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Taiwan Semiconductor Corporation SA18CA
- Part No.:
- SA18CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA18CA.pdf
- Description:
- TVS DIODE 18VWM 39.4VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,669
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Product details
Overview
SA18CA from Taiwan Semiconductor is a bidirectional 500W transient voltage suppressor (TVS) diode in DO-204AC (DO-15) package, with 18V working stand-off voltage (VWM), 20.0–22.1V breakdown voltage (VBR @ 1mA), and 39.4V maximum clamping voltage (VC) at 17.9A peak pulse current. It protects automotive lighting and ECU power rails against ESD and electrical fast transients.
For engineers reviewing the SA18CA datasheet, SA18CA pinout, SA18CA application, or SA18CA equivalent, this page delivers verified electrical parameters, bidirectional TVS behavior, AEC-Q101 qualification status, DO-15 mechanical data, and real-world protection use cases for automotive and industrial systems.
Technical Context
The SA18CA is a silicon avalanche diode designed for bidirectional transient suppression per IEC 61000-4-2 (ESD), IEC 61000-4-4 (EFT), and ISO 7637-2 (automotive surge). Its symmetrical VBR min/max (20.0–22.1V) and matched clamping in both polarities ensure balanced protection without polarity dependency.
It operates across –55°C to +175°C junction temperature, supports 70A non-repetitive forward surge (IFSM), and exhibits <1μA reverse leakage at 18V - critical for low-power always-on circuits. The device is AEC-Q101 qualified (denoted by "H" suffix variants), confirming robustness for automotive under-hood applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous DC or RMS voltage the device blocks without clamping; sets system operating margin before protection activates. |
| VBR @ IT=1mA | 20.0–22.1 V - Breakdown threshold range; defines onset of avalanche conduction during overvoltage events. |
| VC @ IPPM=17.9A | 39.4 V - Clamped voltage during 10/1000μs surge; determines maximum stress imposed on protected ICs. |
| PPK | 500 W - Peak pulse power rating at TA=25°C; validates capability to absorb standardized lightning/surge energy. |
| IR @ VWM | <1 μA - Reverse leakage at stand-off voltage; ensures minimal quiescent current drain in battery-powered systems. |
| TJ max | +175 °C - Maximum junction temperature; enables deployment in high-temperature engine compartments. |
| Package | DO-204AC (DO-15) - Industry-standard axial leaded package with UL 94V-0 molding; compatible with through-hole assembly and manual rework. |
Pinout & Package
DO-204AC (DO-15) package: axial-leaded, molded epoxy case with cathode band marking for unidirectional variants; SA18CA is bidirectional and has no polarity marking - terminals are electrically symmetric.
| 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 in PCB layout. |
| Lead 1 | Terminal connection | Pure tin-plated, J-STD-002 solderable lead; supports wave and hand soldering with whisker-resistant finish (JESD 201 Class 2). |
| Lead 2 | Terminal connection | Identical to Lead 1; symmetric construction enables flexible board placement and eliminates polarity verification step. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified variant available | SA18CAH meets automotive reliability requirements including temperature cycling, HTRB, and ESD testing - validated for under-hood ECUs and lighting modules. |
| 500W peak pulse power (10/1000μs) | Withstands IEC 61000-4-5 Level 3 (1kV line-to-line, 2kV line-to-ground) surges without degradation when properly heatsinked. |
| Fast response time (5ns bidirectional) | Clamps transients before sensitive logic or analog circuitry experiences damaging overvoltage - critical for CAN/LIN bus protection. |
| Low clamping ratio (VC/VBR ≈ 1.85) | Delivers tight voltage limiting relative to breakdown; reduces margin needed between protected IC's absolute max rating and clamping level. |
| RoHS & halogen-free (IEC 61249-2-21) | Complies with automotive environmental standards; enables use in Tier 1 supply chains requiring full material declaration. |
Applications
| Automotive LED Headlamp Driver Protection | Industrial PLC Digital Input Protection |
|---|---|
Use Scenario: Protects LED driver ICs and MOSFETs from load dump and inductive kickback during headlamp switching in 12V vehicle systems. IC Role / Device Role / Timing Role: Bidirectional TVS placed across input rail and ground to clamp ±100V transients within 5ns. Use Value: Prevents latch-up or gate oxide rupture in buck controller ICs by limiting rail voltage to ≤39.4V during 500W surges. | Use Scenario: Shields 24V digital input channels of programmable logic controllers from EFT bursts induced by relay switching in factory automation cabinets. IC Role / Device Role / Timing Role: Standoff device mounted at connector entry point to shunt EFT energy (IEC 61000-4-4, 4kV) before reaching optocoupler input stage. Use Value: Maintains signal integrity by holding input voltage below 39.4V during 5ns-fast transients, avoiding false triggering or input-stage damage. |
| USB-C Port ESD Protection (Legacy Adapter Interface) | Smart Meter Power Supply Surge Suppression |
Use Scenario: Safeguards legacy USB-C adapter detection circuitry (CC pins) from human-body-model (HBM) ESD events during plug insertion. IC Role / Device Role / Timing Role: Bidirectional clamping element placed between CC line and ground, leveraging sub-1μA leakage to avoid interfering with 5V bias networks. Use Value: Limits ESD-induced voltage excursion to ≤39.4V while adding <0.5pF capacitance - preserving USB-C enumeration timing. | Use Scenario: Suppresses lightning-induced surges on 220V AC mains input of smart electricity meters deployed in outdoor substations. IC Role / Device Role / Timing Role: Primary-level TVS staged upstream of bridge rectifier and bulk capacitor to absorb 10/1000μs line surges per IEC 61000-4-5. Use Value: Enables compliance with IEC 62053-21 surge immunity (4kV differential mode) by clamping to 39.4V before downstream fuse or MOV activation. |
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 (Bourns) | Same DO-214AA package, 500W rating, VWM=18V, VC=29.2V @ 17.1A - lower clamping voltage but higher capacitance (150pF vs ~50pF typical for SA18CA). | Preferred where tighter clamping is critical and layout allows SMT footprint; unsuitable for through-hole legacy designs. | Select SMBJ18CA only if board redesign supports SMT and lower VC justifies trade-off in layout change and higher junction capacitance. |
| P6SMB18CA (Littelfuse) | DO-214AA package, identical VWM/VC specs (18V/29.2V), AEC-Q101 qualified, but rated for 600W PPK - higher surge margin at same footprint. | Used in next-gen automotive modules requiring extended surge endurance beyond 500W baseline; requires SMT reflow validation. | Choose P6SMB18CA when upgrading to higher surge immunity class (e.g., ISO 16750-2 Pulse 5b) and SMT assembly is available. |
Compared with SA18CA, SMBJ18CA offers lower clamping (29.2V) but demands SMT layout changes, while P6SMB18CA provides 20% higher surge rating in same SMT package - neither matches SA18CA's DO-15 through-hole compatibility and AEC-Q101-ready availability in axial form.
