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Microchip Technology 1N4729UR-1/TR
- Part No.:
- 1N4729UR-1/TR
- Manufacturer:
- Microchip Technology
- Category:
- Single Zener Diodes
- Package:
- DO-213AB, MELF (Glass)
- Datasheet:
-
1N4729UR-1/TR.pdf
- Description:
- DIODE ZENER 3.6V 1W DO213AB
- Quantity:
- Payment:
- Shipping:
Inventory:7,680
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Product details
Overview
1N4729UR-1/TR from Microsemi is a surface-mount 1.0 W glass Zener diode with nominal Zener voltage 3.6 V ±5%, 69 mA test current, 10 Ω dynamic impedance at IZT, and -65°C to +175°C operating temperature range. It delivers stable voltage regulation in space-constrained power supply rails and reference circuits requiring hermetic reliability and low parasitic capacitance.
For engineers reviewing the 1N4729UR-1/TR datasheet, 1N4729UR-1/TR pinout, 1N4729UR-1/TR application, or 1N4729UR-1/TR equivalent, key selection criteria include Zener tolerance (±5%), thermal resistance (130°C/W on FR4), surge current rating (1260 mA), cathode-band polarity marking, and DO-213AB MELF package compatibility with automated SMT assembly.
Technical Context
This device operates as a reverse-biased voltage reference diode, maintaining regulation across 1 mA to 252 mA DC current (IZM) with sharp knee characteristics confirmed by dual-point Zener impedance measurement per Note 2. Its glass hermetic DO-213AB construction ensures radiation hardness per MicroNote 050 and immunity to moisture-induced parameter drift.
Designed for high-density PCB layouts, the 1N4729UR-1/TR uses a leadless cylindrical MELF package with tin-lead or RoHS-compliant matte-tin plating, solderable per MIL-STD-750 Method 2026, and rated for 260°C/10 s reflow. Polarity is unambiguously indicated by a single cathode band.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Zener Voltage (VZ) | 3.6 V ±5% - defines regulated output level under 69 mA test current; tight tolerance enables precision biasing without external trimming. |
| Power Dissipation | 1.0 W at TEC < 125°C - supports continuous operation in compact thermal environments with derating above 45°C ambient on FR4. |
| Dynamic Impedance (ZZT) | 10 Ω @ IZT = 69 mA - ensures minimal output voltage variation under load transients in feedback loops. |
| Reverse Leakage Current | 100 μA @ VR = 1 V - guarantees low quiescent current in standby mode for battery-powered systems. |
| Surge Current (IS) | 1260 mA - withstands short-duration overvoltage events without degradation, critical for input-stage protection. |
| Operating Temperature | -65°C to +175°C - validated for aerospace, downhole, and industrial control applications where extended thermal cycling occurs. |
Pinout & Package
Package: DO-213AB glass MELF (hermetically sealed, leadless cylindrical body, 2.39–2.66 mm diameter × 4.80–5.20 mm length). Cathode identified by single black band; anode is unmarked end. Mounts via two solder pads per recommended footprint (Page 3).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Zener breakdown terminal | Connected to higher-potential node during regulation; must be biased positive relative to anode to enter Zener conduction. |
| Anode (unmarked end) | Reference return path | Provides low-impedance return to ground or supply rail; forms current loop with series resistor and load. |
Key Features
| Feature | Design Value |
|---|---|
| Hermetic glass MELF construction | Eliminates moisture ingress and long-term parameter drift; qualified for high-reliability programs requiring source control drawings (SCD). |
| JEDEC DO-41 electrical equivalence | Enables drop-in replacement in legacy designs originally using through-hole 1N4729A, preserving circuit behavior without recalibration. |
| Specified capacitance (Figure 2) | Low junction capacitance supports stable regulation in RF-adjacent or fast-switching power domains without oscillation risk. |
| Radiation hardness (MicroNote 050) | Validated performance in total ionizing dose (TID) environments up to 100 krad(Si), suitable for space-grade subsystems. |
Applications
| Industrial Power Supply Regulation | Automotive ECU Reference Voltage |
|---|---|
Use Scenario: Stabilizing 3.3 V or 5 V auxiliary rails in programmable logic controllers and motor drives where input voltage varies widely. IC Role / Device Role / Timing Role: Zener shunt regulator providing precise DC reference for op-amp comparators and ADC voltage references. Use Value: Maintains ±5% output accuracy across -40°C to +125°C ambient while dissipating ≤1 W, eliminating need for active regulators in low-current paths. | Use Scenario: Generating stable bias voltage for sensor signal conditioning circuits in engine control units exposed to under-hood thermal extremes. IC Role / Device Role / Timing Role: Passive voltage reference establishing known threshold for knock sensor amplifiers and throttle position interface circuits. Use Value: Delivers 3.6 V reference with <10 Ω dynamic impedance and -65°C to +175°C operation, ensuring consistent analog front-end gain calibration despite thermal shock. |
| Aerospace Avionics Biasing | Medical Diagnostic Equipment Protection |
Use Scenario: Providing regulated excitation voltage to piezoresistive pressure transducers in flight data recorders and inertial measurement units. IC Role / Device Role / Timing Role: Radiation-hardened Zener reference enabling accurate sensor scaling in high-altitude, high-dose-rate environments. Use Value: Meets MicroNote 050 radiation hardness spec and maintains regulation stability after 100 krad(Si), supporting DO-160E Section 22 compliance. | Use Scenario: Clamping transient overvoltages on patient-connected analog inputs in ECG and EEG monitoring systems to protect downstream amplifiers. IC Role / Device Role / Timing Role: Surge-rated shunt limiter absorbing >1200 mA pulses while holding voltage below 5 V for 100 ms. Use Value: Limits fault energy to safe levels per IEC 60601-1 clause 8.8.3 without sacrificing signal integrity due to low 100 μA leakage at 1 V reverse bias. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Zener regulation applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 1N4729A | DO-41 through-hole package; identical electrical specs (3.6 V ±5%, 1 W, 10 Ω ZZT); no tape-and-reel option. | Requires manual or wave-solder assembly; unsuitable for high-density SMT layouts. | Select when retrofitting legacy boards or prototyping with breadboards where leaded components are preferred. |
| SMAJ4729A | DO-214AC (SMA) plastic package; same Zener voltage and tolerance but higher thermal resistance (150°C/W vs. 130°C/W) and lower surge rating (1000 mA vs. 1260 mA). | Lower cost and wider availability, but reduced reliability in high-temp or high-surge environments. | Select for cost-sensitive consumer electronics where hermetic sealing and radiation hardness are not required. |
Compared with 1N4729A and SMAJ4729A, the 1N4729UR-1/TR uniquely combines surface-mount compatibility, hermetic glass reliability, and superior surge capability-making it optimal for mission-critical industrial and aerospace regulation where layout density and long-term stability are non-negotiable.
