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onsemi SA40CA
- Part No.:
- SA40CA
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA40CA.pdf
- Description:
- TVS DIODE 40VWM 64.5VC DO15
- Quantity:
- Payment:
- Shipping:
Inventory:9,172
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Product details
Overview
SA40CA from Fairchild Semiconductor is a bidirectional 500 W transient voltage suppressor (TVS) diode in DO-15 package, designed for clamping ESD and surge transients on data lines and power rails. It features a 40 V reverse stand-off voltage (VRWM), 44.4–49.1 V breakdown voltage (VBR), 64.5 V clamping voltage (VC) at 7.8 A peak pulse current, and operates up to +175 °C junction temperature.
For engineers reviewing the SA40CA datasheet, pinout, applications, or equivalent options, this device is selected for robust overvoltage protection in industrial I/O, telecom interfaces, and automotive body electronics where fast response (<5 ns), low leakage (<1 µA at 40 V), and high surge capability are required.
Technical Context
The SA40CA is a glass-passivated, bidirectional TVS diode optimized for unidirectional and bidirectional transient suppression on AC-coupled or floating signal paths. Its symmetrical clamping behavior applies equally in both directions, with identical VBR min/max, VC, and IPPM ratings regardless of polarity.
It delivers 500 W peak pulse power on the standardized 10/1000 µs waveform, exhibits low incremental surge resistance for stable clamping under high-current stress, and achieves sub-5 ns response time from 0 V to breakdown-critical for protecting sensitive analog and digital inputs against fast-rising transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power (10/1000 µs) | 500 W - sustains single high-energy surges per IEC 61000-4-5 Level 4 without failure |
| Reverse Stand-off Voltage (VRWM) | 40 V - maximum continuous operating voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 44.4–49.1 V @ 1.0 mA - defines onset of avalanche conduction with tight tolerance band |
| Clamping Voltage (VC) | 64.5 V @ 7.8 A - limits downstream voltage during surge, enabling safe interface with 48 V systems |
| Peak Pulse Current (IPPM) | 7.8 A - maximum transient current it can divert while maintaining specified VC |
| Reverse Leakage (IR) | <1 µA @ 40 V - ensures minimal standby power loss and signal integrity in high-impedance circuits |
| Junction Temperature Range | −65 to +175 °C - supports operation in under-hood automotive and industrial environments |
Pinout & Package
SA40CA is housed in a DO-15 axial-leaded package with no cathode band (bidirectional configuration). Leads are tinned and suitable for wave or reflow soldering with 0.375" lead length derating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (Lead 1) | Transient current entry point (negative polarity) | Accepts surge current when voltage at this terminal drops below cathode by ≥VBR |
| Cathode (Lead 2) | Transient current entry point (positive polarity) | Accepts surge current when voltage at this terminal rises above anode by ≥VBR |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enables stable long-term reliability and moisture resistance in harsh environments |
| Sub-5 ns response time (bidirectional) | Clamps transients before they reach protected ICs, meeting IEC 61000-4-2 and -4-4 timing requirements |
| Low incremental surge resistance | Minimizes voltage overshoot during high di/dt events, improving clamping precision |
| Symmetrical bidirectional clamping | Eliminates need for polarity-aware layout-supports AC-coupled or floating bus protection |
| JEDEC-compliant IFSM rating | 70 A non-repetitive forward surge withstand enables compatibility with fuse-coordinated protection schemes |
Applications
| Industrial PLC Analog Inputs | Automotive Body Control Module (BCM) LIN Bus |
|---|---|
Use Scenario: Protects 4–20 mA current loop inputs from induced surges due to relay switching or nearby motor noise. IC Role / Device Role: Primary overvoltage clamp placed across input terminals before signal conditioning amplifier. Use Value: Limits transient voltage to ≤64.5 V, preventing damage to op-amps and ADCs rated for ±36 V absolute max. |
Use Scenario: Shields LIN transceiver pins from battery dump and load-dump transients in vehicle door modules. IC Role / Device Role: Bidirectional line protector between LIN PHY and external harness connector. Use Value: Withstands 500 W pulses while maintaining <1 µA leakage at 12 V nominal, preserving bus idle state integrity. |
| Telecom DSL Line Interface | AC-DC Power Supply Input Stage |
Use Scenario: Guards ADSL/VDSL line drivers against lightning-induced surges on twisted-pair copper lines. IC Role / Device Role: Secondary surge limiter after gas discharge tube (GDT), handling residual energy. Use Value: Clamps residual transients to 64.5 V within 5 ns, compatible with 75 V-rated line driver ICs. |
Use Scenario: Suppresses differential-mode surges on AC input rectifier outputs before bulk capacitor. IC Role / Device Role: Fast-acting clamp across bridge rectifier output to limit voltage spikes during inrush or short-circuit recovery. Use Value: Handles 7.8 A peak current without thermal runaway, supporting EN 61000-4-5 compliance up to 2 kV. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ40CA (Bourns) | DO-214AA package, 600 W rating, slightly lower VC (64.0 V), same VRWM and VBR range | Surface-mount footprint; requires PCB redesign vs. through-hole SA40CA | Select SMBJ40CA for space-constrained designs needing higher surge margin and SMT assembly |
| P4KE40CA (ON Semiconductor) | DO-41 package, 400 W rating, higher VC (69.4 V), same VRWM but wider VBR tolerance (44.4–51.4 V) | Lower power handling and looser clamping; less effective in high-energy surge environments | Choose P4KE40CA only if cost sensitivity outweighs clamping precision and surge margin requirements |
Compared with SMBJ40CA and P4KE40CA, the SA40CA offers optimal balance of 500 W surge capacity, tight 44.4–49.1 V VBR window, and 64.5 V clamping in a proven DO-15 through-hole package-making it preferred for industrial field I/O and automotive under-hood applications demanding reliability and repeatable performance.
