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Taiwan Semiconductor Corporation SMBJ18CAH
- Part No.:
- SMBJ18CAH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18CAH.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,990
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Product details
Overview
SMBJ18CAH from Taiwan Semiconductor is a bidirectional 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 18 V working stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 21.5 A peak pulse current (IPP), 29.2 V maximum clamping voltage (VC), and 600 W peak pulse power (PPK) with <1.0 ps response time.
For engineers reviewing the SMBJ18CAH datasheet, SMBJ18CAH pinout, SMBJ18CAH application, or SMBJ18CAH equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, low leakage (<1 µA at 18 V), and DO-214AA thermal performance (RθJA = 55 °C/W).
Technical Context
The SMBJ18CAH operates as a bidirectional avalanche diode, symmetrically clamping voltage transients in both polarities without requiring external polarity management. Its glass-passivated junction ensures stable breakdown characteristics and low leakage across -55 °C to +150 °C junction temperature range.
It delivers 600 W non-repetitive peak impulse power under 10/1000 µs waveform, with clamping voltage tightly controlled at 29.2 V @ 21.5 A - enabling robust protection of 24 V automotive ECUs, CAN bus interfaces, and industrial I/O circuits against fast electrical fast transients and load dump surges.
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 / 22.1 V @ 1 mA - Ensures reliable turn-on before system-level damage thresholds in 24 V systems |
| VC @ IPP | 29.2 V @ 21.5 A - Clamps induced surges to safe levels for downstream 3.3 V/5 V logic and microcontrollers |
| PPK | 600 W - Withstands ISO 7637-2 Pulse 5a (load dump) energy without degradation |
| ID @ VWM | <1 µA - Negligible standby leakage in battery-critical applications like always-on vehicle modules |
| TJ max | +150 °C - Supports under-hood deployment in automotive engine control units |
| RθJA | 55 °C/W - Enables thermal design margin on standard 1 oz copper PCBs without heatsinking |
Pinout & Package
DO-214AA (SMB) surface-mount package with matte tin-plated leads; cathode band omitted due to bidirectional configuration; polarity is non-directional; weight ≈ 0.090 g; UL 94V-0 molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional avalanche junction | Either terminal serves as anode or cathode depending on transient polarity - no orientation required during placement |
| Case | Non-electrical mechanical interface | DO-214AA body provides mechanical anchoring and thermal path to PCB copper; no electrical connection |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD stress per JESD47 |
| ISO 7637-2 compliant | Meets Pulse 1 (inductive load disconnect), Pulse 2a/2b (switching transients), and Pulse 3a/3b (board-level EFT) immunity requirements |
| Fast response time | <1.0 ps - Activates before most semiconductor junctions experience avalanche breakdown, preventing latent damage |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for green manufacturing and end-of-life handling |
| Moisture sensitivity level 1 | Unlimited floor life at ≤30 °C/60% RH - eliminates bake requirements prior to reflow soldering |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input |
|---|---|
Use Scenario: Protecting 24 V supply lines and LIN/CAN transceiver pins from load dump and jump-start transients. IC Role / Device Role / Timing Role: Bidirectional clamping TVS placed at connector entry point to shunt surge energy before reaching power management ICs and communication PHYs. Use Value: Limits clamped voltage to 29.2 V - well below 36 V absolute maximum ratings of common 24 V-rated PMICs and transceivers. | Use Scenario: Safeguarding 24 V digital input channels from field-wiring induced surges and ESD events during maintenance. IC Role / Device Role / Timing Role: Primary front-end protection element located between screw-terminal block and optocoupler input stage. Use Value: 21.5 A IPP rating handles 1 kV/500 Ω surge generator pulses per IEC 61000-4-5 Level 3 without degradation. |
| LED Headlamp Driver | Smart Sensor Node Power Rail |
Use Scenario: Shielding buck controller and LED string from alternator ripple and ignition coil coupling in automotive lighting systems. IC Role / Device Role / Timing Role: Parallel-connected TVS across input capacitor to clamp repetitive switching spikes and slow-rising load dump events. Use Value: 600 W PPK and 150 °C TJ max enable sustained operation in confined headlamp housings with minimal derating. | Use Scenario: Securing 3.3 V or 5 V power rail of battery-powered IoT sensors exposed to ESD during handling and installation. IC Role / Device Role / Timing Role: Secondary-stage TVS after primary DC/DC converter, protecting LDOs and MCU VDD pins from board-level EFT. Use Value: Sub-1 µA ID at 18 V prevents measurable battery drain over multi-year deployments in remote monitoring nodes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ18CA | Same VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), but not AEC-Q101 qualified; RθJA = 60 °C/W vs. 55 °C/W | Not suitable for automotive under-hood use; acceptable for commercial-grade industrial controls | Select SMBJ18CAH when AEC-Q101 and tighter thermal resistance are mandatory |
| SAC18CA | Same VWM/VBR/VC specs, but SOD-123FL package (smaller footprint, lower PPK = 400 W, RθJA = 120 °C/W) | Limited to low-energy ESD-only protection; cannot withstand ISO 7637-2 Pulse 5a load dump | Choose SMBJ18CAH where 600 W surge handling and automotive qualification are required |
Compared with SMBJ18CA and SAC18CA, SMBJ18CAH uniquely combines AEC-Q101 qualification, 600 W surge rating, and 55 °C/W thermal resistance - making it the only option among the three validated for under-hood automotive power rail protection.
