CS20-3.6864MABJ-UT Equivalent & Substitute Parts

Part Overview

The CS20-3.6864MABJ-UT is a 3.6864 MHz crystal oscillator manufactured by Citizen Finedevice Co Ltd, designed for fundamental mode operation in 4-SMD, No Lead surface mount packages. This component operates at ±30ppm frequency tolerance with an 18pF load capacitance and 200 Ohms equivalent series resistance. The part is classified as obsolete, making identification of functionally equivalent alternatives necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Frequency	3.6864 MHz
Frequency Tolerance	±30ppm
Load Capacitance	18pF
ESR (Equivalent Series Resistance)	200 Ohms
Operating Mode	Fundamental
Package / Case	4-SMD, No Lead
Operating Temperature Range	-10°C ~ 60°C
Mounting Type	Surface Mount
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the CS20-3.6864MABJ-UT is determined by the following critical parameters: frequency (3.6864 MHz), frequency tolerance (±30ppm), load capacitance (18pF), ESR (200 Ohms), operating mode (Fundamental), and package type (4-SMD, No Lead). Substitute parts must maintain compatibility across these electrical and mechanical specifications to ensure direct replacement without circuit redesign.

The substitute parts identified fall into two categories based on load capacitance deviation:

Category 1 - Exact Load Capacitance Match (18pF): ABC2-3.6864MHZ-4-T maintains the original 18pF load capacitance specification with lower ESR (140 Ohms) and identical frequency tolerance.

Category 2 - Load Capacitance Variation (20pF): ECS-36-20-18-TR, ECS-36-S-18-TR, and ECS-36-20-19A-TR operate at 20pF load capacitance, representing a deviation from the original specification. ECS-36-20-19A-TR additionally differs in package configuration (2-SMD vs. 4-SMD).

Parameter Comparison

Parameter	CS20-3.6864MABJ-UT	ABC2-3.6864MHZ-4-T	ECS-36-20-18-TR	ECS-36-S-18-TR	ECS-36-20-19A-TR
Manufacturer	Citizen Finedevice Co Ltd	Abracon LLC	ECS Inc.	ECS Inc.	ECS Inc.
Frequency	3.6864 MHz	3.6864 MHz	3.6864 MHz	3.6864 MHz	3.6864 MHz
Frequency Tolerance	±30ppm	±30ppm	±30ppm	±30ppm	±30ppm
Load Capacitance	18pF	18pF	20pF	Series	20pF
ESR	200 Ohms	140 Ohms	200 Ohms	200 Ohms	200 Ohms
Operating Mode	Fundamental	Fundamental	Fundamental	Fundamental	Fundamental
Package / Case	4-SMD, No Lead	4-SMD, No Lead	4-SMD, No Lead	4-SMD, No Lead	2-SMD, No Lead
Operating Temperature	-10°C ~ 60°C	-10°C ~ 60°C	-40°C ~ 85°C	-40°C ~ 85°C	-10°C ~ 70°C
Product Status	Obsolete	Active	Active	Active	Active
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Packaging	Not specified	Tape & Reel (TR)	Tape & Reel (TR)	Tape & Reel (TR)	Tape & Reel (TR)

Engineering Selection Recommendations

ABC2-3.6864MHZ-4-T (Abracon LLC) is the primary substitute candidate. It maintains exact electrical compatibility with 18pF load capacitance, ±30ppm frequency tolerance, and 4-SMD package configuration. The lower ESR (140 Ohms vs. 200 Ohms) represents an improvement in circuit performance. The part is active in production with ROHS3 compliance and available in Tape & Reel packaging.

ECS-36-20-18-TR and ECS-36-S-18-TR (ECS Inc.) are secondary options with 4-SMD package compatibility but operate at 20pF load capacitance instead of 18pF. Both parts are active with ROHS3 compliance and extended operating temperature ranges (-40°C ~ 85°C). These parts require circuit validation due to load capacitance deviation.

ECS-36-20-19A-TR (ECS Inc.) is not recommended as a direct substitute due to package configuration change from 4-SMD to 2-SMD, which introduces mechanical incompatibility with the original PCB footprint.

Frequently Asked Questions (FAQ)

Q: Can ABC2-3.6864MHZ-4-T be used as a direct replacement for CS20-3.6864MABJ-UT?

A: Yes. ABC2-3.6864MHZ-4-T maintains identical frequency (3.6864 MHz), frequency tolerance (±30ppm), load capacitance (18pF), operating mode (Fundamental), and package configuration (4-SMD, No Lead). The lower ESR (140 Ohms) is electrically favorable. No circuit modifications are required.

Q: What is the significance of load capacitance differences in the ECS substitute parts?

A: Load capacitance affects the crystal's resonant frequency in the circuit. ECS-36-20-18-TR and ECS-36-S-18-TR operate at 20pF instead of 18pF, requiring circuit tuning validation. The original design was optimized for 18pF; substitution with 20pF parts may introduce frequency offset requiring compensation through circuit adjustment.

Q: Why is ECS-36-20-19A-TR not suitable as a substitute?

A: ECS-36-20-19A-TR uses a 2-SMD package configuration instead of the original 4-SMD package. This creates mechanical incompatibility with the PCB footprint designed for the CS20-3.6864MABJ-UT, preventing direct mounting without redesign.

Q: Are all substitute parts RoHS compliant?

A: ABC2-3.6864MHZ-4-T, ECS-36-20-18-TR, ECS-36-S-18-TR, and ECS-36-20-19A-TR are all ROHS3 compliant. The original CS20-3.6864MABJ-UT RoHS status is not specified in the provided data.

Q: What are the inventory considerations for these substitutes?

A: ABC2-3.6864MHZ-4-T has 4075 units in stock. ECS-36-20-18-TR has 2860 units. ECS-36-S-18-TR has 4160 units. ECS-36-20-19A-TR has 742 units. All parts are available as new original components in Tape & Reel packaging.

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