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HomeProductsCircuit ProtectionTVS - DiodesSMAJ78CHR3G
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SMAJ78CHR3G - Taiwan Semiconductor Corporation

Manufacturer Part Number
SMAJ78CHR3G
Manufacturer
Taiwan Semiconductor
Allelco Part Number
98D-SMAJ78CHR3G
Warranty
1 Year Allelco Warranty - Find out more
Stock Status:
3,600 pcs available, New & Original
Parts Description
TVS DIODE 78VWM 139VC DO214AC
Package
DO-214AC (SMA)
Data sheet
SMAJ78CHR3G.pdf
RoHs Status
ROHS3 Compliant
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Our certification
In stock: 3600
  • Unit Price: $0.241
  • Subtotal: $0.00

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Quantity Unit Price Ext. Price
1+ $0.241 $0.24
The above prices does not include taxes and freight rates, which will be calculated on the order pages.

Specifications

SMAJ78CHR3G Tech Specifications
Taiwan Semiconductor Corporation - SMAJ78CHR3G technical specifications, attributes, parameters and parts with similar specifications to Taiwan Semiconductor Corporation - SMAJ78CHR3G

Product Attribute Attribute Value
Manufacturer Taiwan Semiconductor
Voltage - Reverse Standoff (Typ) 78V
Voltage - Clamping (Max) @ Ipp 139V
Voltage - Breakdown (Min) 86.7V
Type Zener
Supplier Device Package DO-214AC (SMA)
Series Automotive, AEC-Q101, SMAJ
Power Line Protection No
Power - Peak Pulse 400W
Product Attribute Attribute Value
Package / Case DO-214AC, SMA
Package Tape & Reel (TR)
Operating Temperature -55°C ~ 150°C (TJ)
Mounting Type Surface Mount
Current - Peak Pulse (10/1000µs) 2.9A
Capacitance @ Frequency -
Bidirectional Channels 1
Base Product Number SMAJ78
Applications Automotive

Environmental & Export Classifications

ATTRIBUTE DESCRIPTION
RoHs Status ROHS3 Compliant
Moisture Sensitivity Level (MSL) 1 (Unlimited)
REACH Status REACH Unaffected
ECCN EAR99
HTSUS 8541.10.0080

Frequently Asked Questions(FAQ)

