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Vishay General Semiconductor - Diodes Division SMAJ85CAHM3/I
- Part No.:
- SMAJ85CAHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85CAHM3/I.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,887
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Product details
Overview
SMAJ85CAHM3/I from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features 85 V standoff voltage (VWM), 94.4–104 V breakdown voltage (VBR) at 1 mA, 137 V maximum clamping voltage (VC) at 2.2 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform). It is widely deployed to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power systems.
For engineers reviewing the SMAJ85CAHM3/I datasheet, SMAJ85CAHM3/I pinout, SMAJ85CAHM3/I application, or SMAJ85CAHM3/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification status, thermal resistance (RθJA = 120 °C/W), junction temperature range (–55 to +150 °C), and halogen-free RoHS compliance per HM3 suffix.
Technical Context
This device operates as a voltage-clamping protector with symmetrical reverse/forward conduction behavior due to its bidirectional construction. Its glass-passivated junction enables fast response time (<1 ps) and low incremental surge resistance, critical for suppressing ESD and lightning-induced surges on unprotected lines.
The SMAJ85CAHM3/I is rated for 400 W peak pulse power (derated to 300 W above 78 V), with clamping performance validated under standardized 10/1000 μs waveform testing. It meets MSL Level 1 per J-STD-020 and supports reflow soldering up to 260 °C peak temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous reverse operating voltage before clamping initiates; defines safe working margin for 12 V–48 V DC bus protection. |
| VBR min/max | 94.4 V / 104 V at IT = 1 mA - Confirmed breakdown threshold ensures reliable turn-on during overvoltage events without premature conduction. |
| VC @ IPPM | 137 V at 2.2 A - Clamped voltage level determines maximum stress imposed on downstream components during transient suppression. |
| PPPM | 400 W (10/1000 μs) - Peak energy-handling capacity suitable for automotive load-dump and inductive switching transients. |
| ID @ VWM | 1.0 μA - Ultra-low leakage preserves system efficiency and prevents false triggering in high-impedance sensing circuits. |
| TJ max | +150 °C - Enables operation in under-hood automotive environments and thermally constrained industrial enclosures. |
| Package | SMA (DO-214AC) - Standardized surface-mount outline compatible with automated placement and IPC-7351B footprint guidelines. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking. Dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); cathode band omitted per bidirectional design.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (reverse bias) | Accepts surge current when line voltage exceeds –VWM; forms symmetrical clamping path with cathode. |
| Cathode | Transient current entry (forward bias) | Accepts surge current when line voltage exceeds +VWM; completes bidirectional clamping loop with anode. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, humidity testing, and mechanical shock per JESD22 standards. |
| Halogen-free & RoHS-compliant (HM3) | Meets IEC 61249-2-21 and JEDEC J-STD-20E requirements for green manufacturing and end-of-life disposal. |
| MSL Level 1 rating | Unlimited floor life at ≤30 °C/85 % RH; supports standard SMT reflow without baking preconditioning. |
| 400 W peak pulse power | Handles repetitive 10/1000 μs transients common in 12 V/24 V vehicle electrical systems and industrial PLC I/O modules. |
| Low clamping ratio (VC/VBR ≈ 1.39) | Minimizes voltage overshoot across protected devices-critical for safeguarding 100 V-rated MOSFETs and microcontrollers. |
Applications
| Automotive Power Distribution | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Protecting 12 V battery-fed ECUs against load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed across input rails upstream of DC/DC converters and LDOs. Use Value: Limits transient voltage to ≤137 V, preventing damage to 36 V-input regulators and CAN transceivers. |
Use Scenario: Shielding analog sensor outputs (e.g., pressure, temperature) from ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-leakage (1.0 μA) TVS connected between signal line and ground near connector entry point. Use Value: Maintains signal integrity with <1 pF junction capacitance while clamping ±15 kV contact ESD per IEC 61000-4-2. |
| Telecom DC Power Input | Motor Drive Gate Driver Protection |
|
Use Scenario: Safeguarding 48 V PoE-powered equipment inputs from induced surges on long Ethernet runs. IC Role / Device Role / Timing Role: Primary-level TVS mounted directly at RJ45 jack, shunting surge energy before DC/DC isolation stage. Use Value: Withstands 400 W pulses and operates up to +150 °C ambient, ensuring uptime in uncooled telecom cabinets. |
Use Scenario: Preventing gate oxide failure in N-channel MOSFETs driven by isolated gate drivers in BLDC inverters. IC Role / Device Role / Timing Role: Bidirectional TVS across gate-source terminals to clamp Miller-induced voltage spikes during switching transitions. Use Value: Fast response (<1 ps) and low Rsurge limit dV/dt-induced false turn-on and gate overvoltage beyond ±20 V rating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85CAHE3/I | RoHS-compliant but not halogen-free; lacks HM3 material certification. | Approved for commercial/industrial use; excluded from automotive programs requiring halogen-free compliance. | Select when halogen-free content is not mandated and cost optimization is prioritized. |
| SMBJ85CAHM3/I | Same VWM/VBR/VC specs but in SMB (DO-214AA) package - 27 % larger footprint and 10 % higher RθJA (133 °C/W). | Better suited for higher-power derating scenarios where board space allows larger pad layout. | Choose only if PCB layout accommodates 3.99 mm × 2.54 mm footprint and thermal margin requires lower power density. |
Compared with SMAJ85CAHM3/I, SMAJ85CAHE3/I omits halogen-free assurance but retains AEC-Q101 qualification, while SMBJ85CAHM3/I trades compactness for marginally improved surge handling at the expense of board area and thermal performance.
