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Microchip Technology 1N748C/TR
- Part No.:
- 1N748C/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N748C/TR.pdf
- Description:
- DIODE ZENER 3.9V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:7,368
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Product details
Overview
1N748C/TR from Microsemi is a 3.9 V, ±2% tolerance, 500 mW axial-leaded silicon Zener diode in DO-35 (DO-204AH) glass package, qualified to JANTX level per MIL-PRF-19500/127, used for precision voltage regulation in power supply reference and overvoltage protection circuits.
For engineers reviewing the 1N748C/TR datasheet, 1N748C/TR pinout, 1N748C/TR application, or 1N748C/TR equivalent, key selection criteria include Zener voltage tolerance (±2%), dynamic impedance (20 Ω @ 30 mA), temperature coefficient (–0.060 %/°C), RoHS-compliant commercial-grade plating, and military qualification level.
Technical Context
This device operates as a reverse-biased voltage reference with a nominal Zener voltage of 3.9 V at 30 mA test current (IZT), exhibiting low dynamic impedance (20 Ω) and negative temperature coefficient (–0.060 %/°C) typical of low-voltage Zeners below 5 V. It features an internal metallurgical bond for reliability under thermal stress.
Rated for operation from –65 °C to +175 °C, it delivers stable regulation across wide temperature ranges with junction-to-lead thermal resistance of 250 °C/W and maximum average power dissipation of 500 mW at TL = +50 °C (0.375″ lead length), derating linearly to zero at 175 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.9 V ±2% at IZT = 30 mA - defines precise regulation point for reference design |
| Power Dissipation | 500 mW @ TL = +50 °C - supports stable operation in compact through-hole layouts with defined lead length |
| Dynamic Impedance | 20 Ω @ IZT = 30 mA - ensures minimal output voltage variation under load current changes |
| Temp Coefficient | –0.060 %/°C @ 25 °C - enables predictable drift compensation in temperature-sensitive references |
| Reverse Leakage | 2 µA max @ VR = 1.0 V - guarantees low quiescent current in standby regulation paths |
| Junction Temp Range | –65 °C to +175 °C - suitable for aerospace, defense, and high-reliability industrial environments |
| Package | DO-35 (DO-204AH) glass axial - hermetically sealed, RoHS-compliant matte-tin plating, cathode band marked |
Pinout & Package
DO-35 (DO-204AH) glass axial package: hermetically sealed, 0.055–0.090″ body diameter, 1.000–1.500″ overall length, cathode indicated by colored band. Tin-lead or RoHS-compliant matte-tin plating; solderable per MIL-STD-750 method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit ground when used in standard shunt regulator configuration |
| Cathode | Zener breakdown terminal / regulated output node | Banded end; connected to unregulated input; maintains 3.9 V relative to anode during reverse bias |
Key Features
| Feature | Design Value |
|---|---|
| ±2% Zener tolerance (C suffix) | Enables tighter regulation than standard ±5% parts, reducing need for post-regulation trimming |
| JANTX qualification per MIL-PRF-19500/127 | Validated for high-reliability applications requiring screening, burn-in, and lot traceability |
| Metallurgically bonded junction | Improves thermal cycling endurance and long-term parameter stability vs. alloyed construction |
| Low capacitance & ESD robustness | Minimizes signal coupling in RF-adjacent circuits; non-sensitive to ESD per MIL-STD-750 method 1020 |
| RoHS-compliant plating (TR suffix) | Meets environmental compliance for commercial-grade assemblies without sacrificing solderability |
Applications
| Power Supply Reference | Overvoltage Protection |
|---|---|
Use Scenario: Stable 3.9 V reference for linear regulator feedback or ADC reference divider networks. IC Role / Device Role / Timing Role: Shunt voltage reference providing precision bias point independent of load current variation. Use Value: ±2% tolerance and 20 Ω dynamic impedance ensure <±15 mV output deviation across 1–30 mA operating range. | Use Scenario: Clamping transient spikes on low-voltage logic rails (e.g., 3.3 V I/O lines). IC Role / Device Role / Timing Role: Reverse-biased crowbar element diverting excess energy to ground before IC damage threshold. Use Value: Fast turn-on at 3.9 V with sub-µA leakage below 1.0 V prevents false triggering in normal operation. |
| Temperature-Stable Biasing | Military Power Conditioning |
Use Scenario: Generating temperature-compensated bias voltages for op-amp input stages in sensor front-ends. IC Role / Device Role / Timing Role: Primary reference source whose –0.060 %/°C coefficient offsets positive-drift components in analog chains. Use Value: Predictable drift behavior enables first-order compensation without external thermistors or calibration. | Use Scenario: Voltage regulation in avionics DC-DC converter feedback loops operating across –55 °C to +125 °C. IC Role / Device Role / Timing Role: MIL-qualified shunt regulator maintaining setpoint under extreme thermal and vibration stress. Use Value: JANTX screening, hermetic DO-35 package, and –65 °C to +175 °C rating ensure field reliability in flight-critical systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N748A/TR | ±5% tolerance (A suffix) vs. ±2% (C suffix); otherwise identical electrical and mechanical specs | Suitable where looser regulation tolerance is acceptable to reduce cost | Select 1N748A/TR only if system-level testing confirms ±5% VZ meets reference accuracy requirements |
| BZX55C3V9 | Commercial-grade, ±5% tolerance, 500 mW, DO-35, but not MIL-qualified; higher ZZK (~30 Ω) | Appropriate for industrial/commercial designs without military screening or extended temp needs | Choose BZX55C3V9 for cost-sensitive, non-military applications where JANTX qualification is unnecessary |
Compared with 1N748A/TR and BZX55C3V9, the 1N748C/TR provides tighter voltage control and certified high-reliability screening-critical when reference stability and long-term parametric consistency outweigh cost considerations.
