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Vishay General Semiconductor - Diodes Division SMAJ85CAHM3_A/I
- Part No.:
- SMAJ85CAHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85CAHM3_A/I.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,453
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Product details
Overview
SMAJ85CAHM3_A/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), used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power rails.
For engineers reviewing the SMAJ85CAHM3_A/I datasheet, SMAJ85CAHM3_A/I pinout, SMAJ85CAHM3_A/I application, or SMAJ85CAHM3_A/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification status, 137 V VC under 2.2 A surge, MSL Level 1 moisture sensitivity, and halogen-free RoHS compliance per HM3 suffix.
Technical Context
This device operates as a voltage-clamping protection element across bidirectional signal or DC power lines, responding within <1 ps to transient overvoltages induced by inductive switching or ESD events. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 μA at 85 V), while the unmarked SMA package indicates symmetrical terminal behavior with no anode/cathode polarity distinction.
The SMAJ85CAHM3_A/I delivers 400 W peak pulse power up to 78 V and derates to 300 W above 78 V per Fig. 2 of the datasheet; its thermal resistance (RθJA = 120 °C/W) and junction temperature limit (TJ max = 150 °C) define safe continuous power dissipation (PD = 3.3 W) under standard PCB pad layout (0.2" × 0.2" copper).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous reverse operating voltage before clamping initiates; defines upper limit of normal circuit operation. |
| VBR min/max | 94.4 V / 104 V at IT = 1 mA - Confirmed breakdown range ensuring reliable turn-on during transients without premature conduction. |
| VC @ IPPM | 137 V at 2.2 A - Clamped voltage seen by protected circuit during 10/1000 μs surge; determines residual stress on downstream components. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - Peak transient energy absorption capacity using standard 10/1000 μs waveform; critical for lightning/inductive spike immunity. |
| ID @ VWM | ≤1 μA - Reverse leakage current at rated standoff voltage; ensures minimal power loss and signal integrity in high-impedance circuits. |
| Package | SMA (DO-214AC) - Surface-mount outline with 5.28 mm length, 4.50 mm width, and 2.29 mm height; compatible with automated placement and reflow. |
| AEC-Q101 | Qualified - Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per AEC specification. |
| MSL Level | Level 1 (J-STD-020) - No floor life limitation; can be stored indefinitely at ≤30 °C/85 % RH prior to reflow soldering. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking; terminals are matte tin-plated and solderable per J-STD-002 and JESD 22-B102.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Bidirectional transient path | Both terminals function identically; voltage clamping occurs regardless of polarity - no orientation required during placement. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (≤78 V) | Enables robust protection against IEC 61000-4-5 Level 3 surges (1 kV/2 Ω) on 12 V/24 V automotive power nets. |
| AEC-Q101 qualified (HM3 suffix) | Validated for under-hood and ADAS applications requiring extended temperature cycling (-55 °C to +150 °C) and long-term reliability. |
| Halogen-free & RoHS-compliant | Meets environmental compliance requirements for automotive OEMs and industrial equipment sold in EU, China, and Korea. |
| Low clamping ratio (VC/VBR ≈ 1.39) | Minimizes overvoltage exposure to protected ICs - e.g., keeps 3.3 V or 5 V logic rails below destructive thresholds during transients. |
| MSL Level 1 handling | Eliminates bake-out or dry-pack requirements before SMT assembly, reducing manufacturing cost and process complexity. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: 12 V battery line in engine control unit exposed to load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed between power rail and ground to limit transient excursions to ≤137 V. Use Value: Prevents latch-up or gate oxide damage in MCU power supply pins and CAN transceiver VCC inputs during 100 V/100 ms surges. |
Use Scenario: RS-485 communication line connecting PLC to remote temperature sensor in factory automation cabinet. IC Role / Device Role / Timing Role: Line-to-line and line-to-ground transient suppressor on differential pair to maintain signal integrity during EFT bursts. Use Value: Limits common-mode transients to <137 V while preserving <10 pF junction capacitance - avoids data corruption at 10 Mbps rates. |
| Consumer Device USB Port Protection | Telecom Base Station DC Feed Protection |
|
Use Scenario: VBUS line of USB 2.0 port in smart speaker subjected to human-body-model ESD (±8 kV contact discharge). IC Role / Device Role / Timing Role: Primary clamping device shunting ESD current away from USB controller PHY and power management IC. Use Value: Responds in <1 ps to clamp ±8 kV ESD event to <137 V within nanoseconds - meets IEC 61000-4-2 Level 4 immunity. |
Use Scenario: -48 V DC feed line powering remote radio head in 4G/LTE base station, subject to lightning-induced surges. IC Role / Device Role / Timing Role: Secondary protection stage after gas discharge tube (GDT), absorbing residual energy and limiting let-through voltage. Use Value: Clamps 10/1000 μs surge to 137 V at 2.2 A - coordinates with upstream GDT to achieve full IEC 61643-21 Class II compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85CAHE3_A/I | Same electrical specs, but RoHS-compliant without halogen-free certification; uses E3 suffix instead of HM3. | Approved for commercial/industrial use where halogen-free requirement is not mandated (e.g., non-automotive consumer products). | Select when halogen-free material declaration is not required and cost optimization is prioritized over automotive compliance. |
| SMBJ85CAHM3_A/I | Same VWM/VBR/VC ratings but in SMB (DO-214AA) package - larger footprint (4.57 mm × 3.94 mm) and higher PPPM (600 W). | Suitable for higher-energy surge environments (e.g., outdoor telecom enclosures) where board space allows larger package. | Choose when system-level surge testing exceeds 400 W requirements and PCB layout accommodates SMB outline. |
Compared with SMAJ85CAHE3_A/I, the SMAJ85CAHM3_A/I adds halogen-free compliance and AEC-Q101 qualification for automotive use; compared with SMBJ85CAHM3_A/I, it trades 200 W pulse power headroom for 30 % smaller PCB area and identical clamping performance at lower surge levels.
