74FST3253QSR Equivalent & Substitute Parts

Part Overview

The 74FST3253QSR is a 2 x 4:1 Multiplexer/Demultiplexer logic IC manufactured by onsemi in a 16-QSOP surface mount package. This component is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production support. The 74FST3253QSR operates with single supply voltage between 4V and 5.5V across an operating temperature range of -40°C to 85°C, serving applications requiring signal multiplexing and demultiplexing functions in digital logic circuits.

Key Parameters

Parameter	Specification
Part Number	74FST3253QSR
Manufacturer	onsemi
Type	Multiplexer/Demultiplexer
Circuit Configuration	2 x 4:1
Package Type	16-QSOP (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Voltage Supply	4V ~ 5.5V (Single Supply)
Operating Temperature	-40°C ~ 85°C
Product Status	Obsolete
RoHS Status	RoHS non-compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the 74FST3253QSR is determined by the following critical parameters:

Functional Equivalence: All substitute parts maintain the identical 2 x 4:1 multiplexer/demultiplexer circuit configuration with single supply operation.

Electrical Compatibility: Substitute parts operate within overlapping or compatible voltage supply ranges (4.5V ~ 5.5V or 4.75V ~ 5.25V) and maintain the same -40°C to 85°C operating temperature range.

Package Compatibility: Substitute parts use 16-SSOP or 16-QSOP packages with 0.154" (3.90mm) width, ensuring PCB layout compatibility with the original 74FST3253QSR footprint.

Compliance Status: Active and Last Time Buy substitutes offer RoHS3 compliance, addressing regulatory requirements that the obsolete 74FST3253QSR cannot meet.

The substitute parts are grouped into two categories: Direct manufacturer alternatives from Texas Instruments (74CBT series) and functionally equivalent alternatives from Nexperia, Diodes Incorporated, and Renesas Electronics.

Parameter Comparison

Part Number	Manufacturer	Circuit	Package	Voltage Supply	Operating Temp	Product Status	RoHS Status	MSL
74FST3253QSR	onsemi	2 x 4:1	16-QSOP (3.90mm)	4V ~ 5.5V	-40°C ~ 85°C	Obsolete	Non-compliant	1
SN74CBT3253DBQR	Texas Instruments	2 x 4:1	16-SSOP (3.90mm)	4.5V ~ 5.5V	-40°C ~ 85°C	Last Time Buy	ROHS3 Compliant	2
SN74CBT3253CDBQR	Texas Instruments	2 x 4:1	16-SSOP (3.90mm)	4.5V ~ 5.5V	-40°C ~ 85°C	Active	ROHS3 Compliant	2
CBT3253ADS,118	Nexperia USA Inc.	2 x 4:1	16-SSOP (3.90mm)	4.5V ~ 5.5V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
PI5C3253QE	Diodes Incorporated	2 x 4:1	16-QSOP (3.90mm)	4.75V ~ 5.25V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
PI5C3253QEX	Diodes Incorporated	2 x 4:1	16-QSOP (3.90mm)	4.75V ~ 5.25V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
QS3253QG	Renesas Electronics Corporation	2 x 4:1	16-QSOP (3.90mm)	4.75V ~ 5.25V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
QS3253QG8	Renesas Electronics Corporation	2 x 4:1	16-QSOP (3.90mm)	4.75V ~ 5.25V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
SN74CBT3253CDBR	Texas Instruments	2 x 4:1	16-SSOP (5.30mm)	4.5V ~ 5.5V	-40°C ~ 85°C	Active	ROHS3 Compliant	1
SN74CBT3253DBR	Texas Instruments	2 x 4:1	16-SSOP (5.30mm)	4.5V ~ 5.5V	-40°C ~ 85°C	Last Time Buy	ROHS3 Compliant	1

Engineering Selection Recommendations

For New Designs: Select from active product status parts: SN74CBT3253CDBQR (Texas Instruments), CBT3253ADS,118 (Nexperia), PI5C3253QE or PI5C3253QEX (Diodes Incorporated), or QS3253QG/QS3253QG8 (Renesas Electronics). All offer RoHS3 compliance and unlimited or extended moisture sensitivity ratings.

For Existing Production: SN74CBT3253DBQR and SN74CBT3253DBR remain available as Last Time Buy options from Texas Instruments, providing continuity for ongoing manufacturing requirements.

Package Consideration: Parts designated with 16-QSOP package (PI5C3253QE, PI5C3253QEX, QS3253QG, QS3253QG8) match the original 74FST3253QSR footprint exactly. Texas Instruments 74CBT series parts use 16-SSOP packaging with identical 3.90mm width for direct substitution, while SN74CBT3253CDBR and SN74CBT3253DBR use 16-SSOP with 5.30mm width requiring PCB layout verification.

Voltage Supply Range: The 74FST3253QSR operates at 4V minimum; substitute parts operate at 4.5V or 4.75V minimum. Verify system supply voltage meets substitute part requirements.

Frequently Asked Questions (FAQ)

Q: Can I use SN74CBT3253CDBQR as a direct replacement for 74FST3253QSR?

A: Yes. Both parts maintain 2 x 4:1 multiplexer/demultiplexer functionality, operate across -40°C to 85°C, and use compatible 16-SSOP packaging with 3.90mm width. The SN74CBT3253CDBQR operates at 4.5V ~ 5.5V supply voltage and is RoHS3 compliant.

Q: What is the difference between PI5C3253QE and PI5C3253QEX?

A: Both are functionally identical 2 x 4:1 multiplexer/demultiplexer parts from Diodes Incorporated with matching electrical specifications. The primary difference is packaging format: PI5C3253QE is supplied in Tube, while PI5C3253QEX is supplied in Tape & Reel. PI5C3253QEX offers significantly higher inventory availability (36,600 pcs vs. 2,790 pcs).

Q: Are there package width differences I need to consider?

A: Yes. Most substitute parts use 16-SSOP or 16-QSOP with 0.154" (3.90mm) width, matching the original 74FST3253QSR footprint. However, SN74CBT3253CDBR and SN74CBT3253DBR use 16-SSOP with 0.209" (5.30mm) width. Verify PCB layout compatibility before selecting these variants.

Q: What is the minimum supply voltage for substitute parts?

A: Texas Instruments 74CBT series parts require 4.5V minimum. Diodes Incorporated PI5C3253 and Renesas QS3253 parts require 4.75V minimum. The original 74FST3253QSR operates at 4V minimum. Confirm your system supply voltage meets the selected substitute part's minimum requirement.

Q: Which substitute part has the best long-term availability?

A: PI5C3253QEX from Diodes Incorporated shows the highest inventory (36,600 pcs) and active product status, indicating strong long-term availability. QS3253QG and QS3253QG8 from Renesas also maintain active status with substantial inventory levels (3,880 and 2,647 pcs respectively).

Q: Is RoHS compliance required for my application?

A: All substitute parts listed are RoHS3 compliant. The original 74FST3253QSR is RoHS non-compliant. If your application or market requires RoHS compliance, any substitute part from this list meets that requirement.

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