My Inquiry
My Account
Microchip Technology 1N5278B
- Part No.:
- 1N5278B
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N5278B.pdf
- Description:
- DIODE ZENER 170V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:8,782
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
1N5278B from Microsemi is a 500 mW, 170 V, ±5% tolerance glass axial-lead Zener diode in DO-35 (DO-204AH) package, designed for precision voltage regulation in low-power analog reference and overvoltage protection circuits across industrial and aerospace systems.
For engineers reviewing the 1N5278B datasheet, 1N5278B pinout, 1N5278B application, or 1N5278B equivalent, key selection criteria include its 170 V nominal Zener voltage at 0.74 mA test current, 5000 Ω maximum Zener impedance at 0.25 mA, -65°C to +175°C operating temperature range, and cathode-band polarity marking for unambiguous orientation during PCB assembly.
Technical Context
This discrete Zener diode operates in reverse breakdown mode with a sharp knee characteristic verified per JEDEC standards, ensuring stable regulation under varying load and temperature conditions. Its hermetically sealed glass DO-35 package provides inherent radiation hardness and ESD insensitivity per MIL-STD-750 Method 1020.
The device exhibits a +0.110 %/°C temperature coefficient above 100 V, requiring thermal design consideration in high-accuracy references. It delivers minimal capacitance (typical <2 pF at 0 V, per Figure 2), making it suitable for high-frequency bypass and noise-sensitive analog signal conditioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage (VZ) | 170 V at IZT = 0.74 mA - defines precise regulation point for high-voltage reference design |
| Tolerance | ±5% (B suffix) - guarantees voltage accuracy within 8.5 V of nominal for production consistency |
| Power Dissipation | 500 mW at 25°C - sets maximum continuous power handling before thermal derating applies |
| Zener Impedance (ZZK) | 5000 Ω max at IZK = 0.25 mA - indicates dynamic resistance near knee, critical for low-current stability |
| Operating Temperature | -65°C to +175°C - enables deployment in extreme environments including downhole and avionics |
| Thermal Resistance | 250 °C/W junction-to-lead (3/8" lead length) - informs heatsinking requirements for sustained operation |
| Reverse Current (IR) | 10 μA max at VR = 136 V - ensures low leakage below regulation threshold for standby efficiency |
Pinout & Package
Hermetically sealed axial-lead DO-35 (DO-204AH) glass package with tin-lead or RoHS-compliant matte-tin plating; cathode identified by single black band; weight 0.2 g.
| 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 operation; defines regulation polarity and PCB orientation |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with industry-standard 1N52xxB specification for interchangeability and qualification traceability |
| Radiation-hardened construction | Inherently radiation tolerant per MicroNote 050 - validated for space-grade reliability without additional screening |
| Low capacitance | Typical <2 pF (per Figure 2) - minimizes high-frequency coupling in RF-adjacent or fast-switching circuits |
| ESD-insensitive | Passes MIL-STD-750 Method 1020 - eliminates need for external ESD protection in handling and assembly |
| Wide temperature operation | Rated from -65°C to +175°C - supports designs in engine compartments, oil/gas downhole tools, and military platforms |
Applications
| High-Voltage Reference Supply | Aerospace Power Monitoring |
|---|---|
Use Scenario: Generating a stable 170 V reference for ADC input scaling in satellite telemetry power converters. IC Role / Device Role / Timing Role: Zener diode providing primary voltage reference for analog front-end conditioning circuitry. Use Value: ±5% tolerance and +0.110 %/°C tempco enable predictable drift compensation over orbital thermal cycles. | Use Scenario: Overvoltage clamp on 150 V bus monitoring lines in flight control actuator electronics. IC Role / Device Role / Timing Role: Discrete Zener acting as fail-safe shunt protector against transient surges exceeding 170 V. Use Value: 500 mW power rating and 250 °C/W thermal resistance allow reliable energy absorption without thermal runaway. |
| Industrial Sensor Excitation | Downhole Logging Instrumentation |
Use Scenario: Biasing high-impedance piezoresistive pressure sensors requiring stable 170 V excitation in oilfield surface controllers. IC Role / Device Role / Timing Role: Precision Zener regulator establishing fixed sensor supply rail independent of input variation. Use Value: Low 10 μA reverse leakage at 136 V ensures minimal current draw in battery-backed systems. | Use Scenario: Voltage reference in high-temperature (175°C) gamma-ray spectrometry modules deployed in borehole tools. IC Role / Device Role / Timing Role: Primary regulation element maintaining calibration integrity under sustained thermal stress. Use Value: Hermetic DO-35 glass package and -65°C to +175°C rating ensure long-term parametric stability in geothermal environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5278C | ±2% tolerance (C suffix) vs. ±5% (B suffix); same VZ, IZT, package | Higher accuracy required in metrology-grade references where 170 V ±3.4 V is insufficient | Select 1N5278C only if tighter voltage tolerance justifies cost premium and thermal drift remains acceptable |
| MMBZ5278B | Surface-mount SOT-23 package; same 170 V/±5%; lower 350 mW power rating | Used in space-constrained PCBs where axial leads are incompatible with automated placement or board thickness | Choose MMBZ5278B for high-density layouts but verify thermal derating and power margin at elevated ambient temperatures |
Compared with 1N5278B, the 1N5278C offers improved voltage accuracy at identical thermal and mechanical specs, while the MMBZ5278B trades power capability and axial mounting for compactness-neither is pin-compatible, and both require layout revision.
