My Inquiry
My Account
Vishay General Semiconductor - Diodes Division SMAJ78AHM3_A/I
- Part No.:
- SMAJ78AHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78AHM3_A/I.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,752
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMAJ78AHM3_A/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 DC power rails and signal lines. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 126 V maximum clamping voltage (VC) at 3.2 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial power supplies.
For engineers reviewing the SMAJ78AHM3_A/I datasheet, SMAJ78AHM3_A/I pinout, SMAJ78AHM3_A/I application, or SMAJ78AHM3_A/I equivalent, key selection criteria include its AEC-Q101 qualification (HM3 suffix), halogen-free RoHS compliance, 150 °C max junction temperature, and verified clamping performance under repetitive surge conditions per IEC 61000-4-5.
Technical Context
This TVS diode operates as a unidirectional avalanche clamp, responding within <1 ps to transient overvoltages and limiting reverse voltage to ≤126 V at 3.2 A IPPM. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 μA at 78 V), while the SMA package supports automated SMT placement and meets MSL Level 1 reflow profile (260 °C peak).
The device is rated for 40 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine), has 120 °C/W junction-to-ambient thermal resistance, and delivers consistent clamping across -55 °C to +150 °C operating range - enabling use in under-hood automotive modules and industrial motor drives where thermal cycling and ESD robustness are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse working voltage before conduction begins; defines safe operating margin for 72–80 V DC rails. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Confirmed avalanche onset range; ensures reliable triggering above nominal rail voltage. |
| VC (Clamping Voltage) | 126 V at IPPM = 3.2 A - Measured peak voltage during 10/1000 μs surge; determines protected circuit's maximum stress level. |
| PPPM (Peak Pulse Power) | 400 W (≤78 V), 300 W (>78 V) - Validated energy-handling capability per IEC 61000-4-5; defines transient immunity level. |
| ID (Reverse Leakage) | ≤1.0 μA at 78 V - Low leakage preserves system efficiency and prevents false triggering in high-impedance circuits. |
| TJ max. | +150 °C - Enables operation in under-hood automotive environments and enclosed industrial enclosures without derating. |
| Package | SMA (DO-214AC) - Standardized 2-pin SMT outline with 5.0 mm × 5.0 mm copper pad footprint; compatible with IPC-7351B. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, cathode-banded unidirectional configuration. Molded epoxy case meets UL 94 V-0; matte tin-plated leads compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (non-banded end) | Low-side reference terminal | Connected to ground or low-voltage return path; completes clamping loop during transient events. |
| Cathode (banded end) | High-side surge input terminal | Connected to protected line (e.g., 78 V supply rail); conducts avalanche current to anode when V > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified (HM3 suffix) | Validated for automotive-grade reliability including temperature cycling, HTRB, and surge endurance - suitable for engine control units and ADAS power stages. |
| Halogen-free & RoHS-compliant | Meets JEDEC JS709E and IEC 61249-2-21; eliminates brominated flame retardants without compromising UL 94 V-0 flammability rating. |
| 400 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 Level 4 surges (4 kV line-earth) on 78 V systems when mounted per recommended 5.0 mm × 5.0 mm copper pads. |
| Fast response time (<1 ps) | Clamps transients before sensitive downstream components (e.g., gate drivers, ADC references) experience overvoltage stress. |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., inductive switch-off), improving protection margin for 75–85 V logic-supply rails. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 78 V auxiliary power bus in vehicle infotainment head units against load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between VBAT-derived 78 V rail and ground, absorbing 400 W surges without failure. Use Value: Prevents latch-up or permanent damage to PMICs and microcontrollers during ISO 16750-2 load-dump events up to 120 V. |
Use Scenario: Safeguarding analog output lines of pressure sensors in hydraulic control valves exposed to inductive kickback. IC Role / Device Role / Timing Role: Standoff-clamp element on 4–20 mA current-loop outputs, shunting transients before they reach op-amp input stages. Use Value: Maintains signal integrity below 126 V clamping threshold, ensuring sensor accuracy remains unaffected during 100 ns–1 μs spikes. |
| Telecom DC Power Input Protection | Motor Drive Gate Driver Supply Clamp |
Use Scenario: Securing primary 78 V DC input of PoE-powered base station RF modules against lightning-induced surges. IC Role / Device Role / Timing Role: First-line transient suppressor upstream of DC-DC converters and LDOs, diverting surge current to chassis ground. Use Value: Limits input voltage excursion to ≤126 V, preventing overvoltage shutdown or internal FET avalanche in downstream regulators. |
Use Scenario: Clamping bootstrap supply rail of 600 V half-bridge gate drivers in HVAC inverters subjected to shoot-through transients. IC Role / Device Role / Timing Role: Fast-acting unidirectional clamp on isolated 78 V bootstrap capacitor node, suppressing ringing above VBR. Use Value: Avoids gate oxide stress by holding bootstrap voltage within ±5 % of nominal, preserving driver timing margins and MOSFET reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78AHE3_A/I | Same electrical specs, but RoHS-compliant commercial grade (E3) without halogen-free certification or AEC-Q101 qualification. | Lacks automotive qualification; not approved for under-hood or safety-critical ECUs. | Select when cost-sensitive industrial designs require identical clamping but no automotive validation. |
| SMAJ78A-M3/5A | Identical electrical parameters and HM3 halogen-free spec, but packaged in 13" tape-and-reel (5A code) vs. 7" reel (I code). | No functional difference; only packaging and quantity variation (7500 vs. 1800 units per reel). | Choose based on production volume and SMT line feeder compatibility - same device, different logistics format. |
Compared with SMAJ78AHM3_A/I, the SMAJ78AHE3_A/I offers lower cost but excludes automotive qualification and halogen-free assurance, while SMAJ78A-M3/5A provides identical performance in higher-volume packaging - making the HM3_A/I optimal for AEC-Q101–mandated automotive subsystems requiring traceable halogen-free sourcing.
