FST3244MTCX Equivalent & Substitute Parts

Part Overview

The FST3244MTCX is a 4 x 1:1 bus switch logic IC manufactured by onsemi in a 20-TSSOP package. This component is classified as obsolete, making equivalent and substitute parts necessary for ongoing design support and procurement. The FST3244MTCX operates with a single supply voltage between 4V and 5.5V and maintains an operating temperature range of -40°C to 85°C. Identifying compatible substitutes ensures design continuity and supply chain flexibility for applications requiring this bus switch functionality.

Key Parameters

Parameter	FST3244MTCX
Manufacturer	onsemi
Type	Bus Switch
Circuit Configuration	4 x 1:1
Independent Circuits	2
Voltage Supply Source	Single Supply
Voltage - Supply Range	4V ~ 5.5V
Operating Temperature	-40°C ~ 85°C
Mounting Type	Surface Mount
Package / Case	20-TSSOP (0.173", 4.40mm Width)
Moisture Sensitivity Level (MSL)	1 (Unlimited)
Product Status	Obsolete

Substitute Part Grouping Explanation

Substitution for the FST3244MTCX is determined by strict equivalence across the following critical parameters:

Circuit Configuration: 4 x 1:1 bus switch topology
Independent Circuits: 2 circuits
Voltage Supply Range: 4V ~ 5.5V (or compatible subset)
Operating Temperature: -40°C ~ 85°C
Mounting Type: Surface Mount
Package Type: 20-TSSOP, 20-SSOP, or 20-TVSOP (all 20-pin small outline packages)

Substitute parts are grouped into two categories:

Direct Substitutes (Identical Package - 20-TSSOP):

SN74CBT3244CPWR
SN74CBT3244CPW
SN74CBT3244PW
SN74CBT3244PWR

Compatible Substitutes (Alternative Packages - 20-SSOP / 20-TVSOP):

SN74CBT3244CDBQR (20-SSOP)
SN74CBT3244DBQR (20-SSOP)
SN74CBT3244DBR (20-SSOP)
SN74CBT3244CDGVR (20-TVSOP)
SN74CBT3244DGVR (20-TVSOP)

All substitute parts are manufactured by Texas Instruments and maintain the same functional specifications as the FST3244MTCX.

Parameter Comparison

Parameter	FST3244MTCX	SN74CBT3244CPWR	SN74CBT3244CPW	SN74CBT3244CDBQR	SN74CBT3244CDGVR	SN74CBT3244DBR	SN74CBT3244DGVR	SN74CBT3244PW	SN74CBT3244PWR
Manufacturer	onsemi	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments	Texas Instruments
Type	Bus Switch	Bus Switch	Bus Switch	Bus Switch	Bus Switch	Bus Switch	Bus Switch	Bus Switch	Bus Switch
Circuit Configuration	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1	4 x 1:1
Independent Circuits	2	2	2	2	2	2	2	2	2
Voltage Supply Source	Single Supply	Single Supply	Single Supply	Single Supply	Single Supply	Single Supply	Single Supply	Single Supply	Single Supply
Voltage - Supply Range	4V ~ 5.5V	4V ~ 5.5V	4V ~ 5.5V	4V ~ 5.5V	4V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V	4.5V ~ 5.5V
Operating Temperature	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C	-40°C ~ 85°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	20-TSSOP (0.173", 4.40mm)	20-TSSOP (0.173", 4.40mm)	20-TSSOP (0.173", 4.40mm)	20-SSOP (0.154", 3.90mm)	20-TVSOP (0.173", 4.40mm)	20-SSOP (0.209", 5.30mm)	20-TFSOP (0.173", 4.40mm)	20-TSSOP (0.173", 4.40mm)	20-TSSOP (0.173", 4.40mm)
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	2 (1 Year)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)
Product Status	Obsolete	Active	Active	Active	Active	Last Time Buy	Last Time Buy	Last Time Buy	Obsolete
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant

Engineering Selection Recommendations

Primary Recommendation: SN74CBT3244CPWR

SN74CBT3244CPWR is the preferred substitute for FST3244MTCX. This part maintains identical package geometry (20-TSSOP), voltage supply range (4V ~ 5.5V), and operating temperature specifications. The part carries Active product status with ROHS3 compliance, ensuring long-term availability and regulatory alignment. Packaging in Tape & Reel (TR) format supports high-volume production requirements.

