FSAT66L6 Equivalent & Substitute Parts

Part Overview

The FSAT66L6 is a single-circuit SPST-NO (Normally Open) IC switch manufactured by onsemi, designed for high-speed signal switching applications. This component features a 15Ohm on-state resistance and operates across a 1.65V to 5.5V supply voltage range with switching times of 4.5ns (Ton) and 5.5ns (Toff). The device is packaged in a 6-MicroPak surface mount configuration.

The FSAT66L6 is classified as obsolete. Identifying equivalent substitute parts is necessary to maintain design continuity and ensure component availability for new production runs and system upgrades.

Key Parameters

Parameter	Value
Switch Circuit Type	SPST - NO
Multiplexer/Demultiplexer Circuit	1:1
Number of Circuits	1
On-State Resistance (Max)	15Ohm
Voltage - Supply, Single (V+)	1.65V ~ 5.5V
Switch Time Ton (Max)	4.5ns
Switch Time Toff (Max)	5.5ns
-3dB Bandwidth	250MHz
Charge Injection	0.05pC
Channel Capacitance (CS(off), CD(off))	6pF
Current - Leakage (IS(off)) (Max)	10µA
Operating Temperature	-40°C ~ 85°C (TA)
Mounting Type	Surface Mount
Package / Case	6-UFDFN
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the FSAT66L6 is based on the following critical parameters that must be maintained or improved:

Switch Circuit Configuration: SPST - NO topology with 1:1 multiplexer/demultiplexer circuit and single circuit count
Supply Voltage Compatibility: Operating range of 1.65V ~ 5.5V (single supply)
On-State Resistance: Maximum 15Ohm; lower values are acceptable as they reduce insertion loss
Switching Performance: Ton and Toff specifications; faster switching times are acceptable
Bandwidth: Minimum 250MHz; higher bandwidth provides improved signal fidelity
Leakage Current: Maximum 10µA; lower values reduce power consumption
Operating Temperature Range: Minimum -40°C ~ 85°C; extended ranges are acceptable
Package Compatibility: Surface mount configuration with MSL 1 rating

The substitute parts 74LVC1G66GM,115 and 74LVC1G66GM,132 meet all substitution criteria. Both are manufactured by Nexperia USA Inc. and feature improved electrical characteristics compared to the FSAT66L6.

Parameter Comparison

Parameter	FSAT66L6	74LVC1G66GM,115	74LVC1G66GM,132
Manufacturer	onsemi	Nexperia USA Inc.	Nexperia USA Inc.
Product Status	Obsolete	Active	Active
Switch Circuit	SPST - NO	SPST - NO	SPST - NO
Multiplexer/Demultiplexer Circuit	1:1	1:1	1:1
Number of Circuits	1	1	1
On-State Resistance (Max)	15Ohm	10Ohm	10Ohm
Voltage - Supply, Single (V+)	1.65V ~ 5.5V	1.65V ~ 5.5V	1.65V ~ 5.5V
Switch Time Ton (Max)	4.5ns	4.2ns	4.2ns
Switch Time Toff (Max)	5.5ns	5ns	5ns
-3dB Bandwidth	250MHz	500MHz	500MHz
Charge Injection	0.05pC	7.5pC	7.5pC
Channel Capacitance (CS(off), CD(off))	6pF	6.5pF	6.5pF
Current - Leakage (IS(off)) (Max)	10µA	5µA	5µA
Operating Temperature	-40°C ~ 85°C	-40°C ~ 125°C	-40°C ~ 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount
Package / Case	6-UFDFN	6-XFDFN	6-XFDFN
Supplier Device Package	6-MicroPak	6-XSON, SOT886 (1.45x1)	6-XSON, SOT886 (1.45x1)
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant
REACH Status	REACH Unaffected	REACH Unaffected	REACH Unaffected

Engineering Selection Recommendations

Both 74LVC1G66GM,115 and 74LVC1G66GM,132 are direct functional substitutes for the FSAT66L6. The selection between these two Nexperia parts depends on packaging and supply chain considerations, as they are electrically identical.

Advantages of substitution:

Both substitute parts are in active production status, ensuring long-term availability
Both meet or exceed all electrical performance specifications of the FSAT66L6
Both are ROHS3 compliant, supporting modern environmental and regulatory requirements
Extended operating temperature range (-40°C ~ 125°C) provides additional thermal margin
Reduced on-state resistance (10Ohm vs. 15Ohm) improves signal integrity and reduces power dissipation
Lower leakage current (5µA vs. 10µA) reduces standby power consumption
Higher bandwidth (500MHz vs. 250MHz) supports faster signal transitions

Package consideration:

The substitute parts use 6-XFDFN packaging (SOT886 form factor, 1.45x1mm) instead of the original 6-UFDFN (6-MicroPak). Physical dimensions and pin configurations must be verified against PCB layout requirements before implementation.

Frequently Asked Questions (FAQ)

Q: Are the 74LVC1G66GM,115 and 74LVC1G66GM,132 truly equivalent to the FSAT66L6?

A: Both parts are functionally equivalent. They maintain the same SPST-NO switch topology, 1:1 circuit configuration, and supply voltage range. All critical electrical parameters meet or exceed FSAT66L6 specifications. The primary difference is packaging format (6-XFDFN vs. 6-UFDFN), which requires PCB layout verification.

Q: What is the difference between 74LVC1G66GM,115 and 74LVC1G66GM,132?

A: These parts are electrically identical. The difference lies in packaging format: 74LVC1G66GM,115 is supplied in Tape & Reel (TR) format with 24,969 pieces in stock, while 74LVC1G66GM,132 is also in Tape & Reel format with 6,044 pieces in stock. Selection should be based on supply availability and procurement requirements.

Q: Can I use the substitute parts in existing FSAT66L6 designs without modification?

A: Electrical compatibility is confirmed. However, the package change from 6-UFDFN to 6-XFDFN requires PCB footprint verification. Physical dimensions, pin pitch, and land pattern must be confirmed to match the new package specification before board layout implementation.

Q: What are the key performance improvements of the substitute parts?

A: The 74LVC1G66 series offers reduced on-state resistance (10Ohm vs. 15Ohm), faster switching times (4.2ns vs. 4.5ns for Ton), doubled bandwidth (500MHz vs. 250MHz), and lower leakage current (5µA vs. 10µA). These improvements enhance signal fidelity and reduce power consumption.

Q: Are the substitute parts compliant with current environmental regulations?

A: Yes. Both 74LVC1G66GM,115 and 74LVC1G66GM,132 are ROHS3 compliant and REACH unaffected, meeting current environmental and regulatory requirements for electronic components.

Q: What is the operating temperature range difference?

A: The FSAT66L6 operates from -40°C to 85°C, while the substitute parts operate from -40°C to 125°C. The extended upper temperature limit of the substitutes provides additional thermal margin for applications requiring higher operating temperatures.

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