1N4729ATR Equivalent & Substitute Parts

Part Overview

The 1N4729ATR is a Zener diode rated at 3.6 V nominal voltage with 1 W maximum power dissipation in a through-hole DO-41 package. Manufactured by onsemi, this component is classified as obsolete. Due to its obsolete status, equivalent and substitute parts from active manufacturers are necessary for new designs and ongoing production requirements. Substitute parts maintain the core electrical specifications while offering availability from current product lines.

Key Parameters

Parameter	Value
Voltage - Zener (Nom)	3.6 V
Tolerance	±5%
Power - Max	1 W
Impedance (Max)	10 Ohms
Current - Reverse Leakage @ Vr	100 µA @ 1 V
Operating Temperature Range	-65°C ~ 200°C
Mounting Type	Through Hole
Package / Case	DO-204AL, DO-41, Axial

Substitute Part Grouping Explanation

Substitution of the 1N4729ATR is determined by the following critical parameters:

Primary Substitution Criteria:

Zener voltage: 3.6 V nominal
Tolerance: ±5% or tighter
Power rating: 1 W or greater
Impedance: 10 Ohms or lower
Reverse leakage current: 100 µA @ 1 V or lower
Operating temperature range: minimum -65°C to 200°C (or -65°C to 175°C for reduced upper limit applications)
Mounting type: Through Hole
Package compatibility: DO-41 or DO-204AL (axial configuration)

Direct Equivalents maintain all electrical parameters and through-hole axial packaging. These parts are sourced from active manufacturers and provide pin-for-pin compatibility.

Similar Substitutes may vary in one or more parameters such as power rating, tolerance, impedance, or operating temperature range. These parts are suitable when the application permits relaxed specifications or when enhanced performance is acceptable.

Package Variants include surface-mount alternatives (DO-213AB) for applications requiring different assembly methods.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Reverse Leakage @ Vr	Temp Range	Package	Status
1N4729ATR	onsemi	3.6 V	±5%	1 W	10 Ω	100 µA @ 1 V	-65°C ~ 200°C	DO-41	Obsolete
1N4729A,133	NXP USA Inc.	3.6 V	±5%	1 W	10 Ω	100 µA @ 1 V	-65°C ~ 200°C	DO-41	Active
1N4729AG	Microsemi Corporation	3.6 V	±5%	1 W	10 Ω	100 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
1N4729 G	Microsemi Corporation	3.6 V	±10%	1 W	10 Ω	100 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
1N4729AUR	Microchip Technology	3.6 V	±5%	1 W	10 Ω	100 µA @ 1 V	-65°C ~ 175°C	DO-213AB	Active
1N4621-1	Microchip Technology	3.6 V	±5%	500 mW	1700 Ω	3.5 µA @ 2 V	-65°C ~ 175°C	DO-7	Active
1N5914AG	Microsemi Corporation	3.6 V	±10%	1.25 W	9 Ω	75 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
1N5914BG	Microsemi Corporation	3.6 V	±5%	1.25 W	9 Ω	75 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
1N5914CG	Microsemi Corporation	3.6 V	±2%	1.25 W	9 Ω	75 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
1N5914DG	Microsemi Corporation	3.6 V	±1%	1.25 W	9 Ω	75 µA @ 1 V	-65°C ~ 175°C	DO-41	Active
2EZ3.6D5	Microsemi Corporation	3.6 V	±5%	2 W	5 Ω	80 µA @ 1 V	-65°C ~ 150°C	DO-41	Active

Engineering Selection Recommendations

Direct Equivalents for Pin-for-Pin Replacement:

The 1N4729A,133 (NXP USA Inc.) is the primary direct equivalent. It maintains identical electrical specifications and through-hole DO-41 packaging with active product status and full temperature range compatibility (-65°C to 200°C).

The 1N4729AG (Microsemi Corporation) provides equivalent electrical performance with ±5% tolerance and 1 W power rating. The operating temperature range is reduced to -65°C to 175°C, which is acceptable for most applications not requiring the extended upper temperature limit of 200°C.

