SN75121N Equivalent & Substitute Parts

Part Overview

The SN75121N is a 2/0 Driver IC manufactured by Texas Instruments in the 75000 series. This component is classified as an interface driver with through-hole mounting in a 16-DIP package. The product is currently obsolete, making equivalent or substitute parts necessary for new designs or component replacement in legacy systems. The SN75121N operates within a supply voltage range of 4.75V to 5.25V and is rated for operating temperatures from 0°C to 70°C.

Substiute Parts

SN75121N

Texas InstrumentsIn Stock: 5190SN75121N Datasheet

Current PartRFQ

SN65C1167ENSR

Texas InstrumentsIn Stock: 9568SN65C1167ENSR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

The SN65C1167ENSR is identified as a manufacturer-recommended substitute for the SN75121N. Substitution is based on the following criteria:

Functional Compatibility: Both components are Texas Instruments interface ICs within the same product family. The SN65C1167ENSR provides 2/2 driver/receiver functionality (compared to the 2/0 configuration of the SN75121N), offering enhanced capability with full-duplex RS422/RS485 protocol support.

Electrical Parameters: The SN65C1167ENSR operates at 4.5V to 5.5V, which encompasses the SN75121N supply range of 4.75V to 5.25V. The substitute part supports an extended operating temperature range of -40°C to 85°C, exceeding the SN75121N specification of 0°C to 70°C.

Compliance & Certification: Both parts are ROHS3 compliant and REACH unaffected, meeting equivalent regulatory requirements.

Package Consideration: The SN65C1167ENSR uses surface-mount packaging (16-SOIC), whereas the SN75121N uses through-hole packaging (16-DIP). This represents a significant design change requiring PCB layout modification.

Parameter Comparison

Engineering Selection Recommendations

The SN65C1167ENSR is the manufacturer-recommended substitute for the obsolete SN75121N. Selection of this substitute is supported by:

Product Status: The SN75121N is obsolete, while the SN65C1167ENSR is active and in production, ensuring long-term availability and supply chain continuity.

Regulatory Compliance: Both components meet ROHS3 and REACH requirements, maintaining equivalent compliance posture in regulated applications.

Electrical Compatibility: The SN65C1167ENSR supply voltage range (4.5V to 5.5V) is compatible with systems designed for the SN75121N (4.75V to 5.25V). The extended operating temperature range of the substitute provides additional margin for demanding environments.

Functional Enhancement: The SN65C1167ENSR provides bidirectional transceiver capability (2/2 configuration) with RS422/RS485 protocol support, compared to the unidirectional driver configuration (2/0) of the SN75121N. This represents a functional upgrade suitable for applications requiring full-duplex communication.

Package Migration: Transition from through-hole (16-DIP) to surface-mount (16-SOIC) packaging requires PCB redesign. This change is necessary to access the active, supported component.

Frequently Asked Questions (FAQ)

Q: Can the SN65C1167ENSR be used as a direct pin-for-pin replacement for the SN75121N?

A: No. While both are 16-pin interface ICs from Texas Instruments, the SN65C1167ENSR uses surface-mount packaging (16-SOIC) whereas the SN75121N uses through-hole packaging (16-DIP). PCB layout modification is required. Additionally, the functional configuration differs (2/2 transceiver versus 2/0 driver), requiring circuit design review.

Q: What are the key electrical differences between these parts?

A: The SN65C1167ENSR operates at 4.5V to 5.5V supply voltage, which overlaps with but extends beyond the SN75121N range of 4.75V to 5.25V. The substitute supports an extended operating temperature range of -40°C to 85°C compared to 0°C to 70°C for the original part.

Q: Is the SN65C1167ENSR suitable for legacy system repairs?

A: The SN65C1167ENSR can replace the SN75121N functionally, but through-hole to surface-mount conversion requires component rework or board redesign. For legacy systems using through-hole construction, alternative through-hole interface drivers may be more practical for direct replacement.

Q: Are both parts compliant with current regulatory standards?

A: Yes. Both the SN75121N and SN65C1167ENSR are ROHS3 compliant and REACH unaffected, meeting current regulatory requirements for electronic components.

Q: What is the primary reason for substitution?

A: The SN75121N is obsolete and no longer manufactured. The SN65C1167ENSR is the active, manufacturer-recommended alternative from Texas Instruments, ensuring component availability and supply chain support.