9B-4.000MAAJ-B Equivalent & Substitute Parts Reference

Part Overview

The 9B-4.000MAAJ-B is a 4 MHz through-hole crystal oscillator manufactured by TXC CORPORATION, specified for fundamental mode operation with 18pF load capacitance and 150 Ohms equivalent series resistance (ESR). This part is classified as obsolete product status. Equivalent and substitute parts are necessary to maintain design continuity and ensure component availability for production and repair applications. Substitute parts must maintain electrical compatibility within the specified frequency, stability, load capacitance, and ESR parameters while conforming to the HC-49/US package standard.

Substiute Parts

9B-4.000MAAJ-B

TXC CORPORATIONIn Stock: 11679B-4.000MAAJ-B Datasheet

Current PartRFQ

GB0400005

Diodes IncorporatedIn Stock: 1563GB0400005 Datasheet

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GB0400039

Diodes IncorporatedIn Stock: 844GB0400039 Datasheet

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HC49US-FF3F18-4.000MHZ

ILSIIn Stock: 699HC49US-FF3F18-4.000MHZ Datasheet

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Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the 9B-4.000MAAJ-B is determined by the following critical parameters:

Primary Compatibility Criteria:

• Frequency: 4.0000 MHz (exact match required)
• Frequency Stability: ±30ppm (exact match required)
• Package / Case: HC-49/US (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Temperature Range: -20°C to 70°C (exact match required)

Secondary Compatibility Criteria (within acceptable tolerance):

• Load Capacitance: 18pF nominal (±2pF variance acceptable for circuit tuning)
• ESR: 150 Ohms nominal (±30 Ohms variance acceptable for circuit performance)

All identified substitute parts meet the primary compatibility criteria. Variations in load capacitance and ESR are documented in the parameter comparison table and must be evaluated against specific circuit requirements.

Parameter Comparison

Engineering Selection Recommendations

HC49US-FF3F18-4.000MHZ (ILSI) — Preferred Direct Substitute

This part provides exact parameter matching to the 9B-4.000MAAJ-B across all critical specifications: 4.0000 MHz frequency, ±30ppm stability, 18pF load capacitance, and 150 Ohms ESR. The part is active product status, ROHS3 compliant, and REACH unaffected. Dimensional compatibility is confirmed within HC-49/US package specifications. This substitute requires no circuit tuning or design modification.

GB0400039 (Diodes Incorporated) — Compatible Substitute with ESR Match

This part maintains exact frequency, stability, and ESR specifications (150 Ohms) matching the original part. Load capacitance is specified at 20pF versus 18pF nominal. The part is active product status, ROHS3 compliant, and REACH unaffected. Circuit tuning may be required to accommodate the 2pF load capacitance increase.

GB0400005 (Diodes Incorporated) — Compatible Substitute with ESR Variance

This part maintains exact frequency and stability specifications. Load capacitance is specified at 16pF and ESR at 120 Ohms, representing a 2pF decrease in load capacitance and 30 Ohms decrease in ESR from the original specification. The part is active product status, ROHS3 compliant, and REACH unaffected. Circuit tuning and performance verification are required to accommodate both load capacitance and ESR variations.

All three substitute parts are active products with superior compliance status compared to the obsolete original part.

Frequently Asked Questions (FAQ)

Q: Can GB0400005 be used as a direct replacement for 9B-4.000MAAJ-B?

A: GB0400005 is electrically compatible within the 4.0000 MHz frequency class and ±30ppm stability specification. However, the load capacitance differs by 2pF (16pF versus 18pF) and ESR differs by 30 Ohms (120 Ohms versus 150 Ohms). Direct substitution without circuit evaluation is not recommended. Circuit tuning may be necessary to maintain frequency accuracy and oscillator startup characteristics.

Q: What is the difference between GB0400039 and HC49US-FF3F18-4.000MHZ?

A: Both parts are compatible substitutes for the 9B-4.000MAAJ-B. GB0400039 specifies 20pF load capacitance, while HC49US-FF3F18-4.000MHZ specifies 18pF load capacitance matching the original part exactly. HC49US-FF3F18-4.000MHZ provides the closest parameter match and is the preferred substitute. GB0400039 requires circuit tuning for the 2pF load capacitance increase.

Q: Are all substitute parts RoHS and REACH compliant?

A: All three substitute parts are ROHS3 compliant. Regarding REACH status: GB0400005 and GB0400039 are REACH unaffected, while the original 9B-4.000MAAJ-B is REACH affected. Substitute parts offer improved regulatory compliance for new production applications.

Q: Can these parts be used interchangeably in existing designs?

A: HC49US-FF3F18-4.000MHZ provides direct interchangeability with no design modification required. GB0400039 and GB0400005 require circuit evaluation due to load capacitance and ESR variations. Physical dimensions within HC-49/US package specifications are compatible across all parts for through-hole mounting.

Q: What is the inventory status of substitute parts?

A: GB0400005 has 1508 pieces in stock, GB0400039 has 804 pieces in stock, and HC49US-FF3F18-4.000MHZ has 678 pieces in stock. All parts are available as new original components.