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STMicroelectronics SMAJ24CA-TR
- Part No.:
- SMAJ24CA-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ24CA-TR.pdf
- Description:
- TVS DIODE 24VWM 50VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:17,474
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Product details
Overview
SMAJ24CA-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 24 V standoff voltage (VRM), 38.9 V clamping voltage at 10.3 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 SMAJ24CA-TR datasheet, SMAJ24CA-TR pinout, SMAJ24CA-TR application, or SMAJ24CA-TR equivalent, key selection criteria include bidirectional clamping behavior, low leakage (<0.2 µA @ 25 °C), JEDEC DO-214AC (SMA) package compatibility, and IEC 61000-4-2/4-4 compliance for system-level immunity validation.
Technical Context
This TVS diode uses planar silicon junction technology to achieve stable breakdown characteristics across temperature, with a typical dynamic resistance of 0.912 Ω at 25 °C and 0.446 Ω at 85 °C. Its bidirectional architecture enables symmetrical clamping on both polarities without external polarity biasing.
The device meets IEC 61000-4-2 Level 4 (±30 kV air/contact discharge) and IEC 61000-4-4 Level 4 (4 kV), supporting robust front-end protection for CAN transceivers, USB ports, and sensor interfaces where low capacitance (<100 pF at 1 V) and fast response (<1 ns) are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 24 V - maximum continuous reverse working voltage before conduction begins |
| Breakdown Voltage (VBR) | 26.7–28.1 V @ 1 mA - guaranteed avalanche onset range for reliable triggering |
| Clamping Voltage (VCL) | 38.9 V @ 10.3 A (10/1000 µs) - limits transient voltage seen by downstream ICs |
| Peak Pulse Power (PPP) | 400 W @ 10/1000 µs - sustains short-duration surges without degradation |
| Leakage Current (IRM) | ≤0.2 µA @ 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 |
| Package | DO-214AC (SMA) - surface-mount footprint compliant with IPC-7531, MSL Level 1 |
Pinout & Package
Package: DO-214AC (SMA), JEDEC-registered outline with cathode band marking; dimensions per DS1251 Rev 15: D = 2.25–2.90 mm, E = 4.80–5.35 mm, L = 0.75–1.50 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Current entry during positive transients | Connects to protected line; forms symmetrical clamping path with cathode |
| Cathode (banded end) | Current entry during negative transients | Provides bidirectional conduction path; referenced to ground or common rail |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity constraints |
| Low dynamic resistance | 0.912 Ω @ 25 °C ensures minimal voltage overshoot during high-current surges |
| High-temperature reliability | Rated to +150 °C Tj with <1 µA leakage at 85 °C supports under-hood and enclosed industrial use |
| IEC-compliant surge handling | Validated to IEC 61000-4-2 (±30 kV) and IEC 61000-4-4 (4 kV) for certified system immunity |
| Planar junction construction | Delivers tight parameter distribution and long-term stability vs. alloyed or diffused alternatives |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: 24 V DC input rail in programmable logic controllers exposed to load dump and inductive switching noise. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontrollers. Use Value: Limits transients to ≤38.9 V, preventing latch-up or permanent damage to 3.3 V/5 V logic supplies. |
Use Scenario: LIN bus transceiver interface subjected to ISO 7637-2 pulse 1/2a/3a and ESD events. IC Role / Device Role / Timing Role: Bidirectional TVS placed between LIN line and ground to suppress coupled surges. Use Value: Maintains signal integrity below 100 pF capacitance while surviving ±30 kV contact discharge. |
| USB 2.0 Port ESD Protection | Smart Sensor Signal Conditioning |
|
Use Scenario: VBUS and D+/D− lines in industrial USB host ports operating in factory-floor environments. IC Role / Device Role / Timing Role: Low-capacitance TVS array replacement for discrete protection on each data line. Use Value: Clamps ESD pulses within <1 ns while adding <50 pF per line - preserving USB 2.0 eye diagram. |
Use Scenario: Analog output of pressure/temperature sensors connected to PLC analog inputs over long cables. IC Role / Device Role / Timing Role: Secondary protection stage after series ferrite, shunting induced surges to ground. Use Value: Withstands repeated 10/1000 µs surges up to 400 W without parameter drift or leakage increase. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24CA-TR | Higher 600 W PPP rating (10/1000 µs); larger SMB package (DO-214AA) | Preferred where higher surge margin is required and PCB space allows larger footprint | Select when system-level testing reveals >400 W surge exposure or thermal derating is needed |
| SMCJ24CA-TR | 1500 W PPP rating (10/1000 µs); SMC package (DO-214AB), higher VCL (43.5 V) | Used in primary-level protection stages with higher energy threats (e.g., 120 V AC input) | Choose only if clamping voltage margin permits and board layout accommodates 7.11 mm × 6.22 mm footprint |
Compared with SMBJ24CA-TR and SMCJ24CA-TR, SMAJ24CA-TR offers optimal balance of compact size, 400 W surge capability, and 38.9 V clamping - making it ideal for secondary protection where space and voltage margin are constrained.
