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Diodes Incorporated SMAJ85A-13
- Part No.:
- SMAJ85A-13
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85A-13.pdf
- Description:
- TVS DIODE 85VWM 137VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:1,547
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Product details
Overview
SMAJ85A-13 from Diodes Incorporated is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode designed for primary overvoltage protection in DC power lines and signal interfaces. It features a 85V reverse standoff voltage (VRWM), 94.4–104V breakdown voltage (VBR), 137V maximum clamping voltage (VC) at 2.9A peak pulse current (IPP), and operates across –55°C to +150°C. Used in automotive infotainment power rails to suppress load dump transients.
For engineers reviewing the SMAJ85A-13 datasheet, SMAJ85A-13 pinout, SMAJ85A-13 application, or SMAJ85A-13 equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD, peak pulse current handling under ISO 7637-2 Pulse 5a, unidirectional polarity alignment with DC bias, and SMA package thermal derating above +25°C ambient.
Technical Context
This TVS diode operates as a voltage-clamped crowbar device triggered by avalanche breakdown when transient voltage exceeds VRWM. Its glass-passivated die ensures stable VBR tolerance (±5%) and low leakage (<5µA at 85V), critical for low-power always-on circuits.
Clamping performance is defined at 10/1000µs waveform per REA standard, with 137V VC limiting surge energy delivered to downstream components. Thermal design must account for 1.0W steady-state dissipation at TL = +75°C and derating above that temperature per Figure 6.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power | 400W - Sustains single 10/1000µs transients up to 2.9A without failure |
| Reverse Standoff Voltage | 85V - Maximum continuous DC voltage before significant leakage; sets minimum system operating margin |
| Breakdown Voltage | 94.4–104V - Avalanche onset range; defines turn-on threshold under fast transients |
| Clamping Voltage | 137V @ 2.9A - Maximum voltage seen by protected circuit during worst-case surge |
| Package | SMA - Surface-mount plastic case (4.0–4.6mm length); compatible with standard reflow profiles |
| Operating Temperature | –55°C to +150°C - Validated for under-hood automotive environments and industrial control enclosures |
Pinout & Package
Two-terminal SMA package: anode and cathode. Cathode identified by molded band on body. No internal pin numbering-device functions as a bidirectional clamp only in C-suffix variants; SMAJ85A is unidirectional, requiring correct orientation in series with protected line.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; completes clamping path during overvoltage |
| Cathode | High-side surge input | Connected to protected line (e.g., 12V rail); avalanche conduction begins here when VRWM exceeded |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse rating | Enables compliance with ISO 7637-2 Pulse 5a (load dump) without parallel staging |
| Glass passivated die | Ensures ±5% VBR tolerance and <5µA IR at VRWM-critical for battery-backed systems |
| UL 94V-0 mold compound | Meets flammability requirements for enclosed automotive and industrial assemblies |
| Moisture sensitivity Level 1 | Eliminates bake requirement prior to SMT assembly-reduces manufacturing cost and risk |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface |
|---|---|
Use Scenario: 12V battery-fed infotainment head unit exposed to alternator load dump transients up to 120V. IC Role / Device Role: Primary clamping element placed between fuse and DC-DC converter input. Use Value: Limits voltage to ≤137V during 100ms load dump event, preventing damage to 36V-rated buck controller. | Use Scenario: 24V analog sensor signal line (e.g., pressure transducer) routed through noisy factory floor wiring. IC Role / Device Role: Point-of-entry TVS on sensor PCB input connector. Use Value: Clamps ESD (IEC 61000-4-2 ±15kV) and inductive switching spikes to <137V, preserving 24V op-amp input stage integrity. |
| Telecom DC Power Feeds | Medical Equipment Auxiliary Supplies |
Use Scenario: -48V telecom shelf power distribution board subject to hot-swap surges and lightning-induced ring waves. IC Role / Device Role: Secondary protection stage after bulk MOV, placed adjacent to DC-DC module input. Use Value: Responds in <1ns to clamp sub-microsecond transients, complementing slower MOV response for combined surge robustness. | Use Scenario: Isolated 5V auxiliary supply in patient-connected diagnostic device requiring low leakage and high reliability. IC Role / Device Role: Final-stage TVS on isolated output rail before analog front-end. Use Value: Delivers <5µA leakage at 85V standoff-preserves microamp-level sleep current budgets in battery-powered modes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85CA-13 | Bidirectional version; symmetric clamping for AC-coupled or floating lines | Required where protected signal has no fixed DC bias (e.g., RS-485 differential pairs) | Select only if line lacks defined polarity; adds no benefit for unidirectional DC rails |
| SMBJ85A-13 | Same electrical specs but SMB package (higher thermal mass, 600W PPK rating) | Preferred for higher-reliability designs needing margin beyond 400W or improved thermal stability | Choose when board layout allows larger footprint and long-term power cycling is expected |
Compared with SMAJ85CA-13, SMAJ85A-13 offers lower capacitance and tighter VBR tolerance for DC-biased rails; versus SMBJ85A-13, it trades thermal robustness for space savings-ideal for compact automotive modules where 400W surge margin suffices.
