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Alpha & Omega Semiconductor Inc. SMDJ21CA
- Part No.:
- SMDJ21CA
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ21CA.pdf
- Description:
- 1CH 21V BIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:2,127
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Product details
Overview
SMDJ21CA from Alpha & Omega Semiconductor is a bi-directional transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, designed for high-energy surge protection in DC power lines and data interfaces. It features 21.0 V reverse stand-off voltage (VRWM), 23.31–25.73 V breakdown voltage (VBR) at 1 mA, 34.1 V maximum clamping voltage (VC) at 88.0 A peak pulse current, and 3000 W peak pulse power rating on 10/1000 µs waveform.
For engineers reviewing the SMDJ21CA datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping capability, low clamping ratio (VC/VBR ≈ 1.42), JEDEC-compliant DO-214AB surface-mount package, and suitability for IEC 61000-4-2/4-4/4-5 compliant protection circuits in industrial power supplies and automotive ECUs.
Technical Context
The SMDJ21CA operates as a bi-directional avalanche diode, providing symmetrical clamping in both polarities without external polarity constraints. Its glass-passivated junction ensures stable VBR tolerance (±5% typical), while the low thermal resistance (RθJL = 15 °C/W) supports reliable energy dissipation during repetitive transients up to 0.01% duty cycle.
Designed for surface-mount assembly with matte tin lead-free plating, it meets J-STD-020 MSL Level 1 (peak reflow 260 °C) and UL 94V-0 flammability. The fast response time (<1.0 ps) enables effective suppression of ESD and lightning-induced surges before downstream ICs are damaged.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 21.0 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT=1 mA | 23.31–25.73 V - Confirmed breakdown range ensuring tight tolerance for predictable turn-on |
| VC @ IPPM=88.0 A | 34.1 V - Clamped voltage under full 3000 W surge, limiting stress on protected circuitry |
| PPPM (10/1000 µs) | 3000 W - Peak surge power handling capacity for IEC 61000-4-5 Level 4 compliance |
| Polarity | Bi-directional - Enables single-device protection of AC-coupled or floating signal lines |
| TJ max | +150 °C - Extended junction temperature rating supports operation in under-hood automotive environments |
| IR @ VRWM | 2.0 µA - Low leakage preserves efficiency in battery-powered or high-impedance sensing circuits |
Pinout & Package
DO-214AB (SMC J-Bend) surface-mount package with molded plastic case and solderable terminals per MIL-STD-750 Method 2026. Cathode identification via color band applies only to uni-directional variants; SMDJ21CA is bi-directional and has no polarity marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bi-directional avalanche junction | Either terminal serves as cathode or anode depending on instantaneous polarity - no fixed pin assignment |
| Case / Body | Non-conductive molded plastic housing | Provides mechanical strain relief, UL 94V-0 flame resistance, and JEDEC-standard footprint compatibility |
Key Features
| Feature | Design Value |
|---|---|
| Bi-directional clamping | Enables single-component protection of differential buses (e.g., RS-485, CAN FD) without polarity concerns |
| Glass-passivated junction | Ensures long-term VBR stability and reduced parameter drift over temperature and lifetime |
| Low profile DO-214AB package | 0.31×0.31" (8.0×8.0 mm) copper pad layout supports high-current PCB routing and thermal management |
| Fast response time <1.0 ps | Clamps ESD events (IEC 61000-4-2 ±8 kV contact) before logic-level ICs experience latch-up |
| MSL Level 1 reflow compatibility | Supports standard lead-free SMT processes without pre-baking or special handling |
Applications
| Industrial Power Input Protection | Automotive Body Control Module |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary surge shunt device placed upstream of DC-DC converter and microcontroller power rails. Use Value: Clamps 3000 W transients to ≤34.1 V, preventing overvoltage damage to 3.3 V/5 V LDOs and MCU I/O pins. | Use Scenario: LIN bus line protection in door module where wiring harnesses couple battery transients. IC Role / Device Role / Timing Role: Bi-directional TVS across LIN signal pair (LIN_H/L) referenced to chassis ground. Use Value: Symmetrical clamping maintains signal integrity during ±100 V ISO 16750-2 pulses without requiring dual uni-directional devices. |
| RS-485 Data Line Protection | Smart Meter Communication Interface |
Use Scenario: Full-duplex RS-485 transceiver (e.g., MAX13487) in utility metering gateway subjected to induced surges. IC Role / Device Role / Timing Role: Common-mode TVS between A/B lines and ground, leveraging bi-directional behavior for polarity-agnostic protection. Use Value: 34.1 V clamping prevents transceiver output stage saturation and maintains >1.5 V differential margin per EIA/TIA-485-A. | Use Scenario: HAN (Home Area Network) interface in smart electricity meter using PLC (G3-PLC) or RF (Sub-GHz) PHY layers. IC Role / Device Role / Timing Role: Secondary surge clamp on AC mains input rectifier output, supplementing MOV-based primary protection. Use Value: 2.0 µA leakage avoids loading precision voltage references used in metrology ADC front-end stages. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC21CA (Littelfuse) | Same DO-214AB package, identical VRWM (21 V), but higher VC = 35.5 V at 84.6 A; 2000 W PPPM rating | Limited to lower-energy surges (IEC 61000-4-5 Level 3); less margin for 3000 W events | Select when cost sensitivity outweighs need for full Level 4 surge headroom |
| SMCJ21CA (ON Semiconductor) | Identical electrical specs (VRWM=21 V, VBR=23.3–25.7 V, VC=34.1 V), same DO-214AB package, RoHS-compliant | Direct functional replacement with validated automotive qualification (AEC-Q101) | Preferred for automotive OEM designs requiring AEC-Q101 documentation and traceability |
Compared with SAC21CA and SMCJ21CA, the SMDJ21CA delivers superior 3000 W surge capability and tighter VBR tolerance, making it optimal for industrial equipment requiring IEC 61000-4-5 Level 4 immunity - whereas SAC21CA suits cost-driven consumer applications, and SMCJ21CA better fits automotive production with AEC-Q101 compliance.
