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STMicroelectronics SMAJ33CA-TR
- Part No.:
- SMAJ33CA-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ33CA-TR.pdf
- Description:
- TVS DIODE 33VWM 69.7VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:24,364
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Product details
Overview
SMAJ33CA-TR from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for ESD and surge protection in DC power rails and signal lines. It features a 33 V standoff voltage (VRM), 53.3 V clamping voltage at 7.5 A (10/1000 µs), 400 W peak pulse power rating, and operates up to 150 °C junction temperature - deployed in industrial power supplies and automotive body control modules.
For engineers reviewing the SMAJ33CA-TR datasheet, SMAJ33CA-TR pinout, SMAJ33CA-TR application, or SMAJ33CA-TR equivalent, key selection criteria include bidirectional clamping behavior, low leakage (<0.2 µA at 25 °C), JEDEC DO-214AC (SMA) package compatibility, and IEC 61000-4-2/4-4 level 4 compliance for robust system-level ESD immunity.
Technical Context
This TVS diode uses planar silicon junction technology to achieve stable breakdown characteristics across temperature, with a 10.0 × 10⁻⁴/°C temperature coefficient (αT) for both VBR and VCL. Its bidirectional architecture enables symmetrical clamping on AC-coupled or floating lines without polarity constraints.
The device delivers 7.5 A peak pulse current (IPP) under 10/1000 µs waveform while maintaining 53.3 V clamping, and supports 69.7 A under 8/20 µs surge with 33 V clamping - enabling dual-use in both ESD and lightning-induced surge scenarios per IEC 61000-4-2 and IEC 61000-4-4.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 33 V - maximum continuous reverse operating voltage before conduction begins |
| Breakdown Voltage (VBR) | 36.7–38.6 V at 1 mA - precise threshold for reliable overvoltage triggering |
| Clamping Voltage (VCL) | 53.3 V at 7.5 A (10/1000 µs) - limits downstream voltage stress during surge events |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - sustains short-duration surges without thermal failure |
| Leakage Current (IRM) | 0.2 µA at 25 °C - minimizes standby power loss in battery-powered systems |
| Junction Temperature (Tj) | -55 to +150 °C - supports operation in under-hood automotive and industrial environments |
| ESD Rating | ±30 kV contact/air discharge (IEC 61000-4-2) - exceeds Level 4 immunity requirements |
Pinout & Package
Package: JEDEC DO-214AC (SMA), surface-mount, single-row two-terminal configuration with matte tin-plated leads compliant with J-STD-020 MSL level 1 and IPC-7531 footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Cathode Band Side) | Terminal 1 (marked side) | Bidirectional symmetry means either terminal serves as anode or cathode depending on polarity of transient |
| Cathode (Opposite Band Side) | Terminal 2 | No fixed polarity - terminals are functionally identical; device clamps symmetrically across both directions |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection on AC, differential, or floating signal paths without polarity alignment |
| Low dynamic resistance (RD) | 0.884 Ω - ensures minimal voltage overshoot during fast transients |
| High-temperature reliability | Rated for 150 °C Tj - maintains clamping performance in thermally stressed PCB layouts |
| JEDEC-compliant SMA footprint | Compatible with standard reflow profiles and automated assembly per J-STD-020 |
| UL94 V0 flammability rating | Meets safety standards for enclosure-integrated protection in certified end equipment |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: 24 V DC input rail exposed to load dump and ISO 7637-2 pulses in factory automation controllers. IC Role / Device Role / Timing Role: Primary surge clamp placed upstream of DC-DC converters and microcontroller power domains. Use Value: Limits transient voltage to ≤53.3 V during 7.5 A surges, preventing latch-up or damage to 3.3 V/5 V logic supplies. |
Use Scenario: LIN bus transceiver interface subjected to ESD events during vehicle assembly and service. IC Role / Device Role / Timing Role: Bidirectional ESD suppressor directly across LIN signal pair (LIN-H/L). Use Value: Withstands ±30 kV contact discharge without degradation, preserving signal integrity below 100 pF capacitance at 1 MHz. |
| Telecom PoE Interface | Medical Sensor Signal Conditioning |
|
Use Scenario: Ethernet data lines carrying 48 V power in IEEE 802.3af/at PoE switches. IC Role / Device Role / Timing Role: Secondary protection stage after primary gas discharge tube, absorbing residual energy. Use Value: Clamps induced surges to <55 V within nanoseconds, protecting PHY ICs rated for 57 V absolute max. |
