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Taiwan Semiconductor Corporation SMAJ48AH
- Part No.:
- SMAJ48AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ48AH.pdf
- Description:
- TVS DIODE 48VWM 77.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,241
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Product details
Overview
SMAJ48AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in DC power lines. It features a 48 V working stand-off voltage (VWM), 53.3–58.9 V breakdown voltage (VBR) at 1 mA test current, and clamps to ≤77.4 V at 5.2 A peak impulse current under 10/1000 µs waveform - ideal for protecting automotive DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ48AH datasheet, SMAJ48AH pinout, SMAJ48AH application, or SMAJ48AH equivalent, key selection criteria include its AEC-Q101 qualification, 400 W peak pulse power rating (10/1000 µs), <1 ps response time, low leakage (<1 µA @ 48 V), and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance - critical for robust ESD and load-dump protection in harsh environments.
Technical Context
The SMAJ48AH operates as a unidirectional avalanche diode with glass-passivated junction, optimized for fast clamping of inductive switching spikes and ESD events. Its breakdown threshold is tightly specified (53.3–58.9 V), and it maintains stable clamping performance across -55°C to +150°C junction temperature range.
It delivers 400 W peak pulse power at 25°C (derated linearly above), supports 40 A non-repetitive forward surge (8.3 ms half-sine), and exhibits <3.5 V forward voltage at 25 A - enabling reliable overvoltage protection without compromising system efficiency during fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 48 V - maximum continuous reverse operating voltage before conduction begins; sets safe margin below system nominal voltage (e.g., 42 V automotive battery). |
| VBR min/max | 53.3 / 58.9 V @ 1 mA - verified avalanche onset range ensures predictable turn-on during transients without premature triggering. |
| VC @ IPPM | ≤77.4 V @ 5.2 A - clamping voltage limits downstream IC stress during 10/1000 µs surge; enables design margin vs. 60 V-rated components. |
| PPPM | 400 W (10/1000 µs) - sustains high-energy transients common in automotive load-dump and inductive switch-off events. |
| IR @ VWM | <1 µA - negligible standby leakage preserves battery life in always-on systems like telematics or ADAS modules. |
| TJ max | +150 °C - supports operation in under-hood automotive environments and high-temperature industrial enclosures. |
| Response time | <1.0 ps - sub-picosecond junction response ensures suppression before sensitive logic or analog circuitry is damaged. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band marking. Matte tin-plated leads meet J-STD-002 solderability; moisture sensitivity level 1 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side (cathode-banded end is cathode) | Connected to protected line (e.g., 48 V rail); conducts only when reverse voltage exceeds VBR. |
| Cathode | Ground/reference side | Connected to system ground or low-impedance return path; defines polarity and clamping direction. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for under-hood and chassis-mounted applications. |
| Glass-passivated junction | Enhances long-term stability and moisture resistance versus epoxy-passivated alternatives, critical for high-humidity industrial deployments. |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (line impedance coupling) - covers full automotive EMC immunity scope. |
| Low clamping ratio (VC/VBR) | ~1.32 (77.4 V / 58.9 V) - tighter than typical TVS devices, reducing voltage overshoot and improving protection margin for 60 V-rated MOSFETs or controllers. |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive - supports green manufacturing and export compliance for global OEMs. |
Applications
| Automotive On-Board DC/DC Converter | Industrial Switching Mode Power Supply (SMPS) |
|---|---|
Use Scenario: Protecting 48 V input stage of buck converter powering ADAS camera module against load-dump transients up to ±120 V. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and ground, clamping surges within nanoseconds to prevent controller latch-up or MOSFET avalanche failure. Use Value: With 77.4 V clamping and AEC-Q101 qualification, SMAJ48AH ensures functional safety compliance (ISO 26262 ASIL-B) while eliminating need for secondary crowbar circuits. |
Use Scenario: Safeguarding primary-side rectifier output in 48 V telecom rectifier subjected to lightning-induced surges on AC input lines. IC Role / Device Role / Timing Role: Front-end transient suppressor absorbing 400 W pulses per IEC 61000-4-5 Level 4, coordinated with upstream MOV and downstream Y-cap filtering. Use Value: 400 W rating and 10/1000 µs waveform capability enable single-device protection without parallel stacking, reducing BOM count and PCB area. |
| LED Driver Input Protection | Factory Automation I/O Module |
Use Scenario: Shielding constant-current LED driver input from inductive kickback when driving high-power solenoid loads in smart lighting systems. IC Role / Device Role / Timing Role: Fast-response TVS placed across input terminals to clamp flyback voltage spikes before they reach PWM controller IC or gate driver. Use Value: Sub-1 ps response and 5.2 A IPPM ensure suppression occurs before 100 ns - faster than typical gate drivers' propagation delay, preventing false triggering. |
Use Scenario: Protecting 24/48 V digital input channel of PLC I/O module exposed to field wiring transients in factory floor environments. IC Role / Device Role / Timing Role: Primary-level surge protector on signal line, rated for repeated 1 kV/500 A transients per IEC 61000-4-4. Use Value: 150 °C max junction temperature and JESD201 Class 2 whisker resistance allow reliable operation in uncooled control cabinets with ambient temperatures up to 85 °C. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ48H | Wider VBR range (53.3–65.1 V); higher clamping voltage (85.5 V @ 4.7 A); same package and power rating. | Less precise clamping margin; may exceed 60 V rail tolerance in tight-margin designs. | Select SMAJ48H only if cost sensitivity outweighs clamping precision; SMAJ48AH preferred for 60 V-rated downstream components. |
| SMBJ48A | DO-214AA (SMB) package; identical electrical specs but 600 W peak power rating (10/1000 µs); larger footprint. | Higher surge capacity suits infrequent high-energy events (e.g., outdoor telecom); requires PCB layout change. | Choose SMBJ48A when system-level testing reveals 400 W insufficient; SMAJ48AH remains optimal for space-constrained automotive modules. |
Compared with SMAJ48H and SMBJ48A, the SMAJ48AH offers the tightest VBR tolerance and lowest clamping voltage in the SMA footprint - delivering superior protection margin for modern 48 V architectures without increasing board area or cost.
