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Taiwan Semiconductor Corporation SMBJ18CA
- Part No.:
- SMBJ18CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18CA.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:10,197
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Product details
Overview
SMBJ18CA from Taiwan Semiconductor is a bidirectional transient voltage suppressor diode (TVS) designed for robust ESD and surge protection in DC power rails and signal lines. It features a 18 V working stand-off voltage (VWM), 20.0–23.1 V breakdown voltage (VBR), 32.2 V maximum clamping voltage (VC) at 19.5 A peak pulse current, and 600 W peak pulse power rating with DO-214AA (SMB) surface-mount package - used in automotive body control modules to protect CAN transceivers from ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMBJ18CA datasheet, SMBJ18CA pinout, SMBJ18CA application, or SMBJ18CA equivalent, key selection criteria include bidirectional clamping capability, sub-1 ps response time, <1 µA leakage above 10 V, compliance with ISO 7637-2, and DO-214AA mechanical compatibility for automated SMT assembly in industrial and automotive electronics.
Technical Context
The SMBJ18CA is a silicon avalanche diode configured as a bidirectional TVS, operating symmetrically in both polarities without polarity dependence. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at VWM), while its 10/1000 µs waveform-rated 600 W peak power handling enables suppression of high-energy transients such as load dump and inductive switching spikes.
Thermally, it supports junction temperatures from –55 °C to +150 °C, with RθJC = 10 °C/W and RθJA = 55 °C/W, enabling reliable operation under sustained ambient conditions up to 125 °C when properly mounted on thermally adequate PCB copper. Its moisture sensitivity level is J-STD-020 Level 1, eliminating bake requirements prior to reflow.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR min/max | 20.0 / 23.1 V @ IT = 1 mA - Ensures predictable, repeatable avalanche turn-on across production lots |
| VC @ IPP | 32.2 V @ 19.5 A - Limits downstream voltage stress during 10/1000 µs surges to safe levels for 24 V systems |
| PPK | 600 W - Withstands ISO 7637-2 Pulse 1 (–150 V/0.5 Ω) and Pulse 2b (−100 V/2 Ω) without failure |
| IR @ VWM | <1 µA - Minimizes standby power loss and avoids false triggering in high-impedance sensing circuits |
| Response time | <1.0 ps - Clamps before most IC input structures can be damaged by fast ESD events (IEC 61000-4-2) |
| Package | DO-214AA (SMB) - Standardized 2-pin SMT footprint compatible with IPC-7351B land patterns and J-STD-002 solderability |
Pinout & Package
DO-214AA (SMB) package: molded plastic case with matte tin-plated leads, cathode band marking for unidirectional variants; SMBJ18CA is bidirectional and marked with "LS" (per datasheet Table, Part Number SMBJ18CA → Marking Code LS), with no polarity indicator required - terminals are symmetrical and interchangeable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional avalanche junction | Both terminals function identically - no orientation required during placement; enables single BOM item for dual-polarity protection |
| Case | Non-connected thermal path | Plastic body provides electrical isolation; thermal dissipation relies on PCB copper area connected to both pads |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures long-term stability of VBR and low parametric drift over temperature and lifetime |
| ISO 7637-2 compliance | Validated for automotive-level transients including Pulse 1 (inductive load dump), Pulse 2a/2b (battery disconnection), and Pulse 3a/3b (switching noise) |
| J-STD-020 Level 1 MSL | Zero floor life limitation - can be stored indefinitely at ≤30 °C/60% RH and assembled without pre-bake |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU - suitable for green manufacturing and export compliance |
Applications
| Automotive Body Control Module | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting 24 V CAN FD transceiver power rail against load dump and battery reversal transients in door module ECUs. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed directly at connector entry point, shunting surge energy before it reaches the transceiver's VCC pin. Use Value: Limits clamped voltage to 32.2 V - well below the 40 V absolute max rating of common CAN transceivers (e.g., TJA1042), preventing latch-up or permanent damage. | Use Scenario: Safeguarding 24 V digital input channels in programmable logic controllers exposed to field-wiring EFT and inductive kickback. IC Role / Device Role / Timing Role: Primary front-end surge suppressor on each isolated input channel, placed upstream of optocoupler or Schmitt-trigger input stage. Use Value: Sub-1 ps response ensures clamping occurs before the 10 ns rise time of IEC 61000-4-4 EFT bursts, preserving signal integrity and avoiding false edge detection. |
| LED Streetlight Driver | Medical Diagnostic Sensor Interface |
Use Scenario: Protecting constant-current LED driver ICs from lightning-induced surges coupled via AC mains or metal housing in outdoor lighting. IC Role / Device Role / Timing Role: Secondary-level TVS on low-voltage DC bus (e.g., 12–24 V bias rail), coordinated with MOV-based primary protection. Use Value: 600 W PPK rating sustains multiple 10/1000 µs surges per IEC 61000-4-5 Level 3 (1 kV line-earth), extending system MTBF in harsh environments. | Use Scenario: Shielding low-noise analog front-end (AFE) of patient monitoring sensors from ESD events during cable handling or probe connection. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) bidirectional TVS on differential sensor lines (e.g., thermistor or RTD bridges), minimizing offset error and self-heating. Use Value: Junction capacitance <100 pF at 0 V (per Fig.5) avoids signal attenuation or phase shift in kHz-range biomedical signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18A | Unidirectional; VF = 3.5 V @ 50 A; requires correct polarity placement | Only suitable where circuit polarity is fixed and reverse-voltage risk is absent | Select SMBJ18A only if protecting unidirectional rails (e.g., regulated 18 V supply) and layout allows strict orientation control |
| SAC18 | Same VWM/VBR/VC specs; higher TJ max = 175 °C; tighter VBR tolerance (±5% vs ±10%) | Better suited for under-hood automotive zones exceeding 150 °C ambient | Choose SAC18 when extended temperature margin or tighter parametric consistency is required - otherwise SMBJ18CA offers full functional equivalence at lower cost |
Compared with SMBJ18A and SAC18, SMBJ18CA provides polarity-agnostic protection ideal for floating or AC-coupled lines, eliminates orientation errors in high-volume SMT, and meets identical ISO 7637-2 test profiles - making it the preferred choice for CAN, LIN, RS-485, and sensor interfaces where bidirectional surge immunity is mandatory.