Availability
SMBJ18CAH is available at Aetrix Electronics and suitable for automotive electronics, industrial programmable logic controllers, LED lighting drivers, and smart sensor node designs requiring stable component supply and long-term lifecycle support.
Supply support for SMBJ18CAH 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 SMBJH series was developed specifically for AEC-Q101-compliant transient protection in harsh automotive environments - emphasizing robustness, repeatable clamping, and compatibility with automated SMT assembly processes.
FAQ
What is the maximum clamping voltage of SMBJ18CAH and how does it protect downstream components?
The SMBJ18CAH has a maximum clamping voltage (VC) of 29.2 V at 21.5 A peak pulse current. This value ensures that during a 10/1000 µs surge event, the voltage seen by downstream ICs - such as 24 V-rated PMICs or CAN transceivers - remains safely below their absolute maximum ratings. Its fast <1.0 ps response guarantees clamping activation before transient-induced damage occurs, preserving signal integrity and long-term reliability in automotive and industrial systems.
Is SMBJ18CAH unidirectional or bidirectional, and how does that affect circuit layout?
SMBJ18CAH is a bidirectional TVS diode, indicated by the "CAH" suffix and confirmed by symmetric VBR min/max (20.0–22.1 V) and identical electrical behavior in both polarities. This eliminates polarity marking and orientation constraints during PCB layout - either terminal connects freely to the protected line and ground. No series resistor or directional filtering is needed, simplifying protection network design for AC-coupled or floating rails.
Does SMBJ18CAH meet automotive qualification standards, and which tests were performed?
Yes, SMBJ18CAH is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements. Qualification includes stress testing for temperature cycling, high-temperature reverse bias (HTRB), and electrostatic discharge per JESD22-A114. These validations confirm its suitability for under-hood automotive applications including body control modules, lighting systems, and power distribution units where reliability under thermal and electrical stress is critical.
What is the thermal resistance profile of SMBJ18CAH, and why does RθJA matter in real-world layouts?
SMBJ18CAH has a junction-to-ambient thermal resistance (RθJA) of 55 °C/W on standard FR-4 with minimum recommended pad layout. This value directly impacts power derating: at 70 °C ambient, its 600 W PPK rating drops to ~420 W. Lower RθJA versus alternatives (e.g., 60 °C/W for SMBJ18CA) allows higher sustained surge handling on compact PCBs without added copper area or thermal vias - crucial for space-constrained automotive modules.
How does SMBJ18CAH compare to SMAJ18CAH in terms of surge capability and package compatibility?
SMBJ18CAH offers 600 W peak pulse power in DO-214AA (SMB) package, while SMAJ18CAH delivers only 400 W in smaller DO-214AC (SMA). Their pinouts are incompatible: SMB has 4.5 mm body width vs. SMA's 3.5 mm, requiring different footprints and stencil apertures. SMBJ18CAH's higher PPK, lower RθJA (55 vs. 65 °C/W), and AEC-Q101 certification make it the preferred choice for demanding automotive surge protection where SMAJ18CAH would thermally saturate or fail validation.
SMBJ18CAH 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 21.5A
- 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)
SMBJ18CAH FAQ
1.How can I place an order for SMBJ18CAH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18CAH 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 SMBJ18CAH reliable?
The price and inventory of SMBJ18CAH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18CAH is usually 5 days.
3.What payment methods are accepted for SMBJ18CAH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18CAH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18CAH?
SMBJ18CAH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18CAH 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 SMBJ18CAH?
For technical support, including SMBJ18CAH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18CAH requirements.
6.How does Aetrix verify that SMBJ18CAH is sourced from the original manufacturer or authorized distributors?
All SMBJ18CAH 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 SMBJ18CAH meets industry standards.
7.What is the process for return or replacement of SMBJ18CAH?
All SMBJ18CAH units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18CAH, 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 SMBJ18CAH part is unused and in its original packaging.
Return procedure for SMBJ18CAH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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