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Alpha & Omega Semiconductor Inc. SMDJ85A
- Part No.:
- SMDJ85A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ85A.pdf
- Description:
- 1CH 85V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:5,503
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Product details
Overview
SMDJ85A 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 85 V reverse standoff voltage (VRWM), 94.4–104.0 V breakdown voltage (VBR) at 1 mA, 137 V maximum clamping voltage at 21.9 A peak pulse current, and 3000 W peak pulse power rating on 10/1000 µs waveform - deployed in industrial motor drives to protect IGBT gate drivers from inductive switching transients.
For engineers reviewing the SMDJ85A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDS(max), thermal resistance (RθJL = 15 °C/W), unidirectional polarity confirmation, and DO-214AB package compatibility with automated SMT assembly and IPC Class 3 board layouts.
Technical Context
The SMDJ85A operates as a silicon avalanche diode with glass-passivated junction and low-profile DO-214AB (SMC J-Bend) package. Its fast response time (<1.0 ps) enables suppression of ESD and lightning-induced surges before downstream components experience overvoltage stress.
It delivers 3000 W peak pulse power handling under 10/1000 µs waveform with 0.01% duty cycle limitation, and exhibits ±0.1 %/°C temperature coefficient of VBR. Thermal design must account for RθJA = 75 °C/W (on standard PCB) and RθJL = 15 °C/W (to copper pad), requiring ≥8.0 mm × 8.0 mm Cu pads per terminal for rated IPPM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 85.0 V - Maximum continuous reverse operating voltage before leakage exceeds 2.0 µA; sets upper limit for protected line voltage. |
| VBR @ IT=1 mA | 94.4–104.0 V - Confirmed avalanche conduction onset range; ensures reliable triggering above system nominal voltage. |
| Vc @ IPPM | 137.0 V - Clamping voltage at 21.9 A peak pulse current; defines worst-case voltage seen by downstream circuitry during surge. |
| PPPM (10/1000 µs) | 3000 W - Peak surge energy absorption capacity; supports IEC 61000-4-5 Level 4 (4 kV) compliance with proper layout. |
| IFSM (8.3 ms) | 300 A - Single half-sine surge current rating; validates robustness against inrush or fault currents in power supplies. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in enclosed industrial enclosures without active cooling. |
| Polarity | Unidirectional - Cathode band denotes polarity; requires correct orientation in series with positive rail or ground-referenced lines. |
Pinout & Package
DO-214AB (SMC J-Bend) surface-mount package: molded plastic case with matte tin lead-free plating, JEDEC-compliant outline, and cathode band marking on one end. Designed for reflow soldering per J-STD-020 MSL Level 1 (peak 260 °C).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Anode reference / surge return path | Connected to system ground or lower-potential rail; conducts surge current toward ground when VR > VBR. |
| Anode (non-banded end) | Protected line interface | Connected to input/output line being safeguarded; blocks normal operation current but avalanches during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over lifetime and humidity exposure; eliminates parameter drift in humid industrial environments. |
| Built-in strain relief | Reduces mechanical stress at lead-to-body interface during thermal cycling; extends reliability in automotive under-hood applications. |
| Low profile DO-214AB | Height ≤2.6 mm enables use in space-constrained modules such as DIN-rail PLC I/O terminals and PoE injectors. |
| Fast response time <1.0 ps | Clamps transients before propagation across PCB traces; critical for protecting high-speed gate drivers and isolated ADC references. |
| UL 94V-0 flammability rating | Validates safe failure mode under sustained overvoltage; required for UL 61000-1-2 certified industrial equipment. |
Applications
| Industrial Motor Drives | DC Power Input Protection |
|---|---|
|
Use Scenario: Protecting gate driver ICs from flyback voltage spikes generated by IGBT switching in 400 V DC bus inverters. IC Role / Device Role / Timing Role: Unidirectional TVS placed between gate driver output and IGBT gate, referenced to emitter. Use Value: Clamps 137 V at 21.9 A, staying below typical IGBT gate oxide breakdown (±20 V) while absorbing 3000 W surge energy. |
Use Scenario: Safeguarding 24 V/48 V DC inputs of programmable logic controllers against load dump and inductive kickback. IC Role / Device Role / Timing Role: Primary surge clamp on main DC input rail upstream of DC-DC converters and microcontrollers. Use Value: Withstands 300 A IFSM (8.3 ms) and maintains 85 V VRWM margin above nominal 48 V supply, enabling robust field deployment. |
| Telecom Power Feeds | Automotive Body Control Modules |
|
Use Scenario: Protecting PoE-powered Ethernet switches and media converters connected to outdoor cabling exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Secondary-level TVS on 48 V PSE output side, coordinated with primary GDT and series impedance. Use Value: 3000 W PPPM rating meets IEC 61000-4-5 4 kV test requirements when paired with 1 Ω series impedance and proper PCB trace routing. |
