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Microchip Technology 1N4705
- Part No.:
- 1N4705
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N4705.pdf
- Description:
- DIODE ZENER 18V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:9,492
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Product details
Overview
1N4705 from Microsemi is a 500 mW, 18.0 V ±5% axial-leaded Zener diode in DO-7 (DO-204AA) glass package, designed for precision voltage regulation in low-power analog circuits, reference supplies, and overvoltage protection. It delivers stable Zener voltage at 50 mA test current, with ≤0.18 V regulation variation from 10 µA to 100 µA, and operates across –65°C to +175°C.
For engineers reviewing the 1N4705 datasheet, 1N4705 pinout, 1N4705 application, or 1N4705 equivalent, key selection criteria include its 18.0 V nominal Zener voltage, 50 mA Zener test current, 0.18 V max voltage regulation, 0.05 µA max reverse leakage at 13.6 V, and DO-7 hermetic glass package suitability for high-reliability industrial and aerospace environments.
Technical Context
The 1N4705 functions as a two-terminal voltage reference device operating in reverse breakdown, with Zener voltage stabilized by controlled avalanche and Zener mechanisms depending on voltage level. Its regulation performance is specified over 10–100 µA current range and validated at 25°C after thermal stabilization.
It features an internally metallurgically bonded junction in a hermetically sealed DO-7 glass body, enabling radiation hardness per MicroNote 050 and ESD insensitivity per MIL-STD-750 Method 1020. Thermal resistance is 300°C/W junction-to-lead (3/8″ lead length) and 360°C/W junction-to-ambient on FR4.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Nominal Zener Voltage | 18.0 V ±5% - defines regulated output voltage under 50 mA test current; tolerance impacts reference accuracy in feedback loops |
| Zener Test Current | 50 mA - standardized bias point for measuring VZ; ensures consistent specification across production lots |
| Max Voltage Regulation | 0.18 V - difference between VZ at 100 µA and 10 µA; quantifies dynamic impedance effect on regulation stability |
| Max Reverse Leakage | 0.05 µA @ 13.6 V - sets minimum load current requirement to maintain regulation; critical for ultra-low-power standby circuits |
| Steady-State Power | 0.5 W @ TL < 25°C - maximum continuous dissipation with 3/8″ lead length; derates linearly above 25°C per Figure 2 |
| Operating Temperature | –65°C to +175°C - enables use in extended-environment applications including downhole, avionics, and military systems |
| Forward Voltage | ≤1.1 V @ 200 mA - limits forward conduction loss when used bidirectionally or in clamp configurations |
Pinout & Package
Package: DO-7 (DO-204AA), hermetically sealed axial-leaded glass body with tin-lead plated leads per MIL-STD-750 Method 2026. Cathode indicated by color band; device operated with banded end positive relative to unbanded end during Zener regulation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Unbanded lead | Connected to lower-potential node in Zener regulation; carries reverse current during breakdown operation |
| Cathode | Banded lead | Connected to higher-potential node; polarity marking ensures correct orientation in voltage-reference or clamp circuits |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with JEDEC 1N4678–1N4717 standard; ensures interchangeability and qualification traceability across suppliers |
| Hermetic DO-7 package | Enables long-term reliability in humid, corrosive, or high-vacuum environments without encapsulation degradation |
| Guaranteed regulation 10–100 µA | Validated low-current regulation supports energy-efficient biasing in battery-powered sensor nodes and sleep-mode circuits |
| Radiation-hardened construction | Inherently resistant to total ionizing dose (TID) per Microsemi MicroNote 050 - suitable for space-qualified designs |
| Nonsensitive to ESD | Withstands handling per MIL-STD-750 Method 1020 - reduces risk of field failure during manual assembly or rework |
Applications
| Power Supply Reference | Overvoltage Clamp |
|---|---|
Use Scenario: Providing stable 18 V reference for op-amp comparators or ADC voltage references in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Two-terminal shunt voltage regulator establishing precise DC bias point independent of input ripple or load variation. Use Value: Delivers 18.0 V ±5% regulation with ≤0.18 V drift over 10–100 µA, enabling <1% error in 12-bit measurement systems. | Use Scenario: Protecting microcontroller GPIO pins from transient surges in automotive body-control modules. IC Role / Device Role / Timing Role: Bidirectional transient suppressor clamping reverse transients to ~18 V while blocking forward conduction below 1.1 V. Use Value: Limits voltage excursion using 0.05 µA leakage at 13.6 V and withstands 0.5 W surge without degradation in DO-7 hermetic package. |
| Temperature-Stable Bias Generator | Aerospace Voltage Monitor |
