9B25000568 Crystal Equivalent & Substitute Parts

Part Overview

The 9B25000568 is a 25 MHz through-hole crystal manufactured by TXC CORPORATION, designed for fundamental mode operation with ±30ppm frequency stability and 20pF load capacitance. This component is classified as obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this crystal specification.

Substiute Parts

9B25000568

TXC CORPORATIONIn Stock: 10599B25000568 Datasheet

Current PartRFQ

HC49US-FF5F18-25.000MHZ

ILSIIn Stock: 1228HC49US-FF5F18-25.000MHZ Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the 9B25000568 is evaluated based on strict parameter matching across electrical and mechanical specifications. The following criteria determine substitution eligibility:

Mandatory Matching Parameters:

• Frequency: 25 MHz (exact match required)
• Frequency Stability: ±30ppm (substitute must meet or exceed this specification)
• Operating Mode: Fundamental (no overtone operation permitted)
• Package / Case: HC-49/US (physical form factor must be identical)
• Mounting Type: Through Hole (PCB assembly method must be compatible)
• Operating Temperature Range: -40°C ~ 85°C (minimum environmental compliance)
• ESR: 30 Ohms (electrical performance parameter)

Load Capacitance Consideration: Load capacitance is a critical parameter that determines circuit compatibility. Substitutes with load capacitance values differing from 20pF require circuit design verification to ensure oscillator stability and frequency accuracy. The HC49US-FF5F18-25.000MHZ operates at 18pF load capacitance, representing a 2pF reduction from the original specification.

Compliance Parameters: RoHS3 compliance and REACH status are evaluated to ensure regulatory alignment with current manufacturing standards.

Parameter Comparison

Engineering Selection Recommendations

The HC49US-FF5F18-25.000MHZ manufactured by ILSI is identified as a functional substitute for the obsolete 9B25000568. Selection is based on the following engineering criteria:

Electrical Compatibility: Both components operate at 25 MHz with ±30ppm frequency stability and 30 Ohms ESR. The primary electrical variance is load capacitance: the substitute operates at 18pF versus the original 20pF specification. This 2pF difference is within typical HC-49/US component tolerances and does not preclude substitution in applications where the oscillator circuit is designed to accommodate load capacitance variation within standard ranges.

Physical and Mechanical Compatibility: Both crystals utilize the HC-49/US package form factor with through-hole mounting. Dimensional variations (11.50mm vs. 11.10mm length; 5.00mm vs. 4.70mm width; 3.68mm vs. 3.50mm height) remain within HC-49/US package specifications and do not impact PCB assembly or mechanical fit.

Regulatory and Compliance Status: The substitute part maintains ROHS3 compliance, ensuring alignment with current environmental and regulatory requirements. The original part is classified as obsolete, while the substitute is active product status, supporting long-term supply chain availability.

Product Availability: The HC49US-FF5F18-25.000MHZ is available in active inventory (1149 pcs), providing supply continuity for applications currently utilizing the obsolete 9B25000568.

Frequently Asked Questions (FAQ)

Q: Can the HC49US-FF5F18-25.000MHZ directly replace the 9B25000568 without circuit modification?

A: Direct replacement is possible in most applications. Both components share identical frequency (25 MHz), frequency stability (±30ppm), ESR (30 Ohms), operating mode (Fundamental), and temperature range (-40°C ~ 85°C). The load capacitance difference (20pF vs. 18pF) is a 2pF variance. If the oscillator circuit is designed with standard load capacitance tolerance margins (typically ±5pF or greater), no circuit modification is required. Applications with tightly constrained load capacitance specifications should verify oscillator performance during integration testing.

Q: What is the significance of the 2pF load capacitance difference?

A: Load capacitance determines the external capacitive loading required for the crystal to oscillate at its specified frequency. A 2pF difference represents approximately 10% variance from the original 20pF specification. In standard oscillator circuits with tuning capacitors or load capacitance networks, this variance is typically accommodated within normal design tolerances. However, applications with fixed load capacitance or minimal tuning range should evaluate frequency accuracy impact.

Q: Are the physical dimensions compatible with the original PCB layout?

A: Yes. Both components conform to the HC-49/US package standard. The dimensional variations (length: 11.50mm vs. 11.10mm; width: 5.00mm vs. 4.70mm; height: 3.68mm vs. 3.50mm) fall within HC-49/US tolerance specifications. Through-hole mounting compatibility is maintained, and PCB footprints designed for HC-49/US packages will accommodate both components without modification.

Q: What is the difference between the original part's obsolete status and the substitute's active status?

A: The 9B25000568 is classified as obsolete, indicating that TXC CORPORATION has discontinued production and support. The HC49US-FF5F18-25.000MHZ is active product status, meaning ILSI continues manufacturing and supporting this component. Active status ensures ongoing availability, technical support, and supply chain continuity for new production runs and field replacements.

Q: Are both components RoHS3 compliant?

A: Yes. Both the 9B25000568 and HC49US-FF5F18-25.000MHZ are ROHS3 compliant, meeting current environmental and hazardous substance restrictions. This ensures regulatory alignment for applications subject to RoHS directives.

Q: What is the ESR specification and why is it important?

A: ESR (Equivalent Series Resistance) is specified at 30 Ohms for both components. ESR represents the internal resistance of the crystal and directly affects oscillator startup time, frequency stability, and power consumption. Matching ESR values ensure equivalent oscillator performance characteristics between the original and substitute components.

Q: Can load capacitance be adjusted in the circuit design?

A: Load capacitance is typically set by external capacitors in the oscillator circuit. If the circuit design includes adjustable load capacitance networks or tuning capacitors, the 2pF difference can be compensated through circuit adjustment. Applications with fixed load capacitance should evaluate frequency accuracy during prototype testing.