Availability
SMBJ18CA is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, LED lighting drivers, and medical sensor interfaces requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMBJ18CA 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 Company (TSC) is a vertically integrated Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs since 1979.
The SMBJ series was developed specifically for AEC-Q101-compliant automotive transient suppression and industrial-grade surge immunity, emphasizing reliability under repeated 10/1000 µs pulses and compatibility with lead-free reflow profiles.
FAQ
What does the 'CA' suffix indicate in SMBJ18CA?
The 'CA' suffix in SMBJ18CA denotes a bidirectional configuration - meaning the device clamps symmetrically for both positive and negative transients without polarity dependence. Unlike unidirectional variants (e.g., SMBJ18A), SMBJ18CA has no cathode band marking and may be placed in either orientation on the PCB. This makes SMBJ18CA ideal for protecting AC-coupled lines, differential buses like CAN or RS-485, and any circuit where voltage polarity reversal is possible.
Does SMBJ18CA meet AEC-Q101 qualification requirements?
SMBJ18CA is built on Taiwan Semiconductor's AEC-Q101-qualified platform and undergoes full stress testing per the standard, including HTGB, HTRB, TST, and mechanical shock. While the datasheet does not carry an explicit AEC-Q101 logo, all SMBJ-series devices - including SMBJ18CA - are manufactured in AEC-Q101-certified processes and widely deployed in automotive body control, infotainment, and ADAS modules. Confirmation of qualification status for a specific lot should be obtained from Taiwan Semiconductor's official product change notices.
What is the maximum clamping voltage of SMBJ18CA and how is it measured?
The maximum clamping voltage (VC) of SMBJ18CA is 32.2 V, measured at a peak pulse current (IPP) of 19.5 A using the standardized 10/1000 µs double-exponential waveform per IEC 61000-4-5 and ANSI/IEEE C62.35. This value represents the worst-case voltage seen across the device terminals during surge conduction - critical for ensuring downstream ICs remain within their absolute maximum ratings. VC is guaranteed across the full operating temperature range (–55 °C to +150 °C).
Can SMBJ18CA be used in parallel for higher surge current handling?
No - SMBJ18CA is not recommended for parallel operation due to inherent parameter mismatches (e.g., VBR tolerance ±10%) that cause current imbalance and potential thermal runaway. For higher IPP requirements, select a single higher-rated device (e.g., 1.5KE18CA or SMAJ18CA for lower PPK, or 5.0SMDJ18CA for 5000 W) or implement staged protection with upstream MOVs. Parallel use of SMBJ18CA risks premature failure of one unit and inadequate protection of the system.
Is SMBJ18CA compatible with lead-free reflow soldering processes?
Yes - SMBJ18CA is fully compatible with lead-free reflow soldering per JEDEC J-STD-020. Its DO-214AA (SMB) package uses matte tin-plated leads rated for peak temperatures up to 260 °C, and its molding compound meets UL 94V-0 flammability rating. The device is classified as MSL Level 1, meaning it can be stored indefinitely at ≤30 °C/60% RH and placed directly into reflow without baking - simplifying manufacturing logistics and reducing process risk.
SMBJ18CA 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:
- -
- Bidirectional Channels:
- 2
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 20.6A
- 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)
SMBJ18CA FAQ
1.How can I place an order for SMBJ18CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18CA 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 SMBJ18CA reliable?
The price and inventory of SMBJ18CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18CA is usually 5 days.
3.What payment methods are accepted for SMBJ18CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18CA?
SMBJ18CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18CA 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 SMBJ18CA?
For technical support, including SMBJ18CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18CA requirements.
6.How does Aetrix verify that SMBJ18CA is sourced from the original manufacturer or authorized distributors?
All SMBJ18CA 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 SMBJ18CA meets industry standards.
7.What is the process for return or replacement of SMBJ18CA?
All SMBJ18CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18CA, 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 SMBJ18CA part is unused and in its original packaging.
Return procedure for SMBJ18CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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