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STMicroelectronics SMAJ48A-TR
- Part No.:
- SMAJ48A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ48A-TR.pdf
- Description:
- TVS DIODE 48VWM 100VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:29,599
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Product details
Overview
SMAJ48A-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 48 V standoff voltage (VRM), 77.4 V clamping voltage at 5.2 A (10/1000 µs), 400 W peak pulse power rating, and operates up to +150 °C junction temperature - deployed in industrial power supplies, automotive body control modules, and PoE-powered devices.
For engineers reviewing the SMAJ48A-TR datasheet, SMAJ48A-TR pinout, SMAJ48A-TR application, or SMAJ48A-TR equivalent, key selection criteria include clamping voltage margin vs. protected IC VDD, leakage current at elevated temperature, JEDEC DO-214AC (SMA) package thermal performance, and IEC 61000-4-2/4-4 compliance level.
Technical Context
This unidirectional TVS diode uses planar silicon junction technology to achieve low leakage (≤0.2 µA at 25 °C, ≤1 µA at 85 °C) and stable breakdown behavior across –55 °C to +150 °C operating range. Its dynamic resistance of 1.79 Ω (at 25 °C, 10/1000 µs) ensures predictable voltage clamping during fast transients.
The device complies with IEC 61000-4-2 Level 4 (30 kV air/contact discharge) and IEC 61000-4-4 Level 4 (4 kV), meeting MIL-STD-883 Method 3015 for ESD robustness. Its DO-214AC package supports IPC-7531-compliant footprint and J-STD-020 MSL Level 1 handling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 48 V - maximum continuous reverse operating voltage before conduction begins; sets minimum system rail margin. |
| Breakdown Voltage (VBR) | 53.3–56.1 V at 1 mA - precise threshold where avalanche conduction initiates; enables accurate overvoltage trip design. |
| Clamping Voltage (VCL) | 77.4 V at 5.2 A (10/1000 µs) - peak voltage seen by protected circuit during surge; defines worst-case stress on downstream ICs. |
| Peak Pulse Power (PPP) | 400 W (10/1000 µs) - maximum transient energy absorption capability under standard lightning surge waveform. |
| Leakage Current (IRM) | 0.2 µA at 25 °C, 1 µA at 85 °C - ultra-low reverse leakage preserves battery life and avoids false triggering in high-impedance sensing paths. |
| Junction Temperature Range | –55 °C to +150 °C - supports operation in under-hood automotive, industrial motor drives, and outdoor telecom equipment. |
| Package | DO-214AC (SMA) - surface-mount outline per IPC-7531; 2.25–2.90 mm width, 4.80–5.35 mm length; compatible with automated reflow assembly. |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with two coplanar gull-wing leads; cathode indicated by band marking; footprint per IPC-7531 with 5.43 mm pad center-to-center spacing and 2.63 mm pad length.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Low-side reference terminal | Connected to ground or lowest potential node; completes conduction path during positive transients on cathode side. |
| Cathode (banded end) | Protected line connection | Connected to input rail or signal line; clamps voltage to ≤77.4 V when transient exceeds 48 V standoff. |
Key Features
| Feature | Design Value |
|---|---|
| IEC 61000-4-2 Level 4 ESD immunity | 30 kV air/contact discharge - eliminates need for external ESD filters in USB, CAN, and sensor interfaces. |
| Low dynamic resistance (RD) | 1.79 Ω at 25 °C - minimizes clamping voltage rise under high-current surges, improving protection margin. |
| High-temperature leakage stability | 1 µA max at 85 °C - ensures reliable operation in engine control units and industrial PLCs without thermal runaway risk. |
| JEDEC DO-214AC registration | Standardized mechanical dimensions - guarantees compatibility with pick-and-place machines and reflow profiles across contract manufacturers. |
| Planar junction construction | Uniform avalanche distribution - delivers consistent VBR and VCL across production lots and lifetime. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module |
|---|---|
|
Use Scenario: 48 V DC input rail in programmable logic controllers exposed to load dump and inductive switching noise. IC Role / Device Role / Timing Role: Primary surge clamp placed upstream of DC-DC converter input to limit transient voltage to <80 V. Use Value: Withstands 400 W (10/1000 µs) surges while maintaining 0.2 µA leakage - prevents converter latch-up and extends MTBF. |
Use Scenario: LIN bus line in door module subjected to ESD events during assembly and field service. IC Role / Device Role / Timing Role: Unidirectional TVS between LIN transceiver pin and chassis ground to shunt ESD current away from IC pins. Use Value: Clamps 30 kV contact discharge to ≤77.4 V within nanoseconds - protects transceiver I/O without signal distortion. |
| PoE-Powered Device Port | Outdoor Telecom Equipment |
|
