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onsemi SA51CA
- Part No.:
- SA51CA
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA51CA.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO15
- Quantity:
- Payment:
- Shipping:
Inventory:6,140
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Product details
Overview
SA51CA from Fairchild Semiconductor is a bidirectional 500 W transient voltage suppressor (TVS) diode in DO-15 package, designed for clamping ESD and surge transients in power and signal lines. It features a 51 V reverse stand-off voltage (VRWM), 56.7–62.7 V breakdown voltage (VBR), 82.4 V clamping voltage (VC) at 6.1 A peak pulse current, and operates up to +175 °C junction temperature.
For engineers reviewing the SA51CA datasheet, pinout, applications, or equivalent options, this device is selected for robust overvoltage protection in DC power rails, industrial I/O interfaces, and automotive body electronics where fast response (<5 ns), low leakage (<1 µA at 51 V), and high pulse power handling are required.
Technical Context
The SA51CA is a glass-passivated, bipolar junction TVS diode optimized for unidirectional or bidirectional transient suppression on DC or AC lines. Its bidirectional structure enables symmetrical clamping in both polarities without external polarity constraints.
It delivers 500 W peak pulse power on the standardized 10/1000 µs waveform, with low incremental surge resistance and clamping performance verified at 6.1 A IPPM. The device exhibits <1 µA reverse leakage above VRWM and a typical response time of 5.0 ns for bidirectional operation.
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) | 51 V - maximum continuous DC or RMS voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 56.7–62.7 V at 1.0 mA - defines onset of avalanche conduction under transient stress |
| Clamping Voltage (VC) | 82.4 V at 6.1 A IPPM - limits downstream circuit voltage during surge events |
| Peak Pulse Current (IPPM) | 6.1 A - maximum non-repetitive surge current the device can safely divert |
| Reverse Leakage (IR) | <1 µA at 51 V - ensures minimal standby power loss and signal integrity in high-impedance circuits |
| Junction Temperature Range | −65 °C to +175 °C - supports operation in under-hood automotive and industrial environments |
Pinout & Package
SA51CA is housed in a DO-15 axial-leaded package with no cathode band; bidirectional construction means both terminals are functionally identical and interchangeable. Leads are tinned and suitable for wave or hand soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Transient current path terminal | Either lead conducts surge current bidirectionally; no polarity orientation required in PCB layout |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable long-term reliability and moisture resistance in harsh environments |
| 5.0 ns response time (bidirectional) | Clamps transients before sensitive downstream ICs experience overstress |
| Low incremental surge resistance | Minimizes voltage overshoot during high di/dt events, improving clamping accuracy |
| DO-15 mechanical compatibility | Enables drop-in replacement in legacy designs using standard through-hole footprint |
| JEDEC-compliant IFSM rating | Withstands 70 A non-repetitive forward surge, supporting robust inrush and fault-current handling |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protecting 24 V DC sensor inputs and relay driver outputs against load dump and inductive switching transients. IC Role / Device Role / Timing Role: Primary clamping element placed at board-level interface to absorb energy before it reaches microcontroller GPIO or level-shifter ICs. Use Value: Limits transient voltage to ≤82.4 V, preventing latch-up or permanent damage to 3.3 V/5 V logic interfaces downstream. |
Use Scenario: Safeguarding LIN bus transceivers and window motor drivers against battery line disturbances including jump-start spikes and alternator load dump. IC Role / Device Role / Timing Role: Bidirectional TVS placed across VBAT and GND near connector entry point to shunt surge energy before distribution. Use Value: Withstands 500 W pulses and operates up to +175 °C, meeting AEC-Q101 requirements for under-dash placement. |
| DC Power Supply Input Stage | Telecom Remote Terminal Unit (RTU) |
Use Scenario: Front-end protection for 48 V telecom or PoE-powered equipment subjected to lightning-induced surges on input lines. IC Role / Device Role / Timing Role: First-line transient suppressor upstream of DC-DC converters and primary filtering capacitors. Use Value: Clamps 10/1000 µs surges to 82.4 V while maintaining <1 µA leakage, preserving efficiency and standby current budget. |
Use Scenario: Protecting RS-485 communication ports in outdoor utility meters exposed to EFT and surge events per IEC 61000-4-4/4-5. IC Role / Device Role / Timing Role: Bidirectional clamp across differential pair and shield to suppress common-mode transients without distorting signal integrity. Use Value: Symmetrical clamping ensures equal protection on both A/B lines, eliminating need for dual unidirectional devices. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ51CA | DO-214AA package; 600 W rating; slightly lower VC (80.5 V @ 6.2 A); higher IR limit (5 µA) | Surface-mount alternative requiring PCB redesign; better suited for space-constrained designs | Select when SMT assembly and higher surge margin are prioritized over through-hole serviceability |
| P6SMB51CA | Same DO-214AA package as SMBJ51CA; identical electrical specs but manufactured by ON Semiconductor; JEDEC-registered part number | No functional difference; used interchangeably in BOMs where multi-source supply is required | Choose for second-source assurance without changing schematic or layout |
Compared with SA51CA, SMBJ51CA offers higher surge rating and surface-mount compatibility but requires rework of assembly process, while P6SMB51CA provides identical performance with alternate sourcing-neither is pin-compatible due to differing packages, but both serve the same clamping function in revised layouts.
