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Microchip Technology 1N971B
- Part No.:
- 1N971B
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AA, DO-7, Axial
- Datasheet:
-
1N971B.pdf
- Description:
- DIODE ZENER 27V 500MW DO7
- Quantity:
- Payment:
- Shipping:
Inventory:2,932
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Product details
Overview
1N971B from Microsemi is a silicon 500 mW axial-lead Zener diode with nominal Zener voltage 27 V, ±5% tolerance (B suffix), 41 mA maximum DC Zener current (IZM), 750 Ω maximum Zener impedance at 4.6 mA test current, and +0.090 %/°C temperature coefficient - used for precision voltage regulation in low-power analog reference and overvoltage protection circuits.
For engineers reviewing the 1N971B datasheet, 1N971B pinout, 1N971B application, or 1N971B equivalent, key selection factors include its DO-35 glass package thermal resistance (310 °C/W on FR4), 20.6 V minimum Zener voltage at rated current, 5 μA reverse leakage at 20.6 V, and compatibility with lead-free reflow per RoHS e3 option.
Technical Context
The 1N971B operates as a two-terminal voltage reference device, conducting in reverse breakdown to maintain stable output voltage across varying load and line conditions. Its Zener knee is characterized by 4.6 mA test current (IZT) and 750 Ω dynamic impedance (ZZT), with minimal capacitance (<2 pF typical) and radiation-hardened construction per MicroNote 050.
It features a cathode band polarity marking, tin-lead or matte-tin plating per MIL-STD-750 Method 2026, and JEDEC-registered compliance. Thermal derating begins above 50 °C lead temperature, delivering 480 mW at TL < 50 °C and 400 mW at TL = 75 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 27 V - defines regulated output voltage under 4.6 mA test current and 25 °C ambient |
| Zener Tolerance | ±5% (B suffix) - ensures voltage remains within 25.65–28.35 V at IZT and 25 °C |
| Zener Test Current | 4.6 mA - standardized bias point for measuring VZ and ZZT per JEDEC |
| Max Zener Impedance | 750 Ω at 4.6 mA - limits regulation error under dynamic load changes |
| Max DC Zener Current | 13 mA - maximum steady-state reverse current before exceeding 400 mW dissipation at 75 °C lead temp |
| Temp Coefficient | +0.090 %/°C - quantifies VZ drift with temperature; +24.3 mV/°C at 27 V |
| Reverse Leakage | 5 μA at 20.6 V - sets minimum operating current threshold for reliable regulation onset |
Pinout & Package
Package: DO-35 (DO-204AH), hermetically sealed axial-lead glass body, 0.2 g weight, cathode indicated by colored band. Terminals are solderable tin-lead or RoHS-compliant matte tin per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground or lower potential node; reverse-biased operation requires cathode at higher potential |
| Cathode | Zener regulation terminal / voltage reference output | Banded end; supplies regulated 27 V when reverse-biased above breakdown threshold |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener series | Ensures cross-manufacturer interchangeability and standardized test methodology per 1N957B–1N992B family |
| Hermetic DO-35 glass package | Enables operation from –65 °C to +175 °C and intrinsic radiation hardness per MicroNote 050 |
| Low reverse leakage | 5 μA at 20.6 V enables stable regulation in ultra-low-current bias networks and high-impedance references |
| Minimal junction capacitance | <2 pF typical (per Figure 3) supports use in RF decoupling and high-frequency noise suppression |
| Nonsensitive to ESD | Complies with MIL-STD-750 Method 1020 - no special handling required during assembly |
Applications
| Industrial Sensor Signal Conditioning | Legacy Power Supply Overvoltage Clamp |
|---|---|
|
Use Scenario: Stabilizing reference voltage for 4–20 mA transmitter analog front-end ICs in harsh-temperature factory environments. IC Role / Device Role / Timing Role: Zener diode provides fixed 27 V rail for op-amp biasing and ADC reference scaling. Use Value: ±5% tolerance and +0.090 %/°C TC ensure reference stability within ±0.5 V over –40 to +85 °C operating range. |
Use Scenario: Clamping transient surges on unregulated 30 V DC input rails in industrial PLC power modules. IC Role / Device Role / Timing Role: Shunt regulator absorbs excess energy above 27 V to protect downstream linear regulators and microcontrollers. Use Value: 13 mA IZM and 700 mA surge rating (IZSM) handle repetitive 100 ms transients without degradation. |
| Medical Instrument Analog Reference | Aerospace Backup Voltage Monitor |
|
Use Scenario: Generating precision bias for photodiode amplifier stages in portable diagnostic devices requiring low-noise, low-drift references. IC Role / Device Role / Timing Role: Provides low-capacitance (≤2 pF), low-leakage (5 μA) 27 V reference to minimize signal distortion. Use Value: Glass DO-35 package ensures long-term parameter stability and immunity to humidity-induced drift. |