Availability
1N5278B is available at Aetrix Electronics and suitable for high-reliability voltage reference, aerospace power monitoring, and downhole instrumentation requiring stable component supply across extended temperature and radiation environments.
Supply support for 1N5278B 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, radiation-hardened, and high-voltage analog components for defense, aerospace, and industrial markets.
The 1N52xxB series was engineered to deliver JEDEC-standardized Zener regulation with extended temperature range and hermetic packaging for mission-critical analog subsystems where long-term parametric stability is non-negotiable.
FAQ
What is the nominal Zener voltage and test current for the 1N5278B?
The 1N5278B has a nominal Zener voltage of 170 V measured at a test current (IZT) of 0.74 mA. This value is guaranteed per JEDEC specification and forms the basis for regulation accuracy and impedance characterization in the 1N5278B datasheet.
Does the 1N5278B have a specified temperature coefficient, and what is its value?
Yes, the 1N5278B has a temperature coefficient (αVZ) of +0.110 %/°C, measured between 25°C and 125°C at rated IZT. This positive coefficient means its Zener voltage increases linearly with temperature, a key factor in high-accuracy reference design using the 1N5278B.
What is the maximum Zener impedance of the 1N5278B, and at what condition is it specified?
The 1N5278B has a maximum Zener impedance (ZZK) of 5000 Ω, specified at a knee current (IZK) of 0.25 mA. This parameter reflects dynamic resistance near the breakdown knee and directly impacts regulation stability under light-load conditions in circuits using the 1N5278B.
Is the 1N5278B RoHS compliant, and how is compliance indicated?
Yes, RoHS-compliant versions of the 1N5278B are available with the "e3" suffix (e.g., 1N5278Be3), indicating annealed matte-tin plating per MIL-STD-750 Method 2026. Standard 1N5278B units use tin-lead plating unless otherwise specified, so the e3 suffix must appear in the full orderable part number for RoHS assurance.
What is the package type and polarity marking for the 1N5278B?
The 1N5278B uses a hermetically sealed DO-35 (DO-204AH) glass axial-lead package. Polarity is marked by a single black cathode band on the glass body; the banded end is the cathode and must be connected to the higher-potential node during Zener operation in any circuit using the 1N5278B.
1N5278B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Bulk
- 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 FAQ
1.How can I place an order for 1N5278B through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5278B 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 reliable?
The price and inventory of 1N5278B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5278B is usually 5 days.
3.What payment methods are accepted for 1N5278B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5278B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5278B?
1N5278B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5278B 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?
For technical support, including 1N5278B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5278B requirements.
6.How does Aetrix verify that 1N5278B is sourced from the original manufacturer or authorized distributors?
All 1N5278B 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 meets industry standards.
7.What is the process for return or replacement of 1N5278B?
All 1N5278B units undergo pre-shipment inspection (PSI). If there is an issue with 1N5278B, 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 part is unused and in its original packaging.
Return procedure for 1N5278B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5278B Tags
-
MMBZ5240B-7-F
Diodes Incorporated
-
BZT52C5V6T-7
Diodes Incorporated
-
MMSZ5231B-7-F
Diodes Incorporated
-
BZT52C15-7-F
Diodes Incorporated
-
BZX84C3V3LT1G
onsemi
-
MMSZ5245BS-7-F
Diodes Incorporated
-
MMSZ4682T1G
onsemi
-
BZT52C15S-7-F
Diodes Incorporated
-
MM5Z5V1ST1G
onsemi
-
SMAJ4744A-TP
Micro Commercial Co
-
BZT52C3V6LP-7
Diodes Incorporated
-
SMAZ12-13-F
Diodes Incorporated
Tech Hub
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…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
