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Vishay General Semiconductor - Diodes Division SMAJ33CAHM3/I
- Part No.:
- SMAJ33CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ33CAHM3/I.pdf
- Description:
- TVS DIODE 33VWM 53.3VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,856
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Product details
Overview
SMAJ33CAHM3/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 33 V standoff voltage (VWM), 53.3 V maximum clamping voltage at 7.5 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform.
For engineers reviewing the SMAJ33CAHM3/I datasheet, SMAJ33CAHM3/I pinout, SMAJ33CAHM3/I application, or SMAJ33CAHM3/I equivalent, this device is selected for robust ESD and surge protection in automotive sensor interfaces, industrial I/O modules, and telecom line drivers where bidirectional transient suppression and AEC-Q101 qualification are required.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, with breakdown voltage (VBR) ranging from 36.7 V to 40.6 V at 1 mA test current and ±0.1 %/°C temperature coefficient. Its low clamping ratio (VC/VWM ≈ 1.61) ensures effective overvoltage limiting during fast transients.
Designed for automated SMT assembly, it meets MSL Level 1 per J-STD-020, supports 260 °C lead-free reflow, and delivers 40 A non-repetitive forward surge capability (IFSM) - critical for surviving load-dump events in 12 V automotive systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 33 V - Maximum continuous reverse operating voltage before clamping begins; defines safe operating margin for 24–32 V nominal circuits. |
| VBR min/max | 36.7 V / 40.6 V at 1 mA - Confirmed breakdown range ensures predictable turn-on behavior under transient stress. |
| VC @ IPPM | 53.3 V at 7.5 A - Clamping voltage limits downstream IC stress during 10/1000 μs surges; enables compatibility with 3.3 V/5 V logic rails via series impedance. |
| PPPM | 400 W - Peak pulse power handling with 10/1000 μs waveform; sufficient for ISO 7637-2 Pulse 1/2a/3a and IEC 61000-4-5 Level 3 surges. |
| ID @ VWM | 1.0 μA - Ultra-low leakage preserves signal integrity and battery life in always-on sensor nodes. |
| TJ max | +150 °C - Enables operation in under-hood automotive environments and high-temperature industrial enclosures. |
| Package | SMA (DO-214AC) - Standardized 2-pin surface-mount outline with 5.0 mm × 5.0 mm copper pad thermal design; compatible with IPC-7351B footprint. |
Pinout & Package
Package: SMA (DO-214AC), bidirectional configuration - no polarity marking; symmetrical terminals function as anode and cathode depending on transient polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Terminal 1 | Anode/Cathode (bidirectional) | Either terminal conducts during positive or negative transients; no fixed polarity - enables single-device protection of AC-coupled or differential lines. |
| Terminal 2 | Anode/Cathode (bidirectional) | Paired terminal completing the symmetrical clamp path; requires identical PCB trace routing to maintain balanced surge response. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control, ADAS sensors, and infotainment power rails - supports PPAP documentation and zero-defect reliability targets. |
| Halogen-free & RoHS-compliant (HM3 suffix) | Meets EU Directive 2011/65/EU and JEDEC J-STD-201 Class 2 whisker resistance - suitable for green manufacturing and export compliance. |
| 400 W peak pulse power (10/1000 μs) | Handles repetitive surge events up to 0.01 % duty cycle without degradation - ideal for industrial motor drives with frequent switching noise. |
| Low clamping voltage (53.3 V) | Minimizes voltage overshoot across protected ICs - protects 36 V-rated CAN transceivers and 40 V-input DC-DC controllers without derating. |
| MSL Level 1, 260 °C reflow | Eliminates moisture sensitivity concerns and pre-bake requirements - reduces SMT line downtime and improves first-pass yield. |
Applications
| Automotive Sensor Protection | Industrial PLC Analog Input |
|---|---|
|
Use Scenario: Protecting LIN bus and analog sensor outputs (e.g., pressure, temperature) from load dump and inductive kickback in vehicle body electronics. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed between sensor output and microcontroller ADC input or LIN transceiver. Use Value: Prevents latch-up or permanent damage to 5 V tolerant MCU pins during 12 V system transients; maintains signal fidelity below 33 V operating window. |
Use Scenario: Safeguarding 4–20 mA current loop inputs and ±10 V analog inputs in programmable logic controllers against field wiring surges and ESD. IC Role / Device Role / Timing Role: Primary transient suppressor mounted at connector entry point, upstream of precision op-amp front-end. Use Value: Limits transient energy to <100 mJ per event, preserving 16-bit ADC accuracy and avoiding calibration drift caused by repeated overstress. |
| Telecom Line Interface | Consumer USB Power Delivery |
|
Use Scenario: Shielding RS-485/RS-422 transceivers and Ethernet PHYs from lightning-induced surges on outdoor cabling in base station equipment. IC Role / Device Role / Timing Role: First-stage protector on differential pair, coordinated with GDT or MOV secondary stages. Use Value: Responds within <1 ns to clamp common-mode transients up to 1 kV, reducing secondary stage stress and extending system MTBF. |
