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STMicroelectronics SMAJ24A-TR
- Part No.:
- SMAJ24A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ24A-TR.pdf
- Description:
- TVS DIODE 24VWM 50VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:29,045
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Product details
Overview
SMAJ24A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for primary-level 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 SMAJ24A-TR datasheet, SMAJ24A-TR pinout, SMAJ24A-TR application, or SMAJ24A-TR equivalent, key selection criteria include clamping performance under IEC 61000-4-2 (30 kV contact/air), low leakage (<0.2 µA @ 25 °C), JEDEC DO-214AC (SMA) package compatibility, and thermal robustness for high-reliability PCB layouts.
Technical Context
This TVS diode uses planar silicon junction technology to achieve low dynamic resistance (0.912 Ω) and stable clamping across temperature. Its unidirectional configuration enables asymmetric protection on positive-rail circuits without reverse conduction path concerns.
The device meets IEC 61000-4-4 Level 4 (4 kV) and exceeds IEC 61000-4-2 Level 4 (30 kV air/contact discharge), with junction capacitance of ~200 pF at 0 V (f = 1 MHz), making it suitable for <10 Mbps data lines and 24 V DC input stages where capacitive loading must remain constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 24 V - maximum continuous reverse operating voltage before breakdown; sets minimum system rail margin. |
| Breakdown Voltage (VBR) | 26.7–28.1 V @ 1 mA - ensures reliable triggering above nominal rail while avoiding false trips. |
| Clamping Voltage (VCL) | 38.9 V @ 10.3 A (10/1000 µs) - limits downstream voltage stress during surge events. |
| Peak Pulse Power (PPP) | 400 W @ 10/1000 µs - supports common lightning-induced surges per IEC 61000-4-5 Annex C. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C - minimizes standby power loss in battery-backed or energy-sensitive systems. |
| Junction Temperature Range | −55 to +150 °C - enables deployment in under-hood automotive or industrial enclosures without derating. |
| ESD Withstand (IEC 61000-4-2) | 30 kV air / 30 kV contact - exceeds Level 4 for robust human-body-model immunity. |
Pinout & Package
Supplied in JEDEC DO-214AC (SMA) surface-mount package with standardized IPC-7531 footprint. The device has two terminals: cathode (marked band) and anode, mounted on FR4 PCB with 70 µm copper thickness per recommended layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or return path; completes conduction loop during transient clamp. |
| Cathode (banded end) | Protected line connection | Connected to 24 V rail or signal line; absorbs surge energy by avalanche breakdown into ground. |
Key Features
| Feature | Design Value |
|---|---|
| Low clamping ratio (VCL/VBR) | 1.46 - tight voltage control preserves margin between clamp level and IC absolute maximum ratings. |
| High-temperature leakage stability | 1 µA @ 85 °C - ensures predictable leakage behavior in thermally stressed environments. |
| Matte tin-plated leads | JEDEC J-STD-002 compliant - guarantees solderability and intermetallic reliability after reflow. |
| Dynamic resistance (RD) | 0.912 Ω - reduces voltage overshoot during fast-rising transients (e.g., EFT bursts). |
| MSL Level 1 rating | Unlimited floor life - eliminates bake requirements prior to assembly. |
Applications
| Industrial PLC I/O Module | Automotive Body Control Unit (BCU) |
|---|---|
Use Scenario: 24 V DC input protection against load dump and ISO 7637-2 pulse 1/2a/5a. IC Role / Device Role / Timing Role: Primary surge suppressor on main power entry, placed upstream of DC/DC converter and microcontroller LDO. Use Value: Clamps to 38.9 V within nanoseconds, preventing overvoltage damage to 36 V-rated power management ICs and ensuring >100,000 surge cycles per MIL-STD-750 Method 2026. |
Use Scenario: Protection of LIN bus transceiver supply pins against battery reversal and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional rail clamp on 12 V/24 V switched supply feeding LIN PHY ICs. Use Value: Sub-µA leakage avoids battery drain in sleep mode; 150 °C operation sustains functionality during engine bay thermal soak. |
| Telecom Remote Radio Unit (RRU) | Medical Infusion Pump Power Stage |
Use Scenario: Surge suppression on 48 V PoE-derived auxiliary rail exposed to outdoor lightning coupling. IC Role / Device Role / Timing Role: First-line defense before DC/DC isolation stage; coordinated with MOV and gas discharge tube in multi-stage design. Use Value: 400 W rating handles 10/1000 µs surges up to 10.3 A; low capacitance avoids signal integrity impact on 100 Mbps Ethernet management interfaces. |
