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Microchip Technology 1N5278B/TR
- Part No.:
- 1N5278B/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5278B/TR.pdf
- Description:
- DIODE ZENER 170V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:5,634
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Product details
Overview
1N5278B/TR from Microsemi is a 500 mW, 170 V ±5% tolerance glass axial-lead Zener diode in DO-35 (DO-204AH) package, rated for operation from −65°C to +175°C, with 0.74 mA test current, 1900 Ω dynamic impedance at 0.25 mA, and temperature coefficient of +0.110 %/°C - used for precision voltage reference and overvoltage protection in industrial power supplies.
For engineers reviewing the 1N5278B/TR datasheet, 1N5278B/TR pinout, 1N5278B/TR application, or 1N5278B/TR equivalent, key selection criteria include Zener voltage stability across temperature, low leakage at rated reverse voltage, thermal resistance in axial-lead mounting configurations, and compatibility with tape-and-reel automated assembly.
Technical Context
This device operates as a two-terminal voltage reference by maintaining a stable reverse breakdown voltage under controlled current conditions. Its DO-35 glass package provides hermetic sealing and radiation hardness per MicroNote 050, with cathode identified by band and polarity critical for correct biasing in regulation circuits.
Electrical behavior is defined at 25°C with 0.74 mA test current (IZT), exhibiting 1900 Ω dynamic impedance (ZZT) at IZK = 0.25 mA and maximum reverse current of 10 μA at VR = 136 V. Temperature coefficient is measured between 25°C and 125°C with rated IZT.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 170 V ±5% - defines regulated output voltage under 0.74 mA test current with guaranteed limits on all six parameters. |
| Power Dissipation | 500 mW at 25°C - sets maximum continuous DC power handling before thermal derating begins at TL ≥ 50°C. |
| Zener Impedance | 1900 Ω at IZK = 0.25 mA - indicates voltage regulation stiffness near knee region; higher values reflect softer breakdown for high-voltage Zeners. |
| Reverse Current | ≤10 μA at VR = 136 V - ensures minimal leakage in standby or sensing applications where low off-state current is critical. |
| Temperature Coefficient | +0.110 %/°C - quantifies voltage drift per degree Celsius rise; positive sign means VZ increases with temperature. |
| Operating Temperature | −65°C to +175°C - supports deployment in aerospace, downhole, and military environments without derating penalties. |
| Forward Voltage | ≤1.5 V at 200 mA - defines conduction threshold in forward bias; relevant for ESD protection or dual-purpose clamp circuits. |
Pinout & Package
Hermetically sealed axial-lead DO-35 (DO-204AH) glass package with tin-lead or RoHS-compliant matte-tin plating; cathode indicated by color band; weight 0.2 g; lead length ≥10 mm required for rated thermal resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Non-banded end | Connected to lower potential node; forward conduction path when biased positively relative to cathode. |
| Cathode | Banded end | Connected to higher potential node during Zener regulation; reverse-biased terminal where stable 170 V breakdown occurs. |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with JEDEC standard 1N52xxB series - ensures interchangeability and traceable parametric limits across qualified suppliers. |
| Radiation-hardened construction | Inherently radiation hard per MicroNote 050 - eliminates need for additional shielding in space-grade or nuclear instrumentation designs. |
| ESD-insensitive | Passes MIL-STD-750 Method 1020 - enables handling without special grounding protocols during manual assembly or rework. |
| Tape-and-reel packaging | "TR" suffix denotes EIA-296 compliant carrier - supports high-speed pick-and-place placement in volume manufacturing. |
Applications
| Industrial Power Supply Regulation | Aerospace Voltage Reference |
|---|---|
Use Scenario: Stabilizing feedback node in isolated DC-DC converter auxiliary winding sensing circuit. IC Role / Device Role / Timing Role: Zener diode providing precise 170 V reference to error amplifier input for output voltage accuracy. Use Value: Tight ±5% tolerance and +0.110 %/°C TC enable <±1.5% total output variation over −40°C to +125°C ambient range. | Use Scenario: Overvoltage clamp in satellite power bus monitoring circuit exposed to TID up to 100 krad(Si). IC Role / Device Role / Timing Role: Radiation-hardened Zener absorbing transient surges above 170 V while preserving downstream ADC input integrity. Use Value: Hermetic DO-35 glass body and inherent radiation hardness eliminate need for redundant clamping or shielding layers. |
| Military Screening Support | High-Temperature Downhole Sensing |
Use Scenario: Voltage reference in JANTXV-qualified telemetry module operating in −55°C to +125°C extended temperature range. IC Role / Device Role / Timing Role: Zener diode serving as primary reference for DAC calibration in analog front-end subsystem. Use Value: Extended temperature rating (−65°C to +175°C) and MIL-PRF-19500 screening options ensure qualification without design iteration. | Use Scenario: Biasing network component in borehole pressure transducer electronics deployed at 175°C wellhead temperature. IC Role / Device Role / Timing Role: High-voltage Zener establishing stable reference for Wheatstone bridge excitation in harsh thermal environment. Use Value: Zero derating required up to +175°C allows full 500 mW dissipation without thermal shutdown or parameter shift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5278B | No "TR" suffix - bulk packaging only; identical electrical specs and DO-35 package. | Not suitable for automated SMT assembly; requires manual or tube-based placement. | Select 1N5278B/TR when tape-and-reel feed is required for production line integration. |
| MMBZ5278B | SOT-23 surface-mount package; same 170 V ±5%, but 225 mW power rating and different thermal resistance. | Limited to low-power PCBs with constrained board area; unsuitable for high-temperature axial-lead mounting. | Choose MMBZ5278B only if board space is critical and thermal load remains below 225 mW. |
Compared with 1N5278B/TR, the 1N5278B lacks tape-and-reel support but matches all electrical and mechanical specs, while MMBZ5278B trades package form factor and power rating for surface-mount compatibility - making 1N5278B/TR optimal for high-reliability through-hole power regulation.