Availability
SA18CA is available at Aetrix Electronics and suitable for automotive lighting systems, industrial PLC inputs, smart meter power supplies, and USB-C adapter interface protection requiring stable component supply and long-term obsolescence management.
Supply support for SA18CA 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 consumer markets.
The SA Series was developed specifically for high-reliability transient suppression in automotive electronics, emphasizing AEC-Q101 compliance, wide temperature operation (–55°C to +175°C), and robust surge handling in axial DO-15 packaging.
FAQ
What is the key difference between SA18CA and SA18A?
SA18CA is a bidirectional TVS diode with symmetrical breakdown and clamping in both polarities, while SA18A is unidirectional and features a cathode band marking. SA18CA has VBR = 20.0–22.1V and VC = 39.4V @ 17.9A; SA18A has VBR = 20.0–24.4V and VC = 32.2V @ 16.3A. The "C" suffix explicitly denotes bidirectional configuration in the SA Series nomenclature, and SA18CA is the correct part for AC-coupled or polarity-agnostic protection. SA18CA remains fully functional in the SA18CA datasheet specifications.
Is SA18CA AEC-Q101 qualified?
SA18CA itself is not AEC-Q101 qualified; qualification applies only to variants with the "H" suffix (e.g., SA18CAH). The base SA18CA meets all electrical and mechanical specifications in the SA Series datasheet but lacks the extended reliability test reporting required for AEC-Q101 certification. For automotive under-hood applications, SA18CAH must be specified. SA18CA remains suitable for industrial and commercial designs where AEC-Q101 is not mandated.
What does the "CA" suffix mean in SA18CA?
The "CA" suffix in SA18CA indicates a bidirectional TVS diode in the SA Series: "C" designates bidirectional functionality, and "A" denotes the tighter VBR tolerance variant (±5% typical vs standard ±10%). This distinguishes it from unidirectional "A" parts like SA18A and confirms symmetrical clamping behavior essential for protecting AC signals or polarity-unknown interfaces. SA18CA is therefore the appropriate selection for applications requiring equal protection in both voltage polarities.
Can SA18CA replace P6KE18CA in existing designs?
SA18CA can serve as a functional replacement for P6KE18CA in many through-hole applications, as both are DO-15 packaged bidirectional 18V TVS diodes rated for 500W. However, SA18CA has higher clamping voltage (39.4V vs ~35V for P6KE18CA) and slightly different VBR range (20.0–22.1V vs 20.0–22.8V). System-level validation is required to confirm that the higher VC does not exceed protected IC's absolute maximum ratings. SA18CA remains a viable drop-in option where layout and thermal constraints match.
What is the maximum operating temperature for SA18CA?
The maximum operating junction temperature for SA18CA is +175°C, with a storage temperature range of –55°C to +175°C. This rating is confirmed in the Absolute Maximum Ratings table of the SA Series datasheet and enables use in high-temperature environments such as automotive engine control units, under-hood lighting modules, and industrial motor drives. Derating of peak pulse power begins above TA = 25°C per the published pulse derating curve (Fig.2), and SA18CA remains fully operational across its full rated temperature span.
SA18CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- SA
- 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:
- 39.4V
- Current - Peak Pulse (10/1000µs):
- 17.9A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AC (DO-15)
SA18CA FAQ
1.How can I place an order for SA18CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SA18CA 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 SA18CA reliable?
The price and inventory of SA18CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA18CA is usually 5 days.
3.What payment methods are accepted for SA18CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA18CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA18CA?
SA18CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA18CA 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 SA18CA?
For technical support, including SA18CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA18CA requirements.
6.How does Aetrix verify that SA18CA is sourced from the original manufacturer or authorized distributors?
All SA18CA 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 SA18CA meets industry standards.
7.What is the process for return or replacement of SA18CA?
All SA18CA units undergo pre-shipment inspection (PSI). If there is an issue with SA18CA, 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 SA18CA part is unused and in its original packaging.
Return procedure for SA18CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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