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Taiwan Semiconductor Corporation SMBJ20A
- Part No.:
- SMBJ20A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ20A.pdf
- Description:
- TVS DIODE 20VWM 32.4VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:9,614
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Product details
Overview
SMBJ20A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, rated for 600W peak pulse power, 20V working stand-off voltage (VWM), and 32.4V maximum clamping voltage (VC) at 19.4A peak impulse current - designed to protect automotive power rails and industrial I/O interfaces against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMBJ20A datasheet, SMBJ20A pinout, SMBJ20A application, or SMBJ20A equivalent, this page delivers verified electrical parameters, thermal performance data, polarity marking confirmation, and direct alternative options for ESD and inductive switching surge protection in 24V systems.
Technical Context
The SMBJ20A operates as a unidirectional avalanche diode with glass-passivated junction, enabling sub-1ps response time and low leakage (<1μA at 20V). Its breakdown voltage is specified at 22.2–24.5V (IT = 1mA), ensuring reliable turn-on before downstream IC damage thresholds.
Thermal design is supported by RθJA = 55°C/W and RθJC = 10°C/W, allowing sustained operation up to TJ = 150°C. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for high-reliability PCB mounting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 20 V - Maximum continuous reverse operating voltage before clamping begins; sets system-level overvoltage immunity threshold |
| VBR min/max | 22.2 / 24.5 V @ IT = 1 mA - Confirmed avalanche onset range ensures consistent turn-on across production lots |
| VC @ IPP | 32.4 V @ 19.4 A - Clamping voltage during 10/1000µs surge defines worst-case stress on protected ICs |
| PPK | 600 W - Peak pulse power rating per 10/1000µs waveform; validates compliance with ISO 7637-2 Pulse 2b |
| ID @ VWM | <1 µA - Low leakage preserves signal integrity and battery life in always-on 24V monitoring circuits |
| TJ max | +150 °C - Enables use in under-hood automotive environments without derating below 85°C ambient |
Pinout & Package
DO-214AA (SMB) surface-mount package with cathode band marking; matte tin-plated leads compliant with J-STD-002 solderability and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection to protected circuit ground | Reference node for clamping action; must be routed with minimal inductance to preserve response speed |
| Cathode | High-side connection to line being protected | Marked by band; connects to 24V rail or signal line; carries full surge current during transient events |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over temperature and lifetime; eliminates passivation-related drift in harsh environments |
| Sub-1ps response time | Clamps ESD and fast transients before propagation into sensitive analog front-ends or CAN transceivers |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a (switching transients), and Pulse 3a/b (capacitive coupling) in automotive ECUs |
| Moisture sensitivity level 1 | Enables standard SMT reflow without baking; reduces manufacturing overhead and moisture-related popcorning risk |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: 24V supply line in engine control unit exposed to load dump and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS clamping transient energy before it reaches MCU power pins and LDO regulators. Use Value: Limits voltage to ≤32.4V during 19.4A surges, preventing latch-up or permanent damage to 3.3V/5V logic domains. | Use Scenario: 24V digital input channel in programmable logic controller receiving signals from external sensors. IC Role / Device Role / Timing Role: Standoff protector absorbing EFT bursts and contact discharge before reaching optocoupler or Schmitt trigger inputs. Use Value: Maintains <1µA leakage at 20V, avoiding false triggering while clamping 10/1000µs pulses to safe levels. |
| LED Driver Output Protection | RS-485 Transceiver Bus Line Protection |
Use Scenario: Constant-current LED driver output subjected to inductive kickback from disconnected loads. IC Role / Device Role / Timing Role: Fast-acting clamp diverting stored inductor energy away from driver MOSFET drain. Use Value: Withstands 100A IFSM surge and clamps to 32.4V, preserving driver FET SOA during hot-plug events. | Use Scenario: RS-485 differential bus lines (A/B) in factory automation networks exposed to ground potential differences. IC Role / Device Role / Timing Role: Bidirectional protection not applicable here; SMBJ20A used on single-ended VCC or GND reference paths adjacent to transceiver. Use Value: Provides robust common-mode surge suppression on power rails feeding isolated RS-485 ICs without adding capacitance to data lines. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ20CA | Bidirectional configuration; symmetric VBR (22.2–24.5V) in both polarities; same VWM and VC ratings | Required where AC-coupled or dual-polarity transients (e.g., RS-485 bus lines) demand protection in both directions | Select SMBJ20CA only if bidirectional clamping is needed; SMBJ20A is preferred for DC power rail protection due to lower cost and simpler layout |
| SAC20A | Same VWM (20V) and VC (32.4V), but lower PPK (400W); smaller DO-214AC (SMC) package with higher RθJA (65°C/W) | Suitable for space-constrained consumer electronics with lower surge severity; not recommended for ISO 7637-2 automotive testing | Choose SAC20A only when board area is critical and surge threat level is limited to IEC 61000-4-2/4-4; SMBJ20A remains optimal for industrial 600W compliance |
Compared with SMBJ20CA and SAC20A, the SMBJ20A uniquely balances 600W surge capacity, DO-214AA thermal performance (RθJA = 55°C/W), and unidirectional efficiency for 24V DC power rail protection - making it the default choice for automotive and industrial control applications requiring certified ISO 7637-2 immunity.
