ISO7421ED Digital Isolator - Equivalent & Substitute Parts

Part Overview

The ISO7421ED is a general purpose digital isolator manufactured by Texas Instruments, designed for applications requiring galvanic isolation between digital circuits. This 2-channel, 2500Vrms rated isolator operates at 50Mbps with capacitive coupling technology and is housed in an 8-SOIC surface mount package. The device is currently in active production status with ROHS3 compliance and unlimited moisture sensitivity rating (MSL 1). Substitute parts are identified when identical electrical specifications and mechanical compatibility are maintained across the same product family.

Substiute Parts

ISO7421ED

Texas InstrumentsIn Stock: 1449ISO7421ED Datasheet

Current PartRFQ

ISO7421FED

Texas InstrumentsIn Stock: 2080ISO7421FED Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the ISO7421ED is determined by strict equivalence across the following critical parameters:

• Isolation Voltage Rating: 2500Vrms minimum
• Channel Configuration: 2 channels, unidirectional
• Data Rate: 50Mbps
• Common Mode Transient Immunity: 25kV/µs minimum
• Supply Voltage Range: 3V ~ 5.5V
• Package Type: 8-SOIC (0.154", 3.90mm Width)
• Operating Temperature Range: -40°C ~ 125°C
• Technology: Capacitive coupling
• Compliance: ROHS3 compliant, REACH unaffected

The ISO7421FED meets all these criteria and is classified as a parametric equivalent within the ISO7421 product family.

Parameter Comparison

Engineering Selection Recommendations

Both the ISO7421ED and ISO7421FED are active production devices from Texas Instruments with identical electrical and mechanical specifications. Selection between these parts is based on availability and supply chain considerations rather than technical differentiation. Both devices maintain ROHS3 compliance and REACH unaffected status, meeting regulatory requirements for industrial and commercial applications. The 8-SOIC package format ensures compatibility with existing PCB layouts and assembly processes. Inventory availability should be the primary factor in component selection when both parts meet application requirements.

Frequently Asked Questions (FAQ)

Q: Can ISO7421FED be used as a direct replacement for ISO7421ED?

A: Yes. The ISO7421FED is a parametric equivalent with identical isolation voltage, channel configuration, data rate, timing specifications, supply voltage range, operating temperature range, and package dimensions. Direct substitution is supported without circuit modification.

Q: Are there any differences in the 8-SOIC package between these parts?

A: No. Both parts use the identical 8-SOIC (0.154", 3.90mm Width) package. Pin configuration, lead spacing, and PCB footprint requirements are identical.

Q: Do both parts meet the same compliance standards?

A: Yes. Both ISO7421ED and ISO7421FED are ROHS3 compliant, REACH unaffected, and carry MSL 1 (unlimited) moisture sensitivity ratings.

Q: What is the primary reason to consider substitution?

A: Supply chain availability. When the primary part number is unavailable, the ISO7421FED provides equivalent functionality and performance for the same application requirements.

Q: Are the timing characteristics identical?

A: Yes. Propagation delay (11ns maximum for both rising and falling edges), pulse width distortion (3.7ns maximum), and rise/fall times (1.8ns and 1.7ns typical) are identical across both part numbers.