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Microchip Technology 1N5355B/TR8
- Part No.:
- 1N5355B/TR8
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- T-18, Axial
- Datasheet:
-
1N5355B/TR8.pdf
- Description:
- DIODE ZENER 18V 5W T18
- Quantity:
- Payment:
- Shipping:
Inventory:5,168
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Product details
Overview
1N5355B/TR8 from Microsemi is a 5 W axial-leaded silicon Zener diode with a nominal regulation voltage of 18 V ±5%, 2.5 Ω maximum dynamic impedance at 65 mA test current, 75 mA maximum Zener current (IZM), and 0.40 V maximum voltage regulation (ΔVZ) across 10–50% IZM. It operates from –65 °C to +150 °C and is used for precision voltage reference and overvoltage protection in power supply feedback loops.
For engineers reviewing the 1N5355B/TR8 datasheet, 1N5355B/TR8 pinout, 1N5355B/TR8 application, or 1N5355B/TR8 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (25 °C/W junction-to-lead), surge current rating (75 A), reverse leakage (<0.5 µA at 14.4 V), and RoHS-compliant matte-tin plating per MIL-STD-750.
Technical Context
The 1N5355B/TR8 functions as a two-terminal voltage regulator diode operating in reverse breakdown, with Zener voltage specified at 25 °C lead temperature using 65 mA dc test current (IZT). Its low dynamic impedance (2.5 Ω) ensures stable regulation under varying load currents.
Thermal design relies on junction-to-lead thermal resistance of 25 °C/W at 10 mm lead length; derating begins above 25 °C lead temperature per Figure 1. The device exhibits minimal voltage drift versus current-ΔVZ ≤ 0.40 V between 10% and 50% of IZM-and withstands 8.3 ms half-sine surge currents up to 75 A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% at 65 mA - defines regulated output voltage in shunt regulator circuits |
| Power Dissipation | 5.0 W at TL = 25 °C - sets maximum continuous power handling with adequate heat sinking |
| Dynamic Impedance (ZZ) | 2.5 Ω max at IZT = 65 mA - determines output voltage stability under load transients |
| Max Reverse Leakage (IR) | 0.5 µA max at VR = 14.4 V - ensures low standby current in high-impedance bias networks |
| Surge Current (IZSM) | 75 A peak (8.3 ms half-sine) - supports transient overvoltage clamping without failure |
| Voltage Regulation (ΔVZ) | 0.40 V max - quantifies variation between 10% and 50% of IZM, critical for tight-tolerance references |
| Junction-to-Lead Rθ | 25 °C/W - enables thermal modeling when mounted with 10 mm lead length from body |
Pinout & Package
Package: Axial-leaded T-18 plastic case (void-free UL94V-0 epoxy), cathode indicated by band; leads plated with RoHS-compliant matte tin per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-voltage reference node | Connected to circuit ground or lower-potential rail in shunt regulation |
| Cathode | Zener breakdown terminal / regulated voltage node | Banded end; connected to input rail to clamp voltage at 18 V ±5% |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N53xxB series | Industry-standard footprint and electrical behavior for drop-in replacement across multiple vendors |
| ±5% Zener tolerance (B suffix) | Enables tighter regulation than ±10% (A) or ±20% (no suffix) variants in feedback sensing |
| Moisture sensitivity Level 1 | No dry pack required per IPC/JEDEC J-STD-020B - simplifies SMT reflow prep and storage |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Eliminates need for special ESD handling during assembly or field service |
| RoHS-compliant (e3 suffix) | Meets EU Directive 2011/65/EU with matte-tin plating - no lead or hazardous substances |
Applications
| Switching Power Supply Feedback | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Regulates output voltage in flyback or forward converter feedback loop via optocoupler bias network. IC Role / Device Role / Timing Role: Shunt voltage reference providing stable 18 V reference to TL431 or optocoupler LED anode. Use Value: Maintains ±1% output regulation across line/load variations due to low ΔVZ (0.40 V) and stable ZZ (2.5 Ω). |
Use Scenario: Clamps transient spikes on 24 V DC bus in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Two-terminal crowbar element absorbing surge energy before downstream ICs are damaged. Use Value: Withstands 75 A 8.3 ms surges without degradation, enabling robust protection without active components. |
| Programmable Voltage Reference | DC-DC Converter Bias Network |
Use Scenario: Sets precise threshold in adjustable LDO enable circuit or comparator hysteresis network. IC Role / Device Role / Timing Role: Stable 18 V reference source for resistor-divider scaling to lower thresholds (e.g., 5 V, 3.3 V). Use Value: ±5% tolerance and low tempco ensure <±2% total error over –40 °C to +85 °C ambient. |
Use Scenario: Provides startup bias to controller IC (e.g., UC384x) in offline AC-DC adapter primary side. IC Role / Device Role / Timing Role: Zener-fed resistor network delivering regulated gate drive or VCC to PWM IC. Use Value: 5 W power rating supports sustained bias current without thermal runaway under brownout conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N5355B (bulk) | Identical electrical specs; differs only in packaging (ammo pack vs. tape-and-reel TR8) | No functional difference; TR8 enables automated pick-and-place assembly | Select 1N5355B/TR8 for SMT production; use bulk 1N5355B for prototyping or hand-soldered repairs |
| MMBZ5245B (SOT-23) | Same 18 V ±5% rating but 0.35 W power rating, surface-mount, higher ZZ (30 Ω) | Not suitable for >100 mA regulation; limited surge capability (1.5 A) | Choose MMBZ5245B only for low-power signal-level referencing where board space is constrained |
Compared with 1N5355B/TR8, the bulk 1N5355B offers identical performance but lacks tape-and-reel convenience, while MMBZ5245B trades power handling and surge robustness for miniaturization-making 1N5355B/TR8 optimal for 5 W industrial power regulation where reliability and thermal margin are critical.
