Equivalent & Substitute Parts for CLL4729A TR Zener Diode

Part Overview

The CLL4729A TR is a 3.6 V, 1 W surface mount zener diode manufactured by Central Semiconductor Corp in MELF (DO-213AB) package format. This component is classified as obsolete, which necessitates identification of active equivalent and substitute parts for ongoing design support and procurement continuity. The zener diode functions as a voltage regulation and transient protection element in electronic circuits, with specifications including ±5% voltage tolerance, 10 Ohms maximum impedance, and an operating temperature range of -65°C to 200°C.

Key Parameters

Parameter	Value	Unit
Voltage - Zener (Nom)	3.6	V
Tolerance	±5%	-
Power - Max	1	W
Impedance (Max)	10	Ohms
Current - Reverse Leakage @ Vr	100	µA @ 1 V
Voltage - Forward (Vf) (Max) @ If	1.2	V @ 200 mA
Operating Temperature	-65 to 200	°C
Mounting Type	Surface Mount	-
Package / Case	DO-213AB, MELF	-
Moisture Sensitivity Level	1 (Unlimited)	-

Substitute Part Grouping Explanation

Substitution of the CLL4729A TR is determined by strict equivalence across the following critical parameters:

Primary Matching Criteria:

Zener voltage: 3.6 V nominal
Package format: DO-213AB / MELF surface mount
Mounting type: Surface mount
Moisture sensitivity: MSL 1 (Unlimited)
Regulatory compliance: REACH Unaffected, ECCN EAR99

Secondary Compatibility Parameters:

Power rating: 1 W minimum (higher ratings acceptable for thermal margin)
Voltage tolerance: ±5% or tighter
Impedance: 10 Ohms maximum
Forward voltage: 1.2 V maximum @ 200 mA
Operating temperature range: Must support -65°C to 175°C minimum

All substitute parts listed are manufactured by Microchip Technology and maintain electrical and mechanical compatibility with the original CLL4729A TR specification. Substitutes are grouped by power rating and tolerance specifications to facilitate selection based on application requirements.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Reverse Leakage @ 1V	Vf (Max) @ 200mA	Temp Range	Status
CLL4729A TR	Central Semiconductor	3.6 V	±5%	1 W	10 Ω	100 µA	1.2 V	-65 to 200°C	Obsolete
1N5914BUR-1	Microchip Technology	3.6 V	±5%	1.25 W	9 Ω	75 µA	1.2 V	-65 to 175°C	Active
CDLL3822	Microchip Technology	3.6 V	±10%	1 W	10 Ω	75 µA	1.2 V	-65 to 175°C	Active
CDLL3822A	Microchip Technology	3.6 V	±5%	1 W	10 Ω	75 µA	1.2 V	-65 to 175°C	Active
CDLL4729	Microchip Technology	3.6 V	±10%	Not specified	10 Ω	100 µA	1.2 V	-65 to 175°C	Active
CDLL5914B	Microchip Technology	3.6 V	±5%	1.25 W	9 Ω	75 µA	1.2 V	-65 to 175°C	Active
CDLL5914C	Microchip Technology	3.6 V	±2%	1.25 W	9 Ω	75 µA	1.2 V	-65 to 175°C	Active
CDLL5914D	Microchip Technology	3.6 V	±1%	1.25 W	9 Ω	75 µA	1.2 V	-65 to 175°C	Active

Engineering Selection Recommendations

Direct Replacement (Highest Compatibility):

CDLL3822A is the closest functional equivalent to CLL4729A TR. Both components share identical zener voltage (3.6 V), tolerance (±5%), power rating (1 W), and impedance (10 Ohms). CDLL3822A is manufactured by Microchip Technology with active product status, ensuring long-term availability and supply chain stability. The operating temperature range of -65°C to 175°C covers the critical lower and upper bounds of the original specification.

Enhanced Performance Alternatives:

CDLL5914B and CDLL5914C provide increased power dissipation capability (1.25 W) while maintaining ±5% and ±2% voltage tolerance respectively. These parts feature improved impedance characteristics (9 Ohms) and reduced reverse leakage current (75 µA), resulting in superior voltage regulation performance. Selection between these variants depends on tolerance requirements: CDLL5914B for standard ±5% applications, CDLL5914C for precision ±2% voltage regulation.

CDLL5914D offers the tightest voltage tolerance (±1%) with identical 1.25 W power rating and 9 Ohms impedance, suitable for applications requiring maximum voltage accuracy.

Alternative with Relaxed Tolerance:

CDLL3822 maintains 1 W power rating and 10 Ohms impedance but specifies ±10% voltage tolerance. This part is appropriate for applications where voltage regulation tolerance is not critical.

Compliance Considerations:

All substitute parts carry REACH Unaffected and ECCN EAR99 classifications, matching the regulatory profile of the original component. All substitute parts are RoHS non-compliant, consistent with the original CLL4729A TR specification. Moisture sensitivity level remains MSL 1 (Unlimited) across all alternatives.

Frequently Asked Questions (FAQ)

Q: Can CDLL3822A directly replace CLL4729A TR without circuit modification?

A: Yes. CDLL3822A maintains electrical equivalence across all critical parameters: 3.6 V zener voltage, ±5% tolerance, 1 W power rating, 10 Ohms impedance, and identical forward voltage characteristics. Both components use DO-213AB MELF surface mount packaging. No circuit modifications are required.

Q: What is the difference between CDLL5914B, CDLL5914C, and CDLL5914D?

A: These three parts are identical except for voltage tolerance specification. CDLL5914B specifies ±5% tolerance, CDLL5914C specifies ±2% tolerance, and CDLL5914D specifies ±1% tolerance. All three provide 1.25 W power rating and 9 Ohms impedance. Selection depends on the voltage regulation precision required by the application.

Q: Why does CDLL4729 not specify a power rating?

A: The power rating for CDLL4729 is not provided in the available technical data. This part should not be selected as a primary substitute due to incomplete specification documentation. CDLL3822A or CDLL5914B are preferred alternatives with fully documented electrical characteristics.

Q: Is the operating temperature range difference significant?

A: The original CLL4729A TR specifies -65°C to 200°C, while all Microchip substitutes specify -65°C to 175°C. For applications operating above 175°C, the original part or alternative sources must be evaluated. For standard industrial and commercial applications within -65°C to 175°C, all substitute parts are fully compatible.

Q: What is the advantage of lower impedance in CDLL5914 series parts?

A: Lower impedance (9 Ohms versus 10 Ohms) in CDLL5914B, CDLL5914C, and CDLL5914D results in improved voltage regulation characteristics and reduced dynamic impedance effects. This provides superior performance in applications requiring stable voltage reference or transient suppression.

Q: Are all substitute parts available in the same MELF package?

A: Yes. All substitute parts use DO-213AB MELF surface mount package format, ensuring mechanical and electrical compatibility with existing PCB layouts designed for CLL4729A TR.

Q: What is the significance of reverse leakage current differences?

A: The original CLL4729A TR specifies 100 µA reverse leakage at 1 V, while Microchip substitutes specify 75 µA. Lower reverse leakage current improves circuit performance in precision voltage reference and low-power applications. This difference is not critical for standard voltage regulation applications.

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