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onsemi 1SMA20CAT3
- Part No.:
- 1SMA20CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA20CAT3.pdf
- Description:
- TVS DIODE 20VWM 32.4VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,823
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Product details
Overview
1SMA20CAT3 from ON Semiconductor is a bidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed to protect sensitive electronics against ESD and surge events. It features a 20 V working peak reverse voltage (VRWM), 32.4 V clamping voltage at 12.3 A peak pulse current, and <1 ns response time. It is used in automotive power supply rails, industrial control I/O protection, and medical equipment front-end interfaces.
For engineers reviewing the 1SMA20CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surge, junction capacitance (305 pF at 0 V), and AEC-Q101 qualification for automotive-grade reliability.
Technical Context
This device operates as a bidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transient overvoltages across both polarities. Its low zener impedance and fast sub-nanosecond response enable effective suppression of ESD (≥16 kV HBM) and lightning-induced surges.
The 1SMA20CAT3 is rated for 400 W peak pulse power (10/1000 µs waveform), with thermal resistance of 250 °C/W (junction-to-ambient) and 50 °C/W (junction-to-lead). It uses ON Semiconductor's SURMETIC® SMA package (Case 403D), optimized for surface-mount reliability and high-volume automated placement.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Power | 400 W @ 1 ms 10/1000 µs waveform - sustains single high-energy transients without failure |
| Working Peak Reverse Voltage (VRWM) | 20 V - maximum continuous DC or peak AC voltage the device blocks before clamping |
| Clamping Voltage (VC) | 32.4 V @ 12.3 A IPP - limits downstream circuit voltage during surge to safe level |
| Breakdown Voltage (VBR) | 22.2–24.54 V @ 1 mA IT - defines precise avalanche onset range for design margining |
| Junction Capacitance | 305 pF @ 0 V, 1 MHz - impacts high-frequency signal integrity in data-line protection |
| ESD Rating | Class 3 (>16 kV) per HBM - meets IEC 61000-4-2 Level 4 for system-level ESD immunity |
| Response Time | <1 ns - ensures clamping activation before transient energy damages IC inputs |
Pinout & Package
Package: SMA (Surface Mount Assembly), Case 403D - low-profile, void-free molded plastic housing with flat handling surface for precision pick-and-place; RoHS-compliant, Pb-free construction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during positive polarity surge | Bidirectional operation: conducts when voltage exceeds VRWM in either direction |
| Cathode | Current entry terminal during negative polarity surge | Marked by cathode band; functions identically to anode under reverse bias due to symmetrical Zener structure |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC-coupled or floating signal lines without polarity constraints |
| 400 W peak pulse rating | Withstands automotive load-dump and industrial surge test profiles (IEC 61000-4-5) |
| AEC-Q101 qualified | Validated for automotive under-hood and powertrain applications requiring extended temperature and reliability |
| Low profile SMA package | Enables compact PCB layout in space-constrained modules such as ECUs and sensor nodes |
| 16 kV HBM ESD rating | Eliminates need for additional ESD protection on board-level interfaces like CAN or LIN bus lines |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Protecting 12 V battery-supplied microcontroller power inputs from load dump and jump-start transients. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed directly at power entry point before LDO or DC-DC converter. Use Value: Limits voltage to ≤32.4 V during 400 W surge, preventing brownout or latch-up in downstream logic. | Use Scenario: Shielding 24 V digital input channels in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Bidirectional TVS connected between signal line and ground to absorb ±1 kV ring wave transients. Use Value: Clamps within <1 ns to preserve signal timing integrity while meeting IEC 61000-4-4 Level 4 immunity. |
| Medical Equipment Front-End Interface | Telecom Line Card Surge Protection |
Use Scenario: Safeguarding analog sensor inputs (e.g., ECG leads) from electrostatic discharge during clinical handling. IC Role / Device Role / Timing Role: Low-capacitance (305 pF) TVS placed at connector interface to minimize signal distortion. Use Value: Provides Class 3 HBM ESD protection without degrading bandwidth of mV-level biopotential signals. | Use Scenario: Protecting Ethernet PHY or RS-485 transceivers on telecom line cards from lightning-induced surges. IC Role / Device Role / Timing Role: Secondary protection stage after gas discharge tube (GDT), absorbing residual energy below 32.4 V. Use Value: Ensures robustness against repeated 10/1000 µs surges up to 400 W without parameter drift or wear-out. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMA20CAT3G | Identical electrical specs; AEC-Q101 certified with PPAP documentation support | Required for automotive OEM production programs needing full traceability and change control | Select when automotive qualification and process control documentation are mandatory |
| 1SMA20AT3G | Unidirectional version; same VRWM (20 V), but only clamps in one polarity | Suitable for DC-biased lines where reverse conduction is not required | Choose only if circuit topology guarantees unidirectional surge exposure |
Compared with 1SMA20CAT3, SZ1SMA20CAT3G adds automotive-grade process controls and documentation, while 1SMA20AT3G sacrifices bidirectionality for slightly lower capacitance (290 pF) - making the original 1SMA20CAT3 optimal for general-purpose AC or floating-rail protection where polarity-agnostic clamping is essential.
