SN74LS540DB Equivalent & Substitute Parts

Part Overview

The SN74LS540DB is an inverting buffer logic integrated circuit manufactured by Texas Instruments, designed for 8-bit buffering applications with 3-state output capability. This device operates within the 74LS logic family and is housed in a 20-SSOP surface mount package.

The SN74LS540DB has been discontinued at DiGi Electronics. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain availability, and support ongoing production requirements for applications utilizing this component.

Substiute Parts

SN74LS540DB

Texas InstrumentsIn Stock: 978SN74LS540DB Datasheet

Current PartRFQ

SN74LS540DBR

Texas InstrumentsIn Stock: 1297SN74LS540DBR Datasheet

DirectRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN74LS540DB is determined by strict equivalence across the following critical parameters:

Functional Parameters: Logic type (Buffer, Inverting), number of elements (1), bits per element (8), and output type (3-State) must remain identical.

Electrical Parameters: Supply voltage range (4.75V ~ 5.25V), output current specifications (15mA high, 24mA low), and operating temperature range (0°C ~ 70°C) must match exactly.

Physical Parameters: Mounting type (Surface Mount) and package designation (20-SSOP with 0.209" width, 5.30mm) must be identical to ensure mechanical and electrical compatibility with existing PCB layouts.

Compliance Parameters: RoHS3 compliance status must be maintained for regulatory adherence.

The SN74LS540DBR qualifies as a direct substitute based on complete alignment with all specified parameters.

Parameter Comparison

Engineering Selection Recommendations

The SN74LS540DBR is the direct substitute for the SN74LS540DB. Both devices are manufactured by Texas Instruments and share identical electrical, functional, and physical specifications. The primary distinction is product status: the SN74LS540DB is discontinued at DiGi Electronics, while the SN74LS540DBR maintains active status with confirmed inventory availability.

The SN74LS540DBR is supplied in Tape & Reel (TR) packaging format, which is the standard production packaging for high-volume applications. Both parts maintain ROHS3 compliance and are suitable for applications requiring inverting buffer functionality with 3-state output control in 5V logic systems.

Selection of the SN74LS540DBR ensures continued access to equivalent functionality with established supply chain availability and active manufacturer support.

Frequently Asked Questions (FAQ)

Q: Can the SN74LS540DBR be used as a direct replacement for the SN74LS540DB?

A: Yes. The SN74LS540DBR is a direct substitute. Both devices share identical electrical specifications, functional characteristics, and physical package dimensions. The primary difference is packaging format (Tape & Reel versus prototype packaging) and product status (active versus discontinued).

Q: What are the key parameters that determine substitution compatibility?

A: Substitution compatibility is determined by: logic type (Buffer, Inverting), element count (1), bits per element (8), output type (3-State), supply voltage range (4.75V ~ 5.25V), output current ratings (15mA high, 24mA low), operating temperature range (0°C ~ 70°C), and package type (20-SSOP surface mount). All parameters must match exactly.

Q: Are there any differences in pin configuration between these parts?

A: No. Both the SN74LS540DB and SN74LS540DBR use the identical 20-SSOP package with matching pin assignments. PCB layouts and footprints require no modification.

Q: What is the difference between the packaging formats?

A: The SN74LS540DB is supplied in prototype packaging, while the SN74LS540DBR is supplied in Tape & Reel (TR) format. Tape & Reel packaging is standard for production quantities and automated assembly processes. Both formats contain the same die and provide identical electrical performance.

Q: Are both parts RoHS compliant?

A: Yes. Both the SN74LS540DB and SN74LS540DBR are ROHS3 compliant, meeting regulatory requirements for hazardous substance restrictions.

Q: Why is the SN74LS540DB discontinued?

A: The SN74LS540DB has been discontinued at DiGi Electronics. The SN74LS540DBR remains the active equivalent part number for continued sourcing and production support.