Equivalent & Substitute Parts for CLL4729A BK Zener Diode

Part Overview

The CLL4729A BK is a 3.6 V, 1 W Zener diode manufactured by Central Semiconductor Corp in MELF surface mount packaging. This component is classified as obsolete, necessitating identification of active equivalent and substitute parts for ongoing design support and procurement. The part operates across a temperature range of -65°C to 200°C with ±5% voltage tolerance and is suitable for voltage regulation and protection applications in surface mount assemblies.

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 Range	-65 to 200	°C
Mounting Type	Surface Mount	-
Package / Case	DO-213AB, MELF	-
Moisture Sensitivity Level	1 (Unlimited)	-

Substitute Part Grouping Explanation

Substitution eligibility for the CLL4729A BK is determined by the following critical parameters:

Primary Matching Criteria:

Zener voltage: 3.6 V nominal
Mounting type: Surface Mount
Package compatibility: DO-213AB / MELF form factor
Moisture sensitivity: MSL 1 (Unlimited)

Secondary Compatibility Factors:

Power rating: 1 W minimum (higher ratings acceptable for derating applications)
Voltage tolerance: ±5% or tighter
Impedance: 10 Ohms maximum
Reverse leakage current: 100 µA @ 1 V maximum
Forward voltage: 1.2 V @ 200 mA maximum
Operating temperature: -65°C to 175°C minimum (original part extends to 200°C)

All substitute parts listed are manufactured by Microchip Technology and maintain the 3.6 V zener voltage specification with compatible surface mount packaging. Substitutes are grouped by power rating and tolerance specifications.

Parameter Comparison

Part Number	Manufacturer	Vz (Nom)	Tolerance	Power (Max)	Zzt (Max)	Ir @ 1V	Vf @ 200mA	Temp Range	Status
CLL4729A BK	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 (Equivalent Performance):

CDLL3822A is the closest functional equivalent to CLL4729A BK. Both parts specify 3.6 V nominal zener voltage, ±5% tolerance, 1 W maximum power, and 10 Ohms maximum impedance. CDLL3822A is active and available in production quantities (667 Pcs in stock). The operating temperature range is reduced to -65°C to 175°C compared to the original -65°C to 200°C specification.

Enhanced Performance Substitutes (Higher Power Rating):

CDLL5914B, CDLL5914C, and CDLL5914D provide 1.25 W power ratings with improved impedance characteristics (9 Ohms maximum). These parts are suitable for applications requiring additional thermal margin or higher dissipation capability. CDLL5914C offers ±2% tolerance, and CDLL5914D provides ±1% tolerance for precision voltage regulation applications. All three variants are active with substantial inventory availability.

Alternative with Matching Specifications:

1N5914BUR-1 (Microchip Technology) matches the CLL4729A BK in voltage, tolerance, and power rating with enhanced impedance performance. This part is active and available (1038 Pcs in stock).

Compliance Considerations:

All substitute parts are RoHS non-compliant and REACH unaffected, consistent with the original part's compliance status. All parts maintain MSL 1 (Unlimited) moisture sensitivity rating. ECCN and HTSUS classifications remain unchanged across all substitutes.

Temperature Range Limitation:

The original CLL4729A BK operates to 200°C; all substitute parts operate to 175°C maximum. Applications requiring operation above 175°C cannot use these substitutes without design modification.

Frequently Asked Questions (FAQ)

Q: Can CDLL3822A directly replace CLL4729A BK in existing designs?

A: CDLL3822A is functionally equivalent for applications operating within -65°C to 175°C. Both parts specify 3.6 V nominal zener voltage, ±5% tolerance, 1 W power rating, and 10 Ohms maximum impedance. The primary limitation is the reduced upper operating temperature (175°C vs. 200°C). Verify that your application does not require operation above 175°C before substitution.

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

A: All three parts share identical electrical specifications except for voltage tolerance: CDLL5914B specifies ±5%, CDLL5914C specifies ±2%, and CDLL5914D specifies ±1%. All three provide 1.25 W power rating and 9 Ohms maximum impedance. Select CDLL5914D for precision voltage regulation requiring tighter tolerance control; select CDLL5914B for general-purpose applications where ±5% tolerance is acceptable.

Q: Are all substitute parts in the same physical package?

A: Yes. All substitute parts use DO-213AB / MELF surface mount packaging, compatible with the original CLL4729A BK footprint. No PCB layout modifications are required for package compatibility.

Q: What is the significance of the lower reverse leakage current in substitute parts?

A: Substitute parts specify 75 µA @ 1 V reverse leakage compared to the original 100 µA @ 1 V. Lower reverse leakage improves circuit performance in precision applications and reduces standby power consumption. This is a beneficial characteristic and does not affect substitution eligibility.

Q: Why does CDLL4729 not specify a power rating?

A: CDLL4729 data provided does not include a maximum power specification. This part is not recommended as a substitute due to incomplete electrical characterization. Use CDLL3822A or CDLL5914 series parts instead.

Q: Can I use a higher power-rated substitute in a design specified for 1 W?

A: Yes. CDLL5914B, CDLL5914C, and CDLL5914D (1.25 W rated) are suitable for applications designed for 1 W operation. The higher power rating provides additional thermal margin and does not affect circuit function. Verify that circuit impedance and voltage regulation characteristics remain acceptable with the lower impedance (9 Ohms vs. 10 Ohms) of these parts.

Q: What compliance certifications apply to these substitute parts?

A: All substitute parts are RoHS non-compliant, REACH unaffected, and classified as EAR99 for export control purposes. HTSUS classification 8541.10.0050 applies uniformly across all parts. Verify compliance requirements for your specific application and regulatory jurisdiction.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message