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Vishay General Semiconductor - Diodes Division SMAJ85AHM3/I
- Part No.:
- SMAJ85AHM3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85AHM3/I.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,344
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Product details
Overview
SMAJ85AHM3/I from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 85 V stand-off 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, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed in automotive sensor protection, industrial I/O interfaces, and DC power rail surge suppression.
For engineers reviewing the SMAJ85AHM3/I datasheet, SMAJ85AHM3/I pinout, SMAJ85AHM3/I application, or SMAJ85AHM3/I equivalent, key selection criteria include its AEC-Q101 qualification, halogen-free RoHS-compliant construction (HM3 suffix), low thermal resistance (RθJL = 30 °C/W), and verified clamping performance under repetitive 0.01% duty-cycle surges - critical for reliability-critical 12 V/24 V automotive and industrial control systems.
Technical Context
This unidirectional TVS diode operates by avalanche breakdown to limit transient overvoltages before they damage downstream ICs or MOSFETs. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low leakage (<1 μA at 85 V), while the SMA package supports automated SMT placement and meets MSL level 1 (260 °C reflow peak).
The device delivers 400 W peak pulse power up to 78 V and derates to 300 W above 78 V per Fig. 2; clamping occurs within <1 ns response time, with incremental surge resistance optimized to sustain 2.2 A IPPM at VC = 137 V - validated under JEDEC-standard 10/1000 μs waveform conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - maximum continuous reverse operating voltage before conduction begins; defines safe DC/AC working range on protected line |
| VBR (min/max) | 94.4 V / 104 V at IT = 1 mA - guaranteed avalanche initiation window; ensures consistent turn-on across temperature and unit variation |
| VC @ IPPM | 137 V at IPPM = 2.2 A - clamped voltage seen by protected circuit during full-rated transient; limits stress on downstream 100 V-rated components |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - peak surge energy handling with 10/1000 μs waveform; enables robust protection against ISO 7637-2 Pulse 1/2a/5a |
| ID @ VWM | ≤1.0 μA - ultra-low reverse leakage at rated stand-off; prevents measurable power loss or bias shift in high-impedance sensor circuits |
| TJ max. | +150 °C - maximum junction temperature; supports operation in under-hood automotive environments and sealed industrial enclosures |
| RθJL | 30 °C/W - low junction-to-lead thermal resistance; allows effective heat dissipation through PCB copper pads without external heatsinking |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, molded plastic case with matte tin-plated leads; polarity indicated by cathode band (cathode end marked).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry (unidirectional) | Connected to lower-potential side of protected line (e.g., GND or return path); conducts only during forward surge events |
| Cathode | Avalanche clamping node | Connected to higher-potential side (e.g., +12 V rail); initiates breakdown when transient exceeds VBR, shunting surge current to ground |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing - suitable for engine control, ADAS, and body electronics |
| Halogen-free & RoHS-compliant (HM3) | Meets IEC 61249-2-21 and JESD201 Class 2 whisker resistance; eliminates brominated flame retardants without compromising UL 94 V-0 flammability rating |
| 400 W peak pulse power (≤78 V) | Withstands repeated ISO 16750-2 load dump surges up to 35 V for 400 ms and ISO 7637-2 Pulse 5a transients without degradation |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes overvoltage overshoot during fast transients - protects 100 V MOSFETs and CAN transceivers with margin |
| MSL Level 1 (260 °C) | Compatible with standard lead-free reflow profiles; no floor life limitation or baking required prior to assembly |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Guarding |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs from load dump and alternator ripple in passenger vehicles. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and input filter capacitor to clamp transients before LDO or MCU power supply. Use Value: Limits peak voltage to ≤137 V during 100 V/40 ms load dump events, preventing brownout or latch-up in 5 V/3.3 V regulators. |
Use Scenario: Shielding analog outputs of pressure/temperature sensors in PLC modules from EFT and surge coupling. IC Role / Device Role / Timing Role: TVS mounted at connector interface to absorb 4 kV EFT bursts (IEC 61000-4-4) before signal conditioning op-amps. Use Value: Sub-1 ns response and <1 μA leakage preserve mV-level signal integrity and offset stability over temperature. |
| DC Motor Drive Flyback Suppression | Telecom Power Input Stage |
Use Scenario: Snubbing inductive kickback from brushed DC motors in HVAC actuators and seat controls. IC Role / Device Role / Timing Role: Connected anode-to-ground, cathode-to-motor supply rail to clamp flyback spikes during PWM switching. Use Value: 40 A IFSM rating handles repetitive 8.3 ms half-sine surges; 300 W >78 V rating sustains 24 V system transients. |
Use Scenario: Primary-stage surge protection on -48 V telecom power inputs exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Bidirectional configuration not used; unidirectional SMAJ85AHM3/I applied with cathode to -48 V rail and anode to chassis ground. Use Value: 137 V clamping ensures downstream DC/DC converters (rated ≥150 V) remain within safe operating area during 10/1000 μs surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85AHE3/I | Same electrical specs, but RoHS-compliant (E3) without halogen-free certification; no JESD201 Class 2 whisker test compliance | Approved for commercial/industrial use; not qualified for automotive under AEC-Q101 | Select SMAJ85AHM3/I when halogen-free content and automotive qualification are mandatory; choose SMAJ85AHE3/I for cost-sensitive non-automotive designs. |
| SMAJ85A-M3/5A | Identical HM3 material and AEC-Q101 qualification, but packaged in 13" tape-and-reel (5A code) vs. 7" reel (I code); same device marking and electrical behavior | No functional difference; reel size affects SMT line feed compatibility and minimum order quantity | Choose SMAJ85AHM3/I for standard 7" reel integration; select SMAJ85A-M3/5A only when production volume requires larger reels or existing feeder setup uses 13". |
Compared with SMAJ85AHE3/I, SMAJ85AHM3/I adds halogen-free compliance and whisker resistance for automotive deployment; versus SMAJ85A-M3/5A, it differs only in reel packaging - both share identical clamping performance, thermal metrics, and AEC-Q101 validation.
