ASCSM-66.666MHZ-LR-T Equivalent & Substitute Parts

Part Overview

The ASCSM-66.666MHZ-LR-T is a 66.666 MHz MEMS-based XO (Standard) oscillator manufactured by Abracon LLC. This component operates across a wide supply voltage range of 1.7V to 3.6V with CMOS output and Enable/Disable functionality. The part is packaged in a 4-UFBGA, CSPBGA configuration with compact dimensions of 1.79mm × 1.25mm and a maximum seated height of 0.69mm.

The ASCSM-66.666MHZ-LR-T has reached Obsolete product status. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications requiring 66.666 MHz oscillation at low supply voltages.

Substiute Parts

ASCSM-66.666MHZ-LR-T

Abracon LLCIn Stock: 963ASCSM-66.666MHZ-LR-T Datasheet

Current PartRFQ

ASCO-66.666MHZ-L-T3

Abracon LLCIn Stock: 910ASCO-66.666MHZ-L-T3 Datasheet

DirectRFQ

DSC1121CI2-066.6660T

Microchip TechnologyIn Stock: 1127DSC1121CI2-066.6660T Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ASCSM-66.666MHZ-LR-T is determined by the following critical parameters:

Mandatory Matching Criteria:

• Frequency: 66.666 MHz (exact match required)
• Output Type: CMOS
• Function: Enable/Disable capability
• Operating Temperature Range: -40°C ~ 85°C minimum
• Frequency Stability: ±25ppm or better

Flexible Parameters (with design considerations):

• Supply Voltage Range: Minimum 1.7V support preferred; 3.3V or 2.25V ~ 3.6V acceptable if application operates within those ranges
• Base Resonator Type: MEMS preferred for consistency; Crystal-based alternatives acceptable if frequency stability and temperature performance match
• Package Type: Different surface-mount packages acceptable if PCB layout permits
• Supply Current: Higher values acceptable if power budget allows
• Moisture Sensitivity Level: MSL 3 acceptable with appropriate handling procedures

Two substitute parts meet these criteria with varying trade-offs in voltage range, package size, and resonator technology.

Parameter Comparison

Engineering Selection Recommendations

ASCO-66.666MHZ-L-T3 (Abracon LLC): This substitute is suitable for applications where supply voltage is fixed at 3.3V. It maintains the same manufacturer lineage and Enable/Disable functionality. The primary trade-off is reduced frequency stability (±50ppm versus ±25ppm) and slightly higher supply current (8.5mA versus 6.5mA). The package dimensions are comparable to the original part. This option is recommended for designs that do not require the extended low-voltage operation below 3.3V and can tolerate the wider frequency tolerance. Active product status ensures ongoing availability.

DSC1121CI2-066.6660T (Microchip Technology): This substitute provides the closest electrical performance match, maintaining ±25ppm frequency stability and MEMS resonator technology. It supports a supply voltage range of 2.25V to 3.6V, which covers most 3.3V applications while sacrificing the 1.7V minimum of the original part. The significant drawback is substantially higher supply current (35mA maximum) and higher disable-mode current (22mA), making this option unsuitable for ultra-low-power applications. The larger package footprint (3.20mm × 3.20mm) requires PCB layout modification. This part carries AEC-Q100 automotive qualification and MSL 3 moisture sensitivity, indicating suitability for automotive and industrial environments. Active product status and manufacturer recommendation support long-term availability.

Selection Criteria:

• Choose ASCO-66.666MHZ-L-T3 for 3.3V fixed-supply designs prioritizing compact size and low power consumption
• Choose DSC1121CI2-066.6660T for applications requiring automotive qualification, extended voltage range above 2.25V, or where frequency stability at ±25ppm is critical and higher power consumption is acceptable

Frequently Asked Questions (FAQ)

Q: Can the ASCO-66.666MHZ-L-T3 replace the ASCSM-66.666MHZ-LR-T in all applications?

A: No. The ASCO operates at fixed 3.3V supply voltage only, whereas the original part supports 1.7V to 3.6V. If your application requires operation below 3.3V or uses a variable supply voltage, this substitute is not compatible. Additionally, frequency stability is degraded from ±25ppm to ±50ppm.

Q: Why is the DSC1121CI2-066.6660T's supply current so much higher?

A: The DSC1121CI2-066.6660T is a 6-pin package with additional functionality and internal circuitry compared to the 4-pin original design. The higher current consumption reflects this increased complexity. Verify that your power budget accommodates 35mA maximum supply current before selection.

Q: Can I use the DSC1121CI2-066.6660T in a 1.7V application?

A: No. The DSC1121CI2-066.6660T minimum supply voltage is 2.25V. Applications requiring 1.7V operation must retain the original ASCSM-66.666MHZ-LR-T or identify alternative sources.

Q: What is the impact of different package types on PCB design?

A: The original ASCSM uses 4-UFBGA/CSPBGA packaging (1.79mm × 1.25mm). The ASCO-66.666MHZ-L-T3 uses 4-SMD No Lead (1.60mm × 1.20mm), requiring minimal layout changes. The DSC1121CI2-066.6660T uses 6-SMD No Lead (3.20mm × 2.50mm), requiring significant PCB footprint modification. Verify PCB layout compatibility before committing to either substitute.

Q: Does MSL 3 moisture sensitivity affect usability?

A: MSL 3 requires controlled storage and handling procedures (168-hour floor life limit after moisture exposure). If your manufacturing environment does not support MSL 3 protocols, the ASCO-66.666MHZ-L-T3 (Not Applicable MSL) or original part (MSL 1) may be preferable.

Q: Is the AEC-Q100 certification on the DSC1121CI2-066.6660T required for my application?

A: AEC-Q100 certification is mandatory for automotive applications and recommended for industrial/harsh-environment designs. If your application is consumer or general industrial without automotive requirements, this certification is not necessary but does not prevent use.