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Microchip Technology 1N4685
- Part No.:
- 1N4685
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N4685.pdf
- Description:
- DIODE ZENER 3.6V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:5,241
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Product details
Overview
1N4685 from Microsemi is a 3.6 V, 500 mW axial-leaded Zener diode in DO-7 (DO-204AA) glass package, rated for ±5% voltage tolerance, 50 mA Zener test current, and 0.95 V maximum voltage regulation (10–100 µA). It operates from –65°C to +175°C and serves as a precision low-voltage reference in power supply feedback paths and voltage clamp circuits.
For engineers reviewing the 1N4685 datasheet, 1N4685 pinout, 1N4685 application, or 1N4685 equivalent, key selection criteria include its 3.6 V nominal Zener voltage, 50 mA test current, 0.95 V regulation delta, 2.0 mA maximum reverse leakage at 2.0 V, and 150 mA maximum DC Zener current - all critical for low-power analog regulation and overvoltage protection design.
Technical Context
The 1N4685 implements a silicon planar Zener junction with internal metallurgical bonding per MIL-PRF-19500 requirements, enabling stable regulation across wide temperature extremes. Its DO-7 hermetically sealed glass package ensures long-term reliability in harsh environments.
It delivers guaranteed voltage regulation between 10 µA and 100 µA, with specified capacitance (see Figure 3), radiation hardness per MicroNote 050, and ESD insensitivity per MIL-STD-750 Method 1020 - making it suitable for aerospace, industrial control, and high-reliability instrumentation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 3.6 V ±5% - sets precise clamping threshold for low-voltage reference and biasing |
| Zener Test Current | 50 mA - defines operating point where VZ is specified and regulation is optimized |
| Voltage Regulation ΔVZ | 0.95 V max (10–100 µA) - quantifies dynamic impedance-induced variation under light-load conditions |
| Max Reverse Leakage | 2.0 µA at 2.0 V - ensures minimal standby current in voltage-sensing circuits |
| Max DC Zener Current | 150 mA - determines absolute current limit before thermal runaway at TL ≤ 25°C |
| Power Dissipation | 500 mW at TL < 25°C (3/8″ lead length) - defines thermal envelope for axial-lead PCB mounting |
| Operating Temperature | –65°C to +175°C - supports deployment in extended-temperature industrial and aerospace systems |
Pinout & Package
DO-7 (DO-204AA) hermetically sealed axial-leaded glass package with tin-lead plated leads; cathode indicated by color band - banded end is positive during Zener operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference | Connected to circuit ground or lower-potential node when used in reverse-biased regulation |
| Cathode | Zener regulation terminal | Banded end; connected to higher-potential node to enable reverse breakdown at 3.6 V |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with industry-standard 1N-series mechanical and electrical definitions |
| Internally solder-bonded junction | Enhances thermal stability and mechanical robustness per MIL-PRF-19500 |
| Guaranteed regulation 10–100 µA | Enables reliable low-current biasing without external current sources |
| Radiation-hardened construction | Validated per Microsemi MicroNote 050 for total ionizing dose resilience |
| Nonsensitive to ESD | Withstands handling per MIL-STD-750 Method 1020 without parameter shift |
Applications
| Industrial Power Monitoring | Aerospace Sensor Biasing |
|---|---|
Use Scenario: Monitoring 5 V rail integrity in PLC I/O modules using resistor-divider + Zener clamp. IC Role / Device Role / Timing Role: Voltage reference and overvoltage limiter protecting ADC input stages. Use Value: 3.6 V clamping prevents ADC saturation while 0.95 V regulation delta ensures consistent trip point across temperature. | Use Scenario: Providing stable bias voltage to piezoresistive pressure transducer bridges in flight control units. IC Role / Device Role / Timing Role: Low-drift reference source for ratiometric sensor excitation. Use Value: –65°C to +175°C operation and radiation hardness ensure functionality in avionics bays without derating. |
| Medical Instrumentation Clamp | Automotive Body Control Module |
Use Scenario: Protecting op-amp inputs in portable ECG front-ends from ESD-induced transients. IC Role / Device Role / Timing Role: Fast-response shunt clamp absorbing sub-100 ns spikes. Use Value: 2.0 µA leakage at 2.0 V minimizes loading on high-impedance biopotential nodes. | Use Scenario: Regulating 3.3 V auxiliary rail for CAN transceiver logic in under-hood ECUs. IC Role / Device Role / Timing Role: Low-power voltage reference in discrete LDO pre-regulator stage. Use Value: 500 mW rating and 150 mA IZM support transient load surges without thermal shutdown. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4728A | 3.3 V nominal, 1 W rating, DO-41 package, ±5% tolerance | Higher power and different thermal profile; not drop-in due to larger DO-41 footprint | Select when >500 mW dissipation or board-level heat sinking is required |
