FSA4159P6X Equivalent & Substitute Parts

Part Overview

The FSA4159P6X is a single-circuit SPDT (Single Pole Double Throw) analog switch manufactured by onsemi in SC-88 (SOT-363) surface mount packaging. This device operates across a 1.65V to 5.5V supply range with a maximum on-state resistance of 900mOhm and is designed for general-purpose signal routing and multiplexing applications in interface circuits. The part is currently in active production status with 17,400 units in stock.

Equivalent and substitute parts are necessary when the FSA4159P6X reaches end-of-life, when alternative sourcing is required for supply chain resilience, or when design specifications allow for different electrical characteristics within the same functional category.

Key Parameters

Parameter	FSA4159P6X Value
Switch Circuit Configuration	SPDT (Single Pole Double Throw)
Multiplexer/Demultiplexer Circuit	2:1
Number of Circuits	1
On-State Resistance (Max)	900mOhm
Channel-to-Channel Matching (ΔRon)	50mOhm
Supply Voltage Range (V+)	1.65V ~ 5.5V
Switch Time Ton (Max)	30ns
Switch Time Toff (Max)	20ns
-3dB Bandwidth	180MHz
Charge Injection	15pC
Channel Capacitance (CS(off), CD(off))	12pF
Current - Leakage (IS(off)) Max	10nA
Crosstalk	-60dB @ 1MHz
Operating Temperature Range	-40°C ~ 85°C
Package / Case	6-TSSOP, SC-88, SOT-363
Mounting Type	Surface Mount
RoHS Status	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the FSA4159P6X is determined by the following mandatory criteria:

Functional Requirements:

Switch circuit configuration must be SPDT
Multiplexer/Demultiplexer circuit must be 2:1
Single circuit configuration (1 circuit)
Package compatibility: 6-TSSOP, SC-88, or SOT-363

Electrical Compatibility:

Supply voltage range must encompass or match 1.65V ~ 5.5V
On-state resistance must not exceed application requirements
Channel-to-channel matching (ΔRon) must be within acceptable tolerance
Operating temperature range must cover -40°C ~ 85°C minimum

Compliance Requirements:

RoHS3 compliance required
MSL rating of 1 (Unlimited) preferred for manufacturing flexibility

Substitute parts are grouped into two categories based on on-state resistance characteristics: high-resistance devices (900mOhm class) and low-resistance devices (1.2Ohm to 15Ohm class). Selection depends on application impedance requirements and signal integrity specifications.

Parameter Comparison

Part Number	Manufacturer	On-State Resistance (Max)	ΔRon (Max)	Supply Voltage	Ton/Toff (Max)	-3dB Bandwidth	Charge Injection	Leakage Current (Max)	Crosstalk	Operating Temp	Product Status
FSA4159P6X	onsemi	900mOhm	50mOhm	1.65V ~ 5.5V	30ns / 20ns	180MHz	15pC	10nA	-60dB @ 1MHz	-40°C ~ 85°C	Active
NLVASB3157DFT2G	onsemi	7Ohm (Typ)	500mOhm	1.65V ~ 5.5V	—	250MHz	7pC	100nA	-54dB @ 10MHz	-55°C ~ 125°C	Obsolete
1P1G3157QDCKRQ1	Texas Instruments	15Ohm	100mOhm	1.65V ~ 5.5V	5.7ns / 3.8ns	300MHz	7pC	1µA	-54dB @ 10MHz	-40°C ~ 125°C	Active
PI5A3157CEX	Diodes Incorporated	13Ohm	150mOhm	1.65V ~ 5.5V	5.2ns / 4.6ns	250MHz	7pC	100nA	-54dB @ 10MHz	-40°C ~ 85°C	Active
PI5A4157CEX	Diodes Incorporated	1.2Ohm	10mOhm	1.65V ~ 5.5V	18ns / 20ns	150MHz	35pC	20nA	-70dB @ 1MHz	-40°C ~ 85°C	Last Time Buy
TS5A3159ADCKR	Texas Instruments	900mOhm	50mOhm	1.65V ~ 5.5V	30ns / 20ns	100MHz	-20pC	20nA	-64dB @ 1MHz	-40°C ~ 85°C	Active
TS5A3160DCKR	Texas Instruments	900mOhm	50mOhm	1.65V ~ 5.5V	6ns / 13ns	100MHz	36.5pC	20nA	-64dB @ 10MHz	-40°C ~ 85°C	Active
TS5A3160DCKT	Texas Instruments	900mOhm	50mOhm	1.65V ~ 5.5V	6ns / 13ns	100MHz	36.5pC	20nA	-64dB @ 10MHz	-40°C ~ 85°C	Last Time Buy

