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Vishay General Semiconductor - Diodes Division SMAJ28CAHM3_A/H
- Part No.:
- SMAJ28CAHM3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ28CAHM3_A/H.pdf
- Description:
- TVS DIODE 28VWM 45.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,400
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Product details
Overview
SMAJ28CAHM3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal or power lines. It features a 28 V stand-off voltage (VWM), 31.1–34.4 V breakdown voltage (VBR) at 1 mA, 45.4 V maximum clamping voltage (VC) at 8.8 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform), used in automotive sensor protection and industrial I/O interface surge suppression.
For engineers reviewing the SMAJ28CAHM3_A/H datasheet, SMAJ28CAHM3_A/H pinout, SMAJ28CAHM3_A/H application, or SMAJ28CAHM3_A/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification (via HM3 suffix), 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 device operates as a voltage-clamping protector with symmetrical avalanche breakdown in both directions, enabling robust ESD and lightning surge suppression without polarity sensitivity. Its glass-passivated junction ensures stable leakage performance (<1 μA at VWM) and fast response time (<1.0 ps), critical for safeguarding MOSFET gates and microcontroller I/O pins.
The SMAJ28CAHM3_A/H delivers 400 W peak pulse power up to 78 V and derates to 300 W above that threshold, per JEDEC-standard 10/1000 μs waveform testing. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), supporting reliable operation under repetitive surge conditions when mounted per recommended pad layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 28 V - Maximum continuous reverse operating voltage before clamping begins; defines safe signal line operating margin. |
| VBR min/max | 31.1 V / 34.4 V at 1 mA - Confirmed breakdown range ensuring predictable turn-on during transients. |
| VC @ IPPM | 45.4 V at 8.8 A - Clamped voltage level limiting downstream component stress during 10/1000 μs surge events. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - Peak surge energy handling capacity under standardized waveform conditions. |
| ID @ VWM | <1 μA - Ultra-low reverse leakage preserves signal integrity and minimizes standby power loss. |
| TJ max | +150 °C - Enables deployment in under-hood automotive and high-temperature industrial environments. |
| Package | SMA (DO-214AC) - Surface-mount outline with 5.28 mm length, 4.50 mm width, and 2.29 mm height for compact PCB integration. |
Pinout & Package
Package: SMA (DO-214AC), molded plastic case with matte tin-plated leads, MSL Level 1 compliant (peak reflow 260 °C), halogen-free and RoHS-compliant (HM3 suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; cathode-defined polarity absent in bidirectional configuration | No marking on device body; terminals are functionally symmetric for AC or dual-rail transient suppression. |
| Cathode | Current exit terminal in forward bias; not applicable as polarity marker for bidirectional operation | Not designated - bidirectional behavior means either terminal serves as anode or cathode depending on transient polarity. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control modules and ADAS sensor interfaces. |
| 400 W peak pulse power | Withstands IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) on 24 V systems without degradation. |
| Glass passivated junction | Ensures long-term stability of VBR and low leakage across temperature and humidity stress cycles. |
| Low profile SMA package | Enables high-density placement near connectors and ICs while maintaining thermal performance via 0.2" × 0.2" copper pads. |
| Fast response time | <1.0 ps enables clamping before transient energy couples into sensitive circuitry. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
|
Use Scenario: Protecting CAN bus transceivers and analog sensor inputs (e.g., pressure, temperature) from load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed between signal line and ground, absorbing transients before they reach MCU or analog front-end. Use Value: Maintains signal integrity during 12 V/24 V system switching events with clamping voltage limited to 45.4 V, well below typical IC absolute maximum ratings. |
Use Scenario: Shielding digital input/output channels of programmable logic controllers against EFT bursts and surge coupling from motor drives. IC Role / Device Role / Timing Role: Standoff protector on field-side signal traces, activated only during overvoltage events to shunt current away from isolation barriers. Use Value: Enables compliance with IEC 61000-4-4 (EFT) and IEC 61000-4-5 (surge) standards using a single discrete component per line. |
| Consumer Power Adapter Interface | Telecom Line Card Surge Suppression |
|
Use Scenario: Safeguarding USB-C PD port protection circuits and AC-DC adapter secondary-side outputs from induced lightning surges. IC Role / Device Role / Timing Role: Secondary-side TVS placed across DC output rails to clamp common-mode transients before reaching downstream regulators. Use Value: Delivers 400 W surge handling with <1 μA leakage, minimizing no-load power loss while meeting UL 497B recognition requirements. |
