ISO35TDWR RS422/RS485 Digital Isolator Equivalent & Substitute Parts

Part Overview

The ISO35TDWR is a Texas Instruments RS422/RS485 digital isolator featuring 2500Vrms isolation voltage, 3 channels, and 1Mbps data rate in a 16-SOIC surface mount package. This component is Active status and ROHS3 compliant. Substitute parts are necessary when the ISO35TDWR is unavailable, when higher isolation voltage or improved common mode transient immunity is required, or when alternative packaging formats are needed for production requirements.

Substiute Parts

ISO35TDWR

Texas InstrumentsIn Stock: 50246ISO35TDWR Datasheet

Current PartRFQ

MAX14945EWE+

Analog Devices Inc./Maxim IntegratedIn Stock: 1183MAX14945EWE+ Datasheet

MFR RecommendedRFQ

MAX14948EWE+

Analog Devices Inc./Maxim IntegratedIn Stock: 2501MAX14948EWE+ Datasheet

MFR RecommendedRFQ

MAX14948EWE+T

Analog Devices Inc./Maxim IntegratedIn Stock: 27967MAX14948EWE+T Datasheet

MFR RecommendedRFQ

MAX14949EWE+

Analog Devices Inc./Maxim IntegratedIn Stock: 1268MAX14949EWE+ Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the ISO35TDWR is determined by the following critical parameters:

Mandatory Compatibility Criteria:

• Package / Case: 16-SOIC (0.295", 7.50mm Width) — all substitutes must match this footprint
• Type: RS422/RS485 Digital Isolator — functional category must remain identical
• Number of Channels: 3 — channel count must be preserved
• Inputs - Side 1/Side 2: 2/1 — input configuration must match
• Channel Type: Unidirectional — isolation topology must be maintained
• Mounting Type: Surface Mount — assembly method must be compatible
• Operating Temperature: -40°C ~ 85°C — temperature range must be met or exceeded

Allowable Variation Parameters:

• Isolation Voltage: May be equal to or greater than 2500Vrms
• Common Mode Transient Immunity: May be equal to or greater than 25kV/µs
• Data Rate: May be equal to or less than 1Mbps (lower rates are acceptable)
• Voltage - Supply: May overlap with or extend the 3V ~ 3.6V range
• Packaging Format: May differ (Tube, Tape & Reel acceptable as alternatives to Cut Tape)

All four substitute parts meet these criteria and are classified as direct functional equivalents.

Parameter Comparison

Engineering Selection Recommendations

All four substitute parts are Active status products with ROHS3 compliance and REACH unaffected designation, meeting regulatory requirements equivalent to the ISO35TDWR.

MAX14945EWE+ provides the closest isolation voltage specification at 2750Vrms with improved common mode transient immunity at 35kV/µs (Typ). Supply voltage range extends to 1.71V minimum, offering broader compatibility. Data rate is reduced to 500kbps. Moisture sensitivity is improved to MSL 1 (Unlimited). Packaging is Tube format.

MAX14948EWE+ and MAX14948EWE+T are identical in electrical specification, both offering 5000Vrms isolation voltage with 35kV/µs (Typ) common mode transient immunity. Both include propagation delay specifications (1.04µs) and rise/fall time data (900ns Max). Supply voltage range is 1.71V ~ 5.5V and 4.5V ~ 5.5V. The primary difference is packaging: MAX14948EWE+ is supplied in Tube format with 2395 units in stock, while MAX14948EWE+T is supplied in Tape & Reel format with 27925 units in stock.

MAX14949EWE+ offers 5000Vrms isolation with 35kV/µs (Typ) common mode transient immunity. Supply voltage range is 3V ~ 5.5V and 4.5V ~ 5.5V, maintaining compatibility with the ISO35TDWR's 3V minimum requirement. Packaging is Tube format with 1175 units in stock.

Selection between substitutes depends on data rate requirements (1Mbps vs. 500kbps), isolation voltage margin, supply voltage constraints, and packaging format availability.

Frequently Asked Questions (FAQ)

Q: Can MAX14948EWE+ or MAX14949EWE+ be used as direct drop-in replacements for ISO35TDWR?

A: Yes, both parts are direct functional equivalents. All mandatory compatibility criteria are met: identical 16-SOIC package footprint, 3-channel RS422/RS485 configuration with 2/1 input topology, unidirectional channel type, and surface mount assembly. Operating temperature range is identical at -40°C ~ 85°C. The substitutes provide higher isolation voltage (5000Vrms vs. 2500Vrms) and improved common mode transient immunity (35kV/µs vs. 25kV/µs), which are allowable enhancements.

Q: What is the impact of the reduced data rate in MAX14945EWE+, MAX14948EWE+, and MAX14949EWE+?

A: All three substitutes operate at 500kbps maximum data rate compared to the ISO35TDWR's 1Mbps. This reduction is acceptable for applications where the required data rate does not exceed 500kbps. For applications requiring 1Mbps operation, the ISO35TDWR must be retained or alternative isolators with 1Mbps capability must be evaluated.

Q: How do supply voltage ranges differ between the main part and substitutes?

A: The ISO35TDWR operates on 3V ~ 3.6V. MAX14945EWE+ extends this to 1.71V ~ 5.5V and 4.5V ~ 5.5V, offering broader supply compatibility. MAX14948EWE+ and MAX14948EWE+T also support 1.71V ~ 5.5V and 4.5V ~ 5.5V. MAX14949EWE+ supports 3V ~ 5.5V and 4.5V ~ 5.5V, maintaining the 3V minimum of the original part. All substitutes are compatible with the ISO35TDWR's supply voltage specification.

Q: What is the difference between MAX14948EWE+ and MAX14948EWE+T?

A: Both parts are electrically identical with 5000Vrms isolation, 500kbps data rate, and 35kV/µs (Typ) common mode transient immunity. The difference is packaging format: MAX14948EWE+ is supplied in Tube packaging, while MAX14948EWE+T is supplied in Tape & Reel format. MAX14948EWE+T has significantly higher inventory availability (27925 units vs. 2395 units), making it preferable for high-volume production requirements.

Q: Are all substitutes ROHS3 compliant?

A: Yes, all four substitute parts are ROHS3 compliant with REACH unaffected status, matching the regulatory compliance of the ISO35TDWR.

Q: What is the moisture sensitivity difference between ISO35TDWR and the substitutes?

A: The ISO35TDWR has MSL 2 (1 Year) moisture sensitivity. All four substitutes have improved MSL 1 (Unlimited) rating, indicating superior moisture resistance and extended shelf life without baking requirements.