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onsemi 1SMA70AT3
- Part No.:
- 1SMA70AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA70AT3.pdf
- Description:
- TVS DIODE 70VWM 113VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:3,099
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Product details
Overview
1SMA70AT3 from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping high-energy transients in DC power rails and signal lines. It features a 70 V working peak reverse voltage (VRWM), 77.8–86.0 V breakdown voltage (VBR) at 1 A test current, 113 A maximum peak pulse current (IPP), and sub-1 ns response time. It is used to protect automotive ECUs, industrial power supplies, and communication interface circuits against ESD and lightning-induced surges.
For engineers reviewing the 1SMA70AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin over operating voltage, clamping voltage (VC = 113 V @ IPP), surge current capability, ESD robustness (>16 kV HBM), and SMA package thermal performance on FR-4 PCBs.
Technical Context
The 1SMA70AT3 operates as a unidirectional Zener-based TVS diode, conducting only during reverse overvoltage events above its breakdown threshold while remaining high-impedance under normal bias. Its low zener impedance and fast <1 ns response enable effective suppression of ESD (IEC 61000-4-2) and surge (IEC 61000-4-5) transients without affecting system DC operation.
It is rated for 400 W peak pulse power (10/1000 µs waveform), with thermal derating starting at 75°C junction temperature (RJL = 20 °C/W). The device uses ON Semiconductor's Surmetic™ SMA package (Case 403D-02), optimized for top-slide or bottom-mount placement and compatible with standard SMT reflow profiles (260°C/10 s).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 70 V - Minimum continuous reverse standoff voltage before clamping begins; must exceed circuit's max DC or peak AC operating voltage. |
| VBR (min/typ/max) | 77.8 / 81.9 / 86.0 V @ IT = 1 A - Confirmed Zener breakdown range defining turn-on precision and tolerance stack-up in protection design. |
| VC @ IPP | 113 V @ 113 A - Clamping voltage under full 400 W surge; determines maximum stress imposed on protected downstream components. |
| Peak Pulse Power | 400 W @ 1 ms - Maximum non-repetitive transient energy absorption capability per IEC 61000-4-5 10/1000 µs waveform. |
| Response Time | < 1 ns - Enables suppression of fast-rising ESD events before sensitive ICs experience latch-up or gate oxide damage. |
| ESD Rating | > 16 kV HBM - Meets Class 3 human-body model immunity, qualifying for use in handheld and exposed-interface applications. |
Pinout & Package
The 1SMA70AT3 is housed in an SMA (DO-214AC) surface-mount plastic package (Case 403D-02), featuring a flat handling surface, low profile (max height 2.41 mm), and cathode polarity indicated by a molded band. Mounting position is unrestricted; recommended footprint per ON Semiconductor spec 403B.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference | Connected to ground or lower-potential rail; defines current path during reverse transient clamping. |
| Cathode | Reverse-biased Zener terminal / high-side connection | Connected to protected line (e.g., 24 V supply); conducts when voltage exceeds VRWM, shunting surge to ground. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Enables robust protection against IEC 61000-4-5 Level 4 surges (4 kV line-to-ground) without derating in compact layouts. |
| Sub-1 ns response time | Prevents overshoot propagation into microcontroller I/O or CAN transceiver inputs during ESD discharge events. |
| Low zener impedance | Maintains stable clamping voltage across wide current range (1–113 A), reducing voltage excursion uncertainty in protection margins. |
| Pb-free (1SMA70AT3G) option | Complies with RoHS Directive 2011/65/EU without sacrificing surge performance or thermal reliability. |
| Flat handling surface | Ensures consistent pick-and-place accuracy and solder joint uniformity in high-volume SMT assembly. |
Applications
| Automotive Body Control Module (BCM) | Industrial 24 V DC Power Supply Input |
|---|---|
Use Scenario: Protects LIN bus transceivers and microcontroller GPIOs from load-dump and jump-start induced transients in vehicle body electronics. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between LIN line and ground, activated only during negative-going surges exceeding 70 V. Use Value: Limits voltage seen by MAX13041 or TLE6250 transceivers to ≤113 V, preventing permanent damage during ISO 7637-2 Pulse 5a (120 V/100 ms) events. |
Use Scenario: Shields switching regulator controllers (e.g., LM5085) and optocouplers on primary-side feedback paths from AC line surges. IC Role / Device Role / Timing Role: Standoff protector on 24 V input rail, absorbing 400 W transients before they propagate to downstream DC-DC stages. Use Value: Maintains system uptime by preventing brownout resets or MOSFET avalanche failure during EN 61000-4-5 2 kV common-mode surges. |
| RS-485 Communication Port Protection | Medical Equipment Patient-Connected Interface |
Use Scenario: Safeguards isolated RS-485 transceivers (e.g., ADM2483) in factory automation networks exposed to cable coupling noise. IC Role / Device Role / Timing Role: Bidirectional protection not required; unidirectional 1SMA70AT3 placed on receiver input line referenced to local ground. Use Value: Clamps induced surges up to ±113 V within 1 ns, preserving data integrity and avoiding transceiver latch-up during 10/1000 µs transients. |
Use Scenario: Guards auxiliary power rails feeding patient-monitoring analog front-ends (e.g., ADS1292R) against defibrillator leakage currents. IC Role / Device Role / Timing Role: Secondary-level transient suppressor on isolated 5 V or 3.3 V rails, supplementing primary Y-cap filtering. Use Value: Provides >16 kV HBM ESD immunity per IEC 60601-1-2, ensuring no single-event upset or insulation breakdown in safety-critical signal chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ70A | Same VRWM (70 V) and VC (113 V), but higher IPP (123 A) and 600 W rating in larger SMB package (Case 403A). | Better suited for higher-energy surges where board space allows larger footprint; less optimal for ultra-compact designs. | Select SMBJ70A when surge margin >400 W is required and PCB real estate permits SMB mounting. |
| 1.5SMC70A | Same electrical specs (VRWM = 70 V, VC = 113 V), but in larger SMC package (Case 403B) with 1.5 kW peak power rating and higher thermal mass. | Used in high-reliability industrial power systems where long-term thermal cycling endurance is critical. | Choose 1.5SMC70A for mains-connected equipment requiring extended surge lifetime under repeated 10/1000 µs events. |
Compared with SMBJ70A and 1.5SMC70A, the 1SMA70AT3 offers identical clamping performance in the smallest standardized surface-mount TVS footprint (SMA), enabling dense layout in space-constrained automotive and portable medical PCBs without compromising surge immunity.