Availability
SMAJ85CAHM3_A/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor systems, and telecom infrastructure requiring stable component supply with AEC-Q101 validation and halogen-free compliance.
Supply support for SMAJ85CAHM3_A/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, MOSFETs, and protection devices with emphasis on reliability and application-specific performance.
The SMAJ series was developed for compact, high-reliability transient suppression in space-constrained automotive and industrial power systems, emphasizing fast response, low clamping, and AEC-Q101 readiness.
FAQ
What is the clamping voltage of SMAJ85CAHM3_A/I at its rated peak pulse current?
The SMAJ85CAHM3_A/I has a maximum clamping voltage (VC) of 137 V at 2.2 A peak pulse current (IPPM), measured under the standard 10/1000 μs waveform. This value defines the highest voltage that will appear across the protected circuit during a specified transient event, ensuring downstream ICs remain within safe operating limits. The 137 V VC is confirmed in the Electrical Characteristics table on page 2 of Vishay document 88390.
Is SMAJ85CAHM3_A/I suitable for automotive applications?
Yes, SMAJ85CAHM3_A/I is AEC-Q101 qualified, as indicated by the "HM3" suffix in its part number - denoting halogen-free, RoHS-compliant, and automotive-grade reliability validation. It meets requirements for temperature cycling, high-temperature reverse bias, and ESD robustness needed in engine control units, body electronics, and ADAS modules. The device operates from −55 °C to +150 °C and is rated for MSL Level 1 handling.
How does the bidirectional configuration of SMAJ85CAHM3_A/I affect PCB layout?
The SMAJ85CAHM3_A/I is bidirectional, meaning both terminals are functionally identical and no polarity marking exists on the SMA (DO-214AC) package. This eliminates orientation constraints during placement - the device can be mounted in either direction without affecting clamping behavior. Layout requires only two symmetric pads matching the DO-214AC footprint (5.28 mm × 4.50 mm), with no need for silkscreen polarity indicators or design rule checks for cathode alignment.
What is the maximum steady-state power dissipation for SMAJ85CAHM3_A/I?
The SMAJ85CAHM3_A/I has a maximum steady-state power dissipation (PD) of 3.3 W when mounted on an infinite heatsink at TA = 50 °C. In typical PCB layouts using minimum recommended copper pads (0.2" × 0.2"), derating applies per Fig. 2 of the datasheet; actual usable continuous power is lower due to thermal resistance (RθJA = 120 °C/W). This rating governs thermal design for sustained leakage or low-duty-cycle surge conditions - not transient events.
Does SMAJ85CAHM3_A/I meet any industry surge immunity standards out-of-the-box?
The SMAJ85CAHM3_A/I itself is not certified to IEC 61000-4-5 or ISO 7637-2, but its electrical parameters enable system-level compliance: its 137 V clamping voltage and 400 W pulse rating allow designers to meet IEC 61000-4-5 Level 3 (1 kV line-earth, 2 Ω source impedance) and ISO 7637-2 Pulse 1/2/3a/b when combined with appropriate filtering and layout. Validation must occur at the full system level per application requirements.
SMAJ85CAHM3_A/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:
- Active
- 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_A/I FAQ
1.How can I place an order for SMAJ85CAHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85CAHM3_A/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_A/I reliable?
The price and inventory of SMAJ85CAHM3_A/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_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ85CAHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85CAHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85CAHM3_A/I?
SMAJ85CAHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85CAHM3_A/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_A/I?
For technical support, including SMAJ85CAHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85CAHM3_A/I requirements.
6.How does Aetrix verify that SMAJ85CAHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ85CAHM3_A/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_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ85CAHM3_A/I?
All SMAJ85CAHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85CAHM3_A/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_A/I part is unused and in its original packaging.
Return procedure for SMAJ85CAHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ85CAHM3_A/I Tags
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