Availability
SMAJ85AHM3/I is available at Aetrix Electronics and suitable for automotive electronics, industrial sensor interfaces, and telecom power input stages requiring stable component supply, long-term lifecycle support, and traceable halogen-free sourcing.
Supply support for SMAJ85AHM3/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, TVS devices, and optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series was developed for high-energy transient suppression in space-constrained surface-mount applications - targeting automotive, industrial, and communications systems where AEC-Q101 qualification and precise clamping are essential.
FAQ
What is the maximum clamping voltage of the SMAJ85AHM3/I under rated surge conditions?
The SMAJ85AHM3/I exhibits a maximum clamping voltage (VC) of 137 V when subjected to its rated peak pulse current (IPPM) of 2.2 A using the standardized 10/1000 μs waveform. This value is measured at TA = 25 °C with devices mounted on 0.2" × 0.2" copper pads per JEDEC guidelines and represents the upper voltage limit imposed on protected circuitry during worst-case transient events.
Is the SMAJ85AHM3/I suitable for bidirectional transient protection?
No, the SMAJ85AHM3/I is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. It conducts only in reverse breakdown (cathode positive) and forward surge (anode positive). For bidirectional protection, Vishay offers the SMAJ85CA variant; using SMAJ85AHM3/I in bidirectional configurations risks forward conduction failure and inadequate clamping during negative transients.
Does the SMAJ85AHM3/I meet automotive qualification standards?
Yes, the SMAJ85AHM3/I is AEC-Q101 qualified, as confirmed by Vishay's ordering code structure ("HM3" denotes halogen-free, RoHS-compliant, and AEC-Q101 qualified). This qualification covers stress tests including HTGB, HTRB, temperature cycling, and ESD, making SMAJ85AHM3/I appropriate for under-hood and chassis-mounted automotive applications.
What is the thermal resistance from junction to ambient for the SMAJ85AHM3/I?
The typical junction-to-ambient thermal resistance (RθJA) of the SMAJ85AHM3/I is 120 °C/W when mounted on the minimum recommended pad layout (0.2" × 0.2" copper pads per terminal). This value assumes still air conditions and informs thermal design margins - for sustained power dissipation, junction temperature must remain ≤150 °C, limiting average power to ~3.3 W at TA = 50 °C.
How does the HM3 suffix affect the environmental compliance of the SMAJ85AHM3/I?
The HM3 suffix certifies that the SMAJ85AHM3/I is halogen-free (per IEC 61249-2-21), RoHS-compliant, and passes JESD201 Class 2 whisker testing. Unlike E3-suffix variants, HM3 ensures absence of chlorine and bromine-based flame retardants while maintaining UL 94 V-0 flammability rating - critical for automotive OEMs enforcing strict material declarations.
SMAJ85AHM3/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:
- 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:
- 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)
SMAJ85AHM3/I FAQ
1.How can I place an order for SMAJ85AHM3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85AHM3/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 SMAJ85AHM3/I reliable?
The price and inventory of SMAJ85AHM3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85AHM3/I is usually 5 days.
3.What payment methods are accepted for SMAJ85AHM3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85AHM3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85AHM3/I?
SMAJ85AHM3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85AHM3/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 SMAJ85AHM3/I?
For technical support, including SMAJ85AHM3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85AHM3/I requirements.
6.How does Aetrix verify that SMAJ85AHM3/I is sourced from the original manufacturer or authorized distributors?
All SMAJ85AHM3/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 SMAJ85AHM3/I meets industry standards.
7.What is the process for return or replacement of SMAJ85AHM3/I?
All SMAJ85AHM3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85AHM3/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 SMAJ85AHM3/I part is unused and in its original packaging.
Return procedure for SMAJ85AHM3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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