Use Scenario: Analog front-end inputs of patient monitoring devices connected to external electrodes. IC Role / Device Role / Timing Role: Low-leakage (0.2 µA) ESD guard on high-impedance biopotential amplifiers. Use Value: Prevents input-stage saturation during handling ESD while introducing negligible offset error or bias current shift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33CA-TR | Higher 600 W PPP rating (10/1000 µs); larger SMB package (DO-214AA) | Better suited for higher-energy surges; requires larger PCB footprint | Select when surge current exceeds 7.5 A or thermal mass demands lower RθJA |
| SMCJ33CA-TR | 1500 W PPP rating (10/1000 µs); SMC package (DO-214AB), 3× larger than SMA | Used in main AC/DC input stages where energy levels exceed 400 W | Choose only if system-level testing confirms need for >10 A IPP capability |
Compared with SMBJ33CA-TR and SMCJ33CA-TR, SMAJ33CA-TR offers optimal space-constrained protection where 400 W surge handling suffices - delivering identical clamping performance in 40% less board area than SMB and 70% less than SMC, with verified MSL-1 manufacturability.
Availability
SMAJ33CA-TR is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, telecom PoE interfaces, and medical sensor signal conditioning requiring stable component supply and full traceability.
Supply support for SMAJ33CA-TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, power, MCU, and sensor solutions for industrial, automotive, and consumer markets.
The SMAJ series belongs to ST's transient protection portfolio, engineered specifically for compact, high-reliability ESD/surge suppression in space-constrained DC power and signal lines - emphasizing low leakage, tight VBR tolerance, and JEDEC-standardized manufacturability.
FAQ
What is the polarity configuration of SMAJ33CA-TR?
SMAJ33CA-TR is a bidirectional TVS diode: its terminals are functionally identical, with no designated anode or cathode. It clamps symmetrically for positive or negative transients, making it ideal for AC-coupled lines, differential buses like LIN or RS-485, and floating sensor inputs without polarity concerns.
Does SMAJ33CA-TR meet automotive qualification standards?
SMAJ33CA-TR is not AEC-Q200 qualified, but its -55 °C to +150 °C operating junction temperature range, 30 kV ESD rating, and IEC 61000-4-4 level 4 surge immunity make it widely used in non-safety-critical automotive applications such as body control modules, infotainment interfaces, and lighting control units where customer-specific validation is performed.
How does the 0.884 Ω dynamic resistance affect circuit protection?
The 0.884 Ω dynamic resistance (RD) directly determines voltage overshoot during fast transients: for a 7.5 A surge, RD contributes ~6.6 V additional clamping beyond VBR, ensuring total VCL stays at 53.3 V. This low RD value minimizes energy dissipation in downstream components and improves response fidelity for sub-microsecond ESD events.
Can SMAJ33CA-TR replace SMAJ33A-TR in unidirectional designs?
No - SMAJ33A-TR is unidirectional and conducts only in reverse bias, while SMAJ33CA-TR clamps in both directions. Substituting CA for A in a DC-biased rail may cause unintended forward conduction or increased leakage. Use SMAJ33CA-TR only where bidirectional clamping is explicitly required by the circuit topology.
SMAJ33CA-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 69.7V
- Current - Peak Pulse (10/1000µs):
- 33A (8/20µs)
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ33CA-TR FAQ
1.How can I place an order for SMAJ33CA-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ33CA-TR 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 SMAJ33CA-TR reliable?
The price and inventory of SMAJ33CA-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ33CA-TR is usually 5 days.
3.What payment methods are accepted for SMAJ33CA-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ33CA-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ33CA-TR?
SMAJ33CA-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ33CA-TR 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 SMAJ33CA-TR?
For technical support, including SMAJ33CA-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ33CA-TR requirements.
6.How does Aetrix verify that SMAJ33CA-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ33CA-TR 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 SMAJ33CA-TR meets industry standards.
7.What is the process for return or replacement of SMAJ33CA-TR?
All SMAJ33CA-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ33CA-TR, 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 SMAJ33CA-TR part is unused and in its original packaging.
Return procedure for SMAJ33CA-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ33CA-TR Tags
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