ECS-49-20-7S-TR Equivalent & Substitute Parts

Part Overview

The ECS-49-20-7S-TR is a 4.9152 MHz crystal oscillator in 4-SOJ surface mount package with 20pF load capacitance and 150 Ohms equivalent series resistance. This component is classified as Not For New Designs, indicating it has been superseded in the manufacturer's product line. Identifying equivalent and substitute parts is necessary for legacy system support, design continuity, and component sourcing when original inventory becomes unavailable.

Key Parameters

Parameter	Value
Frequency	4.9152 MHz
Frequency Tolerance	±30ppm
Load Capacitance	20pF
ESR (Equivalent Series Resistance)	150 Ohms
Package / Case	4-SOJ, 9.40mm pitch
Mounting Type	Surface Mount
Operating Temperature Range	-10°C ~ 70°C
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution for the ECS-49-20-7S-TR is determined by strict equivalence in the following critical parameters: frequency (4.9152 MHz), frequency tolerance (±30ppm), ESR (150 Ohms), package type (4-SOJ, 9.40mm pitch), and operating temperature range (-10°C ~ 70°C). Load capacitance is a secondary parameter that may vary within acceptable design margins depending on circuit implementation.

The identified substitutes are grouped as follows:

Parametric Equivalent (Full Compatibility): ECS-49-20-7SX-TR matches all critical parameters including load capacitance (20pF), differing only in series designation (ECX-3SX vs. ECX-3S) and RoHS compliance status.

Similar Substitute (Load Capacitance Variation): ECS-49-18-7SX-TR maintains frequency, tolerance, ESR, package, and temperature specifications but with reduced load capacitance (18pF instead of 20pF). This part is suitable only when circuit design accommodates the 2pF load capacitance difference.

Parameter Comparison

Parameter	ECS-49-20-7S-TR	ECS-49-20-7SX-TR	ECS-49-18-7SX-TR
Manufacturer	ECS Inc.	ECS Inc.	ECS Inc.
Frequency	4.9152 MHz	4.9152 MHz	4.9152 MHz
Frequency Tolerance	±30ppm	±30ppm	±30ppm
Frequency Stability	±50ppm	±50ppm	±50ppm
Load Capacitance	20pF	20pF	18pF
ESR	150 Ohms	150 Ohms	150 Ohms
Package / Case	4-SOJ, 9.40mm pitch	4-SOJ, 9.40mm pitch	4-SOJ, 9.40mm pitch
Size / Dimension	0.492" L x 0.181" W (12.50mm x 4.60mm)	0.492" L x 0.181" W (12.50mm x 4.60mm)	0.492" L x 0.181" W (12.50mm x 4.60mm)
Height - Seated (Max)	0.146" (3.70mm)	0.146" (3.70mm)	0.146" (3.70mm)
Operating Temperature	-10°C ~ 70°C	-10°C ~ 70°C	-10°C ~ 70°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
MSL	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Series	ECX-3S	ECX-3SX	ECX-3SX
Product Status	Not For New Designs	Not For New Designs	Not For New Designs
RoHS Status	RoHS non-compliant	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected
Packaging	Tape & Reel (TR)	Tape & Reel (TR)	Tape & Reel (TR)

Engineering Selection Recommendations

For Direct Replacement (Preferred): Select ECS-49-20-7SX-TR when component sourcing requires a substitute. This part provides full parametric equivalence with identical load capacitance (20pF) and maintains all electrical specifications. The upgrade to ROHS3 compliance offers regulatory advantage for new manufacturing batches or systems requiring environmental compliance documentation.

For Load Capacitance-Tolerant Designs: ECS-49-18-7SX-TR is selectable only when circuit design has been verified to accommodate 18pF load capacitance instead of 20pF. The 2pF reduction may affect oscillation frequency stability and startup characteristics depending on circuit topology. This substitution requires design validation before implementation.

Compliance Consideration: Both substitute parts (ECS-49-20-7SX-TR and ECS-49-18-7SX-TR) are ROHS3 compliant, whereas the original ECS-49-20-7S-TR is RoHS non-compliant. Systems requiring RoHS compliance should prioritize the substitute parts.

Frequently Asked Questions (FAQ)

Q: Can ECS-49-20-7SX-TR be used as a direct drop-in replacement for ECS-49-20-7S-TR?

A: Yes. ECS-49-20-7SX-TR is a parametric equivalent with identical frequency (4.9152 MHz), load capacitance (20pF), ESR (150 Ohms), package (4-SOJ, 9.40mm pitch), and operating temperature range (-10°C ~ 70°C). Physical dimensions and mounting characteristics are identical, enabling direct PCB substitution.

Q: What is the difference between ECS-49-20-7S-TR and ECS-49-20-7SX-TR?

A: The primary differences are series designation (ECX-3S vs. ECX-3SX) and RoHS compliance status (non-compliant vs. ROHS3 compliant). All electrical and mechanical parameters are identical.

Q: Can ECS-49-18-7SX-TR replace ECS-49-20-7S-TR?

A: ECS-49-18-7SX-TR maintains frequency, tolerance, ESR, package, and temperature specifications but has 18pF load capacitance instead of 20pF. Substitution is possible only if circuit design has been validated to function with the reduced load capacitance. The 2pF difference may affect frequency stability and oscillator startup behavior.

Q: Are all three parts available in the same packaging format?

A: Yes. All three parts are supplied in Tape & Reel (TR) packaging with identical physical dimensions (0.492" L x 0.181" W, 12.50mm x 4.60mm) and maximum seated height (0.146", 3.70mm).

Q: What is the significance of the "Not For New Designs" status?

A: This designation indicates the part has been superseded in the manufacturer's product line. While the part remains functional and available, ECS Inc. recommends using newer series (ECX-3SX) for new designs. Existing systems using ECS-49-20-7S-TR can continue operation; substitutes are available for component replenishment.

Q: Does load capacitance affect frequency accuracy?

A: Load capacitance is a circuit parameter that influences oscillator frequency. Both the main part (20pF) and substitute ECS-49-18-7SX-TR (18pF) are specified with ±30ppm frequency tolerance. Changing load capacitance may shift actual frequency within the tolerance band. Circuit validation is required when substituting ECS-49-18-7SX-TR.

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