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Alpha & Omega Semiconductor Inc. SMDJ20A
- Part No.:
- SMDJ20A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ20A.pdf
- Description:
- 1CH 20V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:3,740
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Product details
Overview
SMDJ20A from Alpha & Omega Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal interfaces. It features a 20.0 V reverse stand-off voltage, 22.2–24.5 V breakdown voltage at 1 mA test current, 32.4 V maximum clamping voltage at 92.6 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives to safeguard IGBT gate drivers against EFT and lightning-induced transients.
For engineers reviewing the SMDJ20A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surges, thermal resistance (15 °C/W junction-to-lead), unidirectional polarity with cathode band marking, and DO-214AB package compatibility with automated SMT assembly.
Technical Context
The SMDJ20A operates as a silicon avalanche diode optimized for fast transient suppression, with sub-1 ps response time from 0 V to breakdown. Its glass-passivated junction ensures stable VBR drift (<0.1% × VBR/°C), while the low-profile DO-214AB package supports high-current handling via 8.0 mm × 8.0 mm copper pads per terminal.
Rated for -55 °C to +150 °C operating junction temperature, it delivers 3000 W peak pulse power under non-repetitive conditions (duty cycle ≤ 0.01%) and withstands 300 A peak forward surge current (8.3 ms half-sine). Thermal design relies on RθJL = 15 °C/W and RθJA = 75 °C/W values measured on specified PCB layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 20.0 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT=1mA | 22.2–24.5 V - Verified avalanche breakdown range ensuring reliable turn-on margin |
| Vc @ IPPM | 32.4 V - Clamped voltage at 92.6 A peak pulse current, defining protected circuit stress limit |
| PPPM (10/1000µs) | 3000 W - Peak surge energy absorption capability under standard lightning waveform |
| TJ max | +150 °C - Maximum junction temperature enabling operation in high-ambient industrial environments |
| RθJL | 15 °C/W - Junction-to-lead thermal resistance critical for heatsinking via PCB copper pads |
| Polarity | Unidirectional - Cathode-band marked device requiring correct orientation in DC line protection |
Pinout & Package
DO-214AB (SMC J-Bend) molded plastic package with matte tin lead-free plating; JEDEC-compliant case; color band denotes cathode (anode connected to unmarked end).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Surge current sink | Connected to protected line; conducts during overvoltage to shunt energy to ground |
| Anode (unbanded end) | Reference / return path | Typically tied to system ground or lower-potential rail; completes clamping path |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps - Enables clamping before sensitive downstream ICs experience voltage overshoot |
| Glass passivated junction | Stable VBR with 0.1% × VBR/°C tempco - Ensures consistent clamping across industrial temperature range |
| Built-in strain relief | Reduces mechanical stress at lead-to-body interface - Improves reliability under thermal cycling and board flex |
| MSL Level 1 rating | Reflow compatible up to 260 °C peak - Supports standard lead-free SMT reflow without moisture-related failure |
| UL 94V-0 flammability | Self-extinguishing plastic housing - Meets safety requirements for enclosed industrial equipment |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of gate driver ICs and bootstrap circuits against IGBT switching transients and input line surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between gate and source to clamp negative spikes and limit positive overvoltage. Use Value: Limits clamping voltage to 32.4 V at 92.6 A, preventing gate oxide rupture in 20 V-rated drivers while surviving 3000 W surge events. | Use Scenario: Input-stage surge suppression on 24 V or 48 V DC telecom rectifier outputs feeding backplane distribution. IC Role / Device Role / Timing Role: Primary overvoltage clamp on secondary-side DC bus, coordinated with upstream MOVs and fuses. Use Value: Withstands 300 A 8.3 ms surge and maintains <2 µA leakage at 20 V, minimizing standby power loss in always-on systems. |
| Automotive Body Control Modules | Renewable Energy Inverters |
Use Scenario: CAN/LIN bus line protection and 12 V supply rail clamping in BCM ECUs exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS on VBAT-connected microcontroller power inputs and communication transceiver rails. Use Value: Clamps 12 V rail to ≤32.4 V during 10/1000 µs transients, preserving MCU reset thresholds and transceiver common-mode range. | Use Scenario: DC-link overvoltage suppression in solar string inverters subjected to lightning-induced surges on PV input strings. IC Role / Device Role / Timing Role: Secondary-level TVS on MPPT converter input, supplementing primary SPDs and DC fusing. Use Value: Delivers 3000 W peak power rating with 150 °C max junction temperature, supporting outdoor deployment 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 |
|---|---|---|---|
| SAC20A (Littelfuse) | Same DO-214AB package, 20 V VRWM, but 33.2 V clamping voltage at 91 A; slightly higher RθJA (80 °C/W) | Higher clamping voltage reduces margin for 24 V logic rails; requires larger copper area for thermal management | Select when legacy Littelfuse BOM alignment is required and 0.8 V higher clamping is acceptable |
| 1.5KE20A (ON Semiconductor) | Through-hole DO-15 package, identical electrical specs but incompatible with SMT assembly; 1000 W lower PPPM (2000 W) | Not suitable for automated production; limited to prototyping or low-volume repair where hand-soldering is acceptable | Choose only for manual assembly scenarios where footprint change is permissible and 3000 W surge rating is not mandatory |
Compared with SAC20A and 1.5KE20A, the SMDJ20A provides superior thermal performance (RθJL = 15 °C/W), full SMT compatibility, and highest surge rating in its voltage class - making it optimal for high-reliability, volume-manufactured industrial and automotive power systems.
