9B-24.000MAAJ-B Crystal Equivalent & Substitute Parts

Part Overview

The 9B-24.000MAAJ-B is a 24 MHz through-hole crystal oscillator manufactured by TXC CORPORATION. This component operates at a fundamental frequency with 18pF load capacitance and 30 Ohms equivalent series resistance in an HC-49/US package. The part is classified as obsolete, making identification of functionally equivalent substitutes necessary for ongoing system support and procurement planning. Substitute parts must maintain identical electrical specifications and mechanical compatibility to ensure direct replacement without circuit redesign.

Key Parameters

Parameter	Value	Unit	Substitution Criticality
Frequency	24.000	MHz	Critical
Frequency Stability	±30	ppm	Critical
Load Capacitance	18	pF	Critical
ESR (Equivalent Series Resistance)	30	Ohms	Critical
Operating Mode	Fundamental	—	Critical
Package / Case	HC-49/US	—	Critical
Mounting Type	Through Hole	—	Critical
Operating Temperature Range	-20°C to 70°C	—	Critical
RoHS Status	ROHS3 Compliant	—	Compliance

Substitute Part Grouping Explanation

Substitution eligibility for the 9B-24.000MAAJ-B is determined by strict equivalence across the following parameters:

Electrical Equivalence Requirements:

Frequency: 24.000 MHz (exact match required)
Frequency Stability: ±30 ppm (tolerance must not exceed this value)
Load Capacitance: 18 pF (exact match required)
ESR: 30 Ohms (exact match required)
Operating Mode: Fundamental (exact match required)

Mechanical Equivalence Requirements:

Package / Case: HC-49/US (exact match required)
Mounting Type: Through Hole (exact match required)
Operating Temperature Range: -20°C to 70°C (minimum range must be met or exceeded)

Compliance Requirements:

RoHS3 Compliance status must be maintained

The HC49US-FF3F18-24.000MHZ from ILSI meets all electrical and mechanical equivalence criteria and maintains required compliance certifications, qualifying it as a direct substitute for the obsolete 9B-24.000MAAJ-B.

Parameter Comparison

Parameter	9B-24.000MAAJ-B (TXC)	HC49US-FF3F18-24.000MHZ (ILSI)	Match Status
Frequency	24.000 MHz	24.000 MHz	Equivalent
Frequency Stability	±30 ppm	±30 ppm	Equivalent
Frequency Tolerance	±30 ppm	±30 ppm	Equivalent
Load Capacitance	18 pF	18 pF	Equivalent
ESR	30 Ohms	30 Ohms	Equivalent
Operating Mode	Fundamental	Fundamental	Equivalent
Operating Temperature Range	-20°C to 70°C	-20°C to 70°C	Equivalent
Mounting Type	Through Hole	Through Hole	Equivalent
Package / Case	HC-49/US	HC-49/US	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
Product Status	Obsolete	Active	Substitute is Active

Engineering Selection Recommendations

The HC49US-FF3F18-24.000MHZ from ILSI is qualified as a direct substitute for the obsolete 9B-24.000MAAJ-B based on the following factors:

Electrical Compatibility: All critical electrical parameters match exactly, including frequency, stability, load capacitance, and ESR. Both components operate in fundamental mode with identical specifications.

Mechanical Compatibility: Both parts use the HC-49/US package with through-hole mounting. Physical dimensions are within acceptable tolerance for PCB footprint compatibility.

Compliance Status: The ILSI substitute maintains ROHS3 compliance, meeting regulatory requirements equivalent to the original part.

Product Availability: The substitute part is classified as Active, ensuring ongoing procurement availability and supply chain continuity compared to the obsolete original part.

Dimensional Considerations: Minor variations exist in physical dimensions (ILSI: 11.10mm L × 4.70mm W vs. TXC: 11.50mm L × 5.00mm W; ILSI: 3.50mm height vs. TXC: 3.68mm height). These variations remain within HC-49/US package specifications and do not affect electrical performance or PCB compatibility.

Frequently Asked Questions (FAQ)

Q: Can the HC49US-FF3F18-24.000MHZ be used as a direct replacement for the 9B-24.000MAAJ-B without circuit modification?

A: Yes. The substitute part meets all electrical and mechanical equivalence criteria. No circuit redesign or component value adjustment is required. The part can be installed directly into existing PCB footprints designed for HC-49/US through-hole crystals.

Q: What is the significance of the ±30 ppm frequency stability specification?

A: Frequency stability defines the maximum deviation from the nominal 24.000 MHz frequency across the operating temperature range (-20°C to 70°C). Both the original and substitute parts maintain this specification, ensuring equivalent timing accuracy in applications.

Q: Are there any differences in load capacitance requirements between the two parts?

A: No. Both parts specify 18 pF load capacitance. The oscillator circuit must be designed to present this load capacitance to the crystal for proper frequency calibration. Using either part requires identical circuit design.

Q: How do the physical dimensions affect PCB layout compatibility?

A: Both parts conform to the HC-49/US package standard. Minor dimensional variations (approximately 0.4mm in length and 0.18mm in height) fall within standard package tolerances and do not affect PCB footprint compatibility. Existing through-hole patterns designed for HC-49/US packages accommodate both parts.

Q: What is the difference between Frequency Stability and Frequency Tolerance?

A: Both parameters specify ±30 ppm for these parts. Frequency Stability refers to frequency variation across the operating temperature range. Frequency Tolerance refers to the initial accuracy at 25°C. In this case, both values are identical.

Q: Why is the original part classified as obsolete?

A: The 9B-24.000MAAJ-B is no longer manufactured by TXC CORPORATION. The HC49US-FF3F18-24.000MHZ from ILSI provides equivalent functionality and is actively produced, making it the appropriate choice for new procurement and system support.

Q: Are both parts RoHS compliant?

A: Yes. Both the 9B-24.000MAAJ-B and HC49US-FF3F18-24.000MHZ are ROHS3 compliant, meeting environmental and regulatory requirements for electronic components.

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