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Microchip Technology 1N4738P/TR8
- Part No.:
- 1N4738P/TR8
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-204AL, DO-41, Axial
- Datasheet:
-
1N4738P/TR8.pdf
- Description:
- DIODE ZENER 8.2V 1W DO204AL
- Quantity:
- Payment:
- Shipping:
Inventory:3,099
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Product details
Overview
1N4738P/TR8 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 in reverse-biased regulation mode for voltage reference and overvoltage protection in DC power supplies and analog circuits.
For engineers reviewing the 1N4738P/TR8 datasheet, 1N4738P/TR8 pinout, 1N4738P/TR8 application, or 1N4738P/TR8 equivalent, key selection criteria include its DO-41 package thermal resistance (45 °C/W junction-to-lead), -65°C to +150°C operating temperature range, 1.2 V forward voltage max at 200 mA, RoHS-compliant "e3" variant availability, and tape-and-reel packaging (TR8).
Technical Context
The 1N4738P/TR8 functions as a precision voltage reference by maintaining stable reverse breakdown across a broad operating current range (IZK = 0.5 mA to IZM = 550 mA). Its Zener knee impedance (ZZK = 400 Ω at IZK = 0.5 mA) ensures low-noise regulation onset, while its 45 °C/W junction-to-lead thermal resistance enables reliable 1 W dissipation at TL < 105°C with 3/8″ lead length.
Designed for discrete voltage stabilization-not signal switching or rectification-it exhibits tight 5% tolerance (A-suffix), moisture sensitivity level 1 per J-STD-020B, and ESD insensitivity per MIL-STD-750 Method 1020. 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) | 8.2 V ±5% at IZT = 31 mA - defines stable regulation point under standard test conditions |
| Power Dissipation | 1.0 W at TL < 105°C - supports continuous operation without forced cooling when leads are 10 mm from body |
| Dynamic Impedance (ZZT) | 4.5 Ω at IZT = 31 mA - ensures minimal output voltage variation under load current changes |
| Max Regulator Current (IZM) | 550 mA at TA = 50°C - sets upper safe operating current limit for sustained regulation |
| Thermal Resistance | 45 °C/W junction-to-lead - enables thermal design using lead conduction, not PCB copper area alone |
| Operating Temperature | -65°C to +150°C - suitable for industrial, automotive under-hood, and aerospace environments |
| Forward Voltage | ≤1.2 V at IF = 200 mA - confirms low-loss forward conduction during transient polarity reversal |
Pinout & Package
Package: DO-41 (DO-204AL), axial-lead plastic molded epoxy case (UL94V-0), cathode indicated by colored band. Terminals are tin-lead or RoHS-compliant matte-tin plated, solderable per MIL-STD-750 Method 2026.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Reverse-bias reference node | Connected to lower-potential side of regulated circuit; carries full Zener current during regulation |
| Cathode | Regulated output node | Marked by band; held at stable 8.2 V above anode potential when reverse-biased above breakdown threshold |
Key Features
| Feature | Design Value |
|---|---|
| JEDEC-registered Zener | Complies with standardized 1N47xxA series mechanical and electrical specifications for interchangeability |
| Plastic P-suffix construction | Lower thermal resistance vs. glass-body (G-suffix) variants-enables higher power handling in same footprint |
| Tape-and-reel packaging (TR8) | Standard EIA-296 compliant reel format for automated SMT placement compatibility despite axial-lead form factor |
| MIL-STD-750 ESD immunity | No ESD sensitivity per Method 1020-eliminates need for special handling in production environments |
| Moisture Level 1 rating | No dry-pack required per J-STD-020B-reduces BOM prep time and storage cost |
Applications
| DC Power Supply Regulation | Overvoltage Protection Circuit |
|---|---|
Use Scenario: Stabilizing unregulated 12 V DC rail in industrial control modules where input varies ±15%. IC Role / Device Role / Timing Role: Discrete Zener reference providing fixed 8.2 V shunt regulation to protect downstream LDOs and microcontrollers. Use Value: Maintains output within ±5% over 1–500 mA load range without active feedback, reducing component count vs. IC regulators. | Use Scenario: Clamping transient spikes on 5 V logic bus lines exposed to relay coil back-EMF. IC Role / Device Role / Timing Role: Passive crowbar element conducting only above 8.2 V, diverting surge energy to ground before IC damage occurs. Use Value: Limits peak voltage to ≤9.1 V (VZ + VR) with <100 ns response, meeting IEC 61000-4-4 level 3 immunity requirements. |
| Reference Voltage Source | Temperature-Stable Bias Network |
Use Scenario: Generating precise 8.2 V reference for ADC voltage divider in battery-powered sensor nodes. IC Role / Device Role / Timing Role: Low-drift voltage source feeding high-impedance op-amp input; used with trimming resistors for calibration. Use Value: Delivers 8.2 V ±0.41 V over -40°C to +85°C (TC ≈ +3 mV/°C near 8.2 V), enabling 12-bit accuracy without external compensation. | Use Scenario: Setting bias point for Class-A audio amplifier transistor with minimal thermal drift. IC Role / Device Role / Timing Role: Zener-based current source establishing stable emitter current independent of supply fluctuations. Use Value: Achieves <±2% quiescent current variation across -25°C to +70°C due to matched TC with silicon transistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4738A | No TR8 tape-and-reel packaging; bulk or ammo pack only; identical electrical specs and DO-41 package | Not suitable for automated assembly; requires manual loading or vibratory bowl feeders | Select 1N4738A only for prototyping or low-volume hand-soldered builds |
| BZX55C8V2 | Same 8.2 V ±5%, but 500 mW rating, DO-35 package, higher ZZT (15 Ω), and different thermal resistance (500 °C/W junction-to-ambient) | Limited to lower-power regulation; unsuitable for 1 W continuous dissipation or high-current clamping | Choose BZX55C8V2 only when board space is constrained and power demand stays below 300 mW |
Compared with 1N4738P/TR8, 1N4738A lacks tape-and-reel support for SMT lines, while BZX55C8V2 trades power capability and thermal performance for smaller size-making 1N4738P/TR8 optimal for high-reliability, high-current, automated-production Zener applications.