Use Scenario: Adding secondary-level surge immunity to USB-C PD port VBUS lines beyond primary front-end protection in portable docking stations. IC Role / Device Role / Timing Role: Secondary TVS placed after fuse and primary MOV, clamping residual spikes that bypass upstream components. Use Value: Ensures VBUS remains below 28 V during IEC 61000-4-5 4 kV tests - prevents USB PD controller shutdown and maintains negotiated power contracts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ33CAHE3/I | Same electrical specs, but RoHS-compliant with tin-lead finish (not halogen-free); lacks JESD201 Class 2 whisker resistance. | Suitable for commercial-grade industrial controls where halogen-free requirement is not mandated. | Select SMAJ33CAHE3/I only if halogen-free certification is not required and cost optimization is prioritized. |
| SMBJ33CAHM3/I | Same VWM and VC, but SMB (DO-214AA) package - 20 % larger footprint and 10 % higher RθJA (145 °C/W vs. 120 °C/W). | Better suited for lower-power applications or where board space allows larger pads for enhanced thermal dissipation. | Choose SMBJ33CAHM3/I when higher surge repetition rate (>0.01 % duty cycle) or manual rework accessibility is needed. |
Compared with SMAJ33CAHE3/I, the SMAJ33CAHM3/I offers halogen-free compliance and whisker resistance for automotive use; versus SMBJ33CAHM3/I, it provides tighter board space utilization and superior thermal performance in dense layouts - making it optimal for AEC-Q101-compliant compact modules.
Availability
SMAJ33CAHM3/I is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC analog inputs, and telecom line protection requiring stable component supply across multi-year production cycles.
Supply support for SMAJ33CAHM3/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, efficiency, and application-specific validation.
The SMAJ series is engineered for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where robustness against ESD, lightning, and switching surges is mandatory.
FAQ
What is the clamping voltage of SMAJ33CAHM3/I at its rated peak pulse current?
The SMAJ33CAHM3/I has a maximum clamping voltage (VC) of 53.3 V at 7.5 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is measured under standardized test conditions and defines the upper voltage limit imposed on protected circuitry during transient events - critical for ensuring downstream ICs remain within absolute maximum ratings. The SMAJ33CAHM3/I maintains this clamping performance across its full operating temperature range.
Is SMAJ33CAHM3/I suitable for automotive applications?
Yes, SMAJ33CAHM3/I is AEC-Q101 qualified and manufactured with halogen-free, RoHS-compliant materials - meeting stringent automotive reliability and environmental standards. It is explicitly designated for use in engine control units, ADAS sensors, and body electronics where exposure to load dump, jump start, and ISO 7637-2 pulses is expected. The SMAJ33CAHM3/I's 150 °C junction rating and MSL Level 1 handling further validate its suitability for under-hood deployment.
How does the bidirectional configuration of SMAJ33CAHM3/I affect its PCB layout?
The SMAJ33CAHM3/I has no polarity marking and functions identically in both directions - simplifying layout by eliminating orientation constraints. Engineers can place it symmetrically across differential lines (e.g., RS-485) or AC-coupled signals without concern for anode/cathode alignment. However, matched trace lengths and identical copper pour on both terminals are essential to preserve balanced clamping response and avoid skew during fast transients.
What is the thermal resistance of SMAJ33CAHM3/I, and how does it impact power dissipation?
The SMAJ33CAHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value determines steady-state temperature rise under continuous power dissipation - for example, at its rated 3.3 W power dissipation (PD), junction temperature rises ~396 °C above ambient, confirming that PD applies only to DC or low-duty-cycle conditions. The SMAJ33CAHM3/I relies on short-duration pulse handling (PPPM), not continuous power, for surge protection.
Does SMAJ33CAHM3/I require derating at elevated ambient temperatures?
Yes, the peak pulse power rating of SMAJ33CAHM3/I must be derated above TA = 25 °C per Figure 2 in the datasheet - linearly decreasing to ~50 % at 100 °C ambient. This derating ensures safe junction temperature margins during repetitive surge events. For designs operating continuously above 70 °C, thermal simulation or empirical testing with the actual PCB layout is recommended to confirm sustained clamping performance. The SMAJ33CAHM3/I's specified TJ max of +150 °C sets the absolute upper boundary for such validation.
SMAJ33CAHM3/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):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 7.5A
- 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)
SMAJ33CAHM3/I FAQ
1.How can I place an order for SMAJ33CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ33CAHM3/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 SMAJ33CAHM3/I reliable?
The price and inventory of SMAJ33CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ33CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ33CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ33CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ33CAHM3/I?
SMAJ33CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ33CAHM3/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 SMAJ33CAHM3/I?
For technical support, including SMAJ33CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ33CAHM3/I requirements.
6.How does Aetrix verify that SMAJ33CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ33CAHM3/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 SMAJ33CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ33CAHM3/I?
All SMAJ33CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ33CAHM3/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 SMAJ33CAHM3/I part is unused and in its original packaging.
Return procedure for SMAJ33CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ33CAHM3/I Tags
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