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Taiwan Semiconductor Corporation SMAJ85AH
- Part No.:
- SMAJ85AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85AH.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,813
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Product details
Overview
SMAJ85AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in automotive and industrial power rails. It features a 85 V working stand-off voltage (VWM), 94.4–104 V breakdown voltage (VBR), 137 V maximum clamping voltage (VC) at 2.2 A peak impulse current, and 400 W peak pulse power (10/1000 µs). It is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive electronics protection.
For engineers reviewing the SMAJ85AH datasheet, SMAJ85AH pinout, SMAJ85AH application, or SMAJ85AH equivalent, key selection criteria include clamping performance under 10/1000 µs surge, unidirectional polarity marking, AEC-Q101 qualification status, compliance with ISO 7637-2 automotive transient immunity standards, and compatibility with automated SMT placement on DC/DC converter input stages.
Technical Context
The SMAJ85AH operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve sub-1 ps response time from 0 V to VBR min. Its clamping behavior is defined by a tightly controlled 94.4–104 V breakdown range at 1 mA test current and delivers 137 V VC under 2.2 A IPPM - critical for protecting downstream MOSFETs or controllers during load dump events.
It supports continuous operation from –55 °C to +150 °C junction temperature, with <1 µA reverse leakage at 85 V (VWM), and is rated for 40 A non-repetitive forward surge (IFSM, 8.3 ms half-sine). The device is packaged in moisture-sensitive level 1 DO-214AC (SMA) with matte tin-plated leads compliant with J-STD-002 solderability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR min/max | 94.4 V / 104 V @ 1 mA - Ensures reliable turn-on before system overvoltage damages sensitive ICs |
| VC @ IPPM | 137 V @ 2.2 A (10/1000 µs) - Clamped voltage seen by protected circuit during standardized surge event |
| PPPM | 400 W (10/1000 µs) - Peak transient energy absorption capability per single pulse |
| IR @ VWM | <1 µA - Negligible leakage current preserves efficiency in high-impedance bias networks |
| TJ max | +150 °C - Enables use in under-hood automotive environments and thermally constrained PCB layouts |
| Package | DO-214AC (SMA) - Standardized SMT footprint compatible with IPC-7351B land patterns |
Pinout & Package
DO-214AC (SMA) package: surface-mount, single-diode configuration with cathode band marking. Body length 4.5 mm, width 2.7 mm, height 2.2 mm; lead spacing 2.3 mm; matte tin-plated leads meet J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-impedance return path; defines unidirectional clamping direction |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., battery rail); marked by band; conducts when line exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD per stress test plan |
| Glass passivated junction | Enables stable VBR tolerance and long-term leakage stability under thermal/humidity stress |
| Fast response time <1 ps | Clamps transients before propagation into sensitive analog or digital circuitry |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive switch-off), Pulse 2a/2b (load dump coupling), and Pulse 3a/3b (capacitive coupling) immunity requirements |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; supports standard SMT assembly without dry-pack handling |
Applications
| Automotive Load Dump Protection | Industrial DC/DC Input Stage |
|---|---|
Use Scenario: Protecting 12 V/24 V vehicle electronics against alternator load dump transients up to ±120 V. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and DC/DC converter input. Use Value: Clamps surge to ≤137 V within <1 ps, preventing damage to upstream PMICs or microcontrollers rated for 40 V absolute max. | Use Scenario: Safeguarding isolated flyback or buck converters in factory automation I/O modules. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main DC bus feeding converter primary side. Use Value: Absorbs 400 W transient energy (10/1000 µs), enabling robust operation in electrically noisy plant environments. |
| LED Driver Power Input | Telecom Power Supply Front-End |
Use Scenario: Shielding constant-current LED drivers from supply-line surges in streetlight or signage applications. IC Role / Device Role / Timing Role: Standoff-rated TVS on 48 V input rail upstream of active rectification stage. Use Value: Maintains <1 µA leakage at 85 V, avoiding standby power loss while delivering 137 V clamping for EN 61000-4-5 Level 3 compliance. | Use Scenario: Transient suppression on -48 V telecom distribution boards exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Unidirectional clamp referenced to system ground on negative supply rail. Use Value: Operates down to –55 °C and up to +150 °C, supporting extended temperature deployment in outdoor cabinets. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ85A | Identical VWM (85 V), VBR (94.4–104 V), VC (137 V), and package; same AEC-Q101 qualification and ISO 7637-2 compliance | No functional or layout difference; validated drop-in replacement per Littelfuse datasheet Rev. D | Select when dual-sourcing required or Littelfuse supply chain preference applies |
| ON Semiconductor SMAJ85A | VWM = 85 V, VBR = 94.4–104 V, VC = 137 V, same DO-214AC package; AEC-Q101 qualified but ISO 7637-2 compliance not explicitly stated in public datasheet | May require additional system-level validation for automotive Pulse 1/2a/2b if ISO 7637-2 certification is mandatory | Prefer for industrial applications where AEC-Q101 suffices but full ISO 7637-2 traceability is not contractually required |
Compared with Littelfuse SMAJ85A and ON Semiconductor SMAJ85A, the SMAJ85AH offers identical electrical clamping performance and automotive qualification, but only Taiwan Semiconductor's version explicitly documents ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance in its official datasheet - a decisive factor for Tier 1 automotive module design sign-off.
