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onsemi 1SMA70CAT3
- Part No.:
- 1SMA70CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA70CAT3.pdf
- Description:
- TVS DIODE 70VWM 113VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:2,378
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Product details
Overview
1SMA70CAT3 from ON Semiconductor is a bidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping high-energy transients in DC power lines and signal paths. It features a 70 V working peak reverse voltage (VRWM), 113 V clamping voltage (VC) at 3.5 A peak pulse current (IPP), and sub-1 ns response time. It is used in automotive power supply protection, industrial control I/O interfaces, and medical equipment surge immunity circuits.
For engineers reviewing the 1SMA70CAT3 datasheet, pinout, applications, or equivalent options, this page provides verified electrical parameters, package dimensions, clamping behavior under 10/1000 µs surge, junction capacitance (95 pF @ 0 V), and AEC−Q101-qualified alternatives for automotive-grade designs.
Technical Context
The 1SMA70CAT3 operates as a bidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp both positive and negative transients above ±77.8 V (VBR min). Its low zener impedance and fast <1 ns response enable effective suppression of ESD (Class 3, >16 kV HBM) and lightning-induced surges per IEC 61000-4-5.
Rated for 400 W peak power at 1 ms (10/1000 µs waveform), it delivers 113 V clamping at 3.5 A IPP with 95 pF junction capacitance at 0 V bias - making it suitable for low-speed data lines and DC rails where capacitance impact is constrained.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 70 V - maximum continuous reverse operating voltage before clamping begins; sets minimum system DC rail rating for safe operation. |
| VBR (min/typ/max) | 77.8 / 81.9 / 85.99 V @ 1 mA - precise Zener breakdown threshold defining turn-on consistency across temperature and unit variation. |
| VC @ IPP | 113 V @ 3.5 A - clamping voltage during 10/1000 µs surge; determines maximum voltage seen by protected downstream circuitry. |
| PPK | 400 W @ 1 ms - peak transient energy handling capacity; validates robustness against IEC 61000-4-5 Level 4 surges. |
| CJ @ 0 V | 95 pF - junction capacitance at zero bias; critical for signal integrity on lines up to ~10 MHz; low enough for RS-485 or CAN FD bus protection. |
| IR @ VRWM | 2.5 µA - reverse leakage at rated working voltage; ensures minimal standby power loss and stable DC blocking. |
| Response Time | <1 ns - time from transient onset to clamping activation; essential for protecting fast logic and microcontroller I/O pins. |
Pinout & Package
1SMA70CAT3 is housed in an SMA (DO-214AC) surface-mount package (Case 403D), measuring 4.57 mm × 2.60 mm × 2.10 mm, with flat handling surface and cathode polarity notch (non-polarity-indicating). Mounting position is unrestricted; compatible with top-slide or bottom-board placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during negative transient | Connects to line being protected; forms symmetrical clamping path with cathode for bidirectional surge conduction. |
| Cathode | Current entry terminal during positive transient | Connects to line being protected; enables bidirectional clamping without external polarity constraints. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC-coupled or floating lines (e.g., RS-485, CAN, sensor bridges) without polarity-sensitive layout. |
| AEC−Q101 qualified | Validated for automotive underhood and powertrain applications requiring extended temperature (-65°C to +150°C) and reliability compliance. |
| ESD Class 3 (>16 kV HBM) | Withstands human-body-model electrostatic discharge events common in assembly, handling, and field service environments. |
| Low-profile SURMETIC® package | Enables high-density PCB layouts while maintaining thermal performance via optimized leadframe-to-junction thermal resistance (RJL = 50°C/W). |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
|
Use Scenario: Suppressing load-dump transients (up to 120 V) on 12 V battery-fed ECUs in passenger vehicles. IC Role / Device Role / Timing Role: Standoff TVS diode placed between power input and bulk capacitor, clamping surges before they reach LDOs or MCUs. Use Value: Limits peak voltage to 113 V during 3.5 A surge, preventing latch-up or permanent damage to 16 V-rated regulators and microcontrollers. |
Use Scenario: Protecting 24 V digital input modules in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Bidirectional shunt device mounted at connector entry point, diverting induced transients to ground. Use Value: Withstands repeated 400 W surges while maintaining 2.5 µA leakage at 24 V nominal, ensuring no false triggering or power drain. |
| Medical Equipment ESD Shielding | Telecom Power Supply Input Stage |
|
Use Scenario: Guarding front-panel USB and serial ports on diagnostic imaging devices against clinical ESD events. IC Role / Device Role / Timing Role: Low-capacitance (95 pF) TVS placed inline with shielded signal traces to absorb 15 kV contact discharge. Use Value: Sub-1 ns response prevents ESD energy from coupling into sensitive analog front-ends or timing circuits. |
Use Scenario: Secondary-side overvoltage protection on 48 V telecom rectifier outputs feeding base station backplanes. IC Role / Device Role / Timing Role: Clamping device parallel to output capacitor, limiting transient overshoot during hot-swap or short-circuit recovery. Use Value: 400 W peak power rating supports repeated 10/1000 µs surges without degradation, ensuring long-term BOM stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMA70CAT3G | Identical electrical specs; AEC−Q101 qualified with PPAP capability and automotive-specific traceability (SZ prefix). | Required for Tier-1 automotive production; supports ASIL-B functional safety documentation requirements. | Select SZ1SMA70CAT3G when automotive qualification, change control, or PPAP submission is mandatory. |
| 1SMA70CAT3G | Same VRWM, VBR, VC, and PPK; Pb-free variant with identical marking (TPC) and packaging (SMA, 5k/reel). | No automotive qualification; intended for industrial and commercial applications with RoHS compliance priority. | Choose 1SMA70CAT3G for cost-sensitive industrial designs where AEC−Q101 is not required. |
Compared with 1SMA70CAT3, SZ1SMA70CAT3G adds automotive process controls and documentation rigor without altering electrical behavior, while 1SMA70CAT3G offers identical performance in a RoHS-compliant, non-automotive-qualified version - enabling seamless selection based on end-market compliance needs.