Availability
SMAJ48AH is available at Aetrix Electronics and suitable for automotive on-board DC/DC converters, industrial switching mode power supplies, and LED driver input protection requiring stable component supply and AEC-Q101-compliant surge resilience.
Supply support for SMAJ48AH 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power MOSFETs for automotive and industrial markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in 12 V–188 V automotive and industrial power rails, emphasizing low clamping ratio, fast response, and high-temperature reliability.
FAQ
What is the maximum clamping voltage of the SMAJ48AH under standard test conditions?
The SMAJ48AH has a maximum clamping voltage (VC) of 77.4 V when subjected to a 10/1000 µs waveform peak impulse current of 5.2 A. This value is measured at TA = 25°C and represents the upper limit of voltage seen by downstream circuitry during surge events - critical for ensuring compatibility with 60 V-rated components in 48 V systems. The SMAJ48AH consistently achieves this clamping performance across its qualified temperature range.
Is the SMAJ48AH suitable for bidirectional transient protection?
No, the SMAJ48AH is a unidirectional TVS diode, indicated by the absence of "CAH" or "CH" suffix and confirmed by its single-diode DO-214AC configuration with cathode band marking. For bidirectional protection in AC-coupled or floating-rail applications, use SMAJ48CAH (if available) or pair two SMAJ48AH devices in series opposition. The SMAJ48AH's design strictly supports DC line-to-ground clamping.
Does the SMAJ48AH meet automotive qualification standards?
Yes, the SMAJ48AH is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements - validating its suitability for automotive power net protection. It also complies with JESD201 Class 2 whisker resistance and J-STD-020 moisture sensitivity level 1, supporting automated SMT assembly in Tier 1 production lines. The SMAJ48AH's full qualification documentation is available upon request from Taiwan Semiconductor.
How does the SMAJ48AH compare to the SMAJ48H in terms of electrical performance?
The SMAJ48AH offers tighter breakdown voltage tolerance (53.3–58.9 V) versus SMAJ48H (53.3–65.1 V), resulting in more consistent turn-on behavior and lower clamping voltage (77.4 V vs. 85.5 V at rated IPPM). This translates to improved protection margin for 60 V-rated ICs and reduced risk of overvoltage damage during marginal transients. Both share identical package, power rating, and AEC-Q101 qualification, but SMAJ48AH is preferred where clamping precision is critical.
What is the thermal derating behavior of the SMAJ48AH above 25°C ambient?
The SMAJ48AH's peak pulse power (PPPM) is derated linearly above TA = 25°C per Figure 2 in the official datasheet, reaching ~240 W at 100°C ambient. Its steady-state power dissipation remains 1 W regardless of temperature, and maximum junction temperature is rated at +150°C. This derating profile allows reliable operation in under-hood automotive environments and sealed industrial enclosures when mounted on adequate copper area - essential for sustained reliability of the SMAJ48AH in real-world deployments.
SMAJ48AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- 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:
- 77.4V
- Current - Peak Pulse (10/1000µs):
- 5.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ48AH FAQ
1.How can I place an order for SMAJ48AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ48AH 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 SMAJ48AH reliable?
The price and inventory of SMAJ48AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ48AH is usually 5 days.
3.What payment methods are accepted for SMAJ48AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ48AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ48AH?
SMAJ48AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ48AH 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 SMAJ48AH?
For technical support, including SMAJ48AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ48AH requirements.
6.How does Aetrix verify that SMAJ48AH is sourced from the original manufacturer or authorized distributors?
All SMAJ48AH 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 SMAJ48AH meets industry standards.
7.What is the process for return or replacement of SMAJ48AH?
All SMAJ48AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ48AH, 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 SMAJ48AH part is unused and in its original packaging.
Return procedure for SMAJ48AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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