Availability
SMAJ85A-13 is available at Aetrix Electronics and suitable for automotive infotainment power rails, industrial sensor interfaces, telecom DC feeds, and medical auxiliary supplies requiring stable component supply across extended temperature ranges and AEC-Q200-aligned quality standards.
Supply support for SMAJ85A-13 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and integrated circuits, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The SMAJ series belongs to Diodes' transient suppression portfolio, engineered specifically for high-reliability DC line protection in automotive, industrial, and communications equipment where fast response, tight VBR, and AEC-Q200 compatibility are essential.
FAQ
What is the polarity configuration of SMAJ85A-13?
SMAJ85A-13 is a unidirectional TVS diode with cathode indicated by a molded band on the SMA package body. It conducts only when cathode voltage exceeds anode voltage by ≥94.4V, making it suitable for DC lines with fixed polarity. Bidirectional operation requires the SMAJ85CA-13 variant.
Does SMAJ85A-13 meet AEC-Q200 stress testing requirements?
No-SMAJ85A-13 is the standard industrial-grade part. The automotive-qualified version is SMAJ85AQ-13, which undergoes AEC-Q200 qualification including temperature cycling, humidity bias, and mechanical shock tests, and is manufactured in IATF 16949-certified facilities.
How does the 137V clamping voltage impact system design?
The 137V clamping voltage (VC) at 2.9A IPP defines the absolute maximum voltage imposed on downstream components during surge events. Designers must ensure all components on the protected rail-including capacitors, regulators, and connectors-have voltage ratings exceeding 137V with appropriate safety margin, especially for ISO 7637-2 Pulse 5a compliance.
Can SMAJ85A-13 be used in parallel for higher surge current handling?
Not recommended without derating and matching. Parallel connection introduces imbalance due to VBR tolerance (±5%), causing one device to conduct first and potentially fail. For >2.9A IPP, use a single higher-rated device like SMBJ85A-13 or verify matched binning and thermal coupling per Diodes' application note AN-AB100.
SMAJ85A-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Cut Tape (CT)
- 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):
- 2.9A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
SMAJ85A-13 FAQ
1.How can I place an order for SMAJ85A-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85A-13 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 SMAJ85A-13 reliable?
The price and inventory of SMAJ85A-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85A-13 is usually 5 days.
3.What payment methods are accepted for SMAJ85A-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85A-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85A-13?
SMAJ85A-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85A-13 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 SMAJ85A-13?
For technical support, including SMAJ85A-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85A-13 requirements.
6.How does Aetrix verify that SMAJ85A-13 is sourced from the original manufacturer or authorized distributors?
All SMAJ85A-13 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 SMAJ85A-13 meets industry standards.
7.What is the process for return or replacement of SMAJ85A-13?
All SMAJ85A-13 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85A-13, 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 SMAJ85A-13 part is unused and in its original packaging.
Return procedure for SMAJ85A-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ85A-13 Tags
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