What is the peak pulse power rating of the SMAJ78CHR3G TVS diode and how does it influence transient protection design decisions?
The SMAJ78CHR3G provides a peak pulse power rating of 400W, measured at a 10/1000µs waveform. This level of energy absorption capability indicates suitability for handling moderate surge events commonly encountered in automotive and industrial environments. Designers must ensure that the expected transient energy from potential surges—such as ESD or inductive switching spikes—does not exceed this limit to prevent degradation or failure. When selecting protection schemes, the 400W rating allows integration into circuits where clamping energy is managed through proper layout, filtering, or coordination with other suppression elements.
How does the SMAJ78CHR3G compare to other devices in the SMAJ series in terms of breakdown voltage and clamping performance?
The SMAJ78CHR3G features a reverse standoff voltage of 78V and a minimum breakdown voltage of 86.7V, which places it in the high-voltage rail protection category within the SMAJ family. Compared to lower-voltage members like the SMAJ5.0A (5V standoff), this device offers significantly higher voltage thresholds suitable for protecting sensitive loads on 78V systems. Its clamping voltage reaches 139V at rated peak current, reflecting a balance between response speed and energy dissipation. Devices with identical package and power rating but different breakdown voltages serve distinct applications—this model targets systems requiring robust protection above 78V without exceeding 139V during transients.
Is the SMAJ78CHR3G suitable for use in automotive electronics given its qualification status and operating temperature range?
Yes, the SMAJ78CHR3G carries AEC-Q101 qualification, confirming compliance with automotive reliability standards. It operates reliably across a junction temperature range from -55°C to +150°C, which exceeds typical industrial limits and aligns with harsh automotive environments. This makes it appropriate for deployment in infotainment systems, lighting control modules, or battery management interfaces where long-term stability under thermal stress is essential. The automotive grade designation ensures consistency in production testing and failure mode analysis, reducing risk in safety-relevant subsystems.
What is the typical peak pulse current handling capability of the SMAJ78CHR3G, and what design considerations arise from this specification?
The SMAJ78CHR3G can sustain a peak pulse current of 2.9A under a standardized 10/1000µs waveform. This current threshold defines the upper boundary for effective transient suppression before clamping becomes insufficient or component damage occurs. Engineers must evaluate whether downstream circuitry can withstand the residual voltage (up to 139V) presented by this current level. Layout parasitics, trace impedance, and grounding strategies become critical to minimize voltage overshoot beyond the clamped value. Additionally, multiple diodes may be required in parallel only if the total surge current demand exceeds 2.9A, considering mismatch risks and derating factors.
Why might a designer choose the SMAJ78CHR3G over alternative TVS solutions despite its relatively high breakdown voltage?
While higher breakdown voltages reduce sensitivity to normal operating fluctuations, they also increase the likelihood of false triggering during legitimate transients below 86.7V. However, the SMAJ78CHR3G’s 78V standoff voltage provides sufficient margin above common system rails while offering precise protection against overvoltage faults such as load dump or inductive kickback. Its surface-mount DO-214AC packaging enables compact PCB integration, and the 400W pulse power supports demanding surge scenarios without requiring larger packages. For systems operating near 78V—such as some DC bus configurations—this device delivers optimized performance with minimal footprint compared to discrete alternatives.
How should the moisture sensitivity level (MSL) classification impact storage and handling procedures for bulk quantities of SMAJ78CHR3G components?
With an MSL rating of 1, the SMAJ78CHR3G is classified as non-hygroscopic and requires no special drying prior to reflow soldering. This simplifies inventory management and shelf life monitoring in high-volume manufacturing environments. Components can remain indefinitely in standard ambient storage conditions without risk of moisture-induced delamination or popcorning during assembly. As such, procurement and warehousing teams do not need to implement bake cycles or humidity-controlled cabinets, reducing overhead and improving supply chain flexibility.
Can the SMAJ78CHR3G be used bidirectionally, and what implications does this have for circuit configuration?
Yes, the SMAJ78CHR3G is bidirectional, meaning it suppresses voltage transients in both polarities. This characteristic eliminates the need for two unidirectional diodes when protecting differential signals or floating grounds. In balanced lines or single-ended systems with asymmetric voltage swings, a single SMAJ78CHR3G suffices to clamp positive and negative excursions up to ±139V relative to ground. This reduces board space and part count while maintaining symmetrical response, which is advantageous in communication buses, sensor inputs, or power line conditioning applications.
What are the key electrical differences between the SMAJ78CHR3G and a similar Zener-based transient suppressor, particularly regarding response time and energy absorption?
Unlike Zener-only suppressors that rely on slow avalanche mechanisms, the SMAJ78CHR3G utilizes a specialized junction design optimized for fast carrier injection and rapid clamping—typically sub-nanosecond response times. This allows earlier intervention during fast transients like ESD or IEC 61000-4-5 surges. While both types share similar power ratings, the SMAJ series exhibits lower leakage current and more predictable clamping behavior under dynamic conditions. The SMAJ78CHR3G’s semiconductor architecture enables efficient energy absorption up to 400W, making it preferable over passive Zeners in modern high-speed digital circuits where timing precision affects signal integrity.

Parts with Similar Specifications

The three parts on the right have similar specifications to Taiwan Semiconductor Corporation SMAJ78CHR3G

Product Attribute SMAJ78CAHR3G SMAJ78HR3G SMAJ78CAHM3_A/H SMAJ78CE3/TR13
Part Number SMAJ78CAHR3G SMAJ78HR3G SMAJ78CAHM3_A/H SMAJ78CE3/TR13
Manufacturer Taiwan Semiconductor Corporation Taiwan Semiconductor Corporation Vishay General Semiconductor - Diodes Division Microchip Technology
Series - - - -
Current - Peak Pulse (10/1000µs) - - - -
Package - Tape & Reel (TR) Tube Tape & Reel (TR)
Voltage - Reverse Standoff (Typ) - - - -
Supplier Device Package - 196-NFBGA (12x12) 16-PDIP 64-VQFN (9x9)
Type - - - -
Voltage - Breakdown (Min) - - - -
Power - Peak Pulse - - - -
Mounting Type - Surface Mount Through Hole Surface Mount
Operating Temperature - -40°C ~ 85°C 0°C ~ 70°C -40°C ~ 85°C
Applications - - - -
Voltage - Clamping (Max) @ Ipp - - - -
Power Line Protection - - - -
Capacitance @ Frequency - - - -
Bidirectional Channels - - - -
Package / Case - 196-LFBGA 16-DIP (0.300', 7.62mm) 64-VFQFN Exposed Pad
Base Product Number - DAC34H84 MAX500 ADS62P42

