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Taiwan Semiconductor Corporation SMAJ120H
- Part No.:
- SMAJ120H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ120H.pdf
- Description:
- TVS DIODE 120VWM 214VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,263
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Product details
Overview
SMAJ120H from Taiwan Semiconductor is a unidirectional 400W surface-mount Transient Voltage Suppressor (TVS) diode in DO-214AC (SMA) package, with 120V working stand-off voltage (VWM), 133–163V breakdown voltage (VBR), and 214V maximum clamping voltage (VC) at 1.4A peak impulse current - designed for automotive-grade surge protection in DC/DC converters and power supply rails.
For engineers reviewing the SMAJ120H datasheet, SMAJ120H pinout, SMAJ120H application, or SMAJ120H equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, AEC-Q101 qualification status, moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on high-reliability industrial and automotive PCBs.
Technical Context
The SMAJ120H operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its VBR range (133–163V @ 1mA test current). It clamps transients to ≤214V at 1.4A (10/1000μs waveform), delivering 400W peak pulse power at 25°C - derated linearly above that ambient per Fig.2.
Its glass-passivated junction ensures stable leakage (<1μA @ 120V), fast response (<1.0ps), and robustness against ESD and load dump events. Polarity is marked by cathode band; it is not rated for bidirectional use unless specified with CH or CAH suffix.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 120 V - Maximum continuous reverse operating voltage before clamping begins; sets safe margin below system rail. |
| VBR min/max | 133 / 163 V @ 1 mA - Confirmed breakdown threshold range; defines minimum overvoltage trigger point. |
| VC @ IPPM | 214 V @ 1.4 A (10/1000μs) - Clamped voltage during worst-case transient; determines protected circuit's max stress level. |
| PPPM | 400 W (10/1000μs) - Peak surge energy handling capacity; supports ISO 7637-2 compliance up to Pulse 3b. |
| IR @ VWM | <1 μA - Negligible leakage at rated stand-off; avoids standby power loss or false triggering. |
| TJ max | +150 °C - Junction temperature limit enabling operation in under-hood automotive environments. |
| Package | DO-214AC (SMA) - Standardized SMT outline with 0.060g mass; compatible with J-STD-002 soldering and JESD201 Class 2 whisker resistance. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, cathode indicated by band marking; polarity-critical for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to ground or low-voltage return path; forms clamping loop with cathode. |
| Cathode | High-side transient input | Connected to protected line (e.g., 120V rail); conducts avalanche current to anode during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements - enables use in engine control, body electronics, and ADAS power domains. |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal cycling and humidity exposure. |
| Fast response time <1.0 ps | Clamps ESD and fast-edge transients before downstream ICs experience damage - critical for CAN/LIN bus protection. |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Validated against standardized automotive electrical disturbance waveforms - eliminates need for additional filtering stages. |
| MSL Level 1 (per J-STD-020) | Zero floor life limitation; supports unlimited reflow without baking - simplifies manufacturing logistics. |
Applications
| Automotive DC/DC Converter Input Protection | Industrial SMPS Output Rail Clamp |
|---|---|
Use Scenario: Protects 120V intermediate bus in automotive 48V-to-12V DC/DC modules from load dump and alternator surges. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between input rail and chassis ground to shunt transient energy. Use Value: Clamps to 214V within <1ps, limiting stress on synchronous rectifiers and controller ICs during ISO 7637-2 Pulse 5a events. |
Use Scenario: Safeguards regulated 120V output of industrial switch-mode power supplies against coupling-induced transients. IC Role / Device Role / Timing Role: Standoff-clamp device connected across output terminals to suppress overshoot during line switching or fault recovery. Use Value: Maintains <1μA leakage at 120V, avoiding regulation drift while delivering 400W pulse immunity without derating below 78V. |
| On-Board Charger (OBC) Auxiliary Supply | LED Driver High-Voltage Bus Protection |
Use Scenario: Shields auxiliary 120V logic supply in EV on-board chargers from battery-side transients during contactor switching. IC Role / Device Role / Timing Role: Primary overvoltage clamp on isolated auxiliary rail, positioned upstream of LDOs and gate drivers. Use Value: Withstands 40A IFSM surge (8.3ms half-sine), surviving repeated contactor bounce without degradation. |
