HC-49/U-S27000000ABJB 27 MHz Crystal Equivalent & Substitute Parts

Part Overview

The HC-49/U-S27000000ABJB is a 27 MHz fundamental mode crystal oscillator manufactured by Citizen Finedevice Co Ltd, designed for through-hole mounting applications. This component operates at 27 MHz with ±30ppm frequency tolerance and 18pF load capacitance. The part is currently in active production status with 1057 units available in stock. Substitute parts may be required due to supply chain constraints, manufacturing discontinuation of specific variants, or design optimization for alternative ESR and temperature range specifications.

Substiute Parts

HC-49/U-S27000000ABJB

Citizen Finedevice Co LtdIn Stock: 1153HC-49/U-S27000000ABJB Datasheet

Current PartRFQ

9B-27.000MAAJ-B

TXC CORPORATIONIn Stock: 79839B-27.000MAAJ-B Datasheet

DirectRFQ

ECS-270-18-4X-F

ECS Inc.In Stock: 1887ECS-270-18-4X-F Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the HC-49/U-S27000000ABJB is determined by the following critical parameters:

• Frequency: 27 MHz (exact match required)
• Frequency Tolerance: ±30ppm (exact match required)
• Load Capacitance: 18pF (exact match required)
• Package / Case: HC-49/US (exact match required)
• Mounting Type: Through Hole (exact match required)
• Operating Mode: Fundamental (exact match required)

The following parameters allow variation within acceptable engineering limits:

• ESR: 50 Ohms (main part) to 30 Ohms (substitute parts) — lower ESR is acceptable
• Operating Temperature Range: -10°C ~ 60°C (main part) to -20°C ~ 70°C or -10°C ~ 70°C (substitute parts) — extended range is acceptable
• Frequency Stability: ±50ppm (main part) to ±30ppm (substitute parts) — tighter stability is acceptable

Two substitute parts meet these criteria: 9B-27.000MAAJ-B (TXC CORPORATION) and ECS-270-18-4X-F (ECS Inc.).

Parameter Comparison

Engineering Selection Recommendations

ECS-270-18-4X-F is the preferred substitute option. This part maintains active product status, ensuring continued availability and manufacturer support. Both the main part and ECS-270-18-4X-F are ROHS3 compliant with REACH unaffected status, providing equivalent regulatory compliance. The ECS part offers improved ESR performance (30 Ohms versus 50 Ohms) and an extended upper operating temperature limit (70°C versus 60°C), while maintaining identical frequency, tolerance, load capacitance, and package specifications.

9B-27.000MAAJ-B is an alternative substitute but carries obsolete product status, indicating discontinued manufacturing. This part should be selected only when ECS-270-18-4X-F is unavailable. The 9B series provides tighter frequency stability (±30ppm) and a lower operating temperature minimum (-20°C), but REACH affected status requires compliance verification for specific applications.

Frequently Asked Questions (FAQ)

Q: Can 9B-27.000MAAJ-B replace HC-49/U-S27000000ABJB in all applications?

A: 9B-27.000MAAJ-B meets all critical electrical and mechanical substitution criteria. However, its obsolete product status and REACH affected classification require evaluation against your supply chain and regulatory requirements. For new designs, ECS-270-18-4X-F is the recommended choice.

Q: What is the significance of ESR differences between the main part and substitutes?

A: The main part specifies 50 Ohms ESR, while both substitutes specify 30 Ohms. Lower ESR reduces power dissipation and improves circuit efficiency. This difference is acceptable for substitution as it represents improved performance characteristics.

Q: Are the physical dimensions compatible between all three parts?

A: All three parts use the HC-49/US package with through-hole mounting. Dimensional variations exist within the package specification: main part height is 4.60mm maximum, 9B-27.000MAAJ-B is 3.68mm maximum, and ECS-270-18-4X-F is 4.60mm maximum. These variations remain within standard HC-49/US tolerances and do not affect PCB layout compatibility.

Q: Does the extended temperature range of the substitutes affect circuit design?

A: The substitutes offer extended operating ranges (-20°C to 70°C or -10°C to 70°C) compared to the main part (-10°C to 60°C). Extended range capability does not require design changes; it provides additional operational margin for applications requiring wider temperature performance.

Q: What compliance certifications apply to each part?

A: All three parts are ROHS3 compliant. The main part and ECS-270-18-4X-F are REACH unaffected. The 9B-27.000MAAJ-B is REACH affected, requiring compliance assessment for applications subject to REACH regulations.