Availability
1N748C/TR is available at Aetrix Electronics and suitable for power supply reference, overvoltage protection, and military power conditioning applications requiring stable component supply, full traceability, and long-lifecycle support.
Supply support for 1N748C/TR 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 Corporation (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability, radiation-hardened, and aerospace-grade analog and discrete components.
The 1N748C/TR belongs to Microsemi's legacy MIL-PRF-19500/127-qualified Zener diode family, designed specifically for precision voltage regulation in defense, space, and critical infrastructure systems where parameter stability and qualification rigor are mandatory.
FAQ
What is the Zener voltage tolerance of the 1N748C/TR?
The 1N748C/TR has a nominal Zener voltage of 3.9 V with a tolerance of ±2%, denoted by the "C" suffix in its part number. This tighter tolerance is confirmed in the Electrical Characteristics table on page 3 of Microsemi's T4-LDS-0288 datasheet, where 1N748A-1 (±5%) and 1N748C/TR (±2%) are explicitly differentiated. The 1N748C/TR achieves this via tighter process control during manufacturing.
Is the 1N748C/TR qualified to military standards?
Yes, the 1N748C/TR is qualified to JANTX level per MIL-PRF-19500/127, as stated in the DESCRIPTION and FEATURES sections of the T4-LDS-0288 datasheet. This includes screening for temperature cycling, burn-in, and lot traceability. The "TR" suffix indicates tape-and-reel packaging; qualification level is determined by the base part nomenclature (1N748C-1), not the packaging suffix.
What does the "TR" suffix mean in 1N748C/TR?
The "TR" suffix in 1N748C/TR denotes tape-and-reel packaging per EIA-296 standard, enabling automated PCB assembly. It does not affect electrical or qualification specifications. The core device remains the JANTX-qualified 1N748C-1 Zener diode in DO-35 package, with RoHS-compliant matte-tin plating as specified for commercial-grade versions.
What is the maximum power dissipation of the 1N748C/TR?
The 1N748C/TR has an average rated power dissipation of 500 mW at TL = +50 °C with 0.375″ lead length, derating linearly to zero at +175 °C. When mounted on a PCB, it is rated for 400 mW at TA = +55 °C, per the Maximum Ratings table on page 1 of the T4-LDS-0288 datasheet. Thermal resistance junction-to-lead is 250 °C/W.
How is polarity marked on the 1N748C/TR?
The 1N748C/TR uses a cathode band marking on the glass DO-35 body to indicate polarity, as specified in the MECHANICAL and PACKAGING section. The banded end is the cathode and must be held positive relative to the anode for Zener regulation. This marking is visible and consistent across all units, supporting reliable manual and automated orientation during placement.
1N748C/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AH, DO-35, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 3.9 V
- Tolerance:
- ±2%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 23 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 1 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-204AH (DO-35)
1N748C/TR FAQ
1.How can I place an order for 1N748C/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N748C/TR 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 1N748C/TR reliable?
The price and inventory of 1N748C/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N748C/TR is usually 5 days.
3.What payment methods are accepted for 1N748C/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N748C/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N748C/TR?
1N748C/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N748C/TR 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 1N748C/TR?
For technical support, including 1N748C/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N748C/TR requirements.
6.How does Aetrix verify that 1N748C/TR is sourced from the original manufacturer or authorized distributors?
All 1N748C/TR 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 1N748C/TR meets industry standards.
7.What is the process for return or replacement of 1N748C/TR?
All 1N748C/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N748C/TR, 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 1N748C/TR part is unused and in its original packaging.
Return procedure for 1N748C/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N748C/TR Tags
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Diodes Incorporated
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onsemi
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