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Alpha & Omega Semiconductor Inc. SMDJ120A
- Part No.:
- SMDJ120A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ120A.pdf
- Description:
- 1CH 120V UNIDIRECTIONAL 3000W SM
- Quantity:
- Payment:
- Shipping:
Inventory:4,997
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Product details
Overview
SMDJ120A from Alpha & Omega Semiconductor is a unidirectional transient voltage suppressor diode (TVS) designed for high-energy surge protection in DC power lines and signal interfaces. It features a 120 V reverse standoff voltage (VRWM), 133–147 V breakdown voltage (VBR) at 1 mA, 193 V maximum clamping voltage (VC) at 15.6 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives and telecom power supplies.
For engineers reviewing the SMDJ120A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDD rails, thermal resistance (RθJA = 75 °C/W), unidirectional polarity confirmation, and DO-214AB package compatibility with 8.0 mm × 8.0 mm copper pad layouts.
Technical Context
The SMDJ120A operates as a silicon avalanche diode that enters controlled breakdown above its specified VRWM, diverting transient energy away from downstream circuitry. Its glass-passivated junction ensures stable VBR tolerance (±5% typical), while low-profile DO-214AB packaging enables surface-mount integration with built-in strain relief and matte tin lead-free plating.
It delivers sub-1 ps response time from 0 V to breakdown, supports 0.01% duty cycle repetitive surges, and maintains operation across –55 °C to +150 °C junction temperature range. Thermal performance is defined with RθJL = 15 °C/W (junction-to-lead) under standard mounting conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 120 V - Maximum continuous reverse operating voltage before clamping begins; sets upper limit for protected line DC bias. |
| VBR @ IT=1 mA | 133–147 V - Confirmed breakdown range ensures reliable turn-on during transients without premature conduction. |
| VC @ IPPM | 193 V at 15.6 A - Clamping voltage defines worst-case overvoltage seen by downstream components during 10/1000 µs surge. |
| PPPM | 3000 W - Peak pulse power rating determines survivability against IEC 61000-4-5 Level 4 (4 kV/2 Ω) surges. |
| TJ max | +150 °C - Maximum junction temperature enables use in high-ambient industrial environments with adequate PCB copper area. |
| Polarity | Unidirectional - Requires correct cathode orientation; color band denotes cathode terminal for proper DC line placement. |
| RθJA | 75 °C/W - Thermal resistance value used to calculate junction temperature rise under steady-state leakage or repeated low-duty-cycle events. |
Pinout & Package
Package: DO-214AB (SMC J-Bend), molded plastic case with matte tin lead-free plating; JEDEC-compliant surface-mount outline optimized for automated assembly and thermal relief.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | DC return path / ground reference | Connected to system ground or low-side rail; carries full surge current during clamping event. |
| Cathode (banded end) | Protected line input / high-side connection | Connected to line being protected (e.g., +120 V DC bus); avalanche conduction occurs from cathode to anode during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps - Enables suppression of ESD and lightning-induced fast-rising transients before sensitive ICs are damaged. |
| Glass passivated junction | Stable VBR tolerance (±5%) and long-term reliability under thermal cycling and humidity exposure. |
| Built-in strain relief | Reduces mechanical stress on solder joints during board flexure or thermal expansion mismatch. |
| MSL1 rating | Compatible with standard reflow profiles up to 260 °C peak, eliminating moisture sensitivity handling requirements. |
| UL 94V-0 flammability | Self-extinguishing plastic housing meets safety standards for enclosed industrial and telecom equipment. |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of gate drivers and DC-link sensing circuits against IGBT switching transients and load dump events. IC Role / Device Role: Primary overvoltage clamp on 120 V auxiliary supply rails feeding isolated gate driver ICs. Use Value: Limits transient voltage to ≤193 V, preserving gate oxide integrity of 200 V-rated SiC drivers and preventing false triggering. | Use Scenario: Surge suppression on -48 V DC distribution buses in central office power systems exposed to lightning-induced surges. IC Role / Device Role: Unidirectional TVS placed between -48 V rail and chassis ground to shunt common-mode transients. Use Value: Withstands 3000 W pulses per IEC 61000-4-5, maintaining system uptime during outdoor cabinet surges. |
| Renewable Energy Inverters | Transportation Control Units |
Use Scenario: Input-stage protection for MPPT controllers interfacing photovoltaic arrays subject to induced surges from nearby lightning strikes. IC Role / Device Role: Front-end clamping device on PV+ input line rated for 120 V DC string voltage. Use Value: 150 °C TJ max allows operation inside sealed outdoor enclosures without derating at ambient temperatures up to 85 °C. | Use Scenario: Protection of 24 V CAN bus power inputs in rail vehicle control modules subjected to ISO 7637-2 Pulse 1 and Pulse 2a transients. IC Role / Device Role: Secondary-level TVS on 24 V supply rail upstream of DC/DC converters powering CAN transceivers. Use Value: 193 V clamping voltage provides ≥2× margin over 24 V nominal rail, ensuring no disruption to CAN communication during load dump. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC120A (Littelfuse) | Same DO-214AB package, identical VRWM (120 V), but lower PPPM (1500 W) and higher VC (200 V at 15 A). | Not suitable for IEC 61000-4-5 Level 4; limited to Level 3 or lower-energy surges. | Select only when system-level surge testing requires lower cost and reduced clamping precision is acceptable. |
| 1.5KE120A (ON Semiconductor) | Through-hole DO-201 package, same electrical specs but incompatible mounting; RθJA = 60 °C/W (better thermal performance on PTH pads). | Requires PCB redesign; unsuitable for high-density SMT layouts or automated assembly lines. | Choose only for legacy through-hole designs where rework to SMT is not feasible. |
Compared with SAC120A and 1.5KE120A, the SMDJ120A delivers higher surge robustness (3000 W vs. 1500 W or 1500 W), surface-mount compatibility, and tighter VBR tolerance - making it optimal for new industrial SMT designs requiring IEC 61000-4-5 compliance without layout compromise.
