: Avoids unintended turn-on or gate oxide breakdown by holding VGS ≤ ±20 V during dV/dt events up to 50 V/ns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20AHE3_A/I | Same electrical specs, but RoHS-compliant (E3) without halogen-free certification; not AEC-Q101 qualified. | Limited to commercial-grade industrial or consumer systems where automotive qualification is not required. | Select when cost sensitivity outweighs halogen-free or automotive qualification needs. |
| SMBJ20A-HM3_A/I | Same VWM/VBR/VC, but SMB (DO-214AA) package - 29 % larger footprint and 15 % higher RθJA (139 °C/W). | Better thermal margin for sustained surge duty cycles; requires PCB layout change due to larger pad area. | Choose when higher thermal mass or legacy SMB footprint compatibility is prioritized over space-constrained layouts. |
Compared with SMAJ20AHM3_A/I, SMAJ20AHE3_A/I lacks halogen-free and AEC-Q101 validation, while SMBJ20A-HM3_A/I trades compactness for improved thermal derating-making SMAJ20AHM3_A/I optimal for space-constrained, automotive-qualified 24 V systems.
Availability
SMAJ20AHM3_A/I is available at Aetrix Electronics and suitable for automotive ECUs, industrial sensor interfaces, DC-DC converter inputs, and MOSFET gate driver circuits requiring stable component supply with AEC-Q101 assurance and halogen-free compliance.
Supply support for SMAJ20AHM3_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, MOSFETs, and protection devices with emphasis on reliability, automotive qualification, and high-volume manufacturability.
The SMAJ series was engineered specifically for robust, surface-mount transient suppression in automotive power networks and industrial control systems-balancing low clamping voltage, fast response, and AEC-Q101 compliance in compact SMA packages.
FAQ
What is the clamping voltage of the SMAJ20AHM3_A/I under a 10/1000 μs surge?
The SMAJ20AHM3_A/I clamps to a maximum of 32.4 V when subjected to its rated peak pulse current of 12.3 A with a 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and reflects worst-case voltage seen by downstream components during surge events. The SMAJ20AHM3_A/I maintains this clamping performance across its full operating temperature range (−55 °C to +150 °C) when mounted per recommended pad layout.
Is the SMAJ20AHM3_A/I AEC-Q101 qualified?
Yes, the SMAJ20AHM3_A/I is AEC-Q101 qualified, as confirmed by Vishay's ordering code suffix "HM3_A/I", where "H" denotes AEC-Q101 qualification and "M3" indicates halogen-free RoHS compliance. Test reports cover HTOL, temperature cycling, mechanical shock, ESD (HBM ≥8 kV), and surge robustness-validating suitability for automotive powertrain and body electronics applications.
What does the "HM3" suffix mean in SMAJ20AHM3_A/I?
The "HM3" suffix in SMAJ20AHM3_A/I specifies halogen-free, RoHS-compliant construction with AEC-Q101 qualification. "H" = AEC-Q101 qualified; "M3" = halogen-free and RoHS-compliant (per IEC 61249-2-21); "_A/I" denotes packaging variant: "A" = revision code, "I" = 13-inch tape-and-reel (7500 units). This distinguishes it from E3 (RoHS only) or HE3 (AEC-Q101 + RoHS, non-halogen-free) variants.
Can SMAJ20AHM3_A/I be used in bidirectional configurations?
No, SMAJ20AHM3_A/I is a unidirectional TVS diode, identifiable by its cathode band marking and specified VBR/VC parameters for reverse-bias operation only. For bidirectional protection, Vishay offers the SMAJ20CA variant (e.g., SMAJ20CAHM3_A/I), which provides symmetrical clamping in both polarities and no polarity marking. Using SMAJ20AHM3_A/I in bidirectional circuits risks forward conduction and failure during positive transients.
What is the thermal resistance of SMAJ20AHM3_A/I, and how does it affect layout?
The SMAJ20AHM3_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 achieve its full 400 W peak pulse rating, it must be mounted on minimum 5.0 mm × 5.0 mm copper pads per terminal per JEDEC standards. Smaller pads increase thermal impedance, reducing surge capability and risking junction overheating during repetitive transients.
SMAJ20AHM3_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:
- 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:
- 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)
SMAJ20AHM3_A/I FAQ
1.How can I place an order for SMAJ20AHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ20AHM3_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 SMAJ20AHM3_A/I reliable?
The price and inventory of SMAJ20AHM3_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 SMAJ20AHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ20AHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ20AHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ20AHM3_A/I?
SMAJ20AHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ20AHM3_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 SMAJ20AHM3_A/I?
For technical support, including SMAJ20AHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ20AHM3_A/I requirements.
6.How does Aetrix verify that SMAJ20AHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ20AHM3_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 SMAJ20AHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ20AHM3_A/I?
All SMAJ20AHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ20AHM3_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 SMAJ20AHM3_A/I part is unused and in its original packaging.
Return procedure for SMAJ20AHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ20AHM3_A/I Tags
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