Use Scenario: Monitoring primary bus voltage in satellite subsystems where failure detection must operate across extended temperature extremes. IC Role / Device Role / Timing Role: Functions as temperature-stable comparator threshold element in discrete overvoltage detection circuitry. Use Value: Radiation-hardened construction and –65 to +175 °C operating range support mission-critical reliability in LEO orbits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4748A (ON Semiconductor) | 27 V, ±5%, 1 W rating, DO-41 package, 20 Ω Zz, 1000 mA IZM | Higher power handling but larger footprint and lower thermal resistance (100 °C/W vs. 310 °C/W) | Select when >500 mW continuous dissipation or PCB layout allows DO-41 pitch |
| BZX55C27 (Vishay) | 27 V, ±5%, 500 mW, DO-35, 70 Ω Zz, 13 mA IZM, –65 to +175 °C | Lower Zener impedance (70 Ω vs. 750 Ω) but identical package, thermal, and environmental specs | Prefer for improved regulation accuracy in low-noise analog references where tighter dynamic impedance matters |
Compared with 1N971B, the 1N4748A offers higher power margin but requires board redesign, while BZX55C27 delivers superior dynamic regulation with drop-in DO-35 compatibility - making it ideal for noise-sensitive upgrades without layout change.
Availability
1N971B is available at Aetrix Electronics and suitable for industrial sensor signal conditioning, legacy power supply overvoltage clamping, and medical instrument analog reference designs requiring stable component supply and long-lifecycle support.
Supply support for 1N971B 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, RF, and radiation-hardened components for aerospace, defense, and industrial markets.
The 1N957B–1N992B Zener series was engineered for mission-critical voltage reference and protection in extreme environments - emphasizing thermal stability, hermetic sealing, and JEDEC-standardized parametric consistency.
FAQ
What is the Zener voltage tolerance of the 1N971B?
The 1N971B has a nominal Zener voltage of 27 V with ±5% tolerance, designated by the "B" suffix per JEDEC standard. This means its actual breakdown voltage falls between 25.65 V and 28.35 V when measured at 4.6 mA test current and 25 °C ambient temperature, as confirmed in the Electrical Characteristics table on page 2 of the Microsemi datasheet.
Can the 1N971B be used in surface-mount designs?
No - the 1N971B is packaged exclusively in the axial-lead DO-35 (DO-204AH) glass case and is not a surface-mount device. For SMT equivalents, Microsemi offers the MLL971B in DO-213AA (MELF) package; however, the 1N971B itself requires through-hole mounting with 3/8″ lead length for thermal rating compliance.
What is the maximum power dissipation of the 1N971B at room temperature?
The 1N971B is rated for 500 mW steady-state power dissipation at lead temperature (TL) below 50 °C with 3/8″ (10 mm) lead length from the body. When mounted on an FR4 PCB with specified copper pads, its derated power is 480 mW at TA < 25 °C - both values are explicitly stated in the Maximum Ratings section of the Microsemi datasheet.
Does the 1N971B meet RoHS requirements?
Yes - the RoHS-compliant version is designated as 1N971B-e3, where the "e3" suffix indicates annealed matte-tin plating and full compliance with EU RoHS Directive 2011/65/EU. Standard 1N971B uses tin-lead plating; only the e3 variant satisfies lead-free assembly requirements.
How does temperature affect the Zener voltage of the 1N971B?
The 1N971B exhibits a positive temperature coefficient of +0.090 %/°C, meaning its Zener voltage increases by approximately 24.3 mV per degree Celsius rise at 27 V. This value is measured and published in the Electrical Characteristics table and aligns with the curve shown in Figure 2 (Zener Voltage Temperature Coefficient vs. Nominal Zener Voltage).
1N971B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AA, DO-7, Axial
- Packaging:
- Bulk
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 27 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 41 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 20.6 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-7
1N971B FAQ
1.How can I place an order for 1N971B through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N971B 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 1N971B reliable?
The price and inventory of 1N971B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N971B is usually 5 days.
3.What payment methods are accepted for 1N971B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N971B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N971B?
1N971B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N971B 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 1N971B?
For technical support, including 1N971B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N971B requirements.
6.How does Aetrix verify that 1N971B is sourced from the original manufacturer or authorized distributors?
All 1N971B 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 1N971B meets industry standards.
7.What is the process for return or replacement of 1N971B?
All 1N971B units undergo pre-shipment inspection (PSI). If there is an issue with 1N971B, 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 1N971B part is unused and in its original packaging.
Return procedure for 1N971B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N971B 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
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