Secondary Recommendations (Package-Compatible Alternatives):

SN74CBT3244CPW: Identical electrical and package specifications to SN74CBT3244CPWR, differentiated by Tube packaging. Suitable for lower-volume applications.
SN74CBT3244PW: Maintains 20-TSSOP package and electrical specifications with Last Time Buy status. Appropriate for designs with extended component qualification timelines.
SN74CBT3244PWR: Functionally equivalent with Last Time Buy status. Inventory availability at 22,400 units supports near-term procurement.

Alternative Package Options (Functional Equivalence with PCB Layout Modification):

SN74CBT3244CDBQR / SN74CBT3244DBQR / SN74CBT3244DBR: 20-SSOP package variants. Require PCB footprint redesign due to different package dimensions. SN74CBT3244CDBQR offers Active status; SN74CBT3244DBQR and SN74CBT3244DBR carry Last Time Buy designation.
SN74CBT3244CDGVR / SN74CBT3244DGVR: 20-TVSOP package variants. Require PCB footprint redesign. SN74CBT3244CDGVR is Active; SN74CBT3244DGVR is Last Time Buy.

Voltage Supply Consideration:

Parts designated SN74CBT3244DBQR, SN74CBT3244DBR, SN74CBT3244DGVR, SN74CBT3244PW, and SN74CBT3244PWR operate within a narrower voltage range (4.5V ~ 5.5V) compared to the FST3244MTCX (4V ~ 5.5V). Designs requiring operation at 4V supply voltage must select SN74CBT3244CPWR, SN74CBT3244CPW, SN74CBT3244CDBQR, or SN74CBT3244CDGVR.

Frequently Asked Questions (FAQ)

Q: Can SN74CBT3244CPWR be used as a direct replacement for FST3244MTCX without PCB modifications?

A: Yes. SN74CBT3244CPWR maintains identical package geometry (20-TSSOP with 0.173" width and 4.40mm pitch), voltage specifications (4V ~ 5.5V), and operating temperature range (-40°C ~ 85°C). No PCB layout changes are required.

Q: What is the difference between SN74CBT3244CPWR and SN74CBT3244CPW?

A: Both parts are electrically and functionally identical with the same 20-TSSOP package. The difference is packaging format: SN74CBT3244CPWR is supplied in Tape & Reel (TR), while SN74CBT3244CPW is supplied in Tube. Select based on production volume and handling requirements.

Q: Why do some substitute parts have a narrower voltage range (4.5V ~ 5.5V)?

A: SN74CBT3244DBQR, SN74CBT3244DBR, SN74CBT3244DGVR, SN74CBT3244PW, and SN74CBT3244PWR are specified for 4.5V ~ 5.5V operation. If your design requires operation at 4V supply voltage, select SN74CBT3244CPWR, SN74CBT3244CPW, SN74CBT3244CDBQR, or SN74CBT3244CDGVR instead.

Q: Can I use SN74CBT3244CDBQR or SN74CBT3244DGVR as substitutes?

A: These parts are functionally equivalent but require PCB footprint redesign. SN74CBT3244CDBQR and SN74CBT3244DBQR use 20-SSOP packages with different dimensions (0.154" or 0.209" width) compared to the original 20-TSSOP (0.173" width). SN74CBT3244CDGVR and SN74CBT3244DGVR use 20-TVSOP packages. Use only if PCB layout modifications are feasible.

Q: What is the Moisture Sensitivity Level (MSL) difference, and does it matter?

A: FST3244MTCX and most Texas Instruments substitutes carry MSL 1 (Unlimited), meaning no shelf-life restrictions. SN74CBT3244CDBQR and SN74CBT3244DBQR carry MSL 2 (1 Year), requiring storage within one year of manufacture. For applications with extended component storage, select MSL 1 rated parts.

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

A: SN74CBT3244CPWR carries Active product status, ensuring continued manufacturing and supply. Parts with Last Time Buy status (SN74CBT3244PW, SN74CBT3244PWR, SN74CBT3244DBR, SN74CBT3244DGVR) have limited production windows. For new designs, SN74CBT3244CPWR is the recommended choice.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All Texas Instruments SN74CBT3244 variants listed are ROHS3 compliant. The original FST3244MTCX RoHS status is not specified in available documentation.

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