Use Scenario: Protecting Ethernet PHY interfaces and POTS line drivers in telecom central office equipment exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-level transient suppressor on twisted-pair line inputs, coordinated with gas discharge tubes for staged protection. Use Value: Provides precise 45.4 V clamping to prevent damage to 3.3 V/5 V PHY ICs while supporting >100,000 surge events per MIL-STD-883H test method. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28CAHE3_A/H | Same electrical specs but RoHS-compliant commercial grade (E3), not halogen-free or AEC-Q101 qualified. | Lacks automotive qualification; suitable for industrial/commercial designs where AEC-Q101 is not mandated. | Select SMAJ28CAHE3_A/H for cost-sensitive non-automotive applications requiring identical clamping performance. |
| SMBJ28CAHM3_A/H | Higher 600 W peak pulse power rating, same VWM/VBR/VC, larger SMB (DO-214AA) package (5.3 mm × 4.6 mm). | Better thermal dissipation for higher-energy surge environments; requires larger PCB footprint. | Choose SMBJ28CAHM3_A/H when system-level surge testing exceeds 400 W or extended thermal cycling is required. |
Compared with SMAJ28CAHM3_A/H, SMAJ28CAHE3_A/H offers identical clamping but omits AEC-Q101 validation and halogen-free construction, while SMBJ28CAHM3_A/H trades compact size for 50 % higher surge power handling in a physically larger package.
Availability
SMAJ28CAHM3_A/H is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC I/O modules, and telecom line card designs requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ28CAHM3_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, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where consistent clamping performance and AEC-Q101 compliance are mandatory.
FAQ
What does the 'HM3' suffix indicate in SMAJ28CAHM3_A/H?
The HM3 suffix denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. This confirms SMAJ28CAHM3_A/H meets automotive-grade reliability standards including temperature cycling, humidity testing, and surge endurance-critical for use in engine control units and ADAS sensors where long-term field stability is essential.
Is SMAJ28CAHM3_A/H unidirectional or bidirectional?
SMAJ28CAHM3_A/H is a bidirectional TVS diode, as indicated by the 'CA' suffix. It provides symmetrical clamping in both polarities, making it ideal for AC-coupled signal lines, differential buses like CAN or RS-485, and any application where transient polarity cannot be predicted or controlled.
What is the maximum clamping voltage of SMAJ28CAHM3_A/H at its rated peak pulse current?
The maximum clamping voltage (VC) of SMAJ28CAHM3_A/H is 45.4 V at 8.8 A peak pulse current (IPPM), measured under the standard 10/1000 μs waveform. This value ensures protected circuits remain within safe operating limits during surge events, especially when interfacing with 3.3 V or 5 V logic devices.
Can SMAJ28CAHM3_A/H replace SMAJ28A in a design?
No-SMAJ28A is unidirectional, while SMAJ28CAHM3_A/H is bidirectional. Substituting SMAJ28CAHM3_A/H for SMAJ28A would eliminate polarity dependence but may alter circuit behavior in DC-biased applications. Always verify signal path topology and grounding scheme before replacement, as SMAJ28CAHM3_A/H has no cathode marking and functions identically in both directions.
What PCB pad layout is recommended for optimal thermal performance of SMAJ28CAHM3_A/H?
Vishay specifies mounting SMAJ28CAHM3_A/H on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal to achieve rated 400 W peak pulse power. Smaller pads reduce thermal dissipation and cause premature failure under repeated surges; use internal ground planes and thermal vias if board space allows to enhance heat spreading beyond the minimum requirement.
SMAJ28CAHM3_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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 8.8A
- 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)
SMAJ28CAHM3_A/H FAQ
1.How can I place an order for SMAJ28CAHM3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ28CAHM3_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 SMAJ28CAHM3_A/H reliable?
The price and inventory of SMAJ28CAHM3_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 SMAJ28CAHM3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ28CAHM3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ28CAHM3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ28CAHM3_A/H?
SMAJ28CAHM3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ28CAHM3_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 SMAJ28CAHM3_A/H?
For technical support, including SMAJ28CAHM3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ28CAHM3_A/H requirements.
6.How does Aetrix verify that SMAJ28CAHM3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ28CAHM3_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 SMAJ28CAHM3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ28CAHM3_A/H?
All SMAJ28CAHM3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ28CAHM3_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 SMAJ28CAHM3_A/H part is unused and in its original packaging.
Return procedure for SMAJ28CAHM3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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