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Microchip Technology 1N4738AP/TR12
- Part No.:
- 1N4738AP/TR12
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4738AP/TR12.pdf
- Description:
- DIODE ZENER 8.2V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:7,123
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Product details
Overview
1N4738AP/TR12 from Microsemi is a 1.0 W axial-lead silicon Zener diode with nominal zener voltage 8.2 V ±5%, 31 mA test current (IZT), 4.5 Ω dynamic impedance (ZZT), and maximum regulator current 550 mA at TA = 50°C. It operates from –65°C to +150°C and is used for precision voltage regulation in power supply feedback loops, overvoltage protection circuits, and reference voltage generation.
For engineers reviewing the 1N4738AP/TR12 datasheet, 1N4738AP/TR12 pinout, 1N4738AP/TR12 application, or 1N4738AP/TR12 equivalent, key selection criteria include zener voltage tolerance, thermal resistance (45°C/W junction-to-lead), surge current rating (550 mA), RoHS compliance (e3 suffix), and DO-41 package compatibility with standard axial-lead PCB layouts.
Technical Context
This Zener diode functions in reverse-bias breakdown mode to maintain stable output voltage across wide operating current (1–550 mA) and temperature (–65°C to +150°C) ranges. Its 8.2 V nominal regulation point targets mid-range analog and digital supply rail stabilization where tighter than 10% tolerance is required but ultra-precision is not critical.
The device uses void-free thermosetting epoxy encapsulation (UL94V-0), tin-lead or matte-tin plating, and features moisture sensitivity level 1-no dry pack required. Polarity is marked by cathode band; regulation occurs with banded end positive relative to anode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 8.2 V ±5% at IZT = 31 mA - defines primary regulation setpoint for feedback networks |
| Power Dissipation | 1.0 W at TL < 105°C (3/8″ lead length) - sets maximum continuous DC power handling |
| Dynamic Impedance (ZZT) | 4.5 Ω at IZT = 31 mA - determines output voltage variation under load transients |
| Max Regulator Current (IZM) | 550 mA at TA = 50°C - limits usable current range before thermal derating applies |
| Thermal Resistance | 45°C/W junction-to-lead - enables thermal design using lead heatsinking, not PCB copper area alone |
| Reverse Leakage (IR) | 10 μA max at VR = 6 V - ensures low quiescent current in standby or high-impedance bias networks |
| Forward Voltage | 1.2 V max at IF = 200 mA - supports use as clamping diode in bidirectional protection schemes |
Pinout & Package
Package: DO-41 (DO-204AL), axial-lead plastic molded case with cathode band marking. Leads are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reference ground node in Zener configuration | Connected to circuit common; reverse-bias current flows from cathode to anode during regulation |
| Cathode | Regulated output node | Banded end; held at stable 8.2 V above anode when reverse current ≥ IZK (0.5 mA) |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered 1N47xxA series | Industry-standard footprint and electrical behavior-ensures drop-in replacement across multiple suppliers |
| Plastic P-suffix construction | Lower thermal resistance (45°C/W) vs. glass-body G-suffix variants-improves power handling in lead-mounted designs |
| Moisture Sensitivity Level 1 | No dry pack required prior to reflow-reduces manufacturing prep time and cost for high-volume assembly |
| RoHS-compliant e3 option | Meets EU Directive 2011/65/EU without exemption waivers-supports global market access and environmental compliance |
| Nonsensitive to ESD | Qualified per MIL-STD-750 Method 1020-eliminates need for special ESD handling in production and field service |
Applications
| Switch-Mode Power Supply Feedback | Industrial Sensor Reference |
|---|---|
Use Scenario: Stabilizing error amplifier input in isolated flyback or forward converter feedback networks. IC Role / Device Role / Timing Role: Zener reference providing precise 8.2 V threshold to optocoupler LED drive circuit. Use Value: Maintains ±5% output regulation across line/load/temperature variations without requiring active IC reference. | Use Scenario: Generating stable bias voltage for analog sensor signal conditioning stages in PLC modules. IC Role / Device Role / Timing Role: Passive voltage reference for op-amp gain-setting networks and ADC reference dividers. Use Value: Delivers 8.2 V with <4.5 Ω dynamic impedance-minimizes sensor offset drift induced by supply ripple. |
| Overvoltage Clamp Protection | Microcontroller Reset Circuit |
Use Scenario: Clamping transient surges on 9 V rail in automotive body control modules. IC Role / Device Role / Timing Role: Shunt protector limiting voltage to ≤8.2 V + ZZT × ISM during load dump events. Use Value: Absorbs 550 mA peak surge current without degradation-extends system-level ESD immunity beyond IEC 61000-4-5 Level 3. | Use Scenario: Setting reliable reset threshold for 8-bit MCUs operating from unregulated 9 V battery inputs. IC Role / Device Role / Timing Role: Threshold detector enabling reset assertion when supply drops below 8.2 V × 0.95. Use Value: Provides deterministic brown-out detection with no external resistors-reduces BOM count and layout area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4738A (Digi-Key P/N: 1N4738AFSCT-ND) | No TR12 tape-and-reel packaging; bulk or ammo pack only; same DO-41 package and electrical specs | Lacks standardized reel packaging-requires manual loading or custom feeder setup in SMT lines | Select 1N4738AP/TR12 for automated pick-and-place; choose 1N4738A only for prototyping or low-volume hand assembly |
| MMBZ5231BS-7-F (Diodes Inc.) | SOT-23 surface-mount package; 8.2 V ±5%; 200 mW rating; 30 Ω ZZT; 100 mA IZM | Lower power and current capability-suitable only for signal-level references, not power rail regulation | Use MMBZ5231BS-7-F where board space is constrained and load current <50 mA; retain 1N4738AP/TR12 for >100 mA regulation tasks |
Compared with 1N4738A and MMBZ5231BS-7-F, the 1N4738AP/TR12 uniquely combines 1 W power handling, DO-41 axial mechanical robustness, and factory-loaded TR12 tape-and-reel-making it optimal for industrial power supply manufacturing where reliability, thermal margin, and SMT line compatibility are jointly critical.