Substitutes with Relaxed Tolerance:

The 1N4729 G (Microsemi Corporation) offers the same 1 W power rating and DO-41 package but with ±10% tolerance instead of ±5%. This part is suitable for applications where voltage regulation tolerance is not critical.

Enhanced Performance Substitutes:

The 1N5914 series (Microsemi Corporation) provides higher power dissipation at 1.25 W with improved impedance characteristics (9 Ohms versus 10 Ohms) and lower reverse leakage current (75 µA versus 100 µA). Multiple tolerance grades are available: 1N5914AG (±10%), 1N5914BG (±5%), 1N5914CG (±2%), and 1N5914DG (±1%). These parts are suitable for applications requiring enhanced thermal performance or tighter voltage regulation.

The 2EZ3.6D5 (Microsemi Corporation) provides the highest power rating at 2 W with superior impedance (5 Ohms) and lower reverse leakage (80 µA). The operating temperature range is reduced to -65°C to 150°C.

Surface-Mount Alternative:

The 1N4729AUR (Microchip Technology) maintains identical electrical specifications in a surface-mount DO-213AB package for applications requiring SMD assembly.

Lower Power Alternative:

The 1N4621-1 (Microchip Technology) is a 500 mW variant with different impedance and leakage characteristics. This part is suitable only for applications with reduced power dissipation requirements.

Frequently Asked Questions (FAQ)

Q: Can I use 1N4729A,133 as a direct replacement for 1N4729ATR?

A: Yes. The 1N4729A,133 maintains identical electrical specifications (3.6 V, ±5%, 1 W, 10 Ω impedance) and through-hole DO-41 packaging. The primary difference is manufacturer (NXP USA Inc. versus onsemi) and active product status.

Q: What is the difference between 1N4729AG and 1N4729 G?

A: Both are manufactured by Microsemi Corporation in DO-41 packages with 3.6 V nominal voltage and 1 W power rating. The 1N4729AG has ±5% tolerance, while 1N4729 G has ±10% tolerance. The 1N4729AG provides tighter voltage regulation.

Q: Can I substitute a 1N5914 series part for the 1N4729ATR?

A: Yes, with the understanding that the 1N5914 series provides enhanced specifications. These parts offer 1.25 W power rating (versus 1 W), lower impedance (9 Ω versus 10 Ω), and lower reverse leakage current (75 µA versus 100 µA). Multiple tolerance options are available. The operating temperature range is -65°C to 175°C.

Q: Why would I choose the 2EZ3.6D5 over the 1N4729ATR equivalent?

A: The 2EZ3.6D5 provides superior thermal performance with 2 W power dissipation and lower impedance (5 Ω). It is suitable for applications requiring higher power handling or improved voltage regulation stability. The operating temperature range is reduced to -65°C to 150°C.

Q: Is the 1N4729AUR a suitable replacement?

A: The 1N4729AUR is electrically equivalent but uses surface-mount DO-213AB packaging instead of through-hole DO-41. It is suitable only for applications designed for SMD assembly. It is not a direct replacement for through-hole designs.

Q: Can I use the 1N4621-1 as a substitute?

A: The 1N4621-1 is not recommended as a general substitute. It has reduced power rating (500 mW versus 1 W), significantly higher impedance (1700 Ω versus 10 Ω), and different leakage characteristics. It is suitable only for applications with lower power dissipation requirements.

Q: What is the impact of tolerance differences between substitute parts?

A: Tolerance affects the precision of the zener voltage. The 1N4729ATR has ±5% tolerance. Tighter tolerances (±2% or ±1%) provide more precise voltage regulation. Looser tolerances (±10%) are acceptable for applications where voltage variation is not critical. Select tolerance based on circuit requirements.

Q: Are all substitute parts RoHS compliant?

A: The 1N4729ATR does not specify RoHS status. Most substitute parts from Microsemi Corporation and Microchip Technology are listed as RoHS non-compliant. Verify RoHS compliance requirements for your specific application and supply chain.

Q: What is the difference between DO-41 and DO-204AL packaging?

A: DO-41 and DO-204AL are equivalent designations for the same through-hole axial package. Both refer to a two-lead axial component with identical physical dimensions and pin spacing. These terms are interchangeable.

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