Use Scenario: Generating temperature-compensated bias currents in RF front-end LNAs operating from –55°C to +125°C. IC Role / Device Role / Timing Role: Zener reference integrated into current mirror topology where voltage coefficient is mitigated by circuit design. Use Value: Maintains regulation across –65°C to +175°C with known TC curve (Figure 1); enables predictable bias shift modeling. | Use Scenario: Monitoring 28 V aircraft bus voltage with fault detection threshold set at 18 V in flight control interface units. IC Role / Device Role / Timing Role: Precision shunt element in comparator-based undervoltage lockout (UVLO) circuit with radiation-tolerant operation. Use Value: Radiation-hardened DO-7 construction and MIL-PRF-19500 screening options (e.g., JANTXV-1N4705) support DO-160 compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4705A (ON Semiconductor) | Same 18 V nominal, ±5% tolerance, DO-41 package; 0.5 W rating but higher thermal resistance (400°C/W junction-to-ambient) | Less suitable for high-temperature PCB layouts due to reduced power derating margin on FR4 | Select 1N4705A only if DO-41 footprint compatibility is required and ambient temperature remains <70°C |
| BZX55C18 (Vishay) | 18 V ±5%, DO-35 package, 500 mW; tighter 10 µA–100 mA regulation spec but no radiation-hardness documentation | Not qualified for aerospace or high-reliability mil-spec programs requiring MIL-PRF-19500 screening | Prefer BZX55C18 for commercial-grade consumer power supplies where cost and footprint are prioritized over radiation tolerance |
Compared with 1N4705, the 1N4705A offers identical electrical specs but inferior thermal performance in surface-mount-influenced layouts, while BZX55C18 trades radiation hardness and hermetic sealing for broader commercial availability and lower unit cost in non-critical applications.
Availability
1N4705 is available at Aetrix Electronics and suitable for industrial control systems, aerospace power monitoring, and high-reliability reference supply designs requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for 1N4705 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-tolerant, and high-voltage analog components for defense, aerospace, and industrial markets.
The 1N4678–1N4717 series was developed to deliver JEDEC-standard Zener regulation in hermetic DO-7 packages for applications demanding extended temperature operation, ESD immunity, and proven radiation hardness without custom qualification.
FAQ
What is the nominal Zener voltage and tolerance of the 1N4705?
The 1N4705 has a nominal Zener voltage of 18.0 V with a standard tolerance of ±5%, as defined in the Microsemi datasheet. This tolerance applies to all parts in the 1N4678–1N4717 family unless modified by a C (±2%) or D (±1%) suffix. The 1N4705 is not offered with tighter tolerances in the base part number.
What is the maximum power dissipation of the 1N4705 and how does it derate with temperature?
The 1N4705 is rated for 0.5 W steady-state power dissipation at lead temperature (TL) below 25°C with 3/8″ lead length. Power derates linearly above 25°C at 3.33 mW/°C, reaching zero at 175°C. On FR4 board with specified copper area, derating begins at 25°C with 2.78 mW/°C slope per the datasheet's Figure 2.
Does the 1N4705 have radiation-hardness certification, and what documentation supports this?
Yes, the 1N4705 exhibits inherent radiation hardness as described in Microsemi MicroNote 050, which documents its performance under total ionizing dose (TID) exposure. While the base 1N4705 is not screened to MIL-PRF-19500, versions with MQ/MX/MV/MSP prefixes (e.g., JANTXV-1N4705) are fully qualified for high-reliability aerospace use.
What is the reverse leakage current specification for the 1N4705 and at what voltage is it measured?
The 1N4705 has a maximum reverse leakage current of 0.05 µA measured at 13.6 V, which is 75% of its nominal Zener voltage. This low leakage enables reliable regulation in ultra-low-quiescent-current circuits such as battery-backed real-time clocks or sensor wake-up monitors.
Can the 1N4705 be used as a substitute for the 1N4705A or BZX55C18 in existing designs?
The 1N4705 is not a direct drop-in substitute for the 1N4705A (DO-41) or BZX55C18 (DO-35) due to package differences and distinct thermal characteristics. While electrical parameters align closely, mechanical fit, solder thermal profiles, and radiation performance differ - redesign validation is required before substitution in qualified systems.
1N4705 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):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- -
- Current - Reverse Leakage @ Vr:
- 50 nA @ 13.6 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)
1N4705 FAQ
1.How can I place an order for 1N4705 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4705 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 1N4705 reliable?
The price and inventory of 1N4705 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4705 is usually 5 days.
3.What payment methods are accepted for 1N4705?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4705 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4705?
1N4705 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4705 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 1N4705?
For technical support, including 1N4705 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4705 requirements.
6.How does Aetrix verify that 1N4705 is sourced from the original manufacturer or authorized distributors?
All 1N4705 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 1N4705 meets industry standards.
7.What is the process for return or replacement of 1N4705?
All 1N4705 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4705, 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 1N4705 part is unused and in its original packaging.
Return procedure for 1N4705:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4705 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
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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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