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Taiwan Semiconductor Corporation SMBJ78CAH
- Part No.:
- SMBJ78CAH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78CAH.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:2,913
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Product details
Overview
SMBJ78CAH from Taiwan Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, designed for automotive-grade ESD and surge protection. It features a 78 V working stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR), 126 V maximum clamping voltage (VC) at 5.0 A peak impulse current, and 600 W peak pulse power rating - deployed in CAN/LIN bus interfaces, body control modules, and infotainment power rails.
For engineers reviewing the SMBJ78CAH datasheet, SMBJ78CAH pinout, SMBJ78CAH application, or SMBJ78CAH equivalent, key selection criteria include bidirectional clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, AEC-Q101 qualification, low leakage (<1 µA @ 78 V), and thermal robustness (TJ max = 150°C) in harsh-temperature automotive environments.
Technical Context
The SMBJ78CAH implements a glass-passivated silicon junction optimized for fast transient response (<1.0 ps), enabling effective suppression of EFT (electrical fast transients) and load-dump events. Its bidirectional configuration eliminates polarity sensitivity, supporting symmetric surge protection on differential or AC-coupled lines without external orientation constraints.
Thermally, it delivers RθJC = 10°C/W and RθJA = 55°C/W, allowing reliable operation up to 150°C junction temperature. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability standards, confirming suitability for high-reliability automotive PCB assemblies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 86.7 V / 95.8 V @ 1 mA - Confirmed breakdown threshold range ensuring predictable turn-on during overvoltage |
| VC @ IPP | 126 V @ 5.0 A - Clamped voltage level limiting downstream IC stress during 10/1000 µs surge |
| PPK | 600 W - Peak pulse power handling per single 10/1000 µs waveform, derated above 25°C |
| ID @ VWM | <1 µA - Low leakage preserves signal integrity and minimizes standby power loss |
| TJ max | +150°C - Enables deployment in under-hood ECUs and power distribution units |
| Package | DO-214AA (SMB) - Surface-mount footprint compatible with automated placement and reflow |
Pinout & Package
DO-214AA (SMB) package: molded plastic case with matte tin-plated leads, cathode band marking omitted due to bidirectional symmetry; polarity-insensitive terminals support flexible board layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional surge path | Either terminal serves as clamping node - no polarity dependency simplifies routing on differential buses |
| Case | Thermal conduction path | Exposed copper pad area enables direct thermal coupling to PCB copper pour for enhanced power dissipation |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TC, and HAST |
| ISO 7637-2 compliance | Passes Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (EFT) immunity tests |
| Fast response time | <1.0 ps junction response ensures clamping activation before sensitive logic or analog circuitry sustains damage |
| Moisture sensitivity level 1 | No floor life limitation or bake requirement prior to reflow - supports standard SMT assembly flow |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive - suitable for green manufacturing programs |
Applications
| Automotive CAN Bus Protection | LED Headlamp Driver Protection |
|---|---|
Use Scenario: Protects CAN_H/CAN_L differential pair against load dump, jump-start surges, and ESD events in vehicle networking. IC Role / Device Role / Timing Role: Bidirectional TVS clamps both polarities simultaneously to limit voltage excursion within ISO 11898-2 tolerance limits. Use Value: Prevents CAN transceiver latch-up or permanent damage during 12 V/24 V system transients while maintaining signal integrity up to 1 Mbps. | Use Scenario: Shields LED driver ICs and MOSFETs from inductive kickback when switching high-current headlamp loads. IC Role / Device Role / Timing Role: Absorbs energy from flyback voltage spikes generated by relay or MOSFET turn-off in constant-current LED supplies. Use Value: Eliminates need for snubber networks, reduces BOM count, and maintains >95% driver efficiency across -40°C to +125°C ambient. |
| Infotainment Power Rail Protection | Body Control Module (BCM) Input Protection |
Use Scenario: Guards 5 V/3.3 V DC-DC converter inputs in infotainment head units against battery line transients during ignition cycling. IC Role / Device Role / Timing Role: Acts as primary front-end clamp ahead of LDOs and PMICs to prevent brownout or reset conditions. Use Value: Ensures uninterrupted operation during cold-crank (4.5 V) and load-dump (35 V) events per ISO 16750-2, avoiding firmware corruption. | Use Scenario: Safeguards microcontroller GPIOs and LIN transceivers in door modules and seat controllers exposed to wiring harness ESD. IC Role / Device Role / Timing Role: Provides low-capacitance (<50 pF), low-leakage path to ground for fast-rising ESD pulses (IEC 61000-4-2 ±8 kV contact). Use Value: Maintains functional safety integrity without adding signal delay or loading on 10–20 kHz LIN bus timing margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ78CA | Same DO-214AC (SMA) package; slightly higher VC = 129 V @ 5.0 A; lower PPK = 400 W | Lower power handling limits use in high-energy load-dump scenarios; requires layout review for thermal margin | Select when footprint compatibility with existing SMA designs is prioritized over peak surge capacity |
| Vishay SM8S78CAHE3_A/H | DO-214AB (SMC) package; higher PPK = 6600 W; VC = 123 V @ 50 A; AEC-Q101 qualified | Higher surge rating suits 24 V commercial vehicle systems; larger SMC footprint increases board area usage | Choose for heavy-duty truck or off-highway equipment where ISO 7637-2 Pulse 5a (load dump) dominates threat model |
Compared with SMBJ78CAH, SMAJ78CA offers smaller size but reduced surge capability, while SM8S78CAHE3_A/H provides superior energy absorption at the cost of larger footprint and higher system-level thermal mass - SMBJ78CAH balances automotive qualification, 600 W rating, and SMB package density for mainstream passenger vehicle ECUs.
