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Microchip Technology 1N5355/TR8
- Part No.:
- 1N5355/TR8
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- T-18, Axial
- Datasheet:
-
1N5355/TR8.pdf
- Description:
- DIODE ZENER 18V 5W T18
- Quantity:
- Payment:
- Shipping:
Inventory:3,056
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Product details
Overview
1N5355/TR8 from Microsemi is a 5 W axial-leaded silicon Zener diode with a nominal regulation voltage of 18 V, ±5% tolerance (B suffix), 2.5 Ω maximum dynamic impedance at 65 mA test current, and 75 mA maximum Zener current when adequately heat-sunk. It operates across –65 °C to +150 °C and is used for precision voltage reference and overvoltage protection in industrial power supplies.
For engineers reviewing the 1N5355/TR8 datasheet, 1N5355/TR8 pinout, 1N5355/TR8 application, or 1N5355/TR8 equivalent, this page delivers verified electrical parameters, thermal derating behavior, JEDEC T-18 package details, and validated alternative parts for stable voltage regulation design.
Technical Context
This device functions as a two-terminal shunt regulator, maintaining stable output voltage by conducting reverse current above its specified Zener breakdown threshold. Its low dynamic impedance (2.5 Ω) ensures minimal voltage deviation under varying load currents, and its 25 °C/W junction-to-lead thermal resistance enables reliable 5 W operation with 3/8″ lead length heat sinking.
The 1N5355/TR8 exhibits 0.40 V maximum voltage regulation (ΔVZ) between 10% and 50% of IZM, confirming tight regulation stability across its operating range. Its cathode band marking and tin-lead or RoHS-compliant matte-tin plating ensure unambiguous polarity identification and solderability per MIL-STD-750 Method 2026.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% - precise regulation point for 15–21 V system clamping or reference generation |
| Test Current (IZT) | 65 mA - standardized bias point for measuring VZ and dynamic impedance |
| Dynamic Impedance (ZZ) | 2.5 Ω max - low AC resistance ensures <0.165 V variation per 66 mA load change |
| Max Zener Current (IZM) | 75 mA - maximum continuous DC current at 25 °C lead temperature with proper heat sinking |
| Power Dissipation | 5.0 W at TL = 25 °C - rated steady-state power with 3/8″ (10 mm) lead length from body |
| Thermal Resistance | 25 °C/W junction-to-lead - enables thermal design with predictable temperature rise per watt |
| Operating Temperature | –65 °C to +150 °C - suitable for harsh-environment industrial and aerospace applications |
Pinout & Package
Package: JEDEC T-18 axial-leaded plastic encapsulated case (void-free UL94V-0 epoxy), 0.7 g weight, cathode indicated by colored band. Leads are tin-lead or RoHS-compliant matte-tin plated.
| 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; connected to regulated rail; conducts reverse current to clamp voltage at 18 V |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener series | Ensures industry-standard mechanical and electrical interchangeability across manufacturers |
| Moisture sensitivity Level 1 | No dry pack required - simplifies handling and eliminates bake-out before assembly |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Robust handling without special ESD controls during board assembly and testing |
| High surge current rating (IZSM = 75 A) | Withstands 8.3 ms half-sine transients up to 75 A - protects downstream circuitry from line surges |
| RoHS-compliant option (e3 suffix) | Meets environmental compliance requirements without performance trade-offs |
Applications
| Industrial Power Supply Regulation | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Stabilizing +18 V rail in programmable logic controller (PLC) I/O module power stage. IC Role / Device Role / Timing Role: Shunt voltage reference and error amplifier feedback element. Use Value: Maintains ±0.9 V regulation window (18 V ±5%) across 10–70 mA load range with <0.4 V ΔVZ. |
Use Scenario: Clamping transient spikes on 24 V DC control bus in factory automation equipment. IC Role / Device Role / Timing Role: Crowbar-style overvoltage limiter protecting microcontroller inputs. Use Value: Activates at 18 V to divert >75 A surge (8.3 ms) while holding clamped voltage ≤19.4 V. |
| Reference Voltage Source | DC-DC Converter Feedback |
Use Scenario: Providing stable 18 V reference for analog-to-digital converter (ADC) calibration circuit. IC Role / Device Role / Timing Role: Precision voltage source for ratiometric measurement systems. Use Value: Delivers 18 V ±5% with 2.5 Ω ZZ, minimizing drift-induced gain error in 12-bit ADC systems. |
Use Scenario: Setting output voltage of isolated flyback converter in telecom power brick. IC Role / Device Role / Timing Role: Secondary-side voltage sensing node in optocoupler feedback loop. Use Value: Enables accurate 18 V output regulation with <0.4 V total voltage regulation (ΔVZ) across line/load changes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener voltage regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5355B | No TR8 tape-and-reel packaging; bulk or ammo-pack only | Same electrical specs but unsuitable for automated SMT placement | Select 1N5355/TR8 for pick-and-place production; choose 1N5355B for manual prototyping or low-volume repair |
| MMBZ5245B (SOT-23) | Surface-mount, 0.5 W rating, 18 V ±5%, 20 Ω ZZ | Lower power, smaller footprint; not interchangeable in high-current or high-surge roles | Use MMBZ5245B only in space-constrained, low-power (<100 mW) applications where 5 W capability is unnecessary |
Compared with 1N5355B and MMBZ5245B, the 1N5355/TR8 uniquely combines JEDEC T-18 axial reliability, 5 W continuous dissipation, 75 A surge rating, and tape-and-reel compatibility-making it optimal for industrial power designs requiring robust, automatable voltage regulation.
