HCM494000000AHJT Equivalent & Substitute Parts

Part Overview

The HCM494000000AHJT is a 4 MHz surface mount crystal oscillator manufactured by Citizen Finedevice Co Ltd. This component is specified for fundamental mode operation with 18pF load capacitance and 150 Ohms equivalent series resistance in an HC-49/US package. The part is currently active and ROHS3 compliant, making it suitable for new designs. Alternative parts may be required due to inventory constraints, packaging preferences, or specific application requirements.

Substiute Parts

HCM494000000AHJT

Citizen Finedevice Co LtdIn Stock: 717HCM494000000AHJT Datasheet

Current PartRFQ

ECS-40-20-5PDN-TR

ECS Inc.In Stock: 2611ECS-40-20-5PDN-TR Datasheet

SimilarRFQ

ECS-40-20-5PXDN-TR

ECS Inc.In Stock: 9419ECS-40-20-5PXDN-TR Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution for the HCM494000000AHJT is determined by the following critical parameters: frequency (4 MHz), frequency tolerance (±30ppm), ESR (150 Ohms), operating mode (Fundamental), operating temperature range (-40°C to 85°C), package type (HC-49/US), and mounting configuration (Surface Mount). Load capacitance tolerance of ±2pF is acceptable within standard crystal oscillator design margins for this frequency class. The identified substitute parts maintain these core electrical and mechanical specifications while differing in load capacitance (20pF vs. 18pF), packaging format, and product lifecycle status.

Parameter Comparison

Engineering Selection Recommendations

ECS-40-20-5PXDN-TR is the primary substitute for new designs. This part maintains ROHS3 compliance and active product status matching the HCM494000000AHJT. The 2pF load capacitance difference (20pF vs. 18pF) is within acceptable tolerance for 4 MHz fundamental mode crystals. Packaging is available in Cut Tape and Digi-Reel format with higher inventory availability (9400 pcs).

ECS-40-20-5PDN-TR is not recommended for new designs due to its "Not For New Designs" product status and RoHS non-compliance. This part may only be considered for legacy system maintenance or replacement applications where the original specification cannot be modified.

Frequently Asked Questions (FAQ)

Q: Can ECS-40-20-5PXDN-TR directly replace HCM494000000AHJT in existing designs?

A: Yes. Both parts share identical frequency (4 MHz), frequency tolerance (±30ppm), ESR (150 Ohms), operating temperature range (-40°C to 85°C), and HC-49/US package specifications. The 2pF load capacitance difference is within standard design margins for this frequency class.

Q: What is the significance of the load capacitance difference between 18pF and 20pF?

A: Load capacitance specifies the external capacitive load for which the crystal is calibrated. A 2pF difference requires circuit-level verification but does not prevent functional substitution in most applications. Circuit designers should confirm that oscillator tank capacitance can accommodate the 20pF specification.

Q: Why is ECS-40-20-5PDN-TR marked "Not For New Designs"?

A: This designation indicates the manufacturer has discontinued active development and support for this part number. While electrically equivalent, it should not be selected for new product development. Use ECS-40-20-5PXDN-TR instead.

Q: What is the difference between Tape & Reel (TR) and Cut Tape & Digi-Reel packaging?

A: Tape & Reel is continuous reel packaging for automated assembly lines. Cut Tape & Digi-Reel provides flexibility with both cut tape and reel options. Both formats are compatible with standard surface mount assembly equipment.

Q: Are all three parts RoHS compliant?

A: HCM494000000AHJT and ECS-40-20-5PXDN-TR are ROHS3 compliant. ECS-40-20-5PDN-TR is RoHS non-compliant and should not be used in applications requiring RoHS certification.