FSAU3157P6X Equivalent & Substitute Parts

Part Overview

The FSAU3157P6X is a single-circuit SPDT (Single Pole Double Throw) analog switch manufactured by onsemi, housed in a 6-pin SC-88 (SC-70-6) surface mount package. This device operates across a supply voltage range of 1.65V to 5.5V with a maximum on-state resistance of 15Ohm and supports switching frequencies up to 250MHz. The part is currently classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and production continuity.

Key Parameters

Parameter	Value
Manufacturer Part Number	FSAU3157P6X
Manufacturer	onsemi
Switch Circuit Type	SPDT
Multiplexer/Demultiplexer Circuit	2:1
Number of Circuits	1
On-State Resistance (Max)	15Ohm
Channel-to-Channel Matching (ΔRon)	150mOhm
Supply Voltage (V+)	1.65V ~ 5.5V
Switch Time (Ton/Toff)	5.2ns / 4.6ns
-3dB Bandwidth	250MHz
Charge Injection	7pC
Channel Capacitance (CS(off), CD(off))	6.5pF
Leakage Current (IS(off)) Max	100nA
Crosstalk	-54dB @ 10MHz
Operating Temperature	-40°C ~ 85°C
Package / Case	6-TSSOP, SC-88, SOT-363
Mounting Type	Surface Mount
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)
REACH Status	REACH Unaffected

Substitute Part Grouping Explanation

Substitution for the FSAU3157P6X is determined by strict equivalence across the following critical parameters:

Primary Substitution Criteria:

Switch circuit type: SPDT
Multiplexer configuration: 2:1
Number of circuits: 1
On-state resistance: 15Ohm (maximum)
Supply voltage range: 1.65V ~ 5.5V
Package compatibility: 6-pin surface mount (SC-88, SC-70-6, SOT-363)
Operating temperature range: -40°C ~ 85°C minimum

Parametric Equivalent Parts maintain identical electrical specifications and are direct replacements with no design modifications required. These parts are listed as NC7SB3157P6X and NC7SBU3157P6X from onsemi.

Similar Parts share the same functional topology (SPDT 2:1 switch) and package family but may have variations in on-state resistance, switching speed, bandwidth, or operating temperature range. These parts require design verification before substitution.

Parameter Comparison

Part Number	Manufacturer	On-State Resistance (Max)	ΔRon	Supply Voltage	Ton/Toff (Max)	Bandwidth	Leakage Current	Operating Temp	Package	Status
FSAU3157P6X	onsemi	15Ohm	150mOhm	1.65V ~ 5.5V	5.2ns / 4.6ns	250MHz	100nA	-40°C ~ 85°C	SC-88	Obsolete
NC7SB3157P6X	onsemi	15Ohm	150mOhm	1.65V ~ 5.5V	5.2ns / 4.6ns	250MHz	100nA	-40°C ~ 85°C	SC-88	Active
NC7SBU3157P6X	onsemi	15Ohm	150mOhm	1.65V ~ 5.5V	5.2ns / 4.6ns	250MHz	100nA	-40°C ~ 85°C	SC-88	Obsolete
1P1G3157QDCKRQ1	Texas Instruments	15Ohm	100mOhm	1.65V ~ 5.5V	5.7ns / 3.8ns	300MHz	1µA	-40°C ~ 125°C	SC-70-6	Active
PI5A3157CEX	Diodes Incorporated	13Ohm	150mOhm	1.65V ~ 5.5V	5.2ns / 4.6ns	250MHz	100nA	-40°C ~ 85°C	SOT-363-6	Active
PI5A4157CEX-1516	Diodes Incorporated	1.2Ohm	10mOhm	1.65V ~ 5.5V	18ns / 20ns	150MHz	20nA	-40°C ~ 85°C	SOT-363-6	Active
SN74LVC1G3157DCKR	UMW	7Ohm (Typ)	150mOhm (Typ)	1.65V ~ 5.5V	5.2ns / 4.6ns	350MHz	100nA (Max)	-55°C ~ 125°C	SC70-6	Active
STG3157CTR	STMicroelectronics	15Ohm	100mOhm	1.65V ~ 4.3V	15ns / 10ns	250MHz	100nA	-55°C ~ 125°C	SOT-323-6L	Active
TS5A3157DBVR	Texas Instruments	10Ohm	150mOhm	1.65V ~ 5.5V	8.5ns / 6.5ns	300MHz	100nA	-40°C ~ 85°C	SOT-23-6	Active
TS5A3157DCKR	Texas Instruments	10Ohm	150mOhm	1.65V ~ 5.5V	8.5ns / 6.5ns	300MHz	100nA	-40°C ~ 85°C	SC-70-6	Active

Engineering Selection Recommendations

Direct Replacement (Parametric Equivalent):

NC7SB3157P6X is the recommended primary substitute. This onsemi part maintains identical electrical and thermal specifications to the FSAU3157P6X while offering active product status with 48,400 units in stock. It is ROHS3 compliant and carries the same REACH unaffected designation. No circuit modifications are required for this substitution.

