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Vishay General Semiconductor - Diodes Division SA18CA/54
- Part No.:
- SA18CA/54
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA18CA/54.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO204AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,766
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Product details
Overview
SA18CA from Littelfuse is a bidirectional Transient Voltage Suppressor (TVS) diode in DO-204AC (Axial) package, designed for robust overvoltage protection of DC power rails and signal lines. It features 54 V stand-off voltage (VWM), 60 V minimum breakdown voltage (VBR), 96.3 V maximum clamping voltage (VC) at 5.2 A peak pulse current, and 500 W peak pulse power rating with 10/1000 µs waveform - deployed in industrial motor drives and telecom power interfaces.
For engineers reviewing the SA18CA datasheet, SA18CA pinout, SA18CA application, or SA18CA equivalent, key selection criteria include bidirectional clamping symmetry, low clamping ratio (VC/VWM = 1.78), sub-5 ns response time, <1 µA reverse leakage at rated VWM, and DO-204AC axial lead compatibility with through-hole PCB assembly.
Technical Context
The SA18CA operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 MΩ) up to 54 V; during transients exceeding 60 V, it avalanches rapidly (<5 ns) to clamp the line at ≤96.3 V while diverting up to 5.2 A (10/1000 µs). Its bidirectional structure enables symmetric protection on AC-coupled or floating lines without polarity concerns.
Thermal design relies on axial lead soldering (265°C/10 s, 0.375" length, 5 lbs tension) and derating above 25°C ambient per Fig. 2; steady-state dissipation is limited to 3.0 W at TL = 75°C on 40×40 mm copper pad. Junction temperature range spans −55°C to +175°C, supporting harsh industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VWM) | 54 V - maximum continuous reverse working voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 60–73.3 V at 1 mA - guaranteed avalanche onset threshold for reliable clamping activation |
| Clamping Voltage (VC) | 96.3 V at 5.2 A (10/1000 µs) - maximum voltage seen by protected circuit during surge event |
| Peak Pulse Power (PPPM) | 500 W - surge energy handling capacity for non-repetitive transients per REA standard |
| Response Time | <5.0 ns - time from 0 V to VBR in bidirectional mode, enabling protection of fast-edge logic and analog ICs |
| Reverse Leakage (ID) | <1.0 µA at 54 V - negligible standby power loss and minimal impact on high-impedance sensing nodes |
| Operating Temperature | −55°C to +175°C - supports deployment in automotive engine bays, industrial PLCs, and outdoor telecom cabinets |
Pinout & Package
DO-204AC (Axial) package: molded plastic body with glass-passivated junction; solder-plated axial leads compliant with MIL-STD-750 Method 2026; polarity not applicable (bidirectional device - no cathode band).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Surge current path terminal | Either lead serves identically as input/output node; no polarity dependency enables flexible board layout |
| Leads (axial) | Thermal and electrical interface | 0.375" (9.5 mm) lead length supports high-temp soldering (265°C/10 s) and mechanical strain relief |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection of AC lines, differential buses (e.g., RS-485), and floating grounds without external diode pairing |
| UL 94V-0 flammability rating | Plastic housing meets fire-safety requirements for enclosed industrial and medical equipment enclosures |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (e.g., ESD, lightning-induced surges) |
| High-temperature soldering guarantee | Validated 265°C/10 s process ensures reliability in automated wave-solder and hand-solder assembly |
| JEDEC DO-204AC mechanical standard | Ensures consistent lead spacing (0.230"–0.300"), diameter (0.028"–0.034"), and mounting compatibility across suppliers |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
|
Use Scenario: Protection of 48 V DC bus against switching transients from IGBT gate drivers and relay coil flyback. IC Role / Device Role: Shunt TVS placed across bus input capacitor to clamp spikes ≤96.3 V before reaching DC-DC converters and microcontrollers. Use Value: Prevents cumulative degradation of MOSFET gate oxides and avoids latch-up in downstream logic ICs during repetitive 500 W surges. |
Use Scenario: Input-stage surge suppression on −48 V telecom rectifier outputs exposed to lightning-induced longitudinal surges. IC Role / Device Role: Bidirectional clamping element between tip/ring and ground in POTS line interface cards. Use Value: Maintains symmetry in balanced signaling paths while limiting common-mode voltage excursions to <100 V during 10/1000 µs transients. |
| Automotive Body Control Modules | Industrial PLC Analog Inputs |
|
Use Scenario: Protection of LIN bus transceivers and power window motor H-bridge controllers against load dump and jump-start events. IC Role / Device Role: Primary overvoltage clamp on 12 V supply rail upstream of LDO regulators and CAN/LIN PHYs. Use Value: Withstands 500 W pulses without degradation, ensuring functional safety compliance (ISO 7637-2 Pulse 5a) over full temperature range. |
