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onsemi 1SMA70AT3G
- Part No.:
- 1SMA70AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA70AT3G.pdf
- Description:
- TVS DIODE 70VWM 113VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,794
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Product details
Overview
1SMA70AT3G from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed to protect sensitive electronics from high-energy transients. It features a 70 V working peak reverse voltage (VRWM), 77.8–86.0 V breakdown voltage (VBR) at 1 A, 113 V clamping voltage (VC) at 3.5 A peak pulse current, and <1 ns response time - deployed in automotive power rails and industrial DC power supplies.
For engineers reviewing the 1SMA70AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, VC margin relative to IC absolute maximum ratings, surge current capability under 10/1000 µs waveform, and SMA package thermal performance on FR-4 PCBs.
Technical Context
This TVS diode operates in avalanche breakdown mode to clamp overvoltage events. Its unidirectional configuration provides reverse-biased protection only, with forward conduction limited to standard silicon diode behavior (VF ≤ 3.5 V @ 30 A).
It is rated for 400 W non-repetitive peak pulse power (10/1000 µs waveform), exhibits 190 pF junction capacitance at 0 V bias, and maintains stable clamping up to +150°C junction temperature - enabling use in under-hood automotive modules and industrial motor drives where thermal cycling and ESD robustness are critical.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 70 V - must be ≥ continuous DC operating voltage of protected circuit to avoid leakage-induced power loss |
| VBR @ IT=1 A | 77.8–86.0 V - defines minimum and maximum avalanche onset threshold across production lot |
| VC @ IPP=3.5 A | 113 V - maximum voltage seen by downstream IC during 10/1000 µs transient; determines required IC overvoltage margin |
| Peak Pulse Power | 400 W @ 1 ms - supports high-energy surges per IEC 61000-4-5 Level 4 (4 kV, 2 Ω source) |
| Junction Capacitance | 190 pF @ 0 V - impacts signal integrity in data lines; unsuitable for >10 Mbps high-speed interfaces |
| ESD Rating | Class 3 (>16 kV HBM) - exceeds IEC 61000-4-2 Level 4 for system-level ESD immunity |
Pinout & Package
The 1SMA70AT3G is housed in an SMA (DO-214AC) surface-mount package (Case 403D), featuring a low-profile, flat handling surface optimized for automated placement. Cathode is marked by a molded polarity band; mounting position is unrestricted.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink node | Connected to protected line; conducts surge current to ground when reverse voltage exceeds VRWM |
| Anode | Reference / return path | Typically tied to system ground or low-impedance return plane; completes clamping loop during overvoltage event |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Enables robust protection against IEC 61000-4-5 surge events without derating at TL = 25°C |
| <1 ns response time | Clamps transients before sensitive logic or analog circuits experience damaging overvoltage |
| AEC-Q101 qualified (SZ variant) | Validated for automotive under-hood applications including engine control units and body electronics |
| Pb-free SURMETIC® package | RoHS-compliant molding compound with corrosion-resistant leads and 260°C solderability |
Applications
| Automotive Power Distribution | Industrial DC Power Input |
|---|---|
Use Scenario: 12 V battery rail in engine control module exposed to load dump (ISO 7637-2 Pulse 5a, up to 60 V/100 ms). IC Role / Device Role / Timing Role: Primary overvoltage clamp protecting MCU power supply pins and CAN transceiver VCC. Use Value: Clamps peak to 113 V within <1 ns, limiting stress on 36 V-rated input regulators and preserving system uptime. | Use Scenario: 48 V DC input stage of programmable logic controller subjected to switching transients from relay coils and solenoids. IC Role / Device Role / Timing Role: Front-end transient suppressor placed before bulk capacitor and DC-DC converter input. Use Value: Absorbs 400 W surges without degradation, maintaining 70 V VRWM margin above nominal 48 V bus and preventing brownout resets. |
| Medical Equipment AC/DC Adapter | Telecom Power Interface |
Use Scenario: Secondary-side output of isolated medical-grade AC/DC adapter feeding patient-connected monitoring circuitry. IC Role / Device Role / Timing Role: Secondary-side overvoltage limiter ensuring compliance with IEC 60601-1 creepage/clearance and leakage current limits. Use Value: Provides Class 3 ESD immunity and 190 pF capacitance compatible with low-leakage isolation barriers and precision analog front-ends. | Use Scenario: -48 V telecom power feed entering remote radio head enclosure, subject to lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: First-stage protection device mounted at entry point before hot-swap controller and intermediate bus converter. Use Value: Delivers 113 V clamping at 3.5 A with minimal voltage overshoot, safeguarding -48 V tolerant ASICs and FPGAs with 60 V absolute max rating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMA70AT3G | AEC-Q101 qualified; identical electrical specs; SZ prefix denotes automotive-specific traceability and PPAP support | Required for automotive OEM designs needing PPAP documentation and change control | Select SZ1SMA70AT3G when automotive qualification and manufacturing site control are mandatory |
| 1.5SMC70A | Same VRWM/VBR/VC; higher 1500 W peak power; larger SMC (DO-214AB) package with 2.5× footprint area | Better suited for high-surge industrial systems where board space allows larger package | Choose 1.5SMC70A when surge energy exceeds 400 W and thermal mass from larger case improves reliability |
Compared with 1SMA70AT3G, SZ1SMA70AT3G adds automotive qualification without electrical trade-offs, while 1.5SMC70A trades compact SMA size for higher surge capacity - making the original optimal for space-constrained 70 V protection where 400 W suffices.
