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Microchip Technology 1N4742AP/TR12
- Part No.:
- 1N4742AP/TR12
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4742AP/TR12.pdf
- Description:
- DIODE ZENER 12V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:5,836
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Product details
Overview
1N4742AP/TR12 from Microsemi is a 12 V, ±5% tolerance, 1 W axial-lead silicon Zener diode in DO-41 plastic package, rated for 21 mA test current (IZT), 76 Ω dynamic impedance (ZZT), and 9.1 V reverse test voltage (VR), used for precision voltage regulation in power supply feedback loops and reference circuits.
For engineers reviewing the 1N4742AP/TR12 datasheet, 1N4742AP/TR12 pinout, 1N4742AP/TR12 application, or 1N4742AP/TR12 equivalent, key selection criteria include Zener voltage tolerance, thermal resistance (45 °C/W junction-to-lead), surge current rating (380 mA), operating temperature range (–65 °C to +150 °C), and RoHS-compliant "e3" plating option availability.
Technical Context
This discrete Zener diode operates in reverse breakdown to maintain stable voltage across its terminals under varying load and line conditions. It delivers regulated output with 76 Ω dynamic impedance at 21 mA IZT and exhibits a typical temperature coefficient near +0.075 %/°C for 12 V devices per Figure 3.
Designed for through-hole mounting on FR4 PCBs with 1 oz copper, it sustains 1.0 W steady-state dissipation at lead temperature <105 °C (3/8″ from body) or ambient <45 °C, with thermal resistance of 105 °C/W junction-to-ambient under defined board layout conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (Vz) | 12 V ±5% at 21 mA IZT - defines nominal regulation point with tight production control for feedback stability |
| Power Dissipation | 1.0 W at TL < 105 °C - sets maximum continuous thermal load without derating on standard leaded mount |
| Dynamic Impedance | 76 Ω @ 21 mA - determines output voltage variation under changing load current in regulation mode |
| Reverse Leakage | 5 μA @ 9.1 V VR - ensures minimal quiescent current draw below regulation threshold |
| Surge Current (ISM) | 380 mA (½-sine, 1/120 s) - supports transient overvoltage handling in unregulated input stages |
| Operating Temp | –65 °C to +150 °C - enables use in industrial and automotive under-hood environments |
| Thermal Resistance | 45 °C/W junction-to-lead - allows accurate junction temperature estimation from measured lead temp |
Pinout & Package
DO-41 (DO-204AL) plastic axial-lead package with cathode indicated by color band; leads are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / Zener cathode reference ground | Connected to circuit common or lower-potential node; reverse-biased operation requires cathode at higher potential |
| Cathode | Zener regulation terminal / voltage reference output | Banded end; held at stable 12 V relative to anode during breakdown; used as shunt reference in feedback networks |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N47xxAP series | Industry-standard footprint and electrical behavior enabling direct substitution in legacy designs |
| Moisture Sensitivity Level 1 | No dry pack required before PCB assembly - reduces handling cost and process complexity |
| Nonsensitive to ESD | Qualified per MIL-STD-750 Method 1020 - eliminates need for special ESD handling in manufacturing |
| Plastic P-suffix construction | Lower thermal resistance vs. glass-body G-suffix variants - improves power handling in compact layouts |
| RoHS-compliant "e3" option | Matte-tin plating meets EU Directive 2011/65/EU - supports compliance-critical industrial and medical designs |
Applications
| Switching Power Supply Feedback | Overvoltage Protection Clamp |
|---|---|
Use Scenario: Regulating output voltage in isolated flyback or forward converter secondary-side feedback loop. IC Role / Device Role / Timing Role: Shunt voltage reference connected across optocoupler input to set precise output voltage threshold. Use Value: 12 V ±5% regulation with 76 Ω dynamic impedance ensures <±1% output deviation across 10–100% load range. |
Use Scenario: Clamping transient spikes on 12 V rail caused by inductive switching or ESD events. IC Role / Device Role / Timing Role: Passive crowbar element placed between rail and ground to limit voltage excursion above 12.6 V. Use Value: 380 mA surge rating absorbs 100–200 mJ pulses without degradation, extending system reliability. |
| Industrial Sensor Reference | Programmable Logic Controller Input Conditioning |
Use Scenario: Providing stable excitation voltage for resistive bridge sensors in factory automation systems. IC Role / Device Role / Timing Role: Low-drift 12 V reference source for Wheatstone bridge biasing and ADC reference scaling. Use Value: –65 °C to +150 °C operating range and <0.1 %/°C tempco enable accuracy in uncontrolled cabinet environments. |
Use Scenario: Level-shifting and clamping 24 V digital inputs to safe logic thresholds in PLC backplanes. IC Role / Device Role / Timing Role: Input protection device limiting voltage seen by microcontroller GPIO pins to ≤12.6 V. Use Value: 5 μA leakage at 9.1 V ensures minimal loading on upstream current-limited sources during normal operation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4742A (DO-41, no TR) | Same electrical specs but bulk packaging (no tape-and-reel); no TR suffix | Not suitable for automated SMT placement; requires manual or vibration-feed insertion | Select 1N4742AP/TR12 for high-volume pick-and-place assembly; choose 1N4742A for low-volume prototyping or repair |
| BZX55C12 (DO-35) | Smaller DO-35 package; 12 V ±5%, 500 mW rating; 100 Ω ZZT @ 5 mA | Lower power handling and higher impedance limit use to low-current references (<10 mA) | Choose BZX55C12 only where board space is critical and regulation current remains ≤5 mA |
Compared with 1N4742A and BZX55C12, the 1N4742AP/TR12 offers superior power capability (1 W vs. 0.5 W), lower dynamic impedance (76 Ω vs. 100 Ω), and tape-and-reel compatibility - making it optimal for production-grade 12 V shunt regulation where thermal margin and assembly efficiency matter.
