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Microchip Technology 1N957A
- Part No.:
- 1N957A
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AA, DO-7, Axial
- Datasheet:
-
1N957A.pdf
- Description:
- DIODE ZENER 6.8V 500MW DO7
- Quantity:
- Payment:
- Shipping:
Inventory:2,540
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Product details
Overview
1N957A from Microsemi is a silicon 500 mW axial-lead Zener diode with nominal Zener voltage 6.8 V, ±10% tolerance (A suffix), 18.5 mA test current (IZT), 4.5 Ω dynamic impedance (ZZT) at IZT, and maximum reverse leakage current 150 μA at 5.2 V. It regulates voltage in low-power reference and protection circuits across industrial temperature range.
For engineers reviewing the 1N957A datasheet, 1N957A pinout, 1N957A application, or 1N957A equivalent, this part serves as a JEDEC-registered, DO-35 packaged Zener for precision voltage clamping, overvoltage protection, and analog reference design where ±10% voltage tolerance and 0.5 W steady-state dissipation are acceptable.
Technical Context
The 1N957A operates as a reverse-biased voltage-reference diode with sharp breakdown knee, characterized by 6.8 V nominal regulation at 18.5 mA test current and 4.5 Ω dynamic impedance. Its temperature coefficient is +0.05 %/°C, indicating positive drift with rising junction temperature.
It is rated for 0.5 W power dissipation at 3/8″ lead length below 50 °C, derating linearly to zero at 175 °C, and supports surge currents up to 300 mA for 1/120 sec. The device uses hermetically sealed glass DO-35 (DO-204AH) packaging with tin-lead plating and cathode band marking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 6.8 V - stable regulation point under 18.5 mA DC bias; defines clamping threshold in protection circuits |
| Zener Tolerance | ±10% - specified by 'A' suffix; allows 6.12 V to 7.48 V variation at 25 °C, critical for margin analysis |
| Zener Test Current (IZT) | 18.5 mA - standardized bias condition for VZ measurement; sets operating point for stable regulation |
| Zener Impedance (ZZT) | 4.5 Ω @ IZT - low dynamic resistance ensures minimal voltage shift under load current changes |
| Max Reverse Leakage (IR) | 150 μA @ 5.2 V - defines minimum holding voltage before conduction; impacts standby power in high-impedance nodes |
| Power Dissipation | 500 mW @ TL < 50 °C - thermal limit at 3/8″ lead length; requires PCB copper area or airflow for sustained operation |
| Operating Temperature | −65 °C to +175 °C - wide range enables use in automotive under-hood, aerospace, and industrial environments |
Pinout & Package
Package: DO-35 (DO-204AH), hermetically sealed axial-lead glass body, 0.2 g weight, cathode indicated by colored band. Terminals are tin-lead solderable per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential node; forward voltage ≤1.1 V at 200 mA; not used in Zener regulation mode |
| Cathode | Zener regulation terminal | Banded end; connected to higher-potential node during reverse bias; defines regulated output reference point |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener series | Ensures cross-manufacturer compatibility and standardized test conditions per JESD24 |
| ±10% voltage tolerance (A suffix) | Cost-optimized alternative to tighter-tolerance variants (C/D suffixes); suitable for non-critical references |
| Low dynamic impedance (4.5 Ω) | Minimizes output voltage variation under changing load current-critical for stable biasing in analog stages |
| Radiation-hardened construction | Inherently resistant to total ionizing dose (TID), validated per MicroNote 050; qualified for space-adjacent applications |
| ESD robustness | Non-sensitive per MIL-STD-750 Method 1020; eliminates need for external ESD protection in board-level design |
Applications
| Industrial Power Supply Monitoring | Automotive Sensor Reference |
|---|---|
Use Scenario: Monitoring 12 V rail voltage in PLC I/O modules using resistive divider into comparator input. IC Role / Device Role / Timing Role: Provides stable 6.8 V reference against which divided rail voltage is compared. Use Value: Enables accurate undervoltage detection despite ±10% VZ tolerance and −65 °C to +175 °C operation. |
Use Scenario: Biasing bridge-based pressure sensor in engine control unit with limited PCB space. IC Role / Device Role / Timing Role: Supplies regulated excitation voltage to sensor Wheatstone bridge. Use Value: Maintains sensor linearity over temperature due to +0.05 %/°C TC and low ZZT. |
| Legacy Equipment Voltage Clamping | Test & Measurement Calibration Reference |
Use Scenario: Protecting op-amp inputs from transient overvoltage in field-serviceable instrumentation. IC Role / Device Role / Timing Role: Acts as shunt clamp limiting input voltage to 6.8 V ±10%. Use Value: Absorbs 300 mA surge pulses without failure, leveraging 1/120 sec IZSM rating. |
Use Scenario: Generating traceable 6.8 V reference in benchtop calibrator using matched resistor networks. IC Role / Device Role / Timing Role: Serves as primary Zener reference in multi-decade voltage standard chain. Use Value: Delivers stable regulation with 150 μA IR at 5.2 V, minimizing loading error on high-Z dividers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N957B | Same DO-35 package and 6.8 V nominal voltage, but ±5% tolerance (B suffix) and 5.5 Ω ZZT | Higher precision regulation required; tighter VZ stability needed for feedback loops | Select 1N957B when ±5% tolerance is mandatory and 1.0 Ω higher ZZT is acceptable |
| MMBZ5226BS | SOT-23 surface-mount package, 3.0 V Zener, 100 mW rating, ±5% tolerance; not voltage- or power-equivalent | Board space-constrained designs requiring SMT assembly and lower power dissipation | Choose MMBZ5226BS only if 3.0 V reference and SMT compatibility outweigh need for 6.8 V and 500 mW capability |
Compared with 1N957A, the 1N957B offers tighter voltage tolerance at the cost of slightly higher impedance, while the MMBZ5226BS provides SMT compatibility but differs fundamentally in voltage, power, and package-making it a functional alternative only in redesigned systems.
