My Inquiry
My Account
onsemi 1N6278A
- Part No.:
- 1N6278A
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-201AD, Axial
- Datasheet:
-
1N6278A.pdf
- Description:
- TVS DIODE 17.1VWM 27.7VC AXIAL
- Quantity:
- Payment:
- Shipping:
Inventory:3,563
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N6278A from ON Semiconductor is a unidirectional 1500 W Mosorb transient voltage suppressor (TVS) diode designed for parallel clamping protection of sensitive electronics against high-energy surges. It features a 17.1 V working peak reverse voltage (VRWM), 20 V breakdown voltage (VBR) at 1 mA test current, and clamps to 27.7 V at 54 A peak pulse current (IPP), making it suitable for DC power rail protection in industrial power supplies and communication interfaces.
For engineers reviewing the 1N6278A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC's absolute maximum rating, surge current capability under 1 ms 8.3 ms half-sine waveform, UL 497B recognition for isolated loop circuits, and axial leaded Case 41A package compatibility with through-hole PCB layouts.
Technical Context
The 1N6278A operates as a silicon avalanche diode optimized for fast transient suppression. Its <1 ns response time and low dynamic impedance enable effective clamping of ESD events and lightning-induced surges before downstream components experience overvoltage stress. The device exhibits a 0.09 %/°C temperature coefficient of VBR and maintains <5 µA leakage above 10 V at VRWM.
Designed for unidirectional operation, it conducts only during reverse polarity transients while blocking forward current up to its 3.5 V forward voltage limit at 100 A. Thermal resistance is rated at 20 °C/W (junction-to-lead), supporting 5.0 W steady-state dissipation at 75 °C lead temperature with appropriate derating above that point.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Pulse Power | 1500 W @ 1 ms - sustains single high-energy surges without failure per IEC 61000-4-5 Level 4 testing conditions |
| Working Peak Reverse Voltage (VRWM) | 17.1 V - maximum continuous DC or peak AC voltage the device blocks without significant leakage |
| Breakdown Voltage (VBR) | 20 V @ 1 mA - precise avalanche onset threshold enabling predictable clamping behavior |
| Clamping Voltage (VC) | 27.7 V @ 54 A IPP - maximum voltage seen by protected circuit during full-rated surge event |
| Leakage Current (IR) | <5 µA @ VRWM - negligible standby power loss and minimal impact on high-impedance signal paths |
| Response Time | <1 ns - ensures clamping activation before most semiconductor damage thresholds are exceeded |
| ESD Rating | Class 3 (>16 kV HBM) - meets stringent electrostatic discharge immunity requirements for end-equipment certification |
Pinout & Package
1N6278A uses an axial-leaded Surmetic plastic package (Case 41A), with cathode identified by a polarity band. Leads are Pb-free, solderable at 230°C for 10 seconds at 1/16 inch from case body. Mounting position is unrestricted.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during reverse transient | Connected to ground or low-impedance return path to complete clamping loop |
| Cathode | Protected line connection | Connected to the voltage rail or signal line requiring surge protection; polarity band marks this terminal |
Key Features
| Feature | Design Value |
|---|---|
| UL 497B Recognition | Validated for isolated loop circuit protection - enables compliance in telecom and industrial interface designs without additional safety certification effort |
| Low Clamping Ratio (VC/VBR) | 1.385 - tight ratio ensures minimal overvoltage margin between breakdown and clamp, maximizing protection headroom |
| High Surge Current Capacity | 54 A peak pulse current - supports robust protection against 10/1000 µs and 8.3/20 ms surge waveforms per IEC/ANSI standards |
| Pb-Free Lead Finish | RoHS-compliant construction - eliminates hazardous substances while maintaining solderability and thermal performance |
| Temperature-Stable VBR | 0.09 %/°C coefficient - ensures consistent clamping voltage across industrial operating range (−65°C to +175°C) |
Applications
| Industrial Power Supply Protection | RS-485 Interface Protection |
|---|---|
Use Scenario: 24 V DC input rail in programmable logic controller (PLC) power module exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input terminals to clamp positive-going surges to safe levels before they reach upstream regulators and controllers. Use Value: Limits transient voltage to ≤27.7 V, well below 36 V absolute maximum rating of typical 24 V-input DC/DC converters, preventing latch-up or permanent damage. |
Use Scenario: Differential data lines of RS-485 transceiver in factory automation network subject to cable ESD and ground potential differences. IC Role / Device Role / Timing Role: Paired 1N6278A devices (one per line) referenced to local ground, providing common-mode surge suppression on A/B bus lines. Use Value: Clamps fast-rising transients (<1 ns) before they propagate into transceiver inputs, preserving signal integrity and meeting IEC 61000-4-2 Level 4 (15 kV air/8 kV contact) requirements. |
| MEDICAL EQUIPMENT POWER INPUT | NUMERICAL CONTROL SYSTEMS |
Use Scenario: AC/DC adapter output feeding patient-connected monitoring equipment where leakage current and reliability are critical. IC Role / Device Role / Timing Role: Final-stage TVS on low-voltage DC output (e.g., ±12 V rails) to absorb residual transients escaping primary-side protection. Use Value: UL 497B recognition confirms suitability for isolated secondary-side protection, supporting regulatory approval under IEC 60601-1 clause 8.8.3.2. |
Use Scenario: CNC machine control board with stepper motor drivers generating repetitive commutation spikes on shared 24 V supply. IC Role / Device Role / Timing Role: Bulk TVS mounted near power entry connector to absorb repetitive 1500 W surges from motor back-EMF coupling. Use Value: 1500 W peak power rating and 5.0 W steady-state dissipation allow reliable handling of frequent, lower-energy transients without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1.5KE20A | Same electrical specs (VRWM = 17.1 V, VBR = 20 V, VC = 27.7 V), identical Case 41A package, ON Semiconductor dual-part-numbering variant | No functional difference - used interchangeably in BOMs; differs only in marking convention and tape/reel availability | Select 1.5KE20A when sourcing from distributors offering tape-and-reel packaging (RL4 option available) or requiring ON Semiconductor's preferred-device designation |
| SMBJ20A | Surface-mount SMB package (vs. axial), same 20 V VBR but higher 30 V clamping voltage at 43.5 A IPP, lower 600 W peak power rating | Requires PCB redesign for SMT placement; suited for space-constrained boards where axial leads are impractical | Choose SMBJ20A only if board layout prohibits axial components and system-level surge energy remains within 600 W limits - not a drop-in replacement |
Compared with 1N6278A, 1.5KE20A offers identical protection performance in the same through-hole package with enhanced logistics support, while SMBJ20A trades mechanical compatibility and peak power for compactness - requiring careful validation of clamping margin and surge energy budget.
