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Microchip Technology 1N746A/TR
- Part No.:
- 1N746A/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AH, DO-35, Axial
- Datasheet:
-
1N746A/TR.pdf
- Description:
- DIODE ZENER 3.3V 500MW DO204AH
- Quantity:
- Payment:
- Shipping:
Inventory:7,323
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Product details
Overview
1N746A/TR from Microsemi is a 500 mW, 3.3 V ±5% axial-leaded silicon Zener diode in DO-35 (DO-204AH) glass package, qualified to JANTX level per MIL-PRF-19500/127, with 24 Ω dynamic impedance at 30 mA and -0.070 %/°C temperature coefficient - used for precision voltage regulation in power supply reference circuits.
For engineers reviewing the 1N746A/TR datasheet, 1N746A/TR pinout, 1N746A/TR application, or 1N746A/TR equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (250 °C/W junction-to-lead), reverse leakage (5 µA @ 1.0 V), maximum Zener current (120 mA), and RoHS-compliant commercial-grade availability with TR tape-and-reel packaging.
Technical Context
The 1N746A/TR operates as a two-terminal voltage reference device, conducting in reverse breakdown at its nominal 3.3 V Zener voltage when biased above IZK (knee current) and within its 500 mW average power limit. Its internal metallurgical bond ensures stable regulation across -65 °C to +175 °C operating temperature range.
It exhibits low dynamic impedance (24 Ω @ 30 mA), minimal capacitance, and non-sensitivity to ESD per MIL-STD-750 Method 1020. The cathode band denotes polarity, requiring the banded end to be held positive relative to the anode for regulation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage VZ | 3.3 V ±5% at 30 mA - defines precise DC reference point for feedback loops and bias networks. |
| Power Dissipation | 0.5 W @ TL = 50°C - sets maximum continuous power handling on leaded mount; derates linearly to zero at 175°C. |
| Dynamic Impedance ZZT | 24 Ω @ IZT = 30 mA - determines output voltage stability under load current variation. |
| Reverse Leakage IR | 5 µA @ VR = 1.0 V - limits error in high-impedance reference paths near knee voltage. |
| Temp Coefficient αVZ | -0.070 %/°C @ 25°C - quantifies drift magnitude over temperature for precision applications. |
| Junction-to-Lead RθJL | 250 °C/W - governs thermal design margin when leads serve as primary heat path. |
| Operating Temp Range | -65 °C to +175 °C - enables use in aerospace, downhole, and military environments. |
Pinout & Package
DO-35 (DO-204AH) hermetically sealed axial-leaded glass package with tin-lead or RoHS-compliant matte-tin plating; cathode indicated by colored band; weight ≈ 0.2 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reverse-biased reference terminal | Connected to lower-potential node; carries full Zener current during regulation. |
| Cathode | Reverse-biased reference terminal | Banded end; held at regulated 3.3 V output potential; referenced to system ground or bias rail. |
Key Features
| Feature | Design Value |
|---|---|
| MIL-PRF-19500/127 qualification | JANTX-level reliability verified for high-reliability military and aerospace systems. |
| Metallurgical bond construction | Ensures long-term parameter stability and resistance to thermal cycling stress. |
| Low dynamic impedance | 24 Ω at 30 mA enables tight regulation under varying load conditions. |
| ESD immunity | Non-sensitive per MIL-STD-750 Method 1020 - reduces handling and assembly risk. |
| RoHS-compliant option | e3 marking available for commercial-grade 1N746A/TR - supports environmental compliance without performance trade-off. |
Applications
| Power Supply Reference | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Stabilizing feedback voltage in discrete linear regulator or op-amp-based reference circuit. IC Role / Device Role / Timing Role: Two-terminal shunt voltage reference providing fixed 3.3 V reference point. Use Value: Enables ±5% output accuracy with low tempco (-0.070 %/°C) and 24 Ω impedance for stable loop response. | Use Scenario: Clamping transient spikes on low-voltage logic rails or sensor inputs. IC Role / Device Role / Timing Role: Passive overvoltage clamp limiting voltage to 3.3 V + VF during surge events. Use Value: Low 5 µA leakage at 1.0 V ensures minimal standby loading; fast response inherent to Zener structure. |
| Temperature-Stable Bias Network | Aerospace Power Monitoring |
Use Scenario: Generating temperature-compensated bias currents in analog front-ends. IC Role / Device Role / Timing Role: Precision voltage source feeding resistor networks to set bias points. Use Value: -65 °C to +175 °C operation and metallurgical bond ensure consistent behavior across extreme thermal cycles. | Use Scenario: Voltage monitoring in satellite power distribution units requiring radiation-hardened components. IC Role / Device Role / Timing Role: Regulated reference for ADC input scaling or comparator threshold setting. Use Value: Inherent radiation hardness per MicroNote 050 and JANTX qualification support mission-critical reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4728A | Same 3.3 V nominal, ±5% tolerance, but rated 1 W and in DO-41 package; higher thermal mass and different RθJA. | Used where higher power margin or PCB-mount robustness is required; not suitable for space-constrained DO-35 footprints. | Select 1N4728A only if board layout allows DO-41 and >0.5 W dissipation is needed. |
| BZX55C3V3 | 3.3 V ±5%, 500 mW, DO-35, but commercial-grade only; no MIL-PRF-19500 qualification or JANTX reliability screening. | Applicable in cost-sensitive industrial designs where military reliability is not mandated. | Choose BZX55C3V3 for commercial production where MIL-spec testing and extended temp range are unnecessary. |
Compared with 1N746A/TR, 1N4728A offers higher power rating but incompatible package and thermal profile, while BZX55C3V3 matches form-factor and power but lacks military qualification and extended temperature capability - making 1N746A/TR uniquely suited for high-reliability embedded systems requiring both DO-35 fit and JANTX assurance.