Availability
SMBJ78CAH is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, and LED lighting systems requiring stable component supply with AEC-Q101 assurance, ISO 7637-2 compliance, and surface-mount manufacturability.
Supply support for SMBJ78CAH 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and automotive-qualified components since 1979.
The SMBJH series was developed specifically for AEC-Q101-compliant transient suppression in 12 V/24 V automotive subsystems - emphasizing fast response, low leakage, and robust thermal performance in compact SMB packages.
FAQ
What does the 'CAH' suffix indicate in SMBJ78CAH?
The 'CAH' suffix in SMBJ78CAH denotes a bidirectional configuration with AEC-Q101 qualification and halogen-free construction. Unlike unidirectional variants (e.g., SMBJ78H), SMBJ78CAH clamps voltage transients equally in both directions - essential for protecting differential buses like CAN or LIN without polarity concerns. This designation is standardized across Taiwan Semiconductor's SMBJH series.
Is SMBJ78CAH suitable for ISO 16750-2 load dump protection?
Yes, SMBJ78CAH is validated for ISO 16750-2 load dump testing via its compliance with ISO 7637-2 Pulse 5a (simulated alternator load dump). With a 126 V clamping voltage at 5.0 A and 600 W peak power rating, it limits voltage excursions below the 35 V threshold required for 12 V systems - provided proper PCB layout includes adequate copper pour for thermal dissipation during sustained surges.
How does SMBJ78CAH compare to SMBJ78AH in terms of electrical performance?
SMBJ78CAH and SMBJ78AH share identical VWM (78 V), VBR (86.7–95.8 V), and VC (126 V @ 5.0 A) specifications, but differ in configuration: SMBJ78CAH is bidirectional, while SMBJ78AH is unidirectional. This makes SMBJ78CAH suitable for AC or differential signal lines, whereas SMBJ78AH requires correct anode/cathode orientation - critical for applications like CAN bus where polarity must be preserved.
What is the maximum junction temperature rating for SMBJ78CAH?
The maximum junction temperature (TJ max) for SMBJ78CAH is +150°C, as specified in the Absolute Maximum Ratings table. This rating enables reliable operation in under-hood automotive environments and high-power industrial enclosures. Derating begins above TA = 25°C per the Pulse Derating Curve (Fig. 2), requiring thermal design consideration - especially when multiple SMBJ78CAH devices operate simultaneously on shared PCB copper areas.
Does SMBJ78CAH require special handling for moisture sensitivity?
No - SMBJ78CAH is rated Moisture Sensitivity Level 1 (per J-STD-020), meaning it has unlimited floor life and does not require dry pack or baking prior to reflow soldering. This simplifies SMT assembly logistics and eliminates moisture-related popcorning risk during lead-free reflow profiles, supporting high-yield automotive production runs without process modification.
SMBJ78CAH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJH
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 5A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ78CAH FAQ
1.How can I place an order for SMBJ78CAH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78CAH 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 SMBJ78CAH reliable?
The price and inventory of SMBJ78CAH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78CAH is usually 5 days.
3.What payment methods are accepted for SMBJ78CAH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78CAH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78CAH?
SMBJ78CAH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78CAH 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 SMBJ78CAH?
For technical support, including SMBJ78CAH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78CAH requirements.
6.How does Aetrix verify that SMBJ78CAH is sourced from the original manufacturer or authorized distributors?
All SMBJ78CAH 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 SMBJ78CAH meets industry standards.
7.What is the process for return or replacement of SMBJ78CAH?
All SMBJ78CAH units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78CAH, 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 SMBJ78CAH part is unused and in its original packaging.
Return procedure for SMBJ78CAH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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