Availability
SMAJ78AHM3_A/I is available at Aetrix Electronics and suitable for automotive power management, industrial sensor interface protection, telecom DC input hardening, and motor drive gate supply clamping requiring stable component supply across multi-year production cycles.
Supply support for SMAJ78AHM3_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, power efficiency, and automotive-grade validation.
The SMAJ series was developed specifically for high-energy transient suppression in harsh-environment applications - targeting automotive, industrial, and telecom systems where compact size, repeatable clamping, and AEC-Q101 compliance are mandatory.
FAQ
What is the maximum clamping voltage of SMAJ78AHM3_A/I at its rated peak pulse current?
The SMAJ78AHM3_A/I has a maximum clamping voltage (VC) of 126 V at its specified peak pulse current (IPPM) of 3.2 A, measured using the standardized 10/1000 μs waveform. This value defines the upper voltage limit imposed on protected circuitry during surge events and is validated per IEC 61000-4-5 testing conditions. The SMAJ78AHM3_A/I maintains this clamping performance across its full operating temperature range of -55 °C to +150 °C.
Is SMAJ78AHM3_A/I qualified for automotive applications?
Yes, SMAJ78AHM3_A/I is AEC-Q101 qualified, as confirmed by the "HM3" suffix in its part number - indicating halogen-free, RoHS-compliant construction and full automotive reliability testing including temperature cycling, high-temperature reverse bias, and surge endurance. This makes the SMAJ78AHM3_A/I suitable for use in engine control units, ADAS modules, and other under-hood automotive electronics where qualification is mandatory.
What does the "_A/I" suffix mean in SMAJ78AHM3_A/I?
The "_A/I" suffix in SMAJ78AHM3_A/I indicates revision level "A" and packaging format "I", where "I" denotes 7-inch diameter plastic tape-and-reel packaging containing 1800 units. This format is optimized for high-speed SMT placement equipment and aligns with IPC-7351B land pattern recommendations for the SMA (DO-214AC) package. The "A" revision reflects the latest controlled change documented in Vishay's specification 88390 (Rev. 09-Jan-2024).
How does SMAJ78AHM3_A/I differ from SMAJ78A-E3/61?
SMAJ78AHM3_A/I and SMAJ78A-E3/61 share identical electrical specifications (VWM = 78 V, VC = 126 V, PPPM = 400 W), but differ in qualification and material compliance: SMAJ78AHM3_A/I is halogen-free and AEC-Q101 qualified, whereas SMAJ78A-E3/61 is RoHS-compliant commercial grade without halogen-free certification or automotive qualification. Both use the same SMA package and 7-inch tape-and-reel format, but only SMAJ78AHM3_A/I meets automotive Tier-1 requirements.
What is the thermal resistance of SMAJ78AHM3_A/I, and how does it affect layout design?
The SMAJ78AHM3_A/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value requires PCB layout with adequate copper area to maintain junction temperature below 150 °C during repetitive surge events. For high-duty-cycle applications, increasing pad size or adding thermal vias reduces RθJA and improves long-term reliability - especially critical in automotive under-hood environments.
SMAJ78AHM3_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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- 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)
SMAJ78AHM3_A/I FAQ
1.How can I place an order for SMAJ78AHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78AHM3_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 SMAJ78AHM3_A/I reliable?
The price and inventory of SMAJ78AHM3_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 SMAJ78AHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ78AHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78AHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78AHM3_A/I?
SMAJ78AHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78AHM3_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 SMAJ78AHM3_A/I?
For technical support, including SMAJ78AHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78AHM3_A/I requirements.
6.How does Aetrix verify that SMAJ78AHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ78AHM3_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 SMAJ78AHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ78AHM3_A/I?
All SMAJ78AHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78AHM3_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 SMAJ78AHM3_A/I part is unused and in its original packaging.
Return procedure for SMAJ78AHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78AHM3_A/I Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.
Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