Availability
SMAJ85CAHM3/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor systems, and telecom power input protection requiring stable component supply and full traceability.
Supply support for SMAJ85CAHM3/I 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, and protection devices with emphasis on reliability and automotive qualification.
The SMAJ series was developed specifically for robust, surface-mount transient suppression in harsh environments-targeting ISO 7637-2, IEC 61000-4-4, and IEC 61000-4-5 compliant designs across automotive, industrial, and communications infrastructure.
FAQ
What is the clamping voltage of the SMAJ85CAHM3/I under peak surge conditions?
The SMAJ85CAHM3/I exhibits a maximum clamping voltage (VC) of 137 V when subjected to its rated peak pulse current of 2.2 A using the standardized 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and confirmed in Vishay's datasheet revision 09-Jan-2024, Document Number 88390. The clamping performance ensures downstream components see limited overvoltage stress during transient events.
Is the SMAJ85CAHM3/I qualified for automotive applications?
Yes, the SMAJ85CAHM3/I carries AEC-Q101 qualification, verified through stress tests including temperature cycling, highly accelerated life testing (HALT), and mechanical shock per JESD22 standards. Its HM3 suffix confirms halogen-free, RoHS-compliant construction required for modern automotive supply chains. The device is explicitly listed in Vishay's AEC-Q101 qualified product table for the SMAJ family.
What does the "CA" suffix indicate in SMAJ85CAHM3/I?
The "CA" suffix in SMAJ85CAHM3/I denotes a bidirectional configuration-meaning the device provides symmetrical transient suppression in both polarities, with identical breakdown and clamping characteristics for positive and negative voltage excursions. This eliminates need for polarity-aware placement and simplifies layout for AC-coupled or floating signal lines, unlike unidirectional "A" variants which require cathode orientation.
How does the thermal resistance of SMAJ85CAHM3/I affect PCB layout?
The SMAJ85CAHM3/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on minimum recommended copper pads (0.2" × 0.2"). To maintain TJ ≤ 150 °C under sustained 3.3 W power dissipation, designers must allocate ≥250 mm² of 2-oz copper per terminal or add thermal vias. Layout deviations directly impact safe operating area and long-term reliability under repetitive surge conditions.
Can SMAJ85CAHM3/I replace SMAJ85A in existing designs?
No-SMAJ85CAHM3/I is bidirectional while SMAJ85A is unidirectional, making them functionally incompatible without circuit redesign. SMAJ85A includes a cathode band and conducts only in reverse bias; substituting SMAJ85CAHM3/I would eliminate polarity control and risk unintended forward conduction. Direct replacement requires verification of system-level polarity requirements and clamping symmetry needs.
SMAJ85CAHM3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- 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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ85CAHM3/I FAQ
1.How can I place an order for SMAJ85CAHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85CAHM3/I 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 SMAJ85CAHM3/I reliable?
The price and inventory of SMAJ85CAHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85CAHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ85CAHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85CAHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85CAHM3/I?
SMAJ85CAHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85CAHM3/I 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 SMAJ85CAHM3/I?
For technical support, including SMAJ85CAHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85CAHM3/I requirements.
6.How does Aetrix verify that SMAJ85CAHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ85CAHM3/I 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 SMAJ85CAHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ85CAHM3/I?
All SMAJ85CAHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85CAHM3/I, 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 SMAJ85CAHM3/I part is unused and in its original packaging.
Return procedure for SMAJ85CAHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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