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Taiwan Semiconductor Corporation SMBJ120A
- Part No.:
- SMBJ120A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ120A.pdf
- Description:
- TVS DIODE 120VWM 193VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,878
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Product details
Overview
SMBJ120A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal paths. It features a 120 V working stand-off voltage (VWM), 133–147 V breakdown voltage (VBR), 193 V maximum clamping voltage (VC) at 3.2 A peak impulse current, and 600 W peak pulse power rating with sub-1 ps response time - deployed in automotive power supply inputs and industrial I/O interfaces.
For engineers reviewing the SMBJ120A datasheet, SMBJ120A pinout, SMBJ120A application, or SMBJ120A equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD rails, leakage current at operating voltage, thermal derating above 25°C ambient, and DO-214AA (SMB) package compatibility with automated SMT assembly.
Technical Context
The SMBJ120A operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified breakdown range (133–147 V at 1 mA test current). Its glass-passivated junction ensures stable VBR tolerance and low leakage (<1 µA at 120 V), while the 10/1000 µs waveform-rated 600 W peak power handling enables robust immunity against ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transients.
Thermal performance is defined by 10 °C/W junction-to-case and 55 °C/W junction-to-ambient resistance, supporting continuous operation up to +150 °C junction temperature. The device uses a single-die DO-214AA (SMB) package with matte tin-plated leads compliant with J-STD-002 solderability and JESD 201 Class 2 whisker resistance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 120 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 133 / 147 V @ 1 mA - Confirmed avalanche onset range ensuring predictable turn-on margin |
| VC @ IPP | 193 V @ 3.2 A - Clamped voltage during 10/1000 µs surge, defining worst-case stress on downstream circuitry |
| PPK | 600 W - Peak pulse power capability per 10/1000 µs waveform, critical for ISO 7637-2 compliance |
| ID @ VWM | <1 µA - Low leakage preserves system standby power budget and prevents false triggering |
| TJ max | +150 °C - Enables deployment in under-hood automotive or high-temperature industrial enclosures |
| RθJA | 55 °C/W - Determines required PCB copper area and airflow for thermal management at full power |
Pinout & Package
DO-214AA (SMB) surface-mount package with cathode band marking; 2-terminal unidirectional configuration; case meets UL 94V-0 flammability rating and J-STD-020 moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | DC return path / ground reference | Connected to system ground or low-side return; defines polarity-sensitive placement |
| Cathode | Protected line input | Connected to line being protected (e.g., 12 V rail); clamps to anode when overvoltage occurs |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over lifetime and improved humidity resistance vs. epoxy-passivated alternatives |
| Sub-1 ps response time | Enables suppression of fast ESD and EFT events before sensitive ICs experience latch-up or damage |
| ISO 7637-2 compliance | Validated for automotive load dump and switching transient immunity without external filtering |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU RoHS directives for environmentally constrained applications |
| Automated placement compatible | DO-214AA footprint supports high-yield pick-and-place with standard vision alignment systems |
Applications
| Automotive Power Input Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: 12 V battery-fed ECUs exposed to load dump and alternator transients per ISO 7637-2. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and DC-DC input, clamping surges within 193 V to protect regulator ICs. Use Value: Eliminates need for series resistors or RC filters while maintaining <1 µA leakage at nominal 12 V operation. | Use Scenario: 24 V digital input modules receiving signals from field sensors in factory automation. IC Role / Device Role / Timing Role: Standoff protection for optocoupler or MCU GPIO inputs subjected to inductive kickback from solenoid drivers. Use Value: Withstands 3.2 A 10/1000 µs pulses without degradation, preserving signal integrity during repeated switching cycles. |
| LED Driver Overvoltage Clamp | Telecom Line Interface Surge Suppression |
Use Scenario: Constant-current LED drivers powered from unregulated 48 V telecom supplies prone to lightning-induced surges. IC Role / Device Role / Timing Role: Parallel-connected TVS across driver output to limit transient voltage to 193 V, preventing LED string overvoltage failure. Use Value: 600 W peak power rating absorbs energy from multi-kV induced surges without thermal runaway. | Use Scenario: Ethernet-powered (PoE) interface circuits requiring immunity to fast transients on data lines per IEC 61000-4-4. IC Role / Device Role / Timing Role: Bidirectional protection not applicable - SMBJ120A used only on DC bias lines (e.g., PoE power feed), not differential data pairs. Use Value: Sub-1 ps response ensures clamping initiates before EFT bursts reach PHY transceivers, reducing bit error rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ120CA | Bidirectional variant; symmetric VBR (133–147 V) in both polarities; same VWM, VC, and PPK ratings | Required where AC-coupled or reversible polarity lines (e.g., RS-485 bus) need protection | Select SMBJ120CA only if bidirectional clamping is needed; SMBJ120A is lower-cost for DC-only rails. |
| P6SMB120A | Same DO-214AA package and 120 V VWM, but higher VC (200 V @ 3.0 A) and lower PPK (600 W same), from Littelfuse | Marginally higher clamping voltage reduces protection margin for 135 V-tolerant ICs | Acceptable where 7 V higher VC is within system design margin; verify thermal derating curves differ slightly. |
Compared with SMBJ120CA and P6SMB120A, the SMBJ120A offers the lowest clamping voltage (193 V) among 120 V-class unidirectional SMB TVS diodes, delivering tighter overvoltage control for sensitive 135 V-rated regulators and controllers.
