DS8921M Equivalent & Substitute Parts

Part Overview

The DS8921M is a 1/1 transceiver IC for RS422 and RS485 communication protocols, manufactured by Texas Instruments in an 8-SOIC surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The DS8921M operates within a 4.5V to 5.5V supply voltage range and supports full-duplex communication with a 70 mV receiver hysteresis specification.

Substiute Parts

DS8921M

Texas InstrumentsIn Stock: 5178DS8921M Datasheet

Current PartRFQ

DS8921M/NOPB

Texas InstrumentsIn Stock: 1749DS8921M/NOPB Datasheet

DirectRFQ

DS8921AM/NOPB

Texas InstrumentsIn Stock: 1482DS8921AM/NOPB Datasheet

Parametric EquivalentRFQ

SP3490CN-L/TR

MaxLinear, Inc.In Stock: 3739SP3490CN-L/TR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the DS8921M are classified based on the following substitution criteria:

Direct Manufacturer Equivalents maintain identical electrical and mechanical parameters as the original part, differing only in packaging format or product status designation. These parts share the same base product number (DS8921) and are manufactured by Texas Instruments.

Parametric Equivalents provide functional compatibility through matching core specifications: 1/1 transceiver configuration, RS422/RS485 protocol support, full-duplex operation, 8-SOIC package, 4.5V to 5.5V supply voltage range, and 0°C to 70°C operating temperature. These parts maintain the same receiver hysteresis (70 mV) and mechanical footprint.

Manufacturer Recommended Substitutes are cross-manufacturer alternatives that satisfy the primary functional requirements (1/1 transceiver, RS422/RS485 protocols, full-duplex, 8-SOIC package, surface mount) while operating within compatible voltage and temperature ranges. These parts may exhibit variations in secondary parameters such as receiver hysteresis and data rate specifications.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (Active Product Status Required): DS8921M/NOPB and DS8921AM/NOPB are the primary substitutes for the obsolete DS8921M. Both parts are manufactured by Texas Instruments and maintain identical electrical specifications. DS8921M/NOPB and DS8921AM/NOPB are classified as active products, ensuring long-term availability and supply chain continuity. Both parts achieve ROHS3 compliance, addressing regulatory requirements that the original DS8921M does not meet.

For Cross-Manufacturer Substitution: SP3490CN-L/TR, manufactured by MaxLinear, Inc., provides functional compatibility as a 1/1 RS422/RS485 transceiver in an 8-SOIC package. This part is active and RoHS compliant. The SP3490CN-L/TR operates within a 3V to 3.6V supply voltage range, which differs from the DS8921M's 4.5V to 5.5V specification. The receiver hysteresis is specified at 25 mV compared to the DS8921M's 70 mV. Circuit design verification is required to confirm compatibility with existing power supply and signal integrity requirements when selecting this alternative.

Frequently Asked Questions (FAQ)

Q: Can DS8921M/NOPB be used as a direct replacement for DS8921M? A: Yes. DS8921M/NOPB maintains identical electrical and mechanical specifications as DS8921M, including 1/1 transceiver configuration, RS422/RS485 protocol support, full-duplex operation, 70 mV receiver hysteresis, 4.5V to 5.5V supply voltage, and 8-SOIC package. The primary difference is product status (active versus obsolete) and RoHS compliance (ROHS3 versus non-compliant).

Q: What is the difference between DS8921M/NOPB and DS8921AM/NOPB? A: Both parts are Texas Instruments RS422/RS485 transceivers with identical electrical specifications and 8-SOIC packaging. The designation difference (M versus AM) reflects internal product line categorization. Both are active products with ROHS3 compliance and equivalent performance characteristics.

Q: Can SP3490CN-L/TR replace DS8921M in all applications? A: SP3490CN-L/TR provides functional compatibility as a 1/1 RS422/RS485 transceiver in an 8-SOIC package. However, the supply voltage range differs (3V to 3.6V versus 4.5V to 5.5V) and receiver hysteresis is lower (25 mV versus 70 mV). Circuit design verification is required to confirm compatibility with existing power supply architecture and signal integrity requirements.

Q: Are all substitute parts available in the same package? A: Yes. All substitute parts listed are available in 8-SOIC (0.154", 3.90mm Width) surface mount packages, ensuring mechanical compatibility with existing PCB designs and assembly processes.

Q: What is the significance of RoHS compliance for these parts? A: DS8921M is RoHS non-compliant, while DS8921M/NOPB, DS8921AM/NOPB, and SP3490CN-L/TR are RoHS compliant. RoHS compliance is a regulatory requirement in many markets and may be mandated by customer specifications or end-use applications. Active product substitutes provide compliance assurance for new designs.

Q: How does receiver hysteresis affect transceiver selection? A: Receiver hysteresis determines the voltage differential required for the receiver to switch logic states. DS8921M, DS8921M/NOPB, and DS8921AM/NOPB specify 70 mV hysteresis, while SP3490CN-L/TR specifies 25 mV. Higher hysteresis provides greater noise immunity in noisy environments. Lower hysteresis may improve signal detection sensitivity. Application requirements determine the appropriate hysteresis specification.