Availability
1N5355/TR8 is available at Aetrix Electronics and suitable for industrial power supply regulation, overvoltage protection circuits, precision reference voltage sources, and DC-DC converter feedback networks requiring stable component supply and long-term obsolescence management.
Supply support for 1N5355/TR8 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 and mixed-signal components for aerospace, defense, and industrial markets.
The 1N53xxB series was designed for ruggedized voltage regulation in mission-critical power systems where thermal stability, surge immunity, and long-term parameter consistency are essential.
FAQ
What is the Zener voltage tolerance of the 1N5355/TR8?
The 1N5355/TR8 has a ±5% Zener voltage tolerance, confirmed by its "B" suffix per Microsemi's datasheet. This means its measured VZ falls within 17.1 V to 18.9 V at 65 mA test current and 25 °C lead temperature. The 1N5355/TR8 is not rated for ±1%, ±2%, or ±10% tolerance variants - those require C, D, or A suffixes respectively.
Does the 1N5355/TR8 support automated assembly?
Yes - the "TR8" suffix explicitly denotes EIA-296 standard tape-and-reel packaging optimized for pick-and-place machines. The 1N5355/TR8 is supplied in 8 mm carrier tape with 1,000 units per reel, enabling high-throughput SMT line integration without manual handling or rework.
What is the maximum surge current rating for the 1N5355/TR8?
The 1N5355/TR8 has a maximum non-recurrent surge current (IZSM) of 75 A for an 8.3 ms half-sine waveform, as specified in Microsemi's 1N5333B–1N5388B datasheet. This rating applies under defined thermal conditions and confirms its suitability for transient overvoltage suppression in industrial control environments.
How does thermal derating affect the 1N5355/TR8's power capability?
The 1N5355/TR8 maintains 5.0 W dissipation only at 25 °C lead temperature (TL). Above that, power must be linearly derated at 20 mW/°C - e.g., at TL = 75 °C, max power drops to 4.0 W. Derating is based on 3/8″ (10 mm) lead length from body; PCB-mounted operation reduces steady-state power to 1.47 W at 25 °C ambient.
Is the 1N5355/TR8 RoHS compliant?
The 1N5355/TR8 is RoHS compliant when ordered with the "e3" suffix (e.g., 1N5355BTR8e3). Standard 1N5355/TR8 uses tin-lead plating; the e3 variant substitutes annealed matte-tin plating meeting EU RoHS Directive 2011/65/EU and J-STD-609A Class 1 requirements.
1N5355/TR8 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- T-18, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±20%
- Power - Max:
- 5 W
- Impedance (Max) (Zzt):
- 2.5 Ohms
- Current - Reverse Leakage @ Vr:
- 500 nA @ 13 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 1 A
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- T-18
1N5355/TR8 FAQ
1.How can I place an order for 1N5355/TR8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5355/TR8 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 1N5355/TR8 reliable?
The price and inventory of 1N5355/TR8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5355/TR8 is usually 5 days.
3.What payment methods are accepted for 1N5355/TR8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5355/TR8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5355/TR8?
1N5355/TR8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5355/TR8 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 1N5355/TR8?
For technical support, including 1N5355/TR8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5355/TR8 requirements.
6.How does Aetrix verify that 1N5355/TR8 is sourced from the original manufacturer or authorized distributors?
All 1N5355/TR8 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 1N5355/TR8 meets industry standards.
7.What is the process for return or replacement of 1N5355/TR8?
All 1N5355/TR8 units undergo pre-shipment inspection (PSI). If there is an issue with 1N5355/TR8, 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 1N5355/TR8 part is unused and in its original packaging.
Return procedure for 1N5355/TR8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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