Engineering Selection Recommendations

Direct Equivalents (900mOhm Class):

TS5A3159ADCKR and TS5A3160DCKR from Texas Instruments are functionally equivalent to the FSA4159P6X with identical on-state resistance, channel matching, and supply voltage specifications. Both are in active production status. TS5A3160DCKR offers faster switching times (6ns/13ns vs. 30ns/20ns) and improved crosstalk performance (-64dB vs. -60dB), making it suitable for higher-speed applications. TS5A3159ADCKR maintains closer bandwidth characteristics to the original part (100MHz vs. 180MHz).

Low-Resistance Alternatives (1.2Ohm to 15Ohm Class):

PI5A4157CEX (1.2Ohm), PI5A3157CEX (13Ohm), and 1P1G3157QDCKRQ1 (15Ohm) provide significantly lower on-state resistance suitable for applications requiring minimal signal attenuation and lower power dissipation. These parts are appropriate only when circuit design permits lower impedance switching. PI5A4157CEX is in Last Time Buy status; 1P1G3157QDCKRQ1 includes automotive-grade qualification (AEC-Q100) and extended temperature range (-40°C ~ 125°C).

Obsolete Part:

NLVASB3157DFT2G (onsemi) is marked obsolete and should not be selected for new designs despite its lower on-state resistance and extended temperature range.

Packaging Consideration:

All substitute parts maintain compatibility with 6-TSSOP, SC-88, or SOT-363 surface mount packages. Verify specific supplier device package designation during procurement to ensure PCB footprint compatibility.

Frequently Asked Questions (FAQ)

Q: Can I use a low-resistance substitute (1.2Ohm to 15Ohm) in place of the FSA4159P6X (900mOhm)?

A: Yes, if your circuit design permits. Lower on-state resistance reduces signal attenuation and power dissipation but may require circuit re-evaluation for impedance matching and signal integrity. Verify that the lower resistance does not introduce unintended loading effects on your signal source.

Q: What is the difference between TS5A3159ADCKR and TS5A3160DCKR?

A: Both are Texas Instruments 900mOhm equivalents with identical electrical specifications. TS5A3160DCKR offers faster switching times (6ns/13ns vs. 30ns/20ns) and improved crosstalk performance. Select TS5A3160DCKR for high-speed switching applications; TS5A3159ADCKR for general-purpose applications matching the original FSA4159P6X timing.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain RoHS3 compliance and MSL rating of 1 (Unlimited), ensuring compatibility with standard manufacturing processes.

Q: Can I use TS5A3160DCKT (Last Time Buy) for new designs?

A: TS5A3160DCKT is functionally identical to TS5A3160DCKR but is in Last Time Buy status, indicating limited future availability. For new designs, select TS5A3160DCKR (Active status) or TS5A3159ADCKR (Active status) to ensure long-term supply continuity.

Q: What is the significance of package designation differences (SC-88 vs. SC-70-6 vs. SOT-363)?

A: These are equivalent package designations for the same 6-pin surface mount form factor. SC-88, SC-70-6, and SOT-363 refer to identical physical packages with the same PCB footprint. Verify your PCB design uses the standard 6-TSSOP footprint to ensure compatibility with all listed parts.

Q: Should I select 1P1G3157QDCKRQ1 for automotive applications?

A: 1P1G3157QDCKRQ1 includes AEC-Q100 automotive qualification and extended operating temperature range (-40°C ~ 125°C). Select this part only if your application requires automotive-grade certification. For non-automotive applications, other active-status alternatives provide equivalent functionality.

Q: Why does PI5A4157CEX show Last Time Buy status?

A: Last Time Buy status indicates the manufacturer is discontinuing production. While currently available, future procurement may become difficult. For new designs requiring low-resistance switching, consider PI5A3157CEX (13Ohm, Active status) as a longer-term alternative.

Request Quote (Ships tomorrow)

Part Number

Quantity

Company

Contact Name

E-mail

Message