ECS-240-16-4 24 MHz Crystal Equivalent & Substitute Parts

Part Overview

The ECS-240-16-4 is a 24 MHz through-hole crystal oscillator in HC-49/US package with 16pF load capacitance and 30 Ohms ESR. This part carries a "Not For New Designs" status, indicating it is obsolete or being phased out. Identifying equivalent and substitute parts is necessary to support existing designs, ensure supply chain continuity, and transition to active production alternatives.

Key Parameters

Parameter	Value
Frequency	24 MHz
Frequency Tolerance	±30ppm
Load Capacitance	16pF
ESR (Equivalent Series Resistance)	30 Ohms
Operating Mode	Fundamental
Operating Temperature Range	-10°C to 70°C
Package / Case	HC-49/US
Mounting Type	Through Hole
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution of the ECS-240-16-4 is determined by the following critical parameters:

Frequency: All substitutes must operate at 24 MHz
Frequency Tolerance: All substitutes must maintain ±30ppm tolerance
Operating Mode: All substitutes must operate in Fundamental mode
Package / Case: All substitutes must use HC-49/US package
Mounting Type: All substitutes must be through-hole
Operating Temperature Range: All substitutes must support -10°C to 70°C

Load capacitance (16pF, 20pF, 12pF) and ESR (30 Ohms, 40 Ohms) are application-dependent parameters. Substitutes with different load capacitance values are listed as alternatives for designs with different circuit requirements. ESR variations are acceptable within the same frequency and tolerance specifications.

Parameter Comparison

Part Number	Load Capacitance	ESR (Ohms)	Series	Product Status	RoHS Status	Inventory (Pcs)
ECS-240-16-4	16pF	30	HC-49US	Not For New Designs	RoHS non-compliant	714
ECS-240-16-4X	16pF	30	HC-49USX	Active	ROHS3 Compliant	2849
ECS-240-12-4X	12pF	30	HC-49USX	Active	ROHS3 Compliant	5611
ECS-240-20-4	20pF	30	HC-49US	Not For New Designs	RoHS non-compliant	1802
ECS-240-20-4X	20pF	30	HC-49USX	Active	ROHS3 Compliant	16998
ECS-240-20-4VX	20pF	40	HC-49USSX	Active	ROHS3 Compliant	840

Engineering Selection Recommendations

Direct Parametric Equivalent (Recommended for Existing Designs):

ECS-240-16-4X is the direct parametric equivalent of ECS-240-16-4. Both parts maintain identical electrical specifications: 24 MHz frequency, ±30ppm tolerance, 16pF load capacitance, and 30 Ohms ESR. The primary difference is product status and compliance: ECS-240-16-4X is Active and ROHS3 Compliant, whereas ECS-240-16-4 is Not For New Designs and RoHS non-compliant. For designs currently using ECS-240-16-4, transition to ECS-240-16-4X without circuit modification.

Alternative Load Capacitance Options:

ECS-240-20-4X and ECS-240-12-4X are substitutes with different load capacitance values. These parts are suitable only if the circuit design accommodates the alternative load capacitance. ECS-240-20-4X (20pF) and ECS-240-12-4X (12pF) both carry Active status and ROHS3 Compliance. Selection between these alternatives depends on the oscillator circuit's load capacitance requirement.

ESR Variation:

ECS-240-20-4VX operates at 40 Ohms ESR compared to the standard 30 Ohms. This part is suitable only for applications where higher ESR is acceptable. It is Active and ROHS3 Compliant.

Frequently Asked Questions (FAQ)

Q: Can ECS-240-16-4X directly replace ECS-240-16-4 without circuit changes?

A: Yes. ECS-240-16-4X is a parametric equivalent with identical frequency, tolerance, load capacitance, and ESR specifications. The part operates within the same -10°C to 70°C temperature range and uses the same HC-49/US through-hole package.

Q: What is the difference between ECS-240-16-4 and ECS-240-16-4X?

A: Both parts have identical electrical specifications. ECS-240-16-4X is the active production variant with ROHS3 compliance, while ECS-240-16-4 is marked "Not For New Designs" and is RoHS non-compliant. ECS-240-16-4X is recommended for all new and existing designs.

Q: Can I use ECS-240-20-4X instead of ECS-240-16-4?

A: Only if your circuit design supports 20pF load capacitance instead of 16pF. Load capacitance affects oscillator frequency stability and startup characteristics. Verify circuit compatibility before substitution.

Q: Can I use ECS-240-12-4X instead of ECS-240-16-4?

A: Only if your circuit design supports 12pF load capacitance instead of 16pF. Load capacitance affects oscillator frequency stability and startup characteristics. Verify circuit compatibility before substitution.

Q: What does "Not For New Designs" mean?

A: This status indicates the part is obsolete or being phased out. Existing inventory may be available, but the manufacturer does not recommend its use in new designs. Transition to active alternatives such as ECS-240-16-4X.

Q: Are all substitute parts RoHS compliant?

A: ECS-240-16-4X, ECS-240-12-4X, ECS-240-20-4X, and ECS-240-20-4VX are ROHS3 Compliant. ECS-240-16-4 and ECS-240-20-4 are RoHS non-compliant. For applications requiring RoHS compliance, use only the active variants.

Q: Do all parts use the same HC-49/US package?

A: All parts use HC-49/US or HC-49USX/HC-49USSX variants of the same package family. Physical dimensions are consistent across all listed parts, with minor height variations in ECS-240-20-4VX (2.10mm vs. 4.60mm seated height).

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