Alternative Substitutes (Similar Parts):

For applications requiring extended operating temperature range or improved performance characteristics, the following active parts are suitable:

TS5A3157DCKR (Texas Instruments): Offers reduced on-state resistance (10Ohm vs. 15Ohm), improved bandwidth (300MHz vs. 250MHz), and maintains identical supply voltage and switching speed specifications. Package is SC-70-6, compatible with the original design footprint.
1P1G3157QDCKRQ1 (Texas Instruments): Provides extended operating temperature range (-40°C to 125°C), automotive qualification (AEC-Q100), and improved bandwidth (300MHz). On-state resistance and supply voltage remain equivalent. Suitable for automotive and extended-temperature applications.
SN74LVC1G3157DCKR (UMW): Delivers superior on-state resistance (7Ohm typical), highest bandwidth (350MHz), and extended temperature range (-55°C to 125°C). Maintains identical supply voltage and switching characteristics. Recommended for high-frequency or low-resistance applications.

Conditional Substitutes (Performance Trade-offs):

PI5A4157CEX-1516 (Diodes Incorporated): Significantly lower on-state resistance (1.2Ohm) and leakage current (20nA) but with reduced bandwidth (150MHz) and slower switching times (18ns/20ns). Suitable only for low-frequency, low-power applications where resistance minimization is critical.
STG3157CTR (STMicroelectronics): Maintains 15Ohm on-state resistance but has reduced maximum supply voltage (4.3V vs. 5.5V). Extended temperature range (-55°C to 125°C) available. Verify supply voltage compatibility before selection.

Frequently Asked Questions (FAQ)

Q: Can NC7SB3157P6X be used as a direct replacement for FSAU3157P6X?

A: Yes. NC7SB3157P6X is a parametric equivalent with identical on-state resistance, switching speed, bandwidth, leakage current, and operating temperature range. No design modifications are required. The primary advantage is active product status with higher inventory availability.

Q: What is the difference between NC7SB3157P6X and NC7SBU3157P6X?

A: Both are parametric equivalents to FSAU3157P6X with identical electrical specifications. NC7SB3157P6X has active product status with 48,400 units in stock, while NC7SBU3157P6X is obsolete with 17,300 units available. NC7SB3157P6X is the preferred choice for new designs.

Q: Can I use TS5A3157DCKR instead of FSAU3157P6X?

A: TS5A3157DCKR is a suitable alternative with improved performance. It offers lower on-state resistance (10Ohm vs. 15Ohm), higher bandwidth (300MHz vs. 250MHz), and faster switching times. The supply voltage range (1.65V ~ 5.5V) and operating temperature (-40°C ~ 85°C) are identical. Package is SC-70-6, compatible with the original footprint. Design verification is recommended to confirm the lower resistance does not affect circuit behavior.

Q: What are the package compatibility considerations?

A: The FSAU3157P6X uses SC-88 (SC-70-6) packaging. Most substitutes use compatible 6-pin surface mount packages (SC-88, SC-70-6, SOT-363, SOT-323-6L). Verify PCB footprint compatibility before selection. TS5A3157DBVR uses SOT-23-6, which has a different footprint and requires PCB redesign.

Q: Is the 1P1G3157QDCKRQ1 suitable for automotive applications?

A: Yes. The 1P1G3157QDCKRQ1 carries AEC-Q100 automotive qualification and is rated for -40°C to 125°C operating temperature. It maintains equivalent on-state resistance (15Ohm) and supply voltage range (1.65V ~ 5.5V). This part is recommended for automotive designs requiring extended temperature range.

Q: Why does PI5A4157CEX-1516 have such low on-state resistance?

A: PI5A4157CEX-1516 is designed for low-impedance switching applications where signal attenuation must be minimized. The 1.2Ohm on-state resistance comes with trade-offs: reduced bandwidth (150MHz vs. 250MHz) and slower switching times (18ns/20ns vs. 5.2ns/4.6ns). This part is suitable only for low-frequency applications where resistance is the primary design constraint.

Q: What compliance certifications apply to these substitute parts?

A: All listed substitute parts are ROHS3 compliant and REACH unaffected. The 1P1G3157QDCKRQ1 additionally carries AEC-Q100 automotive qualification. Moisture sensitivity level is MSL 1 (unlimited) for all parts, indicating no special handling requirements during storage or assembly.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message