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Microchip Technology 1N4746AP/TR12
- Part No.:
- 1N4746AP/TR12
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4746AP/TR12.pdf
- Description:
- DIODE ZENER 18V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:4,507
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Product details
Overview
1N4746AP/TR12 from Microsemi is a 1 W, 18 V ±5% Zener diode in DO-41 plastic package, rated for 14 mA test current, 20 Ω dynamic impedance at IZT, and 0.25 mA maximum reverse leakage at 13.7 V. It provides stable voltage regulation in power supply reference and overvoltage protection circuits across industrial temperature range.
For engineers reviewing the 1N4746AP/TR12 datasheet, 1N4746AP/TR12 pinout, 1N4746AP/TR12 application, or 1N4746AP/TR12 equivalent, key selection criteria include Zener voltage tolerance (±5%), thermal resistance (45 °C/W junction-to-lead), surge current rating (250 mA), RoHS-compliant "e3" plating option, and tape-and-reel packaging (TR12).
Technical Context
This discrete Zener diode operates in reverse breakdown to maintain a stable 18 V reference across a wide current range (0.25–250 mA). Its 20 Ω dynamic impedance at 14 mA ensures low output variation under load changes, while the −65 °C to +150 °C operating temperature range supports harsh-environment deployment.
The DO-41 axial-leaded package delivers 45 °C/W junction-to-lead thermal resistance at 10 mm lead length, enabling reliable 1 W dissipation without forced cooling. Polarity is marked by cathode band; regulation requires cathode-positive bias relative to anode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 18 V ±5% at 14 mA - defines nominal regulation point with tight production control |
| Power Dissipation | 1.0 W at 25 °C - sets maximum continuous DC power handling before derating |
| Dynamic Impedance (ZZT) | 20 Ω at IZT = 14 mA - determines output voltage stability under varying load current |
| Reverse Leakage Current | 0.25 μA max at VR = 13.7 V - ensures minimal standby power loss in high-impedance bias networks |
| Surge Current (ISM) | 250 mA (½-sine, 1/120 s) - supports transient overvoltage clamping without failure |
| Thermal Resistance | 45 °C/W junction-to-lead - enables passive heat transfer through leads for board-level reliability |
| Forward Voltage | 1.2 V max at 200 mA - defines conduction threshold when used in forward-biased protection paths |
Pinout & Package
DO-41 (DO-204AL) plastic axial-leaded package with cathode indicated by colored band; no internal pins-two terminals only: anode and cathode.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node in Zener regulator configuration | Connected to system ground or lower-potential rail; forms return path during reverse breakdown |
| Cathode | Regulated output node in Zener regulator configuration | Banded end; connected to input voltage source; maintains 18 V above anode under regulation |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N47xxAP series | Ensures global interchangeability and standardized testing per industry baseline |
| Plastic P-suffix construction | Delivers lower thermal resistance vs. glass-body (G-suffix) variants for improved power handling |
| Moisture sensitivity Level 1 | Eliminates dry-pack requirement and simplifies SMT assembly logistics |
| RoHS-compliant "e3" plating option | Supports lead-free soldering at 260 °C for 10 s without degradation |
| Nonsensitive to ESD (MIL-STD-750 Method 1020) | Reduces need for handling precautions during manual assembly or rework |
Applications
| Power Supply Reference | Overvoltage Protection |
|---|---|
Use Scenario: Stabilizing feedback voltage in linear regulator ICs or discrete transistor-based regulators. IC Role / Device Role / Timing Role: Voltage reference element defining output setpoint via resistive divider network. Use Value: 18 V ±5% tolerance and 20 Ω ZZT ensure <1% output drift over 10–100 mA load range. | Use Scenario: Clamping transient spikes on 24 V DC bus lines in industrial PLC I/O modules. IC Role / Device Role / Timing Role: Shunt protection device diverting excess energy to ground during voltage surges. Use Value: 250 mA surge rating and 1 W steady-state dissipation handle repetitive 100 V/100 ns transients. |
| Signal Level Translation | Temperature-Stable Biasing |
Use Scenario: Generating fixed 18 V logic threshold for comparator inputs in analog sensor interfaces. IC Role / Device Role / Timing Role: Precision DC level shifter establishing known switching point independent of supply variation. Use Value: Low knee impedance (ZZK = 50 Ω at IZK = 0.25 mA) ensures sharp turn-on below 13.7 V. | Use Scenario: Providing stable bias current to op-amp input stages in automotive engine control units. IC Role / Device Role / Timing Role: Temperature-compensated current source using Zener-regulated voltage across series resistor. Use Value: −65 °C to +150 °C operation and low TC drift support consistent performance across full vehicle thermal envelope. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4746A | No TR12 tape-and-reel packaging; bulk or ammo pack only | Lacks automated placement compatibility; suitable for prototyping or low-volume hand assembly | Select 1N4746A when reel packaging is unnecessary and cost minimization is prioritized |
| MMSZ4708T1G | Surface-mount SOD-123 package; 18 V ±5%, 500 mW rating; higher ZZT (35 Ω) | Lower power handling and different thermal path; requires PCB layout revision | Select MMSZ4708T1G only when space-constrained designs mandate SMT and 500 mW suffices |
Compared with 1N4746A and MMSZ4708T1G, the 1N4746AP/TR12 uniquely combines 1 W power rating, DO-41 axial form factor, RoHS-compliant e3 plating, and EIA-296 standard tape-and-reel delivery-making it optimal for through-hole production requiring traceable, high-reliability Zener regulation.