Availability
SMBJ120A is available at Aetrix Electronics and suitable for automotive electronics, industrial programmable logic controllers, LED lighting drivers, and telecom power interfaces requiring stable component supply and full traceability.
Supply support for SMBJ120A 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, serving global automotive, industrial, and consumer markets since 1979.
The SMBJ series was developed specifically for high-reliability transient suppression in harsh environments, emphasizing tight VBR tolerance, low leakage, and ISO 7637-2 compliance for automotive-grade power systems.
FAQ
What is the maximum clamping voltage of SMBJ120A and under what test condition is it specified?
The SMBJ120A has a maximum clamping voltage (VC) of 193 V, measured at a peak impulse current (IPP) of 3.2 A using the standardized 10/1000 µs double-exponential surge waveform. This value defines the upper voltage limit imposed on protected circuitry during a transient event and is guaranteed across the full operating temperature range per the datasheet's electrical specifications table.
Is SMBJ120A suitable for bidirectional signal line protection?
No, SMBJ120A is a unidirectional TVS diode intended for DC power rail protection only. Its cathode band marking and asymmetric IV curve mean it conducts only in reverse bias. For bidirectional protection (e.g., AC lines or differential buses), the SMBJ120CA variant must be used - it provides symmetrical clamping in both polarities and is explicitly designated for bipolar applications in the datasheet.
What is the leakage current specification for SMBJ120A at its rated working voltage?
The SMBJ120A exhibits a maximum blocking leakage current (ID) of 1 µA when biased at its 120 V working stand-off voltage (VWM), tested at 25°C ambient. This low leakage ensures minimal impact on standby power consumption in battery-operated or energy-sensitive systems, and remains well below the 5 µA threshold commonly required for automotive microcontroller I/O protection.
Does SMBJ120A meet automotive transient immunity standards?
Yes, SMBJ120A is explicitly validated to meet ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (supply interruption), Pulse 3a (capacitive coupled noise), and Pulse 3b (inductive coupled noise). Its 600 W peak pulse power rating and sub-1 ps response time enable direct compliance without additional filtering components in 12 V and 24 V vehicle electrical systems.
What is the thermal resistance profile of SMBJ120A and how does it affect PCB layout?
SMBJ120A has a junction-to-ambient thermal resistance (RθJA) of 55 °C/W and junction-to-case (RθJC) of 10 °C/W. To maintain TJ ≤ 150 °C at full 600 W surge, the PCB must provide adequate copper area (≥ 1 in² typical) and minimize thermal isolation - especially critical in enclosed industrial enclosures where ambient may exceed 85 °C and derating per Figure 2 applies.
SMBJ120A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 193V
- Current - Peak Pulse (10/1000µs):
- 3.1A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ120A FAQ
1.How can I place an order for SMBJ120A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ120A 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 SMBJ120A reliable?
The price and inventory of SMBJ120A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ120A is usually 5 days.
3.What payment methods are accepted for SMBJ120A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ120A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ120A?
SMBJ120A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ120A 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 SMBJ120A?
For technical support, including SMBJ120A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ120A requirements.
6.How does Aetrix verify that SMBJ120A is sourced from the original manufacturer or authorized distributors?
All SMBJ120A 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 SMBJ120A meets industry standards.
7.What is the process for return or replacement of SMBJ120A?
All SMBJ120A units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ120A, 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 SMBJ120A part is unused and in its original packaging.
Return procedure for SMBJ120A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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