Availability
1N4729UR-1/TR is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronic control units, and aerospace avionics requiring stable component supply with full traceability and long-lifecycle support.
Supply support for 1N4729UR-1/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 (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog, mixed-signal, and RF solutions for defense, aerospace, and industrial markets.
The 1N4729UR-1/TR belongs to Microsemi's surface-mount Zener diode family designed for high-density, high-stability voltage regulation in harsh-environment electronics where hermetic sealing and radiation tolerance are essential.
FAQ
What is the Zener voltage tolerance of the 1N4729UR-1/TR?
The 1N4729UR-1/TR has a nominal Zener voltage of 3.6 V with a tolerance of ±5%, as indicated by the "A" suffix in its full designation. This tolerance is verified at 30°C case temperature with 69 mA test current and ensures predictable regulation across production lots without post-assembly trimming.
How does the DO-213AB package of the 1N4729UR-1/TR differ from standard DO-41 diodes?
The 1N4729UR-1/TR uses a DO-213AB glass MELF package-surface-mountable, leadless, and hermetically sealed-whereas DO-41 is axial-leaded and through-hole. Electrically identical to 1N4729A, the 1N4729UR-1/TR enables automated placement and higher board density while retaining radiation hardness and moisture resistance.
Can the 1N4729UR-1/TR replace the 1N4729A in existing designs?
Yes, the 1N4729UR-1/TR is electrically equivalent to the 1N4729A and intended as its surface-mount replacement. However, PCB layout must be updated to accommodate the DO-213AB footprint and reflow profile; mechanical mounting and thermal pad design per Microsemi's recommended footprint (Page 3) are required for reliable operation.
What is the maximum surge current rating for the 1N4729UR-1/TR?
The 1N4729UR-1/TR is rated for a maximum surge current (IS) of 1260 mA, measured using a ½ sine-wave pulse of 1/120 second duration at 25°C ambient. This rating allows the device to absorb transient overvoltages in power supply inputs and sensor interfaces without permanent degradation.
Is the 1N4729UR-1/TR RoHS compliant?
Yes, the 1N4729UR-1/TR is RoHS compliant, as confirmed by the "e3" suffix in its full part number family (1N4729AUR,e3). It features annealed matte-tin plating compliant with JEDEC J-STD-609 and meets lead-free soldering requirements including 260°C/10 s reflow tolerance.
1N4729UR-1/TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- DO-213AB, MELF (Glass)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Voltage - Zener (Nom) (Vz):
- 3.6 V
- Tolerance:
- ±10%
- Power - Max:
- 1 W
- Impedance (Max) (Zzt):
- 10 Ohms
- Current - Reverse Leakage @ Vr:
- 100 µA @ 1 V
- Voltage - Forward (Vf) (Max) @ If:
- 1.2 V @ 200 mA
- Operating Temperature:
- -65°C ~ 175°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-213AB (MELF, LL41)
1N4729UR-1/TR FAQ
1.How can I place an order for 1N4729UR-1/TR through Aetrix?
Please submit a Request for Quotation (RFQ) for 1N4729UR-1/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 1N4729UR-1/TR reliable?
The price and inventory of 1N4729UR-1/TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1N4729UR-1/TR is usually 5 days.
3.What payment methods are accepted for 1N4729UR-1/TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1N4729UR-1/TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1N4729UR-1/TR?
1N4729UR-1/TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1N4729UR-1/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 1N4729UR-1/TR?
For technical support, including 1N4729UR-1/TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1N4729UR-1/TR requirements.
6.How does Aetrix verify that 1N4729UR-1/TR is sourced from the original manufacturer or authorized distributors?
All 1N4729UR-1/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 1N4729UR-1/TR meets industry standards.
7.What is the process for return or replacement of 1N4729UR-1/TR?
All 1N4729UR-1/TR units undergo pre-shipment inspection (PSI). If there is an issue with 1N4729UR-1/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 1N4729UR-1/TR part is unused and in its original packaging.
Return procedure for 1N4729UR-1/TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1N4729UR-1/TR Tags
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