Availability
SMDJ20A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, and automotive body control modules requiring stable component supply, RoHS-compliant packaging, and traceable sourcing for long-lifecycle programs.
Supply support for SMDJ20A 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 part of AOS's surface-mount TVS portfolio engineered specifically for high-power, high-reliability transient suppression in industrial, automotive, and telecom infrastructure - emphasizing low clamping ratio, robust thermal design, and MSL Level 1 manufacturability.
FAQ
What is the maximum clamping voltage of the SMDJ20A under a 10/1000 µs surge?
The SMDJ20A has a maximum clamping voltage (VC) of 32.4 V when subjected to its rated peak pulse current of 92.6 A on a 10/1000 µs waveform. This value is guaranteed per the manufacturer's datasheet and defines the upper voltage limit imposed on protected circuitry during surge events. The SMDJ20A achieves this clamping performance while dissipating 3000 W peak power, making it suitable for demanding industrial surge environments.
Is the SMDJ20A unidirectional or bidirectional, and how is polarity identified?
The SMDJ20A is a unidirectional TVS diode, indicated by the "A" suffix (as opposed to "CA" for bidirectional variants). Polarity is identified by a color band on the cathode end of the DO-214AB package - the banded terminal must be connected toward the side of the circuit requiring overvoltage protection (e.g., positive rail), while the anode connects to reference ground. This configuration ensures proper conduction only during reverse overvoltage events.
What is the thermal resistance specification for the SMDJ20A, and why does it matter?
The SMDJ20A has a typical junction-to-lead thermal resistance (RθJL) of 15 °C/W and junction-to-ambient (RθJA) of 75 °C/W, measured on 8.0 mm × 8.0 mm copper pads per terminal. These values directly impact sustained surge capability and steady-state power handling: lower RθJL enables efficient heat transfer into the PCB, allowing the SMDJ20A to survive repeated transients without exceeding its 150 °C maximum junction temperature.
Does the SMDJ20A meet lead-free and RoHS compliance requirements?
Yes, the SMDJ20A is a certified AOS Green Product: it is lead-free, RoHS compliant, and halogen-free per AOS' environmental policy. Its matte tin lead finish meets J-STD-020 MSL Level 1 requirements, supporting peak reflow temperatures up to 260 °C. Full compliance documentation, including material declarations and test reports, is available through AOS's official product portal at www.aosmd.com.
Can the SMDJ20A be used in bidirectional surge protection applications?
No - the SMDJ20A is strictly unidirectional. For bidirectional protection at the same 20 V standoff level, the designated variant is SMDJ20CA (with "CA" suffix), which exhibits symmetrical clamping in both polarities. Using the SMDJ20A in a bidirectional configuration would result in forward conduction and potential failure during negative transients. Always match the suffix ("A" vs. "CA") to the required polarity architecture in the target application.
SMDJ20A 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 92.6A
- 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
SMDJ20A FAQ
1.How can I place an order for SMDJ20A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ20A 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 SMDJ20A reliable?
The price and inventory of SMDJ20A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ20A is usually 5 days.
3.What payment methods are accepted for SMDJ20A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ20A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ20A?
SMDJ20A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ20A 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 SMDJ20A?
For technical support, including SMDJ20A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ20A requirements.
6.How does Aetrix verify that SMDJ20A is sourced from the original manufacturer or authorized distributors?
All SMDJ20A 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 SMDJ20A meets industry standards.
7.What is the process for return or replacement of SMDJ20A?
All SMDJ20A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ20A, 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 SMDJ20A part is unused and in its original packaging.
Return procedure for SMDJ20A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ20A Tags
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