SMAJ78CHR3G Datasheet PDF

Download SMAJ78CHR3G pdf datasheets and Taiwan Semiconductor Corporation documentation for SMAJ78CHR3G - Taiwan Semiconductor Corporation.

Datasheets
SMAJ5.0(A) - SMAJ188(A).pdf
PCN Packaging
Mult Dev Pkg/Status Chgs 5/Feb/2021.pdf

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    Needed the exact ST10F269Z2Q6 for servicing an older control unit. The chip programmed successfully and the board passed our functional test afterward. Much easier than redesigning around a newer MCU.

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Shipment

Delivery Time

In-stock items can be shipped within 24 hours. Some parts will be arranged for delivery within 1-2 days from the date all items arrive at our warehouse. And Allelco ships order once a day at about 17:00, except Sunday. Once the goods are shipped, the estimated delivery time depends on the shipping methods and Delivery destination. The table below shows are the logistic time for some common countries.

Delivery Cost

  1. Use your express account for shipment if you have one.
  2. Use our account for the shipment. Refer to the table below for the approximate charges.
(Different time frame / countries / package size has different price.)

Delivery Method

  1. Global Common Shipment by DHL / UPS / FedEx / TNT / EMS / SF we support.
  2. Others more shipping ways, please get in touch with your customer manager.

Common Countries Logistic Time Reference
Region Country Logistic Time(Day)
America United States 5
Brazil 7
Europe Germany 5
United Kingdom 4
Italy 5
Oceania Australia 6
New Zealand 5
Asia India 4
Japan 4
Middle East Israel 6
DHL & FedEx Shipment Charges Reference
Shipment charges(KG) Reference DHL(USD$)
0.00kg-1.00kg USD$30.00 - USD$60.00
1.00kg-2.00kg USD$40.00 - USD$80.00
2.00kg-3.00kg USD$50.00 - USD$100.00
Note:
The above table is for reference only. There may have some data bias for the uncontrollable factors.
Contact us if you have any questions.
  • QC (Quality Warranty)
  • Payment Support
  • Packaging
  • Certifications & Memberships

QC (Quality Warranty)

Allelco is committed to exceeding customer expectations through customer service excellence, order accuracy, and on-time delivery.
This is achieved through our commitment to the continual improvement of our processes, services, and products.


Strict quality inspection builds a solid foundation for electronic component quality.
  1. Visual inspection
  2. Performance testing and reliability verification
  3. Standardized full-process testing
  4. Precise control of every parameter
We eliminate defective components and ensure the stable operation of electronic devices through professional quality standards.
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Payment Support

The payment method can be chosen from the methods shown below: Wire Transfer (T/T, Bank Transfer), Western Union, Credit card, PayPal.
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Contact us if you have any questions.

Packaging

Electrostatic Discharge Protection and Handling

All electrostatic-sensitive components are handled in accordance with electrostatic discharge control procedures. The products are hermetically sealed in anti-static safe packaging to prevent electrostatic damage. Appropriate labeling is also applied for identification and traceability. This ensures product integrity during storage, handling and transportation.


ESD

Certifications & Memberships

Third-party certified, strict quality control. Our certification
  • ISO 9001: 2015
  • ISO 13485: 2016
  • ISO 14001: 2015
  • ISO 28000: 2007
  • ISO 45001: 2018
  • GB/T 27922-2011
  • SMTA
  • IPC
  • ESD
  • PSMA
SMAJ78CHR3G Image

SMAJ78CHR3G

Taiwan Semiconductor Corporation
98D-SMAJ78CHR3G

Want a better price? Add to Cart and Submit RFQ now, we'll contact you immediately.

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