Use Scenario: Guards constant-current LED strings powered from 120V buck-derived bus against lightning-induced surges in outdoor lighting systems. IC Role / Device Role / Timing Role: Parallel-connected transient absorber across LED string input terminals. Use Value: 214V VC ensures LED driver ICs and MOSFETs remain below absolute maximum ratings during 10/1000μs line surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ120AH | Narrower VBR range (133–147V vs. 133–163V); lower VC (193V vs. 214V) at same IPPM. | Better clamping tightness for precision 120V rails where margin to downstream IC abs max is minimal. | Select SMAJ120AH when tighter VBR tolerance and lower clamping voltage are prioritized over worst-case surge headroom. |
| SMBJ120H | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; higher PPPM (600W vs. 400W). | Preferred where board space allows and higher single-pulse energy absorption is required (e.g., heavy-duty industrial controls). | Choose SMBJ120H when 600W peak power rating is needed and DO-214AA footprint is acceptable. |
Compared with SMAJ120AH, the SMAJ120H offers wider VBR tolerance and higher clamping voltage - trading precision for robustness in variable-temperature or high-stress environments; versus SMBJ120H, it sacrifices 200W pulse power for smaller DO-214AC footprint and lower assembly cost.
Availability
SMAJ120H is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial switch-mode power supplies, and LED driver high-voltage bus protection requiring stable component supply across extended temperature ranges and AEC-Q101-compliant sourcing.
Supply support for SMAJ120H 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 automotive-qualified power components.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in automotive and industrial power systems - emphasizing reliability under thermal cycling, humidity, and repetitive surge stress.
FAQ
Is SMAJ120H bidirectional or unidirectional?
The SMAJ120H is a unidirectional TVS diode, intended for clamping positive transients on a referenced rail. Its cathode band marks the high-side terminal; reverse connection will not provide protection. For bidirectional applications, TSC specifies models with CH or CAH suffixes - SMAJ120H itself is not rated for symmetrical surge suppression.
What is the maximum clamping voltage of SMAJ120H under standard test conditions?
The SMAJ120H has a maximum clamping voltage (VC) of 214 V when subjected to a 10/1000μs waveform at 1.4 A peak impulse current (IPPM), measured at TA = 25°C. This value increases with ambient temperature per the derating curve in Figure 2 of the official datasheet.
Does SMAJ120H meet automotive qualification standards?
Yes, SMAJ120H is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements. It also complies with J-STD-020 MSL Level 1, RoHS, and halogen-free standards per IEC 61249-2-21 - confirming suitability for automotive power electronics.
What is the leakage current specification for SMAJ120H at its working voltage?
The SMAJ120H exhibits a maximum reverse leakage current (IR) of 1 μA when biased at its full working stand-off voltage (VWM = 120 V), tested at TA = 25°C. This ultra-low leakage ensures minimal impact on system efficiency and avoids false triggering in high-impedance sensing circuits.
Can SMAJ120H be used in place of SMAJ120AH?
SMAJ120H and SMAJ120AH are not direct substitutes: SMAJ120H has a wider VBR range (133–163V) and higher clamping voltage (214V), while SMAJ120AH offers tighter VBR (133–147V) and lower VC (193V). Substitution requires validation of clamping margin and system overvoltage tolerance - SMAJ120H provides greater surge headroom; SMAJ120AH improves precision clamping.
SMAJ120H 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):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 214V
- Current - Peak Pulse (10/1000µs):
- 1.4A
- 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)
SMAJ120H FAQ
1.How can I place an order for SMAJ120H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ120H 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 SMAJ120H reliable?
The price and inventory of SMAJ120H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ120H is usually 5 days.
3.What payment methods are accepted for SMAJ120H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ120H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ120H?
SMAJ120H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ120H 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 SMAJ120H?
For technical support, including SMAJ120H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ120H requirements.
6.How does Aetrix verify that SMAJ120H is sourced from the original manufacturer or authorized distributors?
All SMAJ120H 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 SMAJ120H meets industry standards.
7.What is the process for return or replacement of SMAJ120H?
All SMAJ120H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ120H, 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 SMAJ120H part is unused and in its original packaging.
Return procedure for SMAJ120H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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