Fox Electronics 603-25-261 Equivalent & Substitute Parts

Part Overview

The Fox Electronics 603-25-261 is a 25 MHz fundamental mode crystal oscillator in 4-SMD, No Lead surface mount package. This part operates at ±20ppm frequency stability with 8pF load capacitance and 50 Ohms ESR across the -40°C to 85°C temperature range. The device is ROHS3 compliant and carries MSL 1 (Unlimited) moisture sensitivity rating. As an active product with 28,600 units in stock, substitute parts may be required for design flexibility, supply chain optimization, or specific application requirements where alternative electrical or mechanical parameters are acceptable.

Substiute Parts

603-25-261

Fox ElectronicsIn Stock: 28701603-25-261 Datasheet

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ABM11-25.000MHZ-D2X-T3

Abracon LLCIn Stock: 3190ABM11-25.000MHZ-D2X-T3 Datasheet

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ECS-250-10-37-JTN-TR

ECS Inc.In Stock: 6278ECS-250-10-37-JTN-TR Datasheet

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ECS-250-6-37-JTN-TR

ECS Inc.In Stock: 2854ECS-250-6-37-JTN-TR Datasheet

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LFXTAL063334

IQD Frequency ProductsIn Stock: 5660LFXTAL063334 Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution of the 603-25-261 is determined by the following critical parameters: frequency (25 MHz), frequency stability (±20ppm), operating temperature range (-40°C to 85°C), mounting type (Surface Mount), package type (4-SMD, No Lead), and operating mode (Fundamental). Load capacitance and ESR values may vary within acceptable ranges depending on circuit design requirements. All substitute parts listed maintain identical frequency, frequency stability, temperature range, and package configuration. Variations in load capacitance (6pF to 10pF) and ESR (50 to 100 Ohms) are permissible substitutions when the receiving circuit is designed to accommodate these electrical parameters. All substitute parts are ROHS3 compliant and active products.

Parameter Comparison

Engineering Selection Recommendations

All listed substitute parts maintain active product status and ROHS3 compliance, ensuring long-term availability and regulatory alignment with the original 603-25-261. The ABM11-25.000MHZ-D2X-T3 (Abracon LLC) and LFXTAL063334 (IQD Frequency Products) feature 10pF load capacitance with 100 Ohms ESR, suitable for circuits designed to accommodate these electrical parameters. The ECS-250-10-37-JTN-TR offers 10pF load capacitance with 80 Ohms ESR in a compact 2.00mm x 1.60mm footprint. The ECS-250-6-37-JTN-TR provides the closest load capacitance match at 6pF with 80 Ohms ESR. All substitute parts are available in Tape & Reel (TR) packaging and maintain the same fundamental operating mode and temperature range as the original part. Selection should be based on circuit load capacitance requirements and available PCB space, as dimensional variations exist between the original part and substitutes.

Frequently Asked Questions (FAQ)

Q: Can the ABM11-25.000MHZ-D2X-T3 directly replace the 603-25-261?

A: Direct replacement is possible if the receiving circuit is designed for 10pF load capacitance and 100 Ohms ESR. Both parts share identical frequency (25 MHz), frequency stability (±20ppm), operating temperature range (-40°C to 85°C), and 4-SMD, No Lead package configuration. The ABM11 is physically smaller (2.00mm x 1.60mm vs. 3.20mm x 2.50mm), which may require PCB layout adjustment.

Q: What is the difference between the ECS-250-10-37-JTN-TR and ECS-250-6-37-JTN-TR?

A: Both ECS parts operate at 25 MHz with ±20ppm stability and identical temperature range. The primary difference is load capacitance: the ECS-250-10-37-JTN-TR specifies 10pF, while the ECS-250-6-37-JTN-TR specifies 6pF. The ECS-250-6-37-JTN-TR load capacitance is closer to the original 603-25-261 (8pF). Both feature 80 Ohms ESR and identical physical dimensions (2.00mm x 1.60mm).

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All listed substitute parts—ABM11-25.000MHZ-D2X-T3, ECS-250-10-37-JTN-TR, ECS-250-6-37-JTN-TR, and LFXTAL063334—are ROHS3 compliant, matching the compliance status of the original 603-25-261.

Q: How do ESR differences affect circuit performance?

A: ESR (Equivalent Series Resistance) affects crystal oscillator startup time and power consumption. The original 603-25-261 specifies 50 Ohms ESR. Substitute parts range from 80 to 100 Ohms ESR. Higher ESR values may increase startup time and power draw. Circuit design must accommodate the selected ESR value; substitution is valid only when the receiving circuit is designed for the substitute part's ESR specification.

Q: What are the moisture sensitivity implications?

A: The original 603-25-261 carries MSL 1 (Unlimited) rating. The ABM11-25.000MHZ-D2X-T3 and LFXTAL063334 are listed as "Not Applicable" for MSL, indicating no moisture sensitivity restrictions. The ECS parts (ECS-250-10-37-JTN-TR and ECS-250-6-37-JTN-TR) carry MSL 1 (Unlimited) rating, matching the original part.

Q: Can I use the LFXTAL063334 in space-constrained applications?

A: The LFXTAL063334 measures 2.50mm x 2.00mm with 0.60mm maximum seated height, offering moderate size reduction compared to the original 603-25-261 (3.20mm x 2.50mm, 0.80mm height). The ECS parts provide the most compact option at 2.00mm x 1.60mm with 0.55mm to 0.55mm maximum height. Selection depends on specific PCB space constraints and load capacitance requirements.