SN75178BP Equivalent & Substitute Parts

Part Overview

The SN75178BP is a Buffer/ReDriver interface IC designed for RS422 and RS485 applications, manufactured by Texas Instruments. This single-channel device operates in the 4.75V to 5.25V supply range with a maximum delay time of 19ns and is packaged in an 8-DIP through-hole configuration. The product is classified as obsolete, making identification of functionally equivalent alternatives essential for ongoing system support and new design implementations.

Substiute Parts

SN75178BP

Texas InstrumentsIn Stock: 4771SN75178BP Datasheet

Current PartRFQ

THVD1500DR

Texas InstrumentsIn Stock: 5000156THVD1500DR Datasheet

MFR RecommendedRFQ

DS8921M/NOPB

Texas InstrumentsIn Stock: 1749DS8921M/NOPB Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the SN75178BP is determined by the following critical parameters:

Protocol Compatibility: Both substitute parts support RS422 and/or RS485 protocols, matching the primary application domain of the original device.

Channel Configuration: The original device provides 1 channel. Substitute parts maintain single-channel architecture to preserve circuit-level compatibility.

Supply Voltage Range: The SN75178BP operates within 4.75V to 5.25V. Substitute parts operate within 4.5V to 5.5V, providing overlapping voltage compatibility within standard 5V systems.

Operating Temperature Range: The original device operates 0°C to 70°C. Substitute parts extend this range, supporting broader environmental conditions while maintaining compatibility within the original specification window.

Package Transition: The original through-hole 8-DIP package is obsolete. Substitute parts transition to surface-mount 8-SOIC packaging, standard for active production components.

RoHS and Regulatory Compliance: All parts maintain ROHS3 compliance and EAR99 classification, ensuring regulatory continuity.

Parameter Comparison

Engineering Selection Recommendations

THVD1500DR is recommended for applications requiring extended operating temperature range (-40°C to 125°C) and RS485-specific protocol support. This part is in active production status with substantial inventory availability, ensuring long-term supply continuity. The extended temperature specification accommodates industrial and harsh environment deployments beyond the original device's 0°C to 70°C window.

DS8921M/NOPB is recommended for applications requiring full-duplex RS422 and RS485 protocol support with operating temperature matching the original specification (0°C to 70°C). This part maintains dual-protocol capability identical to the SN75178BP and is in active production status. Selection of this part preserves the original functional scope while transitioning to current manufacturing technology.

Both substitute parts maintain ROHS3 compliance and regulatory classification consistent with the original device, ensuring compliance continuity in regulated applications.

Frequently Asked Questions (FAQ)

Q: Can the SN75178BP be directly replaced with THVD1500DR or DS8921M/NOPB without circuit modification?

A: Both substitute parts operate within the 5V supply voltage range and support RS485 protocol. However, package transition from 8-DIP through-hole to 8-SOIC surface-mount requires PCB layout and assembly process changes. Functional pin compatibility must be verified against the specific application schematic.

Q: What is the primary difference between the two substitute options?

A: THVD1500DR supports RS485 protocol only with extended temperature range (-40°C to 125°C). DS8921M/NOPB supports both RS422 and RS485 protocols with temperature range matching the original device (0°C to 70°C). Selection depends on protocol requirements and environmental operating conditions.

Q: Why is the SN75178BP classified as obsolete?

A: The through-hole 8-DIP package format has been superseded by surface-mount technology in current manufacturing. Texas Instruments has transitioned this product line to active surface-mount alternatives to align with modern PCB assembly standards.

Q: Are there any supply voltage compatibility concerns when substituting these parts?

A: The original device specifies 4.75V to 5.25V. Both substitute parts specify 4.5V to 5.5V, providing wider tolerance bands. In standard 5V systems, both substitutes operate within the original specification window, ensuring voltage compatibility.

Q: What inventory status should be considered for production planning?

A: THVD1500DR has 5,000,100 pieces in stock. DS8921M/NOPB has 1,691 pieces in stock. Both are active production parts from Texas Instruments, ensuring ongoing availability for new designs and legacy system support.