Availability
1N6278A is available at Aetrix Electronics and suitable for industrial power supplies, RS-485 communication systems, medical equipment power inputs, and numerical control systems requiring stable component supply and long-term obsolescence management.
Supply support for 1N6278A 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 solutions for automotive, industrial, cloud, and medical markets.
The 1N6278A belongs to the Mosorb 1500 W TVS diode family, engineered specifically for high-reliability transient suppression in harsh industrial environments where UL 497B compliance, low clamping ratio, and robust surge handling are mandatory.
FAQ
What is the maximum clamping voltage of the 1N6278A under full-rated surge conditions?
The 1N6278A clamps to a maximum of 27.7 V when subjected to its rated 54 A peak pulse current (IPP) under the standard 1 ms exponential waveform. This value is measured per Figure 5 in the official datasheet and represents the worst-case voltage imposed on the protected circuit during a full 1500 W transient event. Designers must ensure this clamping level remains safely below the absolute maximum voltage rating of downstream components.
Is the 1N6278A suitable for bidirectional transient protection?
No, the 1N6278A is strictly unidirectional and conducts only during reverse-biased transients. It provides no protection against positive-going surges on the anode side. For bidirectional applications such as AC lines or differential data buses requiring symmetrical clamping, use the complementary 1.5KE20CA device - which is explicitly tested and characterized in both polarities and carries the "CA" suffix per ON Semiconductor's ordering nomenclature.
Does the 1N6278A meet UL 497B requirements for isolated loop protection?
Yes, the 1N6278A is UL 497B recognized (File #116110, QVGV2 category) for use in isolated loop circuit protection. This certification covers rigorous testing including strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge performance - confirming its suitability for telecom, process control, and other safety-critical isolation barrier applications where standard TVS diodes may lack formal recognition.
What is the thermal resistance and steady-state power rating of the 1N6278A?
The 1N6278A has a junction-to-lead thermal resistance (RJL) of 20 °C/W and a steady-state power dissipation (PD) of 5.0 W at a lead temperature (TL) of 75 °C. Above 75 °C, power must be linearly derated at 20 mW/°C, reaching zero at 325 °C - though practical operation is limited to the −65°C to +175°C junction temperature range specified in the datasheet.
How does the 1N6278A compare to the SMBJ20A in terms of surge handling capability?
The 1N6278A delivers 1500 W peak pulse power at 1 ms, whereas the SMBJ20A is rated for only 600 W - less than half. Additionally, the 1N6278A clamps at 27.7 V vs. 30 V for the SMBJ20A at lower current (43.5 A), giving it superior voltage limiting. These differences make the 1N6278A more suitable for high-energy industrial transients, while the SMBJ20A serves compact, lower-risk applications where board space precludes axial components.
1N6278A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-201AD, Axial
- Series:
- Mosorb™
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 17.1V
- Voltage - Breakdown (Min):
- 19V
- Voltage - Clamping (Max) @ Ipp:
- 27.7V
- Current - Peak Pulse (10/1000µs):
- -
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- Axial
1N6278A FAQ
1.How can I place an order for 1N6278A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N6278A 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 1N6278A reliable?
The price and inventory of 1N6278A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N6278A is usually 5 days.
3.What payment methods are accepted for 1N6278A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N6278A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N6278A?
1N6278A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N6278A 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 1N6278A?
For technical support, including 1N6278A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N6278A requirements.
6.How does Aetrix verify that 1N6278A is sourced from the original manufacturer or authorized distributors?
All 1N6278A 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 1N6278A meets industry standards.
7.What is the process for return or replacement of 1N6278A?
All 1N6278A units undergo pre-shipment inspection (PSI). If there is an issue with 1N6278A, 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 1N6278A part is unused and in its original packaging.
Return procedure for 1N6278A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N6278A Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