Use Scenario: Protection of motor driver FET gate supply against ESD from operator touch panels and cable disconnect arcs. IC Role / Device Role / Timing Role: Localized clamp on 15–24 V gate drive rail adjacent to half-bridge driver IC. Use Value: 30 kV ESD immunity prevents latch-up in safety-critical motor control logic; UL94 V0 flammability rating satisfies IEC 60601-1 enclosure requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A-TR | 600 W PPP (10/1000 µs), same VRM/VCL but higher IPP (17.3 A), larger SMB package (DO-214AA) | Requires more PCB area; better suited for higher-energy surges where space permits | Select when surge threat exceeds 400 W and board real estate allows SMB footprint. |
| SMCJ24A-TR | 1500 W PPP (10/1000 µs), identical VRM/VCL, DO-214AB package, higher thermal mass | Used in front-end AC/DC inputs or CAN bus protection where sustained energy dissipation is critical | Choose for primary-side protection where IEC 61000-4-5 combination wave testing applies. |
Compared with SMBJ24A-TR and SMCJ24A-TR, SMAJ24A-TR offers optimal balance of compact size, 400 W capability, and low leakage - ideal for space-constrained 24 V DC nodes where moderate surge exposure is expected and thermal budget is limited.
Availability
SMAJ24A-TR is available at Aetrix Electronics and suitable for industrial automation controllers, automotive body electronics, telecom remote units, and medical power subsystems requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMAJ24A-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 Voltage Suppressor portfolio, engineered specifically for cost-effective, high-reliability board-level ESD and surge protection in space-constrained, thermally demanding applications.
FAQ
What is the polarity configuration of SMAJ24A-TR?
SMAJ24A-TR is a unidirectional TVS diode, meaning it conducts only in reverse bias (cathode to anode) during overvoltage events. It behaves like a Zener diode with sharp avalanche breakdown at 26.7–28.1 V and blocks forward current up to 3.5 V typical VF, making it suitable for positive-rail protection only.
Does SMAJ24A-TR meet automotive qualification standards?
SMAJ24A-TR is not AEC-Q200 qualified, but its −55 to +150 °C operating range, 150 °C Tj max, and compliance with IEC 61000-4-2/4-4 make it widely used in non-safety-critical automotive applications such as body control modules and infotainment power rails where customer-specific validation is performed.
How does the 0.912 Ω dynamic resistance affect circuit protection?
The 0.912 Ω RD value directly determines voltage overshoot during fast transients: for a 10 A surge, additional IR drop is ~9.1 V, contributing to total clamping voltage. This low RD ensures tighter VCL control versus higher-RD alternatives, preserving margin for downstream 36 V-rated components.
Can SMAJ24A-TR be used in bidirectional signal line protection?
No - SMAJ24A-TR is unidirectional and unsuitable for AC or bidirectional signal lines (e.g., RS-485, USB). For such applications, the bidirectional variant SMAJ24CA-TR must be used, which clamps symmetrically for both polarities and exhibits matched VBR in either direction.
SMAJ24A-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:
- 1
- Bidirectional Channels:
- -
- 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)
SMAJ24A-TR FAQ
1.How can I place an order for SMAJ24A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ24A-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 SMAJ24A-TR reliable?
The price and inventory of SMAJ24A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ24A-TR is usually 5 days.
3.What payment methods are accepted for SMAJ24A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ24A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ24A-TR?
SMAJ24A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ24A-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 SMAJ24A-TR?
For technical support, including SMAJ24A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ24A-TR requirements.
6.How does Aetrix verify that SMAJ24A-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ24A-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 SMAJ24A-TR meets industry standards.
7.What is the process for return or replacement of SMAJ24A-TR?
All SMAJ24A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ24A-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 SMAJ24A-TR part is unused and in its original packaging.
Return procedure for SMAJ24A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ24A-TR Tags
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