Availability
1SMA70AT3G is available at Aetrix Electronics and suitable for automotive power distribution, industrial DC power input, medical equipment AC/DC adapters, and telecom power interface applications requiring stable component supply and RoHS-compliant sourcing.
Supply support for 1SMA70AT3G 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, sensor, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMA70AT3G belongs to ON Semiconductor's SMA-series unidirectional TVS family, engineered for cost-effective, high-reliability transient suppression in space-constrained surface-mount applications across harsh environments.
FAQ
What is the maximum clamping voltage of the 1SMA70AT3G under standard test conditions?
The 1SMA70AT3G has a maximum clamping voltage (VC) of 113 V when subjected to a 10/1000 µs surge waveform with a peak pulse current (IPP) of 3.5 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. The 1SMA70AT3G maintains this clamping performance consistently across its qualified operating temperature range.
Is the 1SMA70AT3G suitable for bidirectional signal line protection?
No, the 1SMA70AT3G is a unidirectional TVS diode and provides protection only against reverse-polarity transients. It conducts in forward bias like a standard silicon diode (VF ≤ 3.5 V @ 30 A) but does not suppress positive-going transients on AC or differential lines. For bidirectional protection, ON Semiconductor offers the 1SMA70CAT3G variant - the 1SMA70AT3G is strictly for DC rail clamping where polarity is fixed.
What is the junction-to-ambient thermal resistance (RJA) of the 1SMA70AT3G on a standard FR-4 PCB?
The 1SMA70AT3G has a junction-to-ambient thermal resistance (RJA) of 250°C/W when mounted on an FR-4 board using ON Semiconductor's minimum recommended footprint. This value assumes no thermal vias or copper pour enhancements. Derating begins above 25°C ambient, with maximum DC power dissipation dropping from 0.5 W at 25°C to zero at 125°C - a key constraint for sustained surge duty cycles.
Does the 1SMA70AT3G meet automotive qualification standards?
The base 1SMA70AT3G is not AEC-Q101 qualified; however, its automotive-grade counterpart SZ1SMA70AT3G shares identical electrical specifications and adds AEC-Q101 qualification, PPAP capability, and enhanced traceability. If automotive deployment is required, engineers must specify the SZ-prefix part - the 1SMA70AT3G itself is intended for industrial and commercial applications where full automotive certification is not mandated.
What is the typical junction capacitance of the 1SMA70AT3G and how does it affect high-frequency circuits?
The 1SMA70AT3G exhibits a typical junction capacitance of 190 pF at 0 V bias and 1 MHz. This relatively high capacitance makes it unsuitable for protecting high-speed digital lines (e.g., USB 2.0, HDMI, or Ethernet) where sub-5 pF loading is required. It is appropriate for DC power rails and low-frequency analog signals where bandwidth impact is negligible - always verify signal integrity in-circuit when using the 1SMA70AT3G near sensitive RF or timing paths.
1SMA70AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- 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:
- 190pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA70AT3G FAQ
1.How can I place an order for 1SMA70AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA70AT3G 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 1SMA70AT3G reliable?
The price and inventory of 1SMA70AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA70AT3G is usually 5 days.
3.What payment methods are accepted for 1SMA70AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA70AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA70AT3G?
1SMA70AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA70AT3G 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 1SMA70AT3G?
For technical support, including 1SMA70AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA70AT3G requirements.
6.How does Aetrix verify that 1SMA70AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMA70AT3G 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 1SMA70AT3G meets industry standards.
7.What is the process for return or replacement of 1SMA70AT3G?
All 1SMA70AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA70AT3G, 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 1SMA70AT3G part is unused and in its original packaging.
Return procedure for 1SMA70AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA70AT3G Tags
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