Availability
SA40CA is available at Aetrix Electronics and suitable for industrial PLC analog inputs, automotive BCM LIN bus protection, telecom DSL line interfaces, and AC-DC power supply input stages requiring stable component supply and long-lifecycle support.
Supply support for SA40CA 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in power management, analog, and discrete components before its acquisition by ON Semiconductor in 2016; its legacy TVS portfolio remains widely deployed and supported.
The SA40CA belongs to Fairchild's SAxxCA series of bidirectional TVS diodes, engineered specifically for high-reliability transient suppression in industrial automation, automotive electronics, and telecom infrastructure where robustness and consistency are critical.
FAQ
What is the clamping voltage of SA40CA and how is it measured?
The SA40CA has a maximum clamping voltage (VC) of 64.5 V, measured at 7.8 A peak pulse current using the standard 10/1000 µs double-exponential waveform. This value represents the upper voltage limit imposed on protected circuitry during a surge event and is guaranteed across the full operating temperature range. The SA40CA maintains this clamping performance consistently in both polarities due to its bidirectional design.
Is SA40CA suitable for protecting RS-485 communication lines?
Yes, the SA40CA is well-suited for RS-485 line protection. Its 40 V VRWM aligns with common ±12 V or ±15 V RS-485 transceiver common-mode ranges, and its 64.5 V clamping voltage stays safely below typical 70 V absolute maximum ratings. Its bidirectional symmetry protects both A and B lines without polarity concerns, and its sub-5 ns response prevents data corruption during fast transients.
Does SA40CA have a cathode marking, and how is polarity identified?
No, the SA40CA does not have a cathode band or other polarity marking because it is a bidirectional TVS diode. Unlike unidirectional devices in the SAxxA series, the SA40CA functions identically in both directions-its breakdown and clamping characteristics apply symmetrically across both leads. This eliminates orientation constraints during board assembly.
What is the maximum junction temperature rating for SA40CA?
The SA40CA is rated for a maximum operating junction temperature (TJ) of +175 °C, with a storage temperature range of −65 to +175 °C. This high-temperature capability enables use in under-hood automotive applications, industrial motor drives, and enclosed power supplies where ambient temperatures exceed 100 °C. Derating curves in the datasheet define allowable power dissipation versus ambient temperature.
How does SA40CA compare to SA40A in terms of functionality and application?
The SA40CA is bidirectional, while the SA40A is unidirectional. The SA40CA clamps transients of either polarity across its terminals, making it ideal for AC-coupled or floating interfaces like LIN, CAN, or telecom lines. In contrast, SA40A only clamps positive-going transients relative to its cathode and requires correct orientation. Their VRWM, VBR, and VC values differ accordingly-SA40A has lower VC (62.5 V) but cannot protect negative excursions.
SA40CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-204AC, DO-15, Axial
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 7.8A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-15
SA40CA FAQ
1.How can I place an order for SA40CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SA40CA 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 SA40CA reliable?
The price and inventory of SA40CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA40CA is usually 5 days.
3.What payment methods are accepted for SA40CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA40CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA40CA?
SA40CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA40CA 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 SA40CA?
For technical support, including SA40CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA40CA requirements.
6.How does Aetrix verify that SA40CA is sourced from the original manufacturer or authorized distributors?
All SA40CA 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 SA40CA meets industry standards.
7.What is the process for return or replacement of SA40CA?
All SA40CA units undergo pre-shipment inspection (PSI). If there is an issue with SA40CA, 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 SA40CA part is unused and in its original packaging.
Return procedure for SA40CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SA40CA Tags
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onsemi
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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onsemi
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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