Availability
1N4742AP/TR12 is available at Aetrix Electronics and suitable for industrial power supplies, sensor signal conditioning, overvoltage protection circuits, and programmable controller input stages requiring stable component supply and full traceability.
Supply support for 1N4742AP/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 timing solutions for aerospace, defense, and industrial markets.
The 1N4742AP/TR12 belongs to Microsemi's legacy 1N47xxAP Zener diode family, engineered for robust voltage regulation in harsh-environment power systems where long-term stability and JEDEC-standard compatibility are mandatory.
FAQ
What is the Zener voltage tolerance of the 1N4742AP/TR12?
The 1N4742AP/TR12 has a nominal Zener voltage of 12 V with a tolerance of ±5%, as confirmed by the "A" suffix in the part number per Microsemi's datasheet revision C. This tolerance applies at 21 mA test current and 25 °C lead temperature, ensuring predictable regulation performance across production lots.
Does the 1N4742AP/TR12 support automated assembly?
Yes, the "TR12" suffix indicates tape-and-reel packaging per EIA-296 standard, enabling compatibility with high-speed pick-and-place equipment. The 1N4742AP/TR12 is supplied in 12 mm tape width with 10,000 units per reel, optimized for surface-mount and through-hole automated insertion lines.
What is the maximum surge current rating for the 1N4742AP/TR12?
The 1N4742AP/TR12 is rated for a maximum non-repetitive surge current (ISM) of 380 mA, measured using a ½-sine wave pulse of 1/120 second duration at 25 °C ambient. This rating supports transient suppression in DC power rails subject to inductive kick or ESD events.
How does the thermal resistance of the 1N4742AP/TR12 affect PCB layout?
The 1N4742AP/TR12 has a junction-to-lead thermal resistance of 45 °C/W at 3/8″ (10 mm) lead length. To maintain 1 W dissipation, keep lead temperature below 105 °C by minimizing thermal path resistance - avoid narrow traces and ensure ≥4 mm² copper pads per lead on FR4 boards.
Is the 1N4742AP/TR12 RoHS compliant?
Yes, the "e3" designation in the full ordering code (1N4742AP/TR12 e3) confirms RoHS compliance per EU Directive 2011/65/EU. The device uses annealed matte-tin plating instead of tin-lead, verified per Microsemi's documentation and supported by authorized distributor data.
1N4742AP/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):
- 12 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 9 Ohms
- Current - Reverse Leakage @ Vr:
- 5 µA @ 9.1 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)
1N4742AP/TR12 FAQ
1.How can I place an order for 1N4742AP/TR12 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4742AP/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 1N4742AP/TR12 reliable?
The price and inventory of 1N4742AP/TR12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4742AP/TR12 is usually 5 days.
3.What payment methods are accepted for 1N4742AP/TR12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4742AP/TR12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4742AP/TR12?
1N4742AP/TR12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4742AP/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 1N4742AP/TR12?
For technical support, including 1N4742AP/TR12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4742AP/TR12 requirements.
6.How does Aetrix verify that 1N4742AP/TR12 is sourced from the original manufacturer or authorized distributors?
All 1N4742AP/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 1N4742AP/TR12 meets industry standards.
7.What is the process for return or replacement of 1N4742AP/TR12?
All 1N4742AP/TR12 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4742AP/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 1N4742AP/TR12 part is unused and in its original packaging.
Return procedure for 1N4742AP/TR12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4742AP/TR12 Tags
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Diodes Incorporated
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