ISO35DW RS422/RS485 Digital Isolator Equivalent & Substitute Parts

Part Overview

The ISO35DW is a Texas Instruments RS422/RS485 digital isolator rated for 2500Vrms isolation with 3 channels, 1Mbps data rate, and 25kV/µs common mode transient immunity. The device is packaged in 16-SOIC surface mount and operates across -40°C to 85°C. This part is currently in Last Time Buy status, making equivalent and substitute parts necessary for ongoing design support and procurement planning.

Substiute Parts

ISO35DW

Texas InstrumentsIn Stock: 2247ISO35DW Datasheet

Current PartRFQ

ISO35DWR

Texas InstrumentsIn Stock: 18910ISO35DWR Datasheet

MFR RecommendedRFQ

MAX14945EWE+

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

MFR RecommendedRFQ

MAX14945EWE+T

Analog Devices Inc./Maxim IntegratedIn Stock: 1107MAX14945EWE+T 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 is determined by the following critical parameters: package type (16-SOIC), channel configuration (3 channels with 2/1 input distribution), isolation technology (capacitive coupling), RS422/RS485 protocol support, operating temperature range (-40°C to 85°C), and surface mount mounting type.

Substitute parts are grouped into two categories based on isolation voltage and data rate specifications:

Category 1: Direct Functional Equivalent (Same Isolation Voltage)

• ISO35DWR: Identical electrical specifications to ISO35DW with different packaging (Cut Tape & Digi-Reel vs. standard packaging). Active product status provides long-term availability.

Category 2: Enhanced Performance Substitutes (Higher Isolation Voltage and CMTI)

• MAX14945EWE+ / MAX14945EWE+T: 2750Vrms isolation, 35kV/µs CMTI, 500kbps data rate. Wider supply voltage range (1.71V ~ 5.5V, 4.5V ~ 5.5V). Lower MSL rating (1 vs. 2).
• MAX14948EWE+ / MAX14948EWE+T: 5000Vrms isolation, 35kV/µs CMTI, 500kbps data rate. Wider supply voltage range. Lower MSL rating. Includes propagation delay and rise/fall time specifications.
• MAX14949EWE+: 5000Vrms isolation, 35kV/µs CMTI, 500kbps data rate. Supply voltage 3V ~ 5.5V, 4.5V ~ 5.5V. Lower MSL rating.

All substitutes maintain identical package geometry, channel configuration, and operating temperature range. Packaging variants (Tube vs. Tape & Reel) are available for MAX14945 and MAX14948 series.

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No Design Changes Required): ISO35DWR is the primary equivalent, offering identical electrical and functional specifications with active product status. This part is recommended for designs currently using ISO35DW where long-term availability and supply continuity are priorities.

For Enhanced Isolation Requirements: MAX14948EWE+ and MAX14948EWE+T provide doubled isolation voltage (5000Vrms vs. 2500Vrms) with improved CMTI performance (35kV/µs typical). These parts are suitable for applications requiring higher isolation margins or operating in environments with greater common-mode transient stress. The Tape & Reel variant (MAX14948EWE+T) offers higher inventory availability (27,925 pcs).

For Flexible Supply Voltage Requirements: MAX14945 and MAX14948 series support wider supply voltage ranges (1.71V ~ 5.5V) compared to ISO35DW (3.15V ~ 3.6V), enabling use in multi-voltage system architectures. MAX14949EWE+ maintains a narrower supply range (3V ~ 5.5V) while providing 5000Vrms isolation.

For Data Rate Considerations: ISO35DW and ISO35DWR support 1Mbps data rate. All Maxim substitutes operate at 500kbps. Applications requiring 1Mbps operation must use ISO35DWR or remain with ISO35DW inventory.

Compliance and Certifications: All parts are ROHS3 compliant and REACH unaffected. Maxim parts feature MSL 1 (Unlimited) rating versus ISO35DW MSL 2 (1 Year), providing superior moisture handling for extended storage and harsh environments.

Frequently Asked Questions (FAQ)

Q: Can MAX14945, MAX14948, or MAX14949 directly replace ISO35DW in existing designs? A: Electrical substitution is possible due to identical package geometry, channel configuration, and operating temperature range. However, data rate differences must be evaluated: ISO35DW supports 1Mbps while Maxim parts operate at 500kbps. Supply voltage compatibility must be verified for each application. No PCB layout changes are required.

Q: What is the primary difference between ISO35DWR and ISO35DW? A: ISO35DWR is functionally identical to ISO35DW with identical electrical specifications. The difference is packaging format: ISO35DWR is supplied in Cut Tape & Digi-Reel format with active product status, while ISO35DW is in Last Time Buy status. ISO35DWR is recommended for new designs and ongoing production.

Q: Why do MAX14948 and MAX14949 have lower data rates (500kbps vs. 1Mbps)? A: The lower data rate is a specification difference between device families. Applications limited to 500kbps or lower can use these parts. For 1Mbps operation, ISO35DW or ISO35DWR must be used.

Q: Are there packaging differences among the substitute parts? A: Yes. MAX14945 and MAX14948 are available in two packaging formats: Tube and Tape & Reel (TR). ISO35DWR uses Cut Tape & Digi-Reel packaging. All maintain identical 16-SOIC package geometry suitable for surface mount assembly.

Q: What is the advantage of MAX14948 over MAX14945? A: MAX14948 provides doubled isolation voltage (5000Vrms vs. 2750Vrms) and includes published propagation delay and rise/fall time specifications. Both share identical 35kV/µs CMTI and 500kbps data rate. MAX14948 is preferred for high-isolation applications.

Q: Can I use MAX14949EWE+ in place of MAX14948EWE+? A: Both provide 5000Vrms isolation and 35kV/µs CMTI. The primary difference is supply voltage range: MAX14949 operates 3V ~ 5.5V while MAX14948 operates 1.71V ~ 5.5V. MAX14949 is suitable if your design uses 3V minimum supply. MAX14948 offers broader voltage compatibility.

Q: What does MSL 1 (Unlimited) mean compared to MSL 2 (1 Year)? A: MSL (Moisture Sensitivity Level) indicates moisture absorption limits during storage. MSL 1 (Unlimited) allows indefinite shelf storage without baking, while MSL 2 (1 Year) requires baking if storage exceeds one year. Maxim parts offer superior moisture tolerance for extended inventory management.

Q: Are all substitute parts ROHS3 compliant? A: Yes. ISO35DW, ISO35DWR, and all Maxim substitutes (MAX14945, MAX14948, MAX14949 series) are ROHS3 compliant and REACH unaffected, meeting current environmental regulations.