27 MHz Crystal 18pF Through Hole HC-49/US: 9B-27.000MAAJ-B Equivalent & Substitute Parts

Part Overview

The 9B-27.000MAAJ-B is a 27 MHz fundamental mode crystal oscillator manufactured by TXC CORPORATION, designed for through-hole mounting in HC-49/US package configuration. This component operates at 27 MHz with ±30ppm frequency stability and 18pF load capacitance, suitable for applications requiring precise frequency reference in the VHF band.

The 9B-27.000MAAJ-B is classified as obsolete. Identification of equivalent substitute parts is necessary to maintain design continuity and ensure component availability for production, repair, and field replacement applications.

Key Parameters

Parameter	Value	Unit	Substitution Criticality
Frequency	27.0000	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

Substitute Part Grouping Explanation

Substitution of the 9B-27.000MAAJ-B is permissible only with components that maintain electrical and mechanical equivalence across all critical parameters. The following criteria determine valid substitution:

Electrical Equivalence Requirements:

Frequency: 27.0000 MHz (exact match)
Frequency Stability: ±30ppm (equal or tighter tolerance)
Load Capacitance: 18pF (exact match)
ESR: 30 Ohms (exact match)
Operating Mode: Fundamental (exact match)

Mechanical Equivalence Requirements:

Package / Case: HC-49/US (exact match)
Mounting Type: Through Hole (exact match)
Operating Temperature Range: -20°C to +70°C (equal or wider range)

Compliance Requirements:

RoHS3 Compliance status
ECCN and HTSUS classification alignment

The substitute part HC49US-FF3F18-27.000MHZ manufactured by ILSI satisfies all electrical and mechanical equivalence criteria and is therefore classified as a direct substitute.

Parameter Comparison

Parameter	9B-27.000MAAJ-B (TXC)	HC49US-FF3F18-27.000MHZ (ILSI)	Match Status
Frequency	27.0000 MHz	27.0000 MHz	Equivalent
Frequency Stability	±30ppm	±30ppm	Equivalent
Frequency Tolerance	±30ppm	±30ppm	Equivalent
Load Capacitance	18pF	18pF	Equivalent
ESR	30 Ohms	30 Ohms	Equivalent
Operating Mode	Fundamental	Fundamental	Equivalent
Package / Case	HC-49/US	HC-49/US	Equivalent
Mounting Type	Through Hole	Through Hole	Equivalent
Operating Temperature Range	-20°C to +70°C	-20°C to +70°C	Equivalent
RoHS Status	ROHS3 Compliant	ROHS3 Compliant	Equivalent
ECCN	EAR99	EAR99	Equivalent
HTSUS	8541.60.0060	8541.60.0060	Equivalent
Product Status	Obsolete	Active	Substitute is Active

Engineering Selection Recommendations

The HC49US-FF3F18-27.000MHZ manufactured by ILSI is a direct electrical and mechanical equivalent to the obsolete 9B-27.000MAAJ-B. Selection of this substitute part is supported by the following factors:

Compliance Alignment: Both components maintain ROHS3 compliance and identical ECCN/HTSUS classifications, ensuring regulatory equivalence for procurement and export purposes.

Product Status: The ILSI substitute is classified as Active, providing assured long-term availability and supply chain continuity compared to the obsolete TXC original.

Dimensional Compatibility: While minor dimensional variations exist (TXC: 11.50mm × 5.00mm; ILSI: 11.10mm × 4.70mm), both components conform to HC-49/US package specification and are mechanically compatible with standard through-hole PCB footprints designed for this package type.

Electrical Performance: Complete electrical parameter equivalence across frequency, stability, load capacitance, and ESR ensures functional interchangeability without circuit redesign or oscillator tuning adjustment.

Frequently Asked Questions (FAQ)

Q: Can the HC49US-FF3F18-27.000MHZ be used as a direct replacement for the 9B-27.000MAAJ-B without PCB modification?

A: Yes. Both components conform to HC-49/US package specification and share identical electrical parameters. Standard through-hole footprints designed for HC-49/US packages accommodate both components without modification.

Q: Are there differences in physical dimensions between these parts?

A: Minor dimensional variations exist. The TXC 9B-27.000MAAJ-B measures 11.50mm × 5.00mm with 3.68mm seated height. The ILSI HC49US-FF3F18-27.000MHZ measures 11.10mm × 4.70mm with 3.50mm seated height. Both fall within HC-49/US package tolerance and are compatible with standard PCB footprints.

Q: What is the difference in Moisture Sensitivity Level (MSL) between these parts?

A: The TXC original lists MSL as Not Applicable. The ILSI substitute specifies MSL 1 (Unlimited). This indicates the ILSI component has no moisture sensitivity restrictions and does not require special handling or storage conditions.

Q: Are both components RoHS compliant?

A: Yes. Both the 9B-27.000MAAJ-B and HC49US-FF3F18-27.000MHZ are ROHS3 compliant.

Q: What is the availability difference between these parts?

A: The 9B-27.000MAAJ-B is classified as obsolete. The HC49US-FF3F18-27.000MHZ is classified as active, indicating current production and assured availability for future procurement.

Q: Do these crystals require different circuit tuning or load capacitor adjustment?

A: No. Both components specify identical load capacitance (18pF) and ESR (30 Ohms). Existing oscillator circuits designed for the 9B-27.000MAAJ-B require no tuning adjustment when substituting the ILSI equivalent.

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