Availability
SA51CA is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, and DC power supply input stages requiring stable component supply and long-lifecycle support.
Supply support for SA51CA 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 SA51CA belongs to Fairchild's SAxx(C)A family of 500 W axial-leaded TVS diodes, engineered for cost-effective, high-reliability transient suppression in industrial and automotive power interfaces.
FAQ
What is the clamping voltage of the SA51CA and how is it measured?
The SA51CA has a maximum clamping voltage (VC) of 82.4 V, measured at 6.1 A peak pulse current (IPPM) under the standardized 10/1000 µs double-exponential surge waveform. This value represents the upper voltage limit imposed on protected circuitry during a transient event and is guaranteed across the full operating temperature range. The SA51CA maintains this clamping performance consistently due to its low incremental surge resistance and stable avalanche characteristics.
Is the SA51CA unidirectional or bidirectional, and how does that affect circuit design?
The SA51CA is a bidirectional TVS diode, indicated by the "CA" suffix, meaning it provides symmetrical clamping in both polarities without requiring orientation during placement. This eliminates the need for polarity-aware routing or additional components in AC-coupled or floating systems. Unlike unidirectional variants (e.g., SA51A), the SA51CA protects against transients regardless of voltage polarity, making it ideal for LIN bus, RS-485, and dual-rail power inputs where reverse voltage events may occur.
What is the maximum operating temperature for the SA51CA, and does it require derating?
The SA51CA has a maximum operating junction temperature (TJ) of +175 °C and a storage temperature range of −65 °C to +175 °C. Its steady-state power dissipation must be derated above +75 °C ambient, dropping linearly to zero at +175 °C, as shown in Figure 5 of the datasheet. For pulsed operation, the 500 W rating applies only at TA = 25 °C; pulse power capability decreases with increasing ambient temperature per the derating curve in Figure 2. Designers must verify thermal margins in high-temperature enclosures.
Can the SA51CA replace a unidirectional TVS like SA51A in an existing design?
The SA51CA can replace SA51A in most cases where bidirectional protection is acceptable or preferred, but not as a direct drop-in if polarity-sensitive circuit behavior exists (e.g., DC bias networks relying on unidirectional blocking). The SA51CA has identical VRWM, VBR, and VC ratings, but lacks a cathode band and conducts in both directions. Review the application's voltage polarity constraints and ensure no unintended conduction paths are introduced before substitution. Layout changes are unnecessary since both use DO-15.
What standards does the SA51CA meet for surge immunity testing?
The SA51CA is rated for 500 W peak pulse power on the 10/1000 µs waveform defined in IEC 61000-4-5 (surge immunity) and meets the energy-handling requirements for Level 4 (4 kV line-to-earth, 2 kV line-to-line) testing. Its 70 A IFSM rating aligns with JEDEC JESD22-A112 for non-repetitive surge, and its <1 µA leakage supports compliance with IEC 61000-4-2 (ESD) system-level protection schemes. While not certified to AEC-Q101 itself, its construction and temperature rating make it suitable for automotive applications when validated in-system.
SA51CA 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):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 6.1A
- 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
SA51CA FAQ
1.How can I place an order for SA51CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SA51CA 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 SA51CA reliable?
The price and inventory of SA51CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA51CA is usually 5 days.
3.What payment methods are accepted for SA51CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA51CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA51CA?
SA51CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA51CA 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 SA51CA?
For technical support, including SA51CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA51CA requirements.
6.How does Aetrix verify that SA51CA is sourced from the original manufacturer or authorized distributors?
All SA51CA 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 SA51CA meets industry standards.
7.What is the process for return or replacement of SA51CA?
All SA51CA units undergo pre-shipment inspection (PSI). If there is an issue with SA51CA, 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 SA51CA part is unused and in its original packaging.
Return procedure for SA51CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SA51CA Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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onsemi
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D5V0H1B2LP-7B
Diodes Incorporated
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D5V0P1B2LP-7B
Diodes Incorporated
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DESD5V0U1BA-7
Diodes Incorporated
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ESD5Z5.0T1G
onsemi
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DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
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PESD2V0Y1BSFYL
Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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D5V0L1B2WS-7
Diodes Incorporated
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