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onsemi 1SMB8.5AT3
- Part No.:
- 1SMB8.5AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB8.5AT3.pdf
- Description:
- TVS DIODE 8.5VWM 14.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:3,423
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Product details
Overview
1SMB8.5AT3 from ON Semiconductor is a unidirectional 600 W peak power Zener transient voltage suppressor (TVS) designed for parallel clamping protection of sensitive electronics. It features a working peak reverse voltage (VRWM) of 8.5 V, breakdown voltage (VBR) of 9.44 V min @ 1.0 mA, clamping voltage (VC) of 14.4 V @ 41.7 A peak pulse current, and response time < 1.0 ns - deployed in automotive power supplies and industrial I/O interfaces.
For engineers reviewing the 1SMB8.5AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ circuit operating voltage, VC margin below IC absolute maximum ratings, surge current capability (IPP = 41.7 A), UL 497B recognition for isolated loop protection, and SMB package thermal performance under repetitive transients.
Technical Context
The 1SMB8.5AT3 operates as a unidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transient overvoltages above its VBR while maintaining low leakage (< 1.0 µA @ VRWM). Its design centers on fast turn-on (< 1.0 ns) and low dynamic impedance to limit overshoot during ESD or lightning-induced surges.
It is rated for 600 W non-repetitive peak pulse power (10/1000 µs waveform), with thermal derating starting at 75°C junction temperature (RJL = 40 °C/W) and 25°C ambient (RJA = 226 °C/W). The device meets UL 497B for isolated loop circuit protection and Class 3 HBM ESD (>16 kV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 8.5 V - maximum continuous reverse operating voltage before clamping begins; must exceed system DC bus or signal swing. |
| VBR @ IT | 9.44 V min @ 1.0 mA - guaranteed avalanche initiation threshold; ensures predictable turn-on during transients. |
| VC @ IPP | 14.4 V @ 41.7 A - clamped voltage seen by protected circuit during full-rated 600 W surge; defines safe margin vs. downstream IC VMAX. |
| PPK | 600 W @ 1 ms - peak transient energy absorption capacity; validated per 10/1000 µs waveform per Figure 2. |
| IR @ VRWM | 1.0 µA max - ultra-low reverse leakage preserves signal integrity and minimizes standby power loss in high-impedance nodes. |
| Response Time | < 1.0 ns - enables suppression of nanosecond-scale ESD events before downstream components experience overstress. |
| UL Recognition | UL 497B QVGQ2 - certified for use in isolated loop telecom and industrial control protection circuits, not just flammability compliance. |
Pinout & Package
1SMB8.5AT3 is housed in an SMB (DO-214AA) surface-mount plastic package (Case 403A), featuring a cathode band marking and modified L-bend leads for enhanced solder joint reliability. The package supports reflow soldering up to 260°C for 10 seconds and is Pb-free (G suffix).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to ground or lowest potential rail; forms return path for clamped surge current. |
| Cathode | High-side transient input | Connected to protected line (e.g., 12 V supply rail); voltage referenced to anode during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W Peak Pulse Power | Handles high-energy transients (e.g., ISO 7637-2 Load Dump pulses) without degradation in automotive 12 V systems. |
| Clamping Voltage 14.4 V @ 41.7 A | Ensures protected ICs with 16 V absolute maximum rating remain within safe operating limits during worst-case surge. |
| UL 497B Recognition | Validated for telecom and industrial isolated loop applications - includes strike voltage, endurance, and dielectric withstand testing. |
| ESD Rating >16 kV (HBM) | Meets IEC 61000-4-2 Level 4 requirements for system-level ESD immunity without additional external protection. |
| SMB Package Thermal Performance | RJL = 40 °C/W enables sustained operation at 75°C ambient with 3.0 W DC dissipation using standard PCB copper pad layout. |
Applications
| Automotive Power Supply Protection | Industrial PLC Digital Input Protection |
|---|---|
Use Scenario: Suppresses load dump transients (up to 60 V, 100 ms) on 12 V battery-fed ECUs and infotainment modules. IC Role / Device Role / Timing Role: Unidirectional parallel clamping TVS placed between battery rail and ground, activated only during overvoltage events. Use Value: Limits voltage to ≤14.4 V during 41.7 A surge, preventing damage to 16 V-rated DC-DC controllers and microcontrollers. | Use Scenario: Protects 24 V digital input channels in programmable logic controllers from field-wiring induced surges and ESD. IC Role / Device Role / Timing Role: Standoff device across input terminal and common, clamping fast-rising transients before reaching optocoupler input stage. Use Value: Maintains <1.0 µA leakage at 24 V nominal, ensuring clean logic thresholds while surviving repeated 1 kV ring wave surges. |
| Medical Equipment Signal Line Protection | Telecom Isolated Loop Interface |
Use Scenario: Shields analog sensor inputs (e.g., temperature, pressure) in portable diagnostic devices from ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance (1690 pF) unidirectional TVS placed directly at connector entry point, minimizing trace inductance. Use Value: Responds in <1.0 ns to human-body-model ESD, limiting voltage overshoot to <14.4 V and preserving ADC accuracy. | Use Scenario: Provides primary surge protection on RS-485 or current-loop (4–20 mA) interfaces compliant with UL 497B isolated loop standards. IC Role / Device Role / Timing Role: UL-recognized transient suppressor installed on line side of isolation barrier, meeting QVGQ2 protector category requirements. Use Value: Passes UL 497B strike voltage and endurance tests - enabling certification of end equipment without redesigning protection topology. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ8.5A | Same VRWM (8.5 V), identical SMB package, but lower PPK = 600 W (same rating), slightly higher VC = 14.5 V @ 41.5 A. | No UL 497B recognition; lacks isolated loop certification required for telecom infrastructure designs. | Select when UL certification is unnecessary and cost optimization is prioritized over regulatory compliance. |
| 1.5SMC8.5A | Higher PPK = 1500 W, larger SMC (DO-214AB) package, VRWM = 8.5 V, VC = 14.4 V @ 104 A - significantly higher surge capacity. | Requires larger PCB footprint and higher thermal mass; unsuitable for space-constrained automotive modules. | Select when system-level surge testing exceeds IEC 61000-4-5 Level 4 and board area permits larger package. |
Compared with SMBJ8.5A, 1SMB8.5AT3 provides UL 497B certification critical for telecom and medical isolation barriers; compared with 1.5SMC8.5A, it offers identical clamping performance in a 30% smaller SMB footprint ideal for compact automotive ECUs.
