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onsemi SA24A
- Part No.:
- SA24A
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SA24A.pdf
- Description:
- TVS DIODE 24VWM 38.9VC DO15
- Quantity:
- Payment:
- Shipping:
Inventory:4,541
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Product details
Overview
SA24A from Fairchild Semiconductor is a unidirectional 500 W transient voltage suppressor (TVS) diode designed for primary overvoltage protection in DC power lines and signal interfaces. It features a 24 V reverse stand-off voltage (VRWM), 26.7–29.5 V breakdown voltage (VBR) at 1.0 mA, 38.9 V clamping voltage (VC) at 12.8 A peak pulse current (IPPM), and operates up to +175 °C junction temperature.
For engineers reviewing the SA24A datasheet, pinout, applications, or equivalent options, this device is selected for robust surge immunity in industrial power supplies, automotive body electronics, and telecom interface protection where fast response (<1.0 ps), low leakage (<1 µA above 10 V), and stable clamping under 10/1000 µs transients are required.
Technical Context
The SA24A employs a glass-passivated PN junction optimized for high-energy transient suppression on 10/1000 µs waveforms. Its unidirectional architecture provides asymmetric conduction-low forward voltage drop during normal operation and rapid avalanche breakdown during overvoltage events.
It delivers 500 W peak pulse power with 38.9 V clamping at 12.8 A, exhibits <1.0 µA reverse leakage at VRWM, and achieves sub-nanosecond response time from 0 V to breakdown. Thermal performance is rated for 1.0 W steady-state dissipation at 75 °C ambient with 0.375" lead length.
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 degradation |
| Reverse Stand-off Voltage (VRWM) | 24 V - maximum continuous DC or RMS voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 26.7–29.5 V at 1.0 mA - defines reliable avalanche initiation threshold for clamping |
| Clamping Voltage (VC) | 38.9 V at 12.8 A IPPM - limits downstream circuit voltage during worst-case surge |
| Peak Pulse Current (IPPM) | 12.8 A - maximum non-repetitive surge current the device can safely divert |
| Reverse Leakage (IR) | <1.0 µA at 24 V - ensures minimal standby power loss and signal integrity in high-impedance circuits |
| Junction Temperature (TJ) | +175 °C - supports operation in under-hood automotive and industrial environments |
Pinout & Package
SA24A is housed in a DO-15 axial-leaded package with cathode indicated by a color band. The device has two terminals: anode and cathode. Lead length is specified as 0.375" for thermal derating compliance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; connected to protected line ground or low-side return | Provides low-impedance path to ground during surge, enabling clamping action when cathode is held at higher potential |
| Cathode | Current exit terminal in forward bias; connected to protected line or signal rail | Serves as reference node for clamping; voltage at cathode rises no higher than VC during transient, protecting downstream components |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enhances long-term reliability and moisture resistance in humid or contaminated environments |
| 500 W peak pulse power (10/1000 µs) | Meets IEC 61000-4-5 surge immunity requirements for industrial and automotive applications |
| Clamping voltage ≤38.9 V at 12.8 A | Ensures protected ICs with 3.3 V or 5 V rails remain within absolute maximum ratings during surge events |
| Response time <1.0 ps (unidirectional) | Activates faster than most microsecond-scale transients, minimizing voltage overshoot before clamping engages |
| Reverse leakage <1.0 µA at 24 V | Prevents excessive quiescent current in battery-powered or energy-sensitive systems |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protecting 24 V DC input rails of programmable logic controllers (PLCs) against load dump and inductive switching transients. IC Role / Device Role: Primary overvoltage clamp placed between input rail and chassis ground. Use Value: Limits transient voltage to ≤38.9 V, preventing damage to upstream rectifiers and downstream DC-DC controllers rated for 40 V max input. |
Use Scenario: Safeguarding LIN bus transceivers and microcontroller I/O pins in door module ECUs exposed to battery disconnect spikes. IC Role / Device Role: Unidirectional TVS on LIN data line and VCC supply rail. Use Value: Sub-nanosecond response and low capacitance preserve signal integrity while clamping 100 V/10 ms transients to safe levels. |
| Telecom Interface Surge Protection | Factory Automation Sensor Interface |
|
Use Scenario: Shielding RS-485 transceiver inputs in outdoor base station equipment subjected to lightning-induced surges. IC Role / Device Role: Line-to-ground TVS on differential pair inputs. Use Value: 500 W rating handles repeated 1 kV/0.5 J surges per IEC 61000-4-5; low IR avoids loading high-impedance termination networks. |