Availability
1N4738AP/TR12 is available at Aetrix Electronics and suitable for switch-mode power supplies, industrial sensor interfaces, overvoltage clamp circuits, and microcontroller reset networks requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1N4738AP/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 1N4738AP/TR12 belongs to Microsemi's legacy 1N47xxAP Zener series-designed specifically for ruggedized, high-stability voltage regulation in harsh-environment power systems where JEDEC-standardization and long-term obsolescence management are essential.
FAQ
What is the zener voltage tolerance of the 1N4738AP/TR12?
The 1N4738AP/TR12 has a nominal zener voltage of 8.2 V with a tolerance of ±5%, as indicated by the "A" suffix in the part number per JEDEC registration. This tolerance is measured at TL = 25°C ±10°C with 31 mA test current and defines the guaranteed regulation band under specified thermal conditions. The 1N4738AP/TR12 does not support tighter tolerances like ±1% or ±2%-those require suffixes "D" or "C", respectively.
Does the 1N4738AP/TR12 meet RoHS requirements?
Yes, the 1N4738AP/TR12 is RoHS compliant, as confirmed by the "e3" suffix in its full manufacturer designation (1N4738AP,e3/TR12). It contains no lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), or polybrominated diphenyl ethers (PBDE), and conforms to EU Directive 2011/65/EU. The device uses annealed matte-tin plating and UL94V-0 epoxy-both fully compliant with RoHS material restrictions.
What is the maximum steady-state current the 1N4738AP/TR12 can regulate continuously?
The 1N4738AP/TR12 supports a maximum regulator current (IZM) of 550 mA at ambient temperature TA = 50°C when mounted on FR4 with specified copper pads. At higher temperatures, derating applies per Figure 1 in the datasheet: for example, at TA = 75°C, IZM drops to ~400 mA. The 1N4738AP/TR12 must be operated within this limit to avoid thermal runaway or parametric shift.
Can the 1N4738AP/TR12 be used in surface-mount designs?
No, the 1N4738AP/TR12 is packaged in DO-41 (axial-lead), which is through-hole only. For surface-mount equivalents, Microsemi offers the SMAJ4738A and MLL4738A-both SOD-123 and SOD-323 packages rated for 1 W and 8.2 V regulation. These require separate part numbers and are not pin-compatible with the 1N4738AP/TR12 due to differing footprints and thermal paths.
What is the thermal resistance specification for the 1N4738AP/TR12?
The 1N4738AP/TR12 has a thermal resistance of 45°C/W junction-to-lead when measured at 3/8″ (10 mm) lead length from the body, and 105°C/W junction-to-ambient when mounted on FR4 with 1 oz copper, 4 mm² pads, and 1 mm × 25 mm traces. This dual specification allows thermal design either via lead heatsinking (e.g., chassis mounting) or PCB copper area-critical for maintaining safe junction temperature under 1 W dissipation.
1N4738AP/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):
- 8.2 V
- Tolerance:
- ±5%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 4.5 Ohms
- Current - Reverse Leakage @ Vr:
- 10 µA @ 6 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)
1N4738AP/TR12 FAQ
1.How can I place an order for 1N4738AP/TR12 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4738AP/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 1N4738AP/TR12 reliable?
The price and inventory of 1N4738AP/TR12 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4738AP/TR12 is usually 5 days.
3.What payment methods are accepted for 1N4738AP/TR12?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4738AP/TR12 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4738AP/TR12?
1N4738AP/TR12 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4738AP/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 1N4738AP/TR12?
For technical support, including 1N4738AP/TR12 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4738AP/TR12 requirements.
6.How does Aetrix verify that 1N4738AP/TR12 is sourced from the original manufacturer or authorized distributors?
All 1N4738AP/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 1N4738AP/TR12 meets industry standards.
7.What is the process for return or replacement of 1N4738AP/TR12?
All 1N4738AP/TR12 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4738AP/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 1N4738AP/TR12 part is unused and in its original packaging.
Return procedure for 1N4738AP/TR12:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4738AP/TR12 Tags
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MM5Z5V1ST1G
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