Use Scenario: Shielding LIN bus transceivers and sensor interfaces in body control units from battery line transients during jump-start or alternator load dump. IC Role / Device Role / Timing Role: Unidirectional TVS on 12 V supply rail feeding LIN transceivers and Hall-effect sensors. Use Value: 150 °C TJ(max) and MSL Level 1 rating support under-dash mounting; 2.0 µA IR at 85 V ensures minimal standby current drain. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC85A (Littelfuse) | Same DO-214AB package, identical VRWM (85 V) and VBR (94–104 V), but lower PPPM (1500 W) and higher Vc (145 V @ 15 A). | Not suitable for IEC 61000-4-5 Level 4; limited to Level 3 (2 kV) systems or secondary-stage protection only. | Select SMDJ85A when full 3000 W surge handling is required; SAC85A may be used where cost sensitivity outweighs peak power margin. |
| 1.5KE85A (ON Semiconductor) | Through-hole DO-201 package, same electrical specs, but RθJA = 60 °C/W (vs. 75 °C/W) and no MSL1 rating - unsuitable for lead-free reflow. | Requires wave soldering or hand assembly; incompatible with high-volume SMT lines and RoHS-compliant reflow profiles. | Choose SMDJ85A for automated SMT production; 1.5KE85A remains viable only for legacy through-hole designs or prototyping. |
Compared with SAC85A and 1.5KE85A, the SMDJ85A uniquely combines 3000 W surge capability, DO-214AB SMT compatibility, MSL Level 1 reflow readiness, and 150 °C junction rating - making it the only option qualified for high-reliability industrial SMT power rail protection.
Availability
SMDJ85A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power feeds, and automotive body control modules requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant green packaging.
Supply support for SMDJ85A 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 industrial, computing, and consumer markets.
The SMDJxxxA series was engineered specifically for high-power, surface-mount transient suppression in harsh-environment DC power systems - emphasizing low clamping voltage, repeatable avalanche performance, and automated assembly compatibility.
FAQ
What is the maximum clamping voltage of the SMDJ85A at its rated peak pulse current?
The SMDJ85A has a maximum clamping voltage (Vc) of 137.0 V at its rated peak pulse current (IPPM) of 21.9 A under the standard 10/1000 µs waveform. This value is measured per JEDEC test conditions and defines the upper voltage limit imposed on protected circuitry during a full-rated surge event - critical for ensuring downstream ICs remain within absolute maximum ratings.
Is the SMDJ85A suitable for bidirectional surge protection applications?
No, the SMDJ85A is a unidirectional TVS diode, indicated by the "A" suffix and single cathode band marking. For bidirectional protection, the SMDJ85CA variant must be used. Using SMDJ85A in AC-coupled or symmetrical signal lines will result in forward conduction during negative half-cycles and potential device failure.
What PCB layout requirements ensure the SMDJ85A achieves its full 3000 W peak pulse power rating?
To achieve the rated 3000 W PPPM, the SMDJ85A must be mounted on 8.0 mm × 8.0 mm copper pads per terminal, per the datasheet's Note 2. Smaller pads increase thermal resistance, derating both peak current and power capability. Trace width, layer stack-up, and adjacent thermal vias also impact sustained surge performance in repetitive scenarios.
Does the SMDJ85A meet RoHS and halogen-free compliance standards?
Yes, the SMDJ85A is an AOS Green Product: fully RoHS compliant, lead-free, and halogen-free per AOS' Green Policy. It carries UL 94V-0 flammability rating and is qualified for lead-free reflow per J-STD-020 MSL Level 1 (260 °C peak). Full compliance documentation is available at aosmd.com/media/AOSGreenPolicy.pdf.
How does the temperature coefficient affect the SMDJ85A's breakdown voltage in real-world operation?
The SMDJ85A exhibits a typical temperature coefficient of ΔVBR = 0.1 % × VBR @ 25 °C × ΔT. At 100 °C junction temperature (ΔT = +75 °C), VBR increases by ~0.75 V - shifting from 94.4–104.0 V at 25 °C to approximately 95.1–104.8 V. This positive drift improves margin against false triggering at elevated temperatures but must be accounted for in tight-clamp designs.
SMDJ85A 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):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 21.9A
- 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
SMDJ85A FAQ
1.How can I place an order for SMDJ85A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ85A 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 SMDJ85A reliable?
The price and inventory of SMDJ85A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ85A is usually 5 days.
3.What payment methods are accepted for SMDJ85A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ85A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ85A?
SMDJ85A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ85A 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 SMDJ85A?
For technical support, including SMDJ85A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ85A requirements.
6.How does Aetrix verify that SMDJ85A is sourced from the original manufacturer or authorized distributors?
All SMDJ85A 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 SMDJ85A meets industry standards.
7.What is the process for return or replacement of SMDJ85A?
All SMDJ85A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ85A, 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 SMDJ85A part is unused and in its original packaging.
Return procedure for SMDJ85A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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