Use Scenario: 48 V power feed to IP camera via IEEE 802.3af/at Ethernet cable, vulnerable to induced lightning surges. IC Role / Device Role / Timing Role: First-stage protection on PSE-side DC input, coordinated with secondary MOV/GDT stages. Use Value: Fast response (<1 ns) and 77.4 V clamping ensure PoE controller ICs remain below absolute maximum ratings during 4 kV IEC 61000-4-4 events. |
Use Scenario: Remote radio unit powered by 48 V DC supply in cellular base station cabinets exposed to ambient temperature extremes. IC Role / Device Role / Timing Role: Standoff-rated TVS on backplane power entry point to suppress coupled transients from nearby lightning strikes. Use Value: Stable 48 V VRM and 150 °C Tj rating enable uninterrupted operation in desert or arctic environments without derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ48CA-TR | Bidirectional variant; symmetric clamping (±77.4 V); same VRM, VBR, PPP, and package. | Required for AC-coupled or differential signal lines (e.g., RS-485, CAN FD) where polarity reversal occurs. | Select only if bidirectional protection is mandated; otherwise SMAJ48A-TR offers lower leakage in DC-only rails. |
| SMBJ48A-TR | Same electrical specs but SMB (DO-214AA) package; 30% larger footprint; 600 W PPP rating (10/1000 µs). | Used where higher surge margin is needed and PCB space permits larger package; not drop-in compatible due to lead pitch difference. | Choose when system-level testing requires >400 W margin; verify thermal relief and pad layout compatibility before substitution. |
Compared with SMAJ48CA-TR and SMBJ48A-TR, SMAJ48A-TR provides optimal balance of compact DO-214AC footprint, 400 W surge capability, and sub-microamp leakage - making it preferred for space-constrained 48 V DC power rails where unidirectional clamping suffices.
Availability
SMAJ48A-TR is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, PoE-powered device ports, and outdoor telecom equipment requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for SMAJ48A-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, microcontroller, power, and sensing solutions for automotive, industrial, and consumer markets.
The SMAJ series belongs to ST's transient protection portfolio, engineered specifically for high-reliability DC rail and interface protection in harsh environments - emphasizing low leakage, tight VBR tolerance, and full IEC/UL/MIL compliance.
FAQ
What is the maximum clamping voltage of SMAJ48A-TR under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 77.4 V at 5.2 A for the 10/1000 µs waveform, measured at Tamb = 25 °C. This value increases with junction temperature at a coefficient of 10.3 × 10−4/°C, reaching approximately 80.1 V at Tj = 125 °C per the datasheet's αT correction formula.
Can SMAJ48A-TR be used in bidirectional signal lines like RS-485?
No - SMAJ48A-TR is unidirectional and conducts only when cathode voltage exceeds anode by ≥53.3 V. For bidirectional lines, the SMAJ48CA-TR variant must be used, which clamps symmetrically for both polarities and is marked with "CY" per Table 6 of DS1251 Rev 15.
What is the recommended PCB footprint for SMAJ48A-TR?
The recommended footprint follows IPC-7531 for DO-214AC: 2.63 mm pad length, 1.40 mm pad width, 5.43 mm center-to-center spacing, and 1.64 mm solder mask opening. Thermal relief pads with ≥1.2 cm² copper area per lead reduce Rth(j-a) to ≤3.5 °C/W per Figure 12.
Does SMAJ48A-TR meet automotive AEC-Q200 requirements?
No - SMAJ48A-TR is not AEC-Q200 qualified. It meets IEC, UL, and MIL standards for ESD/surge, but lacks the extended temperature cycling, humidity bias, and mechanical shock testing required for automotive qualification. For AEC-Q200 applications, consider ST's Automotive-grade SMxJ series (e.g., SMAJ48A-Q).
SMAJ48A-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):
- 48V
- Voltage - Breakdown (Min):
- 53.3V
- Voltage - Clamping (Max) @ Ipp:
- 100V
- Current - Peak Pulse (10/1000µs):
- 23A (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)
SMAJ48A-TR FAQ
1.How can I place an order for SMAJ48A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ48A-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 SMAJ48A-TR reliable?
The price and inventory of SMAJ48A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ48A-TR is usually 5 days.
3.What payment methods are accepted for SMAJ48A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ48A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ48A-TR?
SMAJ48A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ48A-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 SMAJ48A-TR?
For technical support, including SMAJ48A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ48A-TR requirements.
6.How does Aetrix verify that SMAJ48A-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ48A-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 SMAJ48A-TR meets industry standards.
7.What is the process for return or replacement of SMAJ48A-TR?
All SMAJ48A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ48A-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 SMAJ48A-TR part is unused and in its original packaging.
Return procedure for SMAJ48A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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