Availability
1N4738P/TR8 is available at Aetrix Electronics and suitable for DC power supply regulation, overvoltage protection circuits, reference voltage sources, temperature-stable bias networks, and industrial sensor interface designs requiring stable component supply and long-term obsolescence management.
Supply support for 1N4738P/TR8 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 1N47xxA Zener series was designed for ruggedized voltage regulation in mission-critical power systems where stability, wide temperature operation, and MIL-compatibility are essential.
FAQ
What is the Zener voltage tolerance of the 1N4738P/TR8?
The 1N4738P/TR8 has a nominal Zener voltage of 8.2 V with a tolerance of ±5%, as indicated by the "A" suffix in its JEDEC part number. This tolerance applies at 31 mA test current and 25°C lead temperature. The 1N4738P/TR8 does not offer tighter tolerances (e.g., ±2% or ±1%)-those require C- or D-suffix variants like 1N4738CP/TR8, which are distinct orderable parts.
Does the 1N4738P/TR8 support automated assembly?
Yes, the 1N4738P/TR8 is supplied in EIA-296 standard tape-and-reel format (TR8 designation), enabling direct use in pick-and-place machines. Its DO-41 axial-lead configuration is compatible with axial-feed feeders, and the matte-tin plating ensures reliable solderability per MIL-STD-750 Method 2026-no pre-tinning or special flux required for reflow or wave soldering.
What is the maximum continuous power dissipation for the 1N4738P/TR8?
The 1N4738P/TR8 is rated for 1.0 W steady-state power dissipation at lead temperature (TL) below 105°C with leads trimmed to 3/8″ (10 mm) from the body. Derating is required above that temperature: linear reduction to zero at 175°C. On FR4 PCB with 4 mm² copper pads, max ambient-rated power drops to 1.0 W only below 45°C ambient-confirm layout against Figure 1 in the Microsemi datasheet.
How does the thermal resistance of the 1N4738P/TR8 compare to glass-body Zeners?
The 1N4738P/TR8 features a plastic (P-suffix) DO-41 package with 45 °C/W junction-to-lead thermal resistance-significantly lower than equivalent glass-body (G-suffix) 1N4738G parts, which typically exceed 100 °C/W. This allows the 1N4738P/TR8 to sustain full 1 W dissipation with simpler mechanical mounting and less PCB copper area, improving thermal reliability in compact enclosures.
Is the 1N4738P/TR8 RoHS compliant?
Yes, the 1N4738P/TR8 is available in RoHS-compliant form with the "e3" suffix (e.g., 1N4738P-e3/TR8), indicating annealed matte-tin terminal plating. Standard 1N4738P/TR8 may use Sn/Pb plating unless otherwise specified; always verify the full orderable part number and consult Microchip's official product change notices for compliance status and transition timelines.
1N4738P/TR8 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:
- ±10%
- 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)
1N4738P/TR8 FAQ
1.How can I place an order for 1N4738P/TR8 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4738P/TR8 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 1N4738P/TR8 reliable?
The price and inventory of 1N4738P/TR8 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4738P/TR8 is usually 5 days.
3.What payment methods are accepted for 1N4738P/TR8?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4738P/TR8 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4738P/TR8?
1N4738P/TR8 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4738P/TR8 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 1N4738P/TR8?
For technical support, including 1N4738P/TR8 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4738P/TR8 requirements.
6.How does Aetrix verify that 1N4738P/TR8 is sourced from the original manufacturer or authorized distributors?
All 1N4738P/TR8 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 1N4738P/TR8 meets industry standards.
7.What is the process for return or replacement of 1N4738P/TR8?
All 1N4738P/TR8 units undergo pre-shipment inspection (PSI). If there is an issue with 1N4738P/TR8, 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 1N4738P/TR8 part is unused and in its original packaging.
Return procedure for 1N4738P/TR8:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4738P/TR8 Tags
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MMBZ5240B-7-F
Diodes Incorporated
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BZT52C5V6T-7
Diodes Incorporated
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MMSZ5231B-7-F
Diodes Incorporated
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BZT52C15-7-F
Diodes Incorporated
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BZX84C3V3LT1G
onsemi
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MMSZ5245BS-7-F
Diodes Incorporated
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MMSZ4682T1G
onsemi
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BZT52C15S-7-F
Diodes Incorporated
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MM5Z5V1ST1G
onsemi
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SMAJ4744A-TP
Micro Commercial Co
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BZT52C3V6LP-7
Diodes Incorporated
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SMAZ12-13-F
Diodes Incorporated
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