Equivalent & Substitute Parts for 9B-25.000MAHK-B

Part Overview

The 9B-25.000MAHK-B is a 25 MHz through-hole crystal oscillator manufactured by TXC CORPORATION. This component is classified as obsolete, necessitating identification of active equivalent parts for ongoing production and maintenance applications. The crystal operates at fundamental mode with ±30ppm frequency stability across the industrial temperature range of -40°C to 85°C. Substitute parts must maintain electrical and mechanical compatibility within the HC-49/US package standard.

Substiute Parts

9B-25.000MAHK-B

TXC CORPORATIONIn Stock: 8049B-25.000MAHK-B Datasheet

Current PartRFQ

HC49US-FF5F18-25.000MHZ

ILSIIn Stock: 1228HC49US-FF5F18-25.000MHZ Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 9B-25.000MAHK-B is determined by the following mandatory parameters:

Electrical Parameters (Non-Negotiable):

• Frequency: 25 MHz (exact match required)
• Frequency Stability: ±30ppm (substitute must meet or exceed this specification)
• ESR: 30 Ohms (must match for circuit oscillation margin)
• Operating Mode: Fundamental (defines harmonic content and circuit behavior)
• Operating Temperature Range: -40°C to 85°C (minimum required coverage)

Mechanical Parameters (Non-Negotiable):

• Package / Case: HC-49/US (physical footprint and pin configuration)
• Mounting Type: Through Hole (assembly compatibility)

Load Capacitance Consideration: The main part specifies 20pF load capacitance. Substitute parts with different load capacitance values (such as 18pF) may be used only when the circuit design accommodates the alternative load capacitance specification. This parameter affects frequency trimming and oscillation stability in the host circuit.

Regulatory Compliance: All substitute parts must maintain ROHS3 compliance status to satisfy environmental and regulatory requirements.

Parameter Comparison

Engineering Selection Recommendations

HC49US-FF5F18-25.000MHZ (ILSI) as Primary Substitute:

The HC49US-FF5F18-25.000MHZ meets all critical electrical and mechanical parameters required for substitution of the obsolete 9B-25.000MAHK-B. Both components operate at 25 MHz with ±30ppm frequency stability, 30 Ohms ESR, fundamental mode operation, and identical temperature range coverage (-40°C to 85°C). Both are packaged in HC-49/US through-hole format and maintain ROHS3 compliance.

Load Capacitance Variance:

The substitute part specifies 18pF load capacitance compared to the original 20pF specification. This 2pF difference is within typical crystal design tolerances and does not preclude substitution. The circuit design must accommodate this load capacitance value. If the original circuit was specifically tuned for 20pF load capacitance, frequency trimming adjustments may be required to maintain the target 25 MHz frequency within specification.

Product Status Advantage:

The substitute part carries Active product status, ensuring continued availability and supply chain reliability. The original part is classified as Obsolete, making the substitute the appropriate choice for new designs and ongoing production requirements.

Regulatory and Compliance Status:

Both components satisfy ROHS3 compliance requirements. The substitute part is REACH Unaffected, compared to the original part's REACH Affected status, providing simplified regulatory documentation for certain applications.

Frequently Asked Questions (FAQ)

Q: Can HC49US-FF5F18-25.000MHZ directly replace 9B-25.000MAHK-B without circuit modification?

A: Direct replacement is possible from a physical and electrical standpoint. Both components share identical frequency (25 MHz), frequency stability (±30ppm), ESR (30 Ohms), operating mode (Fundamental), temperature range (-40°C to 85°C), and HC-49/US package format. The 2pF load capacitance difference (20pF vs. 18pF) typically does not require circuit modification in most applications, but circuit validation is necessary to confirm frequency accuracy remains within specification.

Q: What is the significance of the load capacitance difference between these parts?

A: Load capacitance specifies the capacitive load the crystal expects to see in the oscillator circuit. The original part is specified for 20pF load, while the substitute is specified for 18pF load. This difference affects the frequency trimming characteristics. If the circuit was designed with load capacitors tuned for 20pF, the substitute part may exhibit slight frequency offset. Frequency measurement after substitution is recommended to confirm operation within ±30ppm specification.

Q: Are both parts suitable for the same temperature range applications?

A: Yes. Both the 9B-25.000MAHK-B and HC49US-FF5F18-25.000MHZ operate across the identical temperature range of -40°C to 85°C, making them suitable for equivalent industrial and commercial applications within this thermal envelope.

Q: What is the advantage of using the ILSI substitute part?

A: The HC49US-FF5F18-25.000MHZ carries Active product status, ensuring ongoing manufacturing and supply availability. The original TXC part is Obsolete, creating supply chain risk. The substitute part also provides REACH Unaffected status, simplifying regulatory compliance documentation for certain markets.

Q: Are there any package or mounting differences between these parts?

A: No. Both components use the HC-49/US package format with through-hole mounting. Physical dimensions are similar (original: 11.50mm L x 5.00mm W; substitute: 11.10mm L x 4.70mm W), with both fitting standard HC-49/US footprints. Height specifications are also comparable (original: 3.68mm max; substitute: 3.50mm max).

Q: Do both parts meet the same regulatory compliance standards?

A: Both parts are ROHS3 compliant. The substitute part is REACH Unaffected, while the original is REACH Affected. Both carry EAR99 ECCN classification and identical HTSUS code (8541.60.0060). The substitute's REACH Unaffected status may simplify compliance documentation for certain jurisdictions.