Availability
1SMA70AT3 is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, and medical device interfaces requiring stable component supply and long-term lifecycle support.
Supply support for 1SMA70AT3 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 part of onsemi) is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete devices for automotive, industrial, and communications markets.
The 1SMA70AT3 belongs to ON Semiconductor's SMA-series Zener TVS family, engineered specifically for cost-sensitive, high-volume transient suppression in DC-powered systems where fast response, precise clamping, and SMT manufacturability are essential.
FAQ
What is the clamping voltage of the 1SMA70AT3 under maximum surge conditions?
The 1SMA70AT3 has a maximum clamping voltage (VC) of 113 V when subjected to its rated peak pulse current (IPP) of 113 A, measured using the standard 10/1000 µs waveform. This value is guaranteed across the full operating temperature range and defines the upper voltage limit imposed on protected circuitry during a 400 W transient event. The 1SMA70AT3 maintains this clamping performance without degradation under repeated non-repetitive surges.
Is the 1SMA70AT3 suitable for bidirectional transient protection?
No, the 1SMA70AT3 is a unidirectional TVS diode and conducts only during reverse-bias overvoltage events. For bidirectional protection-such as on AC lines or differential buses like RS-485-ON Semiconductor specifies separate parts (e.g., 1SMA70CAT3). Using the 1SMA70AT3 in bidirectional configurations risks forward conduction during positive transients, potentially damaging the device or failing to suppress the surge.
What is the thermal resistance and power derating behavior of the 1SMA70AT3?
The 1SMA70AT3 has a junction-to-lead thermal resistance (RJL) of 20 °C/W and a junction-to-ambient resistance (RJA) of 250 °C/W on a standard FR-4 board. Its DC power dissipation derates linearly above 75°C (for lead-mounted) or 25°C (for ambient-mounted), dropping to zero at 150°C. Peak pulse power remains rated at 400 W regardless of ambient temperature, as it is non-repetitive and thermally limited by junction mass, not steady-state dissipation.
Does the 1SMA70AT3 meet RoHS and lead-free requirements?
Yes, the 1SMA70AT3G variant is the Pb-free version of the 1SMA70AT3, fully compliant with RoHS Directive 2011/65/EU. Both variants share identical electrical specifications and thermal performance; the "G" suffix denotes lead-free terminations and compatible with standard SnAgCu reflow profiles. ON Semiconductor confirms no performance trade-offs between the standard and Pb-free versions of the 1SMA70AT3.
How does the 1SMA70AT3 compare to the 1SMA64AT3 in terms of voltage rating and application fit?
The 1SMA70AT3 has a higher working peak reverse voltage (VRWM = 70 V) than the 1SMA64AT3 (VRWM = 64 V), making it appropriate for circuits operating near 60–65 V DC, such as 48 V telecom systems or heavy-duty vehicle auxiliary rails. Its breakdown voltage range (77.8–86.0 V) also provides greater margin above typical 72 V load-dump peaks. Selecting 1SMA70AT3 instead of 1SMA64AT3 avoids premature clamping in higher-voltage systems while maintaining identical surge handling capability.
1SMA70AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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
1SMA70AT3 FAQ
1.How can I place an order for 1SMA70AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA70AT3 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 1SMA70AT3 reliable?
The price and inventory of 1SMA70AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA70AT3 is usually 5 days.
3.What payment methods are accepted for 1SMA70AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA70AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA70AT3?
1SMA70AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA70AT3 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 1SMA70AT3?
For technical support, including 1SMA70AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA70AT3 requirements.
6.How does Aetrix verify that 1SMA70AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA70AT3 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 1SMA70AT3 meets industry standards.
7.What is the process for return or replacement of 1SMA70AT3?
All 1SMA70AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA70AT3, 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 1SMA70AT3 part is unused and in its original packaging.
Return procedure for 1SMA70AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA70AT3 Tags
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