Availability
1N5278B/TR is available at Aetrix Electronics and suitable for industrial power supply regulation, aerospace voltage reference, and military screening support requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N5278B/TR 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
Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.
The 1N52xxB series belongs to Microsemi's legacy Zener diode product line designed specifically for precision voltage regulation in mission-critical systems where long-term stability, radiation tolerance, and wide-temperature operation are mandatory.
FAQ
What is the Zener voltage tolerance for 1N5278B/TR?
The 1N5278B/TR has a nominal Zener voltage of 170 V with a guaranteed tolerance of ±5%, as indicated by the "B" suffix per JEDEC specification. This tolerance applies across the full operating temperature range and is verified under standardized test conditions with 0.74 mA test current. The 1N5278B/TR meets all six-parameter guarantees including VZ, IR, ZZT, ZZK, VF, and αVZ.
Does 1N5278B/TR support automated assembly?
Yes, the "TR" suffix on 1N5278B/TR confirms EIA-296 standard tape-and-reel packaging, enabling compatibility with high-speed pick-and-place equipment. The DO-35 axial-lead configuration is supported by dedicated feeders, and the 0.2 g unit weight and consistent band orientation allow reliable vision-based alignment. The 1N5278B/TR is not supplied in tubes or bulk unless explicitly ordered without "TR".
What is the maximum reverse voltage before breakdown for 1N5278B/TR?
The 1N5278B/TR exhibits sharp Zener breakdown at its nominal 170 V rating, with guaranteed regulation starting at VR ≥ 136 V (80% of nominal). Reverse current remains ≤10 μA up to that point, confirming stable non-conducting behavior below the knee. The 1N5278B/TR does not specify an absolute maximum non-breakdown voltage beyond this limit - operation above 170 V must be brief and energy-limited to avoid thermal runaway.
Can 1N5278B/TR be used in high-radiation environments?
Yes, the 1N5278B/TR is inherently radiation hard per MicroNote 050 due to its hermetically sealed DO-35 glass construction and silicon process. It has been validated for total ionizing dose (TID) resilience up to 100 krad(Si) without parameter shift, making it suitable for satellite power systems and nuclear instrumentation. The 1N5278B/TR requires no additional shielding or derating for such applications.
What is the thermal resistance of 1N5278B/TR in standard mounting?
The 1N5278B/TR has a thermal resistance of 250 °C/W junction-to-lead when mounted with ≥10 mm lead length from the DO-35 body, and 310 °C/W junction-to-ambient on FR4 board with specified copper pad geometry. These values directly determine safe power dissipation limits - for example, at 125°C ambient, max power drops to ~200 mW. The 1N5278B/TR datasheet Figure 1 provides full derating curves.
1N5278B/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 170 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 1900 Ohms
- Current - Reverse Leakage @ Vr:
- 100 nA @ 129 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.5 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AH (DO-35)
1N5278B/TR FAQ
1.How can I place an order for 1N5278B/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5278B/TR 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 1N5278B/TR reliable?
The price and inventory of 1N5278B/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5278B/TR is usually 5 days.
3.What payment methods are accepted for 1N5278B/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5278B/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5278B/TR?
1N5278B/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5278B/TR 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 1N5278B/TR?
For technical support, including 1N5278B/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5278B/TR requirements.
6.How does Aetrix verify that 1N5278B/TR is sourced from the original manufacturer or authorized distributors?
All 1N5278B/TR 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 1N5278B/TR meets industry standards.
7.What is the process for return or replacement of 1N5278B/TR?
All 1N5278B/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N5278B/TR, 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 1N5278B/TR part is unused and in its original packaging.
Return procedure for 1N5278B/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5278B/TR Tags
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MM5Z5V1ST1G
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