Availability
1SMB8.5AT3 is available at Aetrix Electronics and suitable for automotive power supply protection, industrial PLC digital input protection, medical equipment signal line protection, and telecom isolated loop interface applications requiring stable component supply and long-term lifecycle support.
Supply support for 1SMB8.5AT3 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMB8.5AT3 belongs to the SMB series of unidirectional Zener TVS diodes, engineered specifically for robust, high-surge, low-clamping protection in harsh environments where reliability and regulatory compliance (UL 497B) are mandatory.
FAQ
What is the clamping voltage of the 1SMB8.5AT3 under full-rated surge conditions?
The 1SMB8.5AT3 has a maximum clamping voltage (VC) of 14.4 V when subjected to its peak pulse current (IPP) of 41.7 A, measured using the standard 10/1000 µs waveform. This value is guaranteed across temperature and ensures protected circuitry remains below typical 16 V absolute maximum ratings. The 1SMB8.5AT3 achieves this via low dynamic impedance and optimized Zener junction design.
Does the 1SMB8.5AT3 meet UL 497B requirements for isolated loop protection?
Yes, the entire 1SMB5.0AT3 series - including the 1SMB8.5AT3 - holds UL 497B recognition under file #E210057 in the QVGQ2 protector category. This certification covers strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge testing - confirming suitability for telecom and industrial isolated loop interfaces. The 1SMB8.5AT3 is explicitly listed in the UL documentation.
What is the maximum reverse leakage current of the 1SMB8.5AT3 at its working voltage?
The 1SMB8.5AT3 specifies a maximum reverse leakage current (IR) of 1.0 µA at its working peak reverse voltage (VRWM) of 8.5 V and TA = 25°C. This ultra-low leakage preserves signal integrity in high-impedance sensor interfaces and minimizes standby power loss in always-on automotive modules. The 1SMB8.5AT3 maintains this specification across its full operating temperature range (−65°C to +150°C).
Is the 1SMB8.5AT3 compatible with lead-free reflow soldering processes?
Yes, the 1SMB8.5AT3 is offered in a Pb-free version (denoted by the "G" suffix) and qualified for standard lead-free reflow profiles. Its SMB package withstands peak temperatures up to 260°C for 10 seconds, complying with J-STD-020 moisture sensitivity level (MSL) 1 requirements. The 1SMB8.5AT3's thermosetting plastic body and corrosion-resistant leads ensure reliable solder joint formation without voiding or delamination.
How does the 1SMB8.5AT3 compare to bidirectional TVS diodes in surge protection applications?
The 1SMB8.5AT3 is unidirectional and optimized for DC-biased lines like 12 V automotive rails or 24 V PLC inputs, where reverse conduction is not required. Bidirectional variants (e.g., 1SMB8.5CAT3) provide symmetrical clamping for AC signals or floating buses but exhibit higher capacitance and reduced surge margin in DC applications. For 1SMB8.5AT3 deployments, the unidirectional structure delivers lower leakage and tighter VBR tolerance - critical for precision voltage monitoring paths.
1SMB8.5AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 8.5V
- Voltage - Breakdown (Min):
- 9.44V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 41.7A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 1690pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB8.5AT3 FAQ
1.How can I place an order for 1SMB8.5AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB8.5AT3 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 1SMB8.5AT3 reliable?
The price and inventory of 1SMB8.5AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB8.5AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB8.5AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB8.5AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB8.5AT3?
1SMB8.5AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB8.5AT3 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 1SMB8.5AT3?
For technical support, including 1SMB8.5AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB8.5AT3 requirements.
6.How does Aetrix verify that 1SMB8.5AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB8.5AT3 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 1SMB8.5AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB8.5AT3?
All 1SMB8.5AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB8.5AT3, 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 1SMB8.5AT3 part is unused and in its original packaging.
Return procedure for 1SMB8.5AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB8.5AT3 Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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ESD5Z5.0T1G
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Diodes Incorporated
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Toshiba Semiconductor and Storage
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D5V0L1B2WS-7
Diodes Incorporated
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