Availability
SMDJ120A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, renewable energy inverters, and transportation control units requiring stable component supply and consistent surge protection performance across production batches.
Supply support for SMDJ120A 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
Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in MOSFETs, TVS diodes, and power ICs for high-efficiency power conversion and protection.
The SMDJ series is engineered specifically for high-power transient suppression in industrial, telecom, and automotive auxiliary systems - emphasizing rugged DO-214AB packaging, low clamping ratio, and AEC-Q200 readiness for harsh environments.
FAQ
What is the maximum clamping voltage of the SMDJ120A under a 10/1000 µs surge?
The SMDJ120A has a maximum clamping voltage (VC) of 193 V at 15.6 A peak pulse current under a 10/1000 µs waveform. This value is measured per industry-standard test conditions and defines the highest voltage imposed on protected circuitry during a full-rated surge event. The SMDJ120A maintains this clamping performance consistently due to its tightly controlled avalanche characteristics and low dynamic impedance.
Is the SMDJ120A RoHS and halogen-free compliant?
Yes, the SMDJ120A is an AOS Green Product, certified RoHS compliant and halogen-free per IEC 61249-2-21. It uses matte tin lead-free plating and complies with AOS' environmental policy, including reduced bromine and chlorine content. Documentation confirming compliance is available in the AOS Green Policy document referenced in the official datasheet Rev. 1.2.
Can the SMDJ120A be used in bidirectional configurations?
No - the SMDJ120A is strictly unidirectional. For bidirectional operation at 120 V, the correct part is SMDJ120CA, which features symmetrical breakdown in both polarities. Using the SMDJ120A in reverse-biased configurations will result in immediate failure, as its cathode band must face the positive line being protected.
What is the thermal resistance junction-to-ambient (RθJA) for the SMDJ120A?
The SMDJ120A has a typical RθJA of 75 °C/W when mounted on 8.0 mm × 8.0 mm copper pads per terminal, per JEDEC standards. This value assumes standard FR-4 PCB material and natural convection cooling. Designers must verify actual board layout and copper area to ensure junction temperature remains below 150 °C under worst-case leakage and surge repetition conditions.
Does the SMDJ120A meet MSL level requirements for surface-mount reflow?
Yes, the SMDJ120A is rated MSL1 per J-STD-020, with a maximum peak reflow temperature of 260 °C. No floor life limitation or dry-pack requirement applies, simplifying manufacturing logistics. This rating is validated through AOS qualification testing and confirmed in the Rev. 1.2 datasheet, page 1.
SMDJ120A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- 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:
- 193V
- Current - Peak Pulse (10/1000µs):
- 15.6A
- Power - Peak Pulse:
- 3000W (3kW)
- 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-214AB
SMDJ120A FAQ
1.How can I place an order for SMDJ120A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ120A 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 SMDJ120A reliable?
The price and inventory of SMDJ120A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ120A is usually 5 days.
3.What payment methods are accepted for SMDJ120A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ120A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ120A?
SMDJ120A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ120A 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 SMDJ120A?
For technical support, including SMDJ120A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ120A requirements.
6.How does Aetrix verify that SMDJ120A is sourced from the original manufacturer or authorized distributors?
All SMDJ120A 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 SMDJ120A meets industry standards.
7.What is the process for return or replacement of SMDJ120A?
All SMDJ120A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ120A, 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 SMDJ120A part is unused and in its original packaging.
Return procedure for SMDJ120A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ120A Tags
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