Availability
SMDJ21CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, RS-485 data line protection, and smart meter communication interfaces requiring stable component supply and consistent surge performance across production batches.
Supply support for SMDJ21CA 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 high-efficiency MOSFETs, TVS diodes, and power ICs for computing, consumer, industrial, and automotive markets.
The SMDJ series is engineered for robust transient suppression in harsh environments, targeting applications demanding high peak power handling, low clamping voltage, and JEDEC-standard surface-mount reliability.
FAQ
What is the clamping voltage of the SMDJ21CA under maximum rated surge current?
The SMDJ21CA exhibits a maximum clamping voltage (VC) of 34.1 V when subjected to its rated peak pulse current (IPPM) of 88.0 A on a 10/1000 µs waveform. This value is measured per JEDEC standards and defines the upper voltage limit imposed on protected circuitry during worst-case surge events, ensuring downstream components remain within safe operating limits.
Is the SMDJ21CA suitable for protecting CAN FD bus lines?
Yes, the SMDJ21CA is suitable for CAN FD bus protection due to its bi-directional configuration, 34.1 V clamping voltage, and fast <1.0 ps response time. Its 21.0 V VRWM aligns with typical CAN FD common-mode voltage ranges, and the DO-214AB package allows placement directly across the differential pair without polarity constraints - provided board layout maintains controlled impedance and minimizes parasitic inductance.
Does the SMDJ21CA have AEC-Q101 qualification for automotive use?
No, the SMDJ21CA is not AEC-Q101 qualified per Alpha & Omega Semiconductor's published documentation. For automotive applications requiring AEC-Q101 certification, the functionally equivalent SMCJ21CA from ON Semiconductor is recommended - it shares identical electrical parameters and DO-214AB packaging while carrying formal AEC-Q101 qualification for stress testing and reliability validation.
How does the thermal resistance of the SMDJ21CA affect PCB layout?
The SMDJ21CA has a typical junction-to-lead thermal resistance (RθJL) of 15 °C/W, meaning effective heat transfer requires direct copper connections from both terminals to ≥8.0 mm × 8.0 mm copper pads. Layouts must avoid narrow traces or thermal reliefs on these pads, as insufficient copper area increases junction temperature during repeated surges and risks parametric shift or premature failure.
What is the leakage current specification for the SMDJ21CA at its rated VRWM?
The SMDJ21CA specifies a maximum reverse leakage current (IR) of 2.0 µA at its rated reverse stand-off voltage (VRWM) of 21.0 V and ambient temperature of 25 °C. This low leakage ensures minimal power loss in always-on systems and avoids loading high-impedance sensor inputs or reference circuits in precision analog designs.
SMDJ21CA 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 21V
- Voltage - Breakdown (Min):
- 23.31V
- Voltage - Clamping (Max) @ Ipp:
- 34.1V
- Current - Peak Pulse (10/1000µs):
- 88A
- 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
SMDJ21CA FAQ
1.How can I place an order for SMDJ21CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ21CA 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 SMDJ21CA reliable?
The price and inventory of SMDJ21CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ21CA is usually 5 days.
3.What payment methods are accepted for SMDJ21CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ21CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ21CA?
SMDJ21CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ21CA 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 SMDJ21CA?
For technical support, including SMDJ21CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ21CA requirements.
6.How does Aetrix verify that SMDJ21CA is sourced from the original manufacturer or authorized distributors?
All SMDJ21CA 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 SMDJ21CA meets industry standards.
7.What is the process for return or replacement of SMDJ21CA?
All SMDJ21CA units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ21CA, 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 SMDJ21CA part is unused and in its original packaging.
Return procedure for SMDJ21CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ21CA Tags
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