Availability
1N4746AP/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and telecom line-card protection requiring stable component supply with full RoHS compliance and EIA-296 tape-and-reel packaging.
Supply support for 1N4746AP/TR12 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, RF, and discrete components for aerospace, defense, and industrial markets.
The 1N4746AP/TR12 belongs to Microsemi's legacy 1N47xxAP Zener diode family, engineered for precision voltage regulation in mission-critical power and protection circuits where long-term stability and MIL-grade screening options matter.
FAQ
What is the Zener voltage tolerance for 1N4746AP/TR12?
The 1N4746AP/TR12 has a nominal Zener voltage of 18 V with a tolerance of ±5%, as confirmed by the "A" suffix in its JEDEC part number per Microsemi's datasheet. This tolerance applies at 14 mA test current and 25 °C lead temperature. The "P" suffix denotes plastic DO-41 packaging, and "TR12" indicates EIA-296 standard tape-and-reel packaging with 12 mm carrier tape width.
Does 1N4746AP/TR12 support lead-free soldering processes?
Yes, the 1N4746AP/TR12 is offered in RoHS-compliant version with "e3" matte-tin plating, qualified for lead-free soldering at 260 °C for up to 10 seconds per MIL-STD-750 Method 2026. Its void-free epoxy case meets UL94V-0 flammability rating, and the device retains full 1 W power rating post-reflow when mounted with proper thermal relief.
What is the maximum surge current rating for 1N4746AP/TR12?
The 1N4746AP/TR12 has a maximum non-repetitive surge current (ISM) of 250 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25 °C ambient. This rating enables robust transient suppression in 24 V systems, such as clamping inductive kickback from solenoids or relay coils without degradation.
How does the thermal resistance of 1N4746AP/TR12 compare between junction-to-lead and junction-to-ambient?
The 1N4746AP/TR12 specifies 45 °C/W junction-to-lead thermal resistance at 10 mm lead length, but 105 °C/W junction-to-ambient when mounted on FR4 with 4 mm² copper pads. This 2.3× difference highlights the critical role of lead conduction in heat removal-designers must route leads to thermal planes or heatsinks to sustain 1 W operation beyond brief pulses.
Can 1N4746AP/TR12 be used in place of 1N4746A in existing designs?
Yes, the 1N4746AP/TR12 is functionally identical to 1N4746A in electrical and thermal specifications-the "P" denotes plastic packaging (vs. glass "G"), and "TR12" adds tape-and-reel packaging. No circuit or layout changes are needed; only handling and placement equipment must accommodate the reel format. Both share identical Zener voltage, impedance, and temperature ratings.
1N4746AP/TR12 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-204AL, DO-41, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 18 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 20 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 13.7 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 150°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AL (DO-41)
1N4746AP/TR12 FAQ
1.How can I place an order for 1N4746AP/TR12 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4746AP/TR12 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 1N4746AP/TR12 reliable?
The price and inventory of 1N4746AP/TR12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4746AP/TR12 is usually 5 days.
3.What payment methods are accepted for 1N4746AP/TR12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4746AP/TR12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4746AP/TR12?
1N4746AP/TR12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4746AP/TR12 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 1N4746AP/TR12?
For technical support, including 1N4746AP/TR12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4746AP/TR12 requirements.
6.How does Aetrix verify that 1N4746AP/TR12 is sourced from the original manufacturer or authorized distributors?
All 1N4746AP/TR12 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 1N4746AP/TR12 meets industry standards.
7.What is the process for return or replacement of 1N4746AP/TR12?
All 1N4746AP/TR12 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4746AP/TR12, 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 1N4746AP/TR12 part is unused and in its original packaging.
Return procedure for 1N4746AP/TR12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4746AP/TR12 Tags
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