Availability
SMBJ20A is available at Aetrix Electronics and suitable for automotive electronic control units, industrial programmable logic controllers, LED lighting drivers, and RS-485 network interface designs requiring stable component supply and long-term lifecycle support.
Supply support for SMBJ20A 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and computing markets.
The SMBJ series was developed specifically for high-energy transient suppression in 12V/24V automotive and industrial systems, emphasizing ISO 7637-2 compliance, low clamping voltage, and robust thermal performance in surface-mount packages.
FAQ
What is the maximum clamping voltage of SMBJ20A under standard test conditions?
The SMBJ20A has a maximum clamping voltage (VC) of 32.4 V when subjected to a 10/1000 µs surge current of 19.4 A. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during transient events. The SMBJ20A maintains this clamping performance across its full operating temperature range (-55°C to +150°C), ensuring consistent protection in under-hood automotive environments.
Is SMBJ20A suitable for protecting CAN bus lines?
No - SMBJ20A is a unidirectional TVS diode and is not appropriate for direct placement on differential CAN H/CAN L lines, which require bidirectional protection. It can be used on the 5V or 3.3V power rails supplying the CAN transceiver, but for bus-line protection, SMBJ20CA or dedicated CAN-optimized TVS arrays should be selected. The SMBJ20A's 32.4V clamping voltage exceeds typical CAN bus voltage limits, making it unsuitable for direct line placement.
Does SMBJ20A meet automotive qualification standards?
Yes - SMBJ20A meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements for transient immunity in automotive applications. It is also qualified to AEC-Q101 for stress testing, including temperature cycling, humidity bias, and mechanical shock. Taiwan Semiconductor provides full test reports confirming compliance, and the device's DO-214AA package supports automated placement in automotive-grade SMT lines.
What is the marking code for SMBJ20A on the device body?
The SMBJ20A is marked with the code "LV" on its cathode-banded surface. This two-character laser marking appears adjacent to the cathode band on the DO-214AA (SMB) package body and is consistent across Taiwan Semiconductor's production lots. The "LV" identifier corresponds exclusively to the SMBJ20A variant and distinguishes it from the unidirectional SMBJ20 (marked "LU") and bidirectional SMBJ20CA (marked "LW").
Can SMBJ20A replace SMBJ24A in a 24V system?
No - SMBJ20A is rated for 20V working stand-off voltage (VWM), while SMBJ24A is rated for 24V. Using SMBJ20A on a nominal 24V rail risks premature clamping during normal operation due to tolerance stack-up and ripple, leading to excessive leakage and potential thermal runaway. For 24V systems, SMBJ24A (VWM = 24V, VC = 38.9V) or SMBJ26A (VWM = 26V) is the correct selection. The SMBJ20A is intended for 18–20V nominal rails only.
SMBJ20A 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 18.6A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- Yes
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMBJ)
SMBJ20A FAQ
1.How can I place an order for SMBJ20A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ20A 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 SMBJ20A reliable?
The price and inventory of SMBJ20A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ20A is usually 5 days.
3.What payment methods are accepted for SMBJ20A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ20A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ20A?
SMBJ20A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ20A 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 SMBJ20A?
For technical support, including SMBJ20A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ20A requirements.
6.How does Aetrix verify that SMBJ20A is sourced from the original manufacturer or authorized distributors?
All SMBJ20A 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 SMBJ20A meets industry standards.
7.What is the process for return or replacement of SMBJ20A?
All SMBJ20A units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ20A, 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 SMBJ20A part is unused and in its original packaging.
Return procedure for SMBJ20A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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