Availability
1SMA20CAT3 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial PLC I/O hardening, and medical sensor interface protection requiring stable component supply and long-term lifecycle assurance.
Supply support for 1SMA20CAT3 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
ON Semiconductor is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and cloud power applications.
The 1SMA20CAT3 belongs to the SMA-series Zener TVS family, engineered specifically for high-reliability transient suppression in harsh environments-emphasizing surge robustness, fast response, and automotive qualification.
FAQ
What is the clamping voltage of the 1SMA20CAT3 under standard surge conditions?
The 1SMA20CAT3 has a maximum clamping voltage (VC) of 32.4 V at 12.3 A peak pulse current (IPP), measured using the industry-standard 10/1000 µs double-exponential surge waveform. This value ensures downstream components see no more than 32.4 V during transient events, protecting logic-level ICs and microcontrollers connected to the same rail. The 1SMA20CAT3 maintains this clamping performance across its operating temperature range of −65 °C to +150 °C.
Is the 1SMA20CAT3 suitable for automotive applications?
Yes, the 1SMA20CAT3 is qualified to AEC-Q101 standards and supports PPAP documentation, making it suitable for automotive applications including body control modules, infotainment power supplies, and sensor interfaces. While the SZ-prefix variant (SZ1SMA20CAT3G) is explicitly designated for automotive with enhanced site control, the 1SMA20CAT3 itself shares identical electrical and thermal specifications and is widely deployed in production automotive systems where full PPAP is not mandated.
How does the 1SMA20CAT3 differ from unidirectional TVS diodes like 1SMA20AT3G?
The 1SMA20CAT3 is bidirectional, meaning it clamps overvoltage transients of either polarity symmetrically - ideal for AC lines, floating grounds, or differential buses. In contrast, 1SMA20AT3G is unidirectional and only clamps in reverse bias, requiring correct polarity orientation. Both share the same VRWM (20 V) and VC (32.4 V), but the 1SMA20CAT3's symmetrical structure results in higher junction capacitance (305 pF vs. 290 pF), a trade-off for polarity-agnostic protection.
What is the thermal resistance and derating behavior of the 1SMA20CAT3?
The 1SMA20CAT3 has a junction-to-ambient thermal resistance (RJA) of 250 °C/W and junction-to-lead resistance (RJL) of 50 °C/W. Its DC power dissipation is rated at 0.5 W at 25 °C ambient, derating linearly by 4.0 mW/°C above that temperature. For pulsed operation, peak power remains 400 W for non-repetitive 1 ms events, but repetitive surges require derating per Figure 3 in the datasheet to avoid thermal runaway.
Can the 1SMA20CAT3 be used in high-frequency signal paths?
The 1SMA20CAT3 exhibits 305 pF junction capacitance at 0 V bias, which may load high-speed signal lines (e.g., >10 MHz analog or digital traces). It is appropriate for power rail and low-to-medium speed data lines (e.g., CAN, RS-232, or sensor outputs), but not recommended for RF or high-speed serial interfaces like USB 2.0 or HDMI. For such applications, lower-capacitance TVS devices or specialized ESD arrays should be considered instead of the 1SMA20CAT3.
1SMA20CAT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 12.3A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- 305pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA20CAT3 FAQ
1.How can I place an order for 1SMA20CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA20CAT3 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 1SMA20CAT3 reliable?
The price and inventory of 1SMA20CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA20CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMA20CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA20CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA20CAT3?
1SMA20CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA20CAT3 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 1SMA20CAT3?
For technical support, including 1SMA20CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA20CAT3 requirements.
6.How does Aetrix verify that 1SMA20CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA20CAT3 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 1SMA20CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMA20CAT3?
All 1SMA20CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA20CAT3, 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 1SMA20CAT3 part is unused and in its original packaging.
Return procedure for 1SMA20CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA20CAT3 Tags
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