Use Scenario: Protecting analog 4–20 mA current loop receivers from wiring fault transients in robotic arm control cabinets. IC Role / Device Role: Rail-to-rail TVS across loop supply input. Use Value: Stable 24 V VRWM matches standard loop supply; 175 °C TJ rating ensures reliability near motor drives and inverters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A (ON Semiconductor) | DO-214AA package; 24 V VRWM, 38.9 V VC at 12.9 A; same 500 W rating but 10% lower thermal resistance | Surface-mount footprint requires PCB redesign; better thermal performance in compact layouts | Select when automated assembly and space-constrained designs outweigh through-hole manufacturing preference |
| P6KE27A (Littelfuse) | DO-15 package; 27 V VRWM, 43.0 V VC at 11.6 A; 600 W rating but higher clamping voltage | Higher clamping increases stress on downstream 3.3 V logic; suitable only where protected ICs tolerate >43 V | Choose only if system-level margin allows higher VC and VRWM tolerance exceeds 27 V nominal rail |
Compared with SMBJ24A and P6KE27A, the SA24A offers identical DO-15 through-hole compatibility and optimal clamping for 24 V systems, making it preferred for legacy industrial designs requiring proven mechanical robustness and direct replacement without layout change.
Availability
SA24A is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and telecom interface protection requiring stable component supply and long-lifecycle support.
Supply support for SA24A 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 leading designer of high-performance analog and power semiconductors, acquired by ON Semiconductor in 2016; its legacy TVS portfolio remains widely deployed in industrial and automotive systems.
The SAxxA series was developed specifically for cost-effective, high-reliability transient suppression in 24 V–170 V DC power and signal lines, emphasizing ruggedness, repeatable clamping, and wide temperature operation.
FAQ
What is the clamping voltage of the SA24A under a 10/1000 µs surge?
The SA24A clamps to a maximum of 38.9 V when subjected to its rated peak pulse current of 12.8 A on a 10/1000 µs waveform. This value is measured per industry-standard test conditions and ensures protected circuitry remains within safe operating limits during transient events. The SA24A maintains this clamping performance consistently across its qualified temperature range.
Is the SA24A unidirectional or bidirectional?
The SA24A is a unidirectional transient voltage suppressor, indicated by the absence of the "C" suffix in its part number. It conducts only in reverse breakdown mode and must be installed with correct polarity-cathode toward the protected line. Bidirectional variants (e.g., SA24CA) are explicitly marked and exhibit symmetrical clamping in both directions.
What package type does the SA24A use?
The SA24A uses the DO-15 axial-leaded package, a standardized through-hole outline with 0.375" lead length used for thermal derating compliance. The cathode is identified by a color band on the body. This package enables manual or wave-solder assembly and provides mechanical stability in high-vibration environments.
Can the SA24A replace the SA24CA in a circuit?
No-the SA24A is unidirectional and cannot substitute for the bidirectional SA24CA without circuit redesign. The SA24CA clamps symmetrically for AC-coupled or floating signal lines, whereas the SA24A only protects against polarity-specific overvoltages. Replacing SA24CA with SA24A risks failure during negative-going transients.
What is the maximum operating junction temperature for the SA24A?
The SA24A has a maximum operating junction temperature of +175 °C, verified per Absolute Maximum Ratings in the Fairchild datasheet. This rating supports deployment in under-hood automotive modules, industrial motor drives, and other high-ambient-temperature applications where thermal management is critical. Derating curves apply above 75 °C ambient.
SA24A 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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 38.9V
- Current - Peak Pulse (10/1000µs):
- 12.8A
- 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
SA24A FAQ
1.How can I place an order for SA24A through Aetrix?
Please submit a Request for Quotation (RFQ) for SA24A 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 SA24A reliable?
The price and inventory of SA24A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SA24A is usually 5 days.
3.What payment methods are accepted for SA24A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SA24A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SA24A?
SA24A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SA24A 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 SA24A?
For technical support, including SA24A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SA24A requirements.
6.How does Aetrix verify that SA24A is sourced from the original manufacturer or authorized distributors?
All SA24A 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 SA24A meets industry standards.
7.What is the process for return or replacement of SA24A?
All SA24A units undergo pre-shipment inspection (PSI). If there is an issue with SA24A, 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 SA24A part is unused and in its original packaging.
Return procedure for SA24A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SA24A Tags
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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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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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