Availability
SMAJ24CA-TR is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, USB 2.0 port ESD protection, and smart sensor signal conditioning requiring stable component supply and full traceability.
Supply support for SMAJ24CA-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, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.
The SMAJ series belongs to ST's transient protection portfolio, engineered specifically for high-reliability, low-leakage, bidirectional ESD/surge suppression in space-constrained, thermally demanding applications.
FAQ
What is the difference between SMAJ24A-TR and SMAJ24CA-TR?
SMAJ24A-TR is unidirectional - conducts only during reverse-biased transients - while SMAJ24CA-TR is bidirectional, providing symmetrical clamping for both positive and negative voltage excursions. The 'C' suffix denotes bidirectional configuration, essential for AC-coupled or floating signal lines like LIN or RS-485.
Does SMAJ24CA-TR meet automotive qualification standards?
SMAJ24CA-TR is not AEC-Q200 qualified, but its −55 to +150 °C operating range, 150 °C max junction temperature, and IEC 61000-4-2/4-4 compliance make it widely used in non-safety-critical automotive subsystems such as body control modules and infotainment interfaces where customer-specific stress testing is performed.
Can SMAJ24CA-TR be used in parallel for higher surge current handling?
No - paralleling TVS diodes is not recommended due to mismatched breakdown voltages causing uneven current sharing. For higher surge ratings, select a single device with appropriate PPP (e.g., SMBJ24CA-TR for 600 W) or implement staged protection with series impedance.
What is the thermal resistance (Rth(j-a)) of SMAJ24CA-TR on a standard FR4 PCB?
On a standard FR4 board with 70 µm copper and recommended IPC-7531 footprint, Rth(j-a) is approximately 120 °C/W for a single pulse. This value drops significantly with added copper area - e.g., 4.5 °C/W with 5 cm² copper pour per lead - enabling sustained operation near Tj max.
SMAJ24CA-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):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 50V
- Current - Peak Pulse (10/1000µs):
- 46A (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)
SMAJ24CA-TR FAQ
1.How can I place an order for SMAJ24CA-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ24CA-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 SMAJ24CA-TR reliable?
The price and inventory of SMAJ24CA-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ24CA-TR is usually 5 days.
3.What payment methods are accepted for SMAJ24CA-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ24CA-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ24CA-TR?
SMAJ24CA-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ24CA-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 SMAJ24CA-TR?
For technical support, including SMAJ24CA-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ24CA-TR requirements.
6.How does Aetrix verify that SMAJ24CA-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ24CA-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 SMAJ24CA-TR meets industry standards.
7.What is the process for return or replacement of SMAJ24CA-TR?
All SMAJ24CA-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ24CA-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 SMAJ24CA-TR part is unused and in its original packaging.
Return procedure for SMAJ24CA-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ24CA-TR Tags
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