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Taiwan Semiconductor Corporation SMBJ78CH
- Part No.:
- SMBJ78CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78CH.pdf
- Description:
- 600W, 96.4V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:7,963
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Product details
Overview
SMBJ78CH from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, designed for high-energy ESD and surge protection in automotive and industrial power rails. It features a 78 V working stand-off voltage (VWM), 86.7–106 V breakdown voltage (VBR), 139 V maximum clamping voltage (VC) at 4.5 A peak pulse current (IPP), and 600 W peak pulse power rating with sub-1 ps response time.
For engineers reviewing the SMBJ78CH datasheet, SMBJ78CH pinout, SMBJ78CH application, or SMBJ78CH equivalent, key selection criteria include bidirectional clamping capability, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, AEC-Q101 qualification, and low leakage (<1 µA at 78 V) for battery-sensitive systems.
Technical Context
The SMBJ78CH implements a glass-passivated silicon junction optimized for fast transient suppression in bidirectional signal and power lines. Its unidirectional counterpart (SMBJ78H) shares identical VWM and VC but lacks symmetrical conduction - the CH suffix explicitly denotes bipolar operation with matched forward/reverse electrical characteristics.
Thermal performance is defined by RθJC = 10 °C/W and RθJA = 55 °C/W, enabling reliable operation up to TJ = +150 °C. It meets JESD201 Class 2 whisker resistance and J-STD-020 Level 1 moisture sensitivity, supporting lead-free reflow without popcorn risk.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous DC or RMS voltage the device blocks without significant leakage |
| VBR min/max | 86.7 V / 106 V @ 1 mA - Confirmed breakdown threshold range ensuring robust margin above VWM |
| VC @ IPP | 139 V @ 4.5 A - Clamped voltage during 10/1000 µs surge, limiting downstream IC stress |
| PPK | 600 W - Peak pulse power handling per single transient event per IEC 61000-4-5 |
| ID @ VWM | <1 µA - Ultra-low leakage preserves battery life in always-on automotive modules |
| Response time | <1.0 ps - Enables suppression of nanosecond-scale ESD events before system damage occurs |
| Package | DO-214AA (SMB) - Industry-standard surface-mount outline compatible with automated placement and IPC-7351B footprints |
Pinout & Package
DO-214AA (SMB) package: molded plastic case with matte tin-plated leads, cathode band marking absent (bidirectional symmetry). Weight ≈ 0.090 g. UL 94V-0 rated molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional terminal pair | No polarity marking required; identical clamping behavior in both directions for AC line or floating bus protection |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive under-hood and chassis applications per stress test requirements including temperature cycling, HTRB, and ESD |
| ISO 7637-2 compliant | Withstands Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) without degradation |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal/humidity stress vs. epoxy-passivated alternatives |
| Level 1 MSL | Zero bake requirement prior to SMT reflow; supports standard JEDEC-compliant assembly processes |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU Directive 2011/65/EU for environmentally constrained supply chains |
Applications
| Automotive Power Line Protection | Industrial CAN Bus Transient Suppression |
|---|---|
Use Scenario: 12 V/24 V battery rail in engine control units exposed to load dump and alternator ripple. IC Role / Device Role: Primary overvoltage clamp placed upstream of LDOs and microcontrollers. Use Value: Limits transients to ≤139 V, preventing latch-up or gate oxide rupture in 3.3 V/5 V logic powered from protected rails. |
Use Scenario: Two-wire CAN FD physical layer subjected to EFT bursts and cable coupling noise in factory automation. IC Role / Device Role: Bidirectional TVS across CANH–CANL differential pair, referenced to ground. Use Value: Maintains signal integrity by clamping common-mode surges while preserving <1 pF junction capacitance to avoid bit error rate degradation. |
| LED Driver Input Stage Protection | Smart Sensor Power Input Guarding |
Use Scenario: Constant-current LED driver IC input in outdoor signage subject to lightning-induced surges on long feeder cables. IC Role / Device Role: First-line defense against 600 W transients before input capacitors and controller ICs. Use Value: Absorbs energy without thermal runaway due to 150 °C max junction rating and 10 °C/W thermal resistance to case. |
Use Scenario: Low-power IoT sensor node with lithium coin cell supply and wake-on-event circuitry. IC Role / Device Role: Standby-mode protector on VDD rail where leakage must remain below 1 µA. Use Value: Delivers <0.5 µA typical ID at 78 V, extending battery life beyond 10 years in duty-cycled deployments. |
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 VWM (78 V), slightly higher VC (140 V @ 4.3 A), identical DO-214AC (SMA) footprint but smaller thermal mass | Lower PPK (400 W); unsuitable for ISO 7637-2 Pulse 1 (load dump) in 24 V systems | Select only for space-constrained 12 V designs where 400 W surge margin suffices |
| Vishay SMA6J78A | Same VWM and bidirectional configuration, but rated for 600 W with VC = 134 V @ 4.7 A; AEC-Q101 qualified | Higher IPP (4.7 A vs. 4.5 A) and tighter VBR tolerance (±5% vs. ±10%), better for precision clamping | Preferred when tighter parametric control and extended surge margin are required, despite 10% cost premium |
Compared with SMBJ78CH, SMAJ78CA offers smaller size but reduced surge capacity, while SMA6J78A delivers tighter VBR and higher IPP - making it suitable for next-generation automotive ECUs demanding enhanced transient immunity without layout change.