| BZX55C3V6 | 3.6 V nominal, 500 mW, DO-35 package, ±5% tolerance, higher typical leakage (5 µA @ 1 V) | Same voltage but DO-35 body - smaller size, lower thermal mass, less rugged than DO-7 | Choose for space-constrained consumer designs where MIL-grade ruggedness is not mandatory |
Compared with 1N4685, the 1N4728A offers higher power but requires PCB layout change, while BZX55C3V6 matches voltage and power but trades DO-7 ruggedness for compactness - making 1N4685 optimal for high-reliability, extended-temperature, and radiation-exposed use cases.
Availability
1N4685 is available at Aetrix Electronics and suitable for industrial power monitoring, aerospace sensor biasing, medical instrumentation clamp, and automotive body control module applications requiring stable component supply across extended temperature ranges and long product lifecycles.
Supply support for 1N4685 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-performance analog and mixed-signal components.
The 1N4685 belongs to Microsemi's legacy 1N4678–1N4717 DO-7 Zener series, engineered for military, aerospace, and industrial applications demanding extreme temperature operation, hermetic sealing, and proven long-term stability.
FAQ
What is the nominal Zener voltage and tolerance of the 1N4685?
The 1N4685 has a nominal Zener voltage of 3.6 V with a standard tolerance of ±5%, indicated by the absence of a suffix letter. Tighter tolerances (±2% or ±1%) are available with C or D suffixes, respectively - but the base 1N4685 part is ±5%.
What is the maximum Zener current rating for the 1N4685?
The 1N4685 is rated for a maximum DC Zener current (IZM) of 150 mA at lead temperature ≤25°C with 3/8″ lead length. This corresponds to its 500 mW power dissipation limit and must be derated above 25°C per the published power derating curve.
Does the 1N4685 have radiation hardness certification?
Yes, the 1N4685 is inherently radiation hard as documented in Microsemi MicroNote 050. Its DO-7 construction and silicon process meet requirements for total ionizing dose (TID) resilience, supporting use in space-qualified and nuclear instrumentation systems.
How is polarity marked on the 1N4685 package?
The 1N4685 uses a cathode band marking on its DO-7 glass body: the banded end is the cathode and must be held at a higher potential than the anode to achieve Zener breakdown regulation at 3.6 V. Forward voltage is ≤1.1 V at 200 mA.
Is the 1N4685 suitable for high-temperature operation?
Yes, the 1N4685 is fully rated for continuous operation from –65°C to +175°C. Its thermal resistance is 300°C/W junction-to-lead (3/8″ lead length), and it maintains specified electrical parameters across this full range - confirmed per JEDEC testing methodology.
1N4685 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):
- 3.6 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- 7.5 µA @ 2 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.1 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AH (DO-35)
1N4685 FAQ
1.How can I place an order for 1N4685 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4685 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 1N4685 reliable?
The price and inventory of 1N4685 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4685 is usually 5 days.
3.What payment methods are accepted for 1N4685?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4685 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4685?
1N4685 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4685 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 1N4685?
For technical support, including 1N4685 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4685 requirements.
6.How does Aetrix verify that 1N4685 is sourced from the original manufacturer or authorized distributors?
All 1N4685 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 1N4685 meets industry standards.
7.What is the process for return or replacement of 1N4685?
All 1N4685 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4685, 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 1N4685 part is unused and in its original packaging.
Return procedure for 1N4685:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4685 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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Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
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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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