FPXLF040 Equivalent & Substitute Parts

Part Overview

The FPXLF040 is a 4.0 MHz crystal oscillator manufactured by Fox Electronics, designed for surface mount applications with a 20pF load capacitance and 150 Ohms equivalent series resistance. This component operates in fundamental mode across a temperature range of -10°C to 70°C with ±50ppm frequency stability.

The FPXLF040 is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this frequency standard.

Substiute Parts

FPXLF040

Fox ElectronicsIn Stock: 1037FPXLF040 Datasheet

Current PartRFQ

ECS-40-20-7SX-TR

ECS Inc.In Stock: 17622ECS-40-20-7SX-TR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the FPXLF040 is determined by strict alignment of the following critical parameters:

Mandatory Matching Parameters:

• Frequency: 4.0000 MHz (exact match required)
• Load Capacitance: 20pF (exact match required)
• ESR: 150 Ohms (exact match required)
• Operating Mode: Fundamental (exact match required)
• Operating Temperature Range: -10°C to 70°C (minimum coverage required)
• Mounting Type: Surface Mount (exact match required)
• Moisture Sensitivity Level: MSL 1 or better (exact match or superior required)

Allowable Variations:

• Frequency Tolerance: May be equal to or tighter than ±50ppm
• Package configuration: May differ while maintaining mechanical and electrical compatibility
• Frequency Stability: May be equal to or tighter than ±50ppm

The ECS-40-20-7SX-TR meets all mandatory matching parameters and qualifies as a direct substitute for the FPXLF040.

Parameter Comparison

Engineering Selection Recommendations

The ECS-40-20-7SX-TR is a qualified substitute for the FPXLF040 based on electrical parameter equivalence and compliance alignment. Both components share identical frequency, load capacitance, ESR, operating temperature range, and regulatory classifications (REACH Unaffected, EAR99).

The ECS-40-20-7SX-TR offers a tighter frequency tolerance specification (±30ppm versus ±50ppm), which provides improved frequency accuracy without introducing incompatibility. The package configuration differs (4-SOJ versus 4-SMD, No Lead); however, physical dimensions remain identical, supporting direct mechanical substitution in existing PCB layouts.

The ECS-40-20-7SX-TR carries a product status of "Not For New Designs," indicating it is suitable for replacement and maintenance applications but not recommended for new product development. For new designs, consultation with the manufacturer regarding current production alternatives is advised.

Frequently Asked Questions (FAQ)

Q: Can the ECS-40-20-7SX-TR be used as a direct replacement for the FPXLF040 in existing designs?

A: Yes. The ECS-40-20-7SX-TR meets all critical electrical parameters: 4.0 MHz frequency, 20pF load capacitance, 150 Ohms ESR, and identical operating temperature range. Physical dimensions are identical, supporting direct PCB substitution.

Q: What is the difference between the 4-SMD, No Lead package and the 4-SOJ package?

A: Both packages maintain identical external dimensions (12.50mm × 4.60mm × 3.70mm max height). The primary difference is internal lead configuration and pitch spacing (9.40mm for 4-SOJ). Electrical performance and mechanical fit on existing PCBs remain compatible.

Q: Does the tighter frequency tolerance of the ECS-40-20-7SX-TR (±30ppm) affect compatibility?

A: No. Tighter tolerance specifications are compatible with designs specified for ±50ppm. The substitute component will perform within the original design specification and exceed the accuracy requirement.

Q: Are there regulatory or compliance differences between these parts?

A: No. Both components share identical REACH status (REACH Unaffected), ECCN classification (EAR99), and Moisture Sensitivity Level (MSL 1). Regulatory compliance is equivalent.

Q: Why is the ECS-40-20-7SX-TR marked "Not For New Designs"?

A: This designation indicates the part is in mature production status and suitable for replacement and maintenance applications. For new product development, contact ECS Inc. to identify current-generation alternatives with extended lifecycle support.