Availability
SMBJ78CH is available at Aetrix Electronics and suitable for automotive infotainment power rails, industrial CAN FD networks, and outdoor LED lighting systems requiring stable component supply across multi-year production cycles.
Supply support for SMBJ78CH 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 power MOSFETs for automotive and industrial markets.
The SMBJH series was developed specifically for AEC-Q101-compliant transient protection in harsh environment applications, emphasizing robustness, low leakage, and repeatable clamping performance under thermal cycling.
FAQ
What does the "CH" suffix indicate in SMBJ78CH?
The "CH" suffix in SMBJ78CH designates a bidirectional configuration - meaning the device provides symmetrical clamping in both forward and reverse directions, unlike unidirectional variants (e.g., SMBJ78H) that conduct only in one polarity. This enables use across AC-coupled lines or floating buses without polarity concerns, and is confirmed in the datasheet's "Devices for Bipolar Applications" section.
Is SMBJ78CH AEC-Q101 qualified?
Yes, SMBJ78CH is explicitly AEC-Q101 qualified per the provided datasheet (Version A2102, Page 1). This certification covers stress tests including high-temperature reverse bias (HTRB), temperature cycling, and electrostatic discharge (ESD), validating its suitability for automotive powertrain and body electronics applications.
What is the maximum clamping voltage of SMBJ78CH and under what test condition?
The maximum clamping voltage (VC) of SMBJ78CH is 139 V, measured at a peak pulse current (IPP) of 4.5 A using the standardized 10/1000 µs double-exponential surge waveform. This value is specified in the Electrical Specifications table on Page 3 of the datasheet and defines the upper voltage limit imposed on protected circuits during transient events.
Does SMBJ78CH have polarity markings on the package?
No, SMBJ78CH has no cathode band or polarity marking because it is a bidirectional TVS diode. The DO-214AA (SMB) package is symmetric, and electrical behavior is identical regardless of orientation - a key distinction from unidirectional SMBJxH parts, which feature a visible cathode band per the Package Outline Dimensions diagram on Page 7.
What standards does SMBJ78CH meet for automotive transient immunity?
SMBJ78CH meets ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling). This compliance is explicitly stated in the FEATURES section (Page 1) and verified through characterization per ANSI/IEEE C62.35 definitions cited in the datasheet notes.
SMBJ78CH 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:
- 139V
- Current - Peak Pulse (10/1000µs):
- 4.5A
- 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)
SMBJ78CH FAQ
1.How can I place an order for SMBJ78CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78CH 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 SMBJ78CH reliable?
The price and inventory of SMBJ78CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78CH is usually 5 days.
3.What payment methods are accepted for SMBJ78CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78CH?
SMBJ78CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78CH 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 SMBJ78CH?
For technical support, including SMBJ78CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78CH requirements.
6.How does Aetrix verify that SMBJ78CH is sourced from the original manufacturer or authorized distributors?
All SMBJ78CH 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 SMBJ78CH meets industry standards.
7.What is the process for return or replacement of SMBJ78CH?
All SMBJ78CH units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78CH, 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 SMBJ78CH part is unused and in its original packaging.
Return procedure for SMBJ78CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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