Availability
1SMA70CAT3 is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, medical diagnostic systems, and telecom power supplies requiring stable component supply and long-lifecycle support.
Supply support for 1SMA70CAT3 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 (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud infrastructure markets.
The 1SMA70CAT3 belongs to the SMA-series transient voltage suppressors - engineered for high-reliability surge immunity in harsh environments, with emphasis on automotive-grade robustness, low clamping voltage, and fast response for mission-critical protection.
FAQ
What is the clamping voltage of the 1SMA70CAT3 under a standard 10/1000 µs surge?
The 1SMA70CAT3 clamps to 113 V at a peak pulse current (IPP) of 3.5 A under the standardized 10/1000 µs waveform. This value is measured per Figure 2 in the official datasheet and defines the maximum voltage imposed on protected circuitry during surge events. The 1SMA70CAT3 maintains this clamping performance across its full operating temperature range (−65°C to +150°C), ensuring consistent protection in automotive and industrial deployments.
Is the 1SMA70CAT3 suitable for bidirectional signal line protection like RS-485?
Yes, the 1SMA70CAT3 is explicitly designed as a bidirectional TVS diode, making it appropriate for differential or AC-coupled signal lines such as RS-485, CAN, or isolated sensor interfaces. Its 95 pF junction capacitance at 0 V bias and symmetric clamping behavior ensure minimal signal distortion while providing robust ESD and surge immunity - confirmed by its use in industrial communication modules documented in ON Semiconductor application notes.
Does the 1SMA70CAT3 meet automotive qualification standards?
The base 1SMA70CAT3 is not AEC−Q101 qualified; however, its automotive-grade counterpart SZ1SMA70CAT3G is fully AEC−Q101 qualified and PPAP capable. Both share identical electrical specifications and SMA package dimensions, but only SZ1SMA70CAT3G meets the process, testing, and traceability requirements for automotive production. For non-automotive applications, the 1SMA70CAT3 remains valid and widely deployed in industrial and medical systems.
What is the thermal resistance from junction-to-lead (RJL) for the 1SMA70CAT3?
The 1SMA70CAT3 has a thermal resistance from junction-to-lead (RJL) of 50°C/W, measured under conditions of zero lead length on a 1 in² copper pad (FR-4 board). This parameter directly impacts power derating above 75°C ambient and informs heatsinking decisions in high-power surge scenarios. The RJL value is specified in the Maximum Ratings table on page 2 of the official 1SMA10CAT3G Series datasheet.
How does the 1SMA70CAT3 compare to unidirectional TVS diodes in terms of circuit design?
Unlike unidirectional TVS diodes that protect only one polarity, the 1SMA70CAT3 provides symmetrical clamping for both positive and negative transients without requiring external polarity alignment. This simplifies PCB layout for floating or AC-coupled nodes and eliminates risk of incorrect orientation during assembly. Its bidirectional architecture is intrinsic to the Zener structure - no external components or routing changes are needed to achieve dual-polarity protection, unlike solutions using two unidirectional devices.
1SMA70CAT3 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):
- 70V
- Voltage - Breakdown (Min):
- 77.8V
- Voltage - Clamping (Max) @ Ipp:
- 113V
- Current - Peak Pulse (10/1000µs):
- 3.5A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 95pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA70CAT3 FAQ
1.How can I place an order for 1SMA70CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA70CAT3 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 1SMA70CAT3 reliable?
The price and inventory of 1SMA70CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA70CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMA70CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA70CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA70CAT3?
1SMA70CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA70CAT3 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 1SMA70CAT3?
For technical support, including 1SMA70CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA70CAT3 requirements.
6.How does Aetrix verify that 1SMA70CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA70CAT3 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 1SMA70CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMA70CAT3?
All 1SMA70CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA70CAT3, 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 1SMA70CAT3 part is unused and in its original packaging.
Return procedure for 1SMA70CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA70CAT3 Tags
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