Availability
SMAJ85AH is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial DC/DC converters, and LED lighting power supplies requiring stable component supply across multi-year production cycles.
Supply support for SMAJ85AH 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers, with global distribution and AEC-Q101-compliant production lines.
The SMAJ series is engineered for high-reliability transient suppression in automotive and industrial power systems, emphasizing tight VBR tolerance, low clamping ratio, and robust surge endurance under harsh thermal and mechanical conditions.
FAQ
What is the clamping voltage of SMAJ85AH under a 10/1000 µs surge?
The SMAJ85AH has a maximum clamping voltage (VC) of 137 V when subjected to a 2.2 A peak impulse current with a 10/1000 µs waveform. This value is measured per standard test conditions in the Taiwan Semiconductor datasheet and represents the upper limit of voltage imposed on the protected circuit during such a transient event. The SMAJ85AH maintains this clamping performance across its specified operating temperature range.
Is SMAJ85AH unidirectional or bidirectional?
SMAJ85AH is a unidirectional transient voltage suppressor, indicated by the absence of "C" or "CA" in its part number suffix and confirmed by its cathode-band marking and single-polarity IV curve. It conducts only when the cathode is positive relative to the anode, making it suitable for DC rail protection where polarity is fixed - unlike bidirectional variants such as SMAJ85CH which protect AC or reversible lines.
Does SMAJ85AH meet automotive qualification standards?
Yes, SMAJ85AH is AEC-Q101 qualified and explicitly certified to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transient immunity requirements per Taiwan Semiconductor's official documentation. This makes SMAJ85AH suitable for front-end protection in automotive ECUs, body control modules, and ADAS power supplies where standardized surge resilience is mandated.
What is the maximum operating temperature for SMAJ85AH?
The SMAJ85AH has a maximum junction temperature (TJ max) of +150 °C and a storage temperature range of –55 °C to +150 °C. Its DO-214AC package and glass-passivated junction enable stable operation in under-hood automotive environments and thermally dense industrial PCBs, provided PCB copper area and airflow meet thermal derating guidelines in Figure 2 of the datasheet.
How does SMAJ85AH differ from SMAJ85H?
SMAJ85AH has a tighter breakdown voltage range (94.4–104 V) compared to SMAJ85H (94.4–115 V), resulting in more consistent clamping behavior and reduced risk of premature conduction. Both share identical VWM (85 V), VC (137 V), and PPPM (400 W), but the "A" grade offers improved VBR uniformity - critical for designs requiring precise overvoltage threshold control without margin stacking.
SMAJ85AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- 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):
- 2.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ85AH FAQ
1.How can I place an order for SMAJ85AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85AH 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 SMAJ85AH reliable?
The price and inventory of SMAJ85AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85AH is usually 5 days.
3.What payment methods are accepted for SMAJ85AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85AH?
SMAJ85AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85AH 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 SMAJ85AH?
For technical support, including SMAJ85AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85AH requirements.
6.How does Aetrix verify that SMAJ85AH is sourced from the original manufacturer or authorized distributors?
All SMAJ85AH 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 SMAJ85AH meets industry standards.
7.What is the process for return or replacement of SMAJ85AH?
All SMAJ85AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85AH, 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 SMAJ85AH part is unused and in its original packaging.
Return procedure for SMAJ85AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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