Availability
1N957A is available at Aetrix Electronics and suitable for industrial power supply monitoring, automotive sensor reference, legacy equipment voltage clamping, and test & measurement calibration requiring stable component supply across extended temperature ranges.
Supply support for 1N957A 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 discrete components for aerospace, defense, and industrial markets.
The 1N957A belongs to Microsemi's legacy JEDEC-registered 1N957–1N992 Zener series, designed for ruggedized voltage regulation in harsh-environment analog circuits where long-term stability and wide temperature operation are essential.
FAQ
What is the Zener voltage tolerance of the 1N957A?
The 1N957A has a nominal Zener voltage of 6.8 V with ±10% tolerance, as designated by the 'A' suffix per Microsemi's documentation. This means the actual measured VZ at 18.5 mA and 25 °C falls between 6.12 V and 7.48 V. The tolerance is wider than the ±5% offered by the 1N957B variant, making the 1N957A appropriate for less stringent reference applications.
What is the maximum power dissipation rating for the 1N957A?
The 1N957A is rated for 500 mW steady-state power dissipation when lead temperature (TL) is maintained below 50 °C at 3/8″ (10 mm) from the body. At ambient temperature (TA) on FR4 with defined copper pads, its derated power drops to 480 mW at TA < 25 °C. Derating follows a linear curve to zero at +175 °C junction temperature.
Does the 1N957A have a RoHS-compliant version?
Yes-the RoHS-compliant version of the 1N957A is designated as 1N957Ae3, where the 'e3' suffix indicates annealed matte-tin plating compliant with EU RoHS Directive 2011/65/EU. The electrical and thermal specifications remain identical to the standard 1N957A; only the terminal finish differs.
How is polarity marked on the 1N957A?
The 1N957A uses a cathode band-typically a single dark-colored ring near one end of the DO-35 glass body-to indicate the cathode terminal. For proper Zener regulation, the banded end must be held at a higher potential than the anode. Forward voltage is guaranteed ≤1.1 V at 200 mA, but forward conduction is not the intended operating mode.
What is the temperature coefficient of the 1N957A?
The 1N957A has a Zener voltage temperature coefficient of +0.05 %/°C, meaning its regulated voltage increases by approximately 0.05% per degree Celsius rise in junction temperature. This positive TC is typical for Zeners below ~5 V; above that, coefficients increase gradually, reaching +0.11 %/°C for higher-voltage variants in the same family.
1N957A 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):
- 6.8 V
- Tolerance:
- ±10%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 4.5 Ohms
- Current - Reverse Leakage @ Vr:
- 150 µA @ 5.2 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
1N957A FAQ
1.How can I place an order for 1N957A through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N957A 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 1N957A reliable?
The price and inventory of 1N957A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N957A is usually 5 days.
3.What payment methods are accepted for 1N957A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N957A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N957A?
1N957A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N957A 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 1N957A?
For technical support, including 1N957A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N957A requirements.
6.How does Aetrix verify that 1N957A is sourced from the original manufacturer or authorized distributors?
All 1N957A 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 1N957A meets industry standards.
7.What is the process for return or replacement of 1N957A?
All 1N957A units undergo pre-shipment inspection (PSI). If there is an issue with 1N957A, 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 1N957A part is unused and in its original packaging.
Return procedure for 1N957A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N957A Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZT52C15-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
onsemi
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SMAJ4744A-TP
Micro Commercial Co
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BZT52C3V6LP-7
Diodes Incorporated
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SMAZ12-13-F
Diodes Incorporated
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