Use Scenario: Guarding 4–20 mA current loop inputs against ESD and field-wiring faults in factory automation sensors. IC Role / Device Role: Low-leakage (≤1 µA) bidirectional suppressor placed across loop terminals before precision op-amp front-end. Use Value: Preserves measurement accuracy (<0.1% error) while clamping transients to <100 V - below ADC input damage threshold. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ54CA | DO-214AA (SMB) surface-mount package; identical VWM (54 V), VC (93.6 V @ 5.3 A), but lower PPPM (600 W) | Requires rework of PCB layout for SMT assembly; better thermal performance in forced-air-cooled systems | Select when space-constrained designs demand SMT footprint and higher peak power margin is needed |
| P6KE54CA | DO-15 axial package; same VWM/VC specs but lower PPPM (600 W), higher IPPM (6.4 A), and slower response (~10 ns) | Legacy-compatible replacement with proven field reliability; less effective for <5 ns ESD events | Choose for cost-sensitive, non-ESD-critical applications where DO-15 footprint reuse is mandatory |
Compared with SMBJ54CA and P6KE54CA, the SA18CA offers optimal balance of axial through-hole manufacturability, 5 ns response for ESD immunity, and UL 94V-0 compliance - making it preferred for new industrial control and telecom hardware where safety certification and fast transient rejection are jointly required.
Availability
SA18CA is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, automotive body control modules, and PLC analog inputs requiring stable component supply with full traceability and long-term lifecycle support.
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
Littelfuse is a global leader in circuit protection, specializing in fuses, TVS diodes, and surge suppression solutions for industrial, automotive, and consumer markets.
The SAxxCA series was engineered specifically for cost-effective, high-reliability overvoltage protection in space-constrained through-hole applications - emphasizing fast response, bidirectional symmetry, and UL-certified safety.
FAQ
What is the clamping voltage of the SA18CA under a 10/1000 µs surge?
The SA18CA clamps to a maximum of 96.3 V when subjected to a 5.2 A peak pulse current with a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and represents the upper limit of voltage stress imposed on protected circuitry during standardized surge events - critical for verifying compatibility with downstream IC absolute maximum ratings.
Is the SA18CA unidirectional or bidirectional?
The SA18CA is a bidirectional TVS diode, as indicated by the "CA" suffix. Its symmetrical structure provides identical clamping behavior in both polarities, eliminating the need for polarity-aware placement and enabling use on AC lines, differential buses, and floating grounds - unlike unidirectional variants such as SA18A.
What package type does the SA18CA use, and what are its mechanical dimensions?
The SA18CA uses the JEDEC DO-204AC (axial lead) package: body diameter 0.028–0.034 inches (0.71–0.86 mm), overall length 0.104–0.140 inches (2.6–3.6 mm), lead diameter 0.020 inches (0.51 mm), and lead spacing 0.230–0.300 inches (5.8–7.6 mm). These dimensions ensure compatibility with standard axial through-hole footprints and wave-solder tooling.
Does the SA18CA meet UL flammability requirements?
Yes, the SA18CA's plastic package is certified to UL 94V-0 flammability standard - meaning it self-extinguishes within 10 seconds after flame removal and produces no flaming drips. This qualification supports compliance in industrial enclosures, medical devices, and other safety-critical applications governed by IEC 62368-1 and UL 60950-1.
What is the maximum operating temperature range for the SA18CA?
The SA18CA operates across a junction temperature range of −55°C to +175°C. This wide span enables deployment in under-hood automotive modules, outdoor base stations, and high-ambient industrial controls - with derating applied above 25°C ambient per Figure 2 in the datasheet to maintain 500 W peak pulse capability.
SA18CA/54 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- 17.1A
- 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/54 FAQ
1.How can I place an order for SA18CA/54 through Aetrix?
Please submit a Request for Quotation (RFQ) for SA18CA/54 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/54 reliable?
The price and inventory of SA18CA/54 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA18CA/54 is usually 5 days.
3.What payment methods are accepted for SA18CA/54?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA18CA/54 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA18CA/54?
SA18CA/54 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA18CA/54 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/54?
For technical support, including SA18CA/54 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA18CA/54 requirements.
6.How does Aetrix verify that SA18CA/54 is sourced from the original manufacturer or authorized distributors?
All SA18CA/54 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/54 meets industry standards.
7.What is the process for return or replacement of SA18CA/54?
All SA18CA/54 units undergo pre-shipment inspection (PSI). If there is an issue with SA18CA/54, 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/54 part is unused and in its original packaging.
Return procedure for SA18CA/54:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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