AS-7.3728-16-EXT Equivalent & Substitute Parts

Part Overview

The AS-7.3728-16-EXT is a 7.3728 MHz through-hole crystal manufactured by Raltron Electronics, designed for fundamental mode operation in timing and frequency control applications. This active product features a 16pF load capacitance, 70 Ohms equivalent series resistance, and HC-49/US package configuration. The part is ROHS3 compliant with MSL 1 rating, indicating unlimited moisture sensitivity protection.

Substitute parts are identified to provide design flexibility when the primary part is unavailable or when alternative manufacturers are preferred for supply chain optimization, while maintaining electrical and mechanical compatibility within specified tolerances.

Substiute Parts

AS-7.3728-16-EXT

Raltron ElectronicsIn Stock: 1682AS-7.3728-16-EXT Datasheet

Current PartRFQ

ECS-73-18-4XEN

ECS Inc.In Stock: 1131ECS-73-18-4XEN Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the AS-7.3728-16-EXT is determined by the following critical parameters:

Mandatory Matching Criteria:

• Frequency: 7.3728 MHz (exact match required)
• Frequency Tolerance: ±30ppm (substitute must meet or exceed this specification)
• Package / Case: HC-49/US (physical form factor)
• Mounting Type: Through Hole (PCB assembly compatibility)
• Operating Temperature Range: -40°C to 85°C (environmental operating envelope)

Allowable Variation Parameters:

• Load Capacitance: Substitutes with different load capacitance values (16pF vs. 18pF) are acceptable when the circuit design accommodates the variation through load network adjustment
• ESR (Equivalent Series Resistance): Substitutes with ESR values within ±15% of the primary part specification are acceptable for oscillator circuit compatibility

Compliance Requirements:

• RoHS3 compliance status must be maintained
• MSL rating of 1 (Unlimited) must be preserved

Parameter Comparison

Engineering Selection Recommendations

Primary Part: AS-7.3728-16-EXT

The AS-7.3728-16-EXT remains the primary selection when available. This Raltron Electronics part is active in production with 1615 units in stock, ensuring supply continuity. The part meets all regulatory requirements with ROHS3 compliance and MSL 1 rating.

Substitute Part: ECS-73-18-4XEN

The ECS-73-18-4XEN from ECS Inc. is a qualified substitute when the primary part is unavailable. This part maintains identical frequency, tolerance, stability, operating temperature range, package type, and mounting configuration. The substitute is also ROHS3 compliant with MSL 1 rating.

Key Differences Requiring Circuit Evaluation:

The load capacitance difference (16pF vs. 18pF) requires circuit design verification. The oscillator load network must accommodate the 2pF increase. The ESR increase from 70 Ohms to 80 Ohms (14.3% higher) is within acceptable oscillator performance margins for most applications but should be confirmed against specific circuit requirements.

Inventory and Availability:

ECS-73-18-4XEN has 1036 units in stock, providing secondary supply assurance. Both parts are active products with ongoing manufacturer support.

Frequently Asked Questions (FAQ)

Q: Can ECS-73-18-4XEN be used as a direct drop-in replacement for AS-7.3728-16-EXT?

A: Physical and electrical compatibility exists for HC-49/US package mounting and through-hole PCB assembly. However, the 2pF load capacitance difference (18pF vs. 16pF) requires circuit design verification. The oscillator load network must be evaluated to confirm stable operation at the specified frequency and tolerance. ESR compatibility is within acceptable ranges.

Q: What is the impact of the load capacitance difference?

A: Load capacitance affects the oscillator circuit's resonant frequency and stability characteristics. A 2pF increase may require adjustment of the external load capacitors in the oscillator circuit to maintain the specified ±30ppm frequency tolerance. Circuit simulation or empirical testing is necessary to confirm performance with the substitute part.

Q: Are both parts compliant with current regulatory standards?

A: Both AS-7.3728-16-EXT and ECS-73-18-4XEN are ROHS3 compliant and REACH unaffected. Both carry MSL 1 (Unlimited) moisture sensitivity ratings, indicating equivalent environmental protection requirements.

Q: What is the significance of the ESR difference?

A: The ESR increase from 70 Ohms to 80 Ohms represents a 14.3% increase. This affects oscillator startup time and power consumption characteristics. For most applications operating within the -40°C to 85°C temperature range, this variation is within acceptable oscillator design margins. Application-specific requirements should be confirmed.

Q: Are there physical dimension differences that affect PCB layout?

A: Both parts use the HC-49/US package with identical length (0.447" / 11.35mm) and height (0.138" / 3.50mm). The width differs slightly (0.197" vs. 0.183"), but this minor variation does not affect standard through-hole PCB footprint compatibility.

Q: What frequency specifications must be maintained for substitution?

A: The frequency must be exactly 7.3728 MHz. The frequency tolerance of ±30ppm and frequency stability of ±50ppm must be met or exceeded. These parameters are non-negotiable for circuit timing accuracy.

Q: Can substitution occur in both directions?

A: Yes. The AS-7.3728-16-EXT and ECS-73-18-4XEN are mutually substitutable within the constraints of load capacitance circuit compatibility and ESR performance verification.