Availability
1N5355B/TR8 is available at Aetrix Electronics and suitable for switching power supplies, overvoltage protection circuits, and programmable voltage reference designs requiring stable component supply, consistent parametric performance, and long-term obsolescence management.
Supply support for 1N5355B/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 harsh-environment power systems, emphasizing thermal robustness, surge immunity, and JEDEC-standard compatibility across military and commercial applications.
FAQ
What is the Zener voltage tolerance of the 1N5355B/TR8?
The 1N5355B/TR8 has a Zener voltage tolerance of ±5%, as indicated by the "B" suffix in its part number. This means its measured breakdown voltage at 65 mA test current falls within 17.1 V to 18.9 V at 25 °C lead temperature. This tolerance is tighter than the ±10% offered by "A"-suffix variants and supports more precise regulation in feedback networks.
Can the 1N5355B/TR8 be used in surface-mount designs?
No-the 1N5355B/TR8 is an axial-leaded T-18 package device intended for through-hole mounting. For surface-mount equivalents, Microsemi offers the SMBJ5355B (DO-214AA) and SMBG5355B (DO-214AB), which share identical electrical specifications but require different PCB footprints and reflow profiles.
What is the maximum steady-state power dissipation for the 1N5355B/TR8 on a standard FR4 PCB?
When mounted on a standard FR4 PCB (1 oz copper, 4 mm² pads, 1 mm track width, 25 mm length), the 1N5355B/TR8 has a steady-state power rating of 1.47 W at 25 °C ambient temperature. This is significantly lower than its 5 W rating at 25 °C lead temperature, reflecting higher junction-to-ambient thermal resistance (85 °C/W) in that configuration.
Does the 1N5355B/TR8 meet RoHS requirements?
Yes-the "e3" designation in Microsemi's documentation confirms the 1N5355B/TR8 is RoHS compliant, with matte-tin-plated leads meeting EU Directive 2011/65/EU. Lead content is below threshold limits, and the void-free epoxy body complies with UL94V-0 flammability standards.
How does the voltage regulation (ΔVZ) specification impact circuit performance?
The 1N5355B/TR8 specifies ΔVZ ≤ 0.40 V-the difference between voltage measured at 10% and 50% of its 75 mA maximum Zener current. This low value ensures minimal output voltage shift under changing load conditions, making it suitable for applications like precision feedback loops where regulation stability directly affects system accuracy.
1N5355B/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:
- ±5%
- 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
1N5355B/TR8 FAQ
1.How can I place an order for 1N5355B/TR8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N5355B/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 1N5355B/TR8 reliable?
The price and inventory of 1N5355B/TR8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N5355B/TR8 is usually 5 days.
3.What payment methods are accepted for 1N5355B/TR8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N5355B/TR8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N5355B/TR8?
1N5355B/TR8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N5355B/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 1N5355B/TR8?
For technical support, including 1N5355B/TR8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N5355B/TR8 requirements.
6.How does Aetrix verify that 1N5355B/TR8 is sourced from the original manufacturer or authorized distributors?
All 1N5355B/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 1N5355B/TR8 meets industry standards.
7.What is the process for return or replacement of 1N5355B/TR8?
All 1N5355B/TR8 units undergo pre-shipment inspection (PSI). If there is an issue with 1N5355B/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 1N5355B/TR8 part is unused and in its original packaging.
Return procedure for 1N5355B/TR8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N5355B/TR8 Tags
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