Availability
1N746A/TR is available at Aetrix Electronics and suitable for aerospace power monitoring, military-grade voltage reference design, and radiation-tolerant embedded systems requiring stable component supply across extended lifecycle windows.
Supply support for 1N746A/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) designs high-reliability analog and mixed-signal semiconductors for aerospace, defense, and industrial markets.
The 1N746A/TR belongs to Microsemi's legacy MIL-qualified Zener diode family, engineered specifically for precision voltage regulation in harsh-environment applications demanding extended temperature range and radiation tolerance.
FAQ
What is the Zener voltage and tolerance of the 1N746A/TR?
The 1N746A/TR has a nominal Zener voltage of 3.3 V with a ±5% tolerance, measured at 30 mA test current (IZT). This tolerance is denoted by the "A" suffix in the part number per Microsemi's nomenclature. The 1N746A/TR maintains this specification across its full operating temperature range of -65 °C to +175 °C when properly mounted.
Is the 1N746A/TR RoHS compliant?
Yes, the 1N746A/TR is available in a RoHS-compliant version marked with the "e3" suffix, though this option applies to commercial-grade units only. The standard 1N746A/TR retains tin-lead plating unless specified otherwise. RoHS compliance does not affect electrical parameters or mechanical dimensions of the 1N746A/TR.
What does the "TR" suffix mean in 1N746A/TR?
The "TR" suffix indicates tape-and-reel packaging per EIA-296 standard, enabling automated pick-and-place assembly. It does not alter the electrical or thermal specifications of the 1N746A/TR. The underlying device remains identical to the bulk or ammo-pack versions - only the packaging format changes for manufacturing efficiency.
How is the polarity marked on the 1N746A/TR?
The cathode of the 1N746A/TR is identified by a visible color band on the glass body. For proper Zener regulation, the banded end must be held at a higher potential than the unmarked (anode) end. This polarity marking is consistent across all DO-35 packaged devices in the 1N746A-1 series and is critical for correct circuit operation of the 1N746A/TR.
What is the maximum Zener current rating for the 1N746A/TR?
The 1N746A/TR has a maximum Zener current (IZM) of 120 mA at 25 °C, derived from its 500 mW power rating and 3.3 V nominal voltage. At elevated temperatures, this value decreases due to thermal derating - for example, it drops to approximately 80 mA at 100 °C ambient when mounted on a PCB. Exceeding IZM risks parametric shift or failure of the 1N746A/TR.
1N746A/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):
- 3.3 V
- Tolerance:
- ±5%
- Power - Max:
- 500 mW
- Impedance (Max) (Zzt):
- 28 Ohms
- Current - Reverse Leakage @ Vr:
- 5 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)
1N746A/TR FAQ
1.How can I place an order for 1N746A/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N746A/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 1N746A/TR reliable?
The price and inventory of 1N746A/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N746A/TR is usually 5 days.
3.What payment methods are accepted for 1N746A/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N746A/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N746A/TR?
1N746A/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N746A/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 1N746A/TR?
For technical support, including 1N746A/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N746A/TR requirements.
6.How does Aetrix verify that 1N746A/TR is sourced from the original manufacturer or authorized distributors?
All 1N746A/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 1N746A/TR meets industry standards.
7.What is the process for return or replacement of 1N746A/TR?
All 1N746A/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N746A/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 1N746A/TR part is unused and in its original packaging.
Return procedure for 1N746A/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N746A/TR Tags
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