ISO7321FCDR Digital Isolator Equivalent & Substitute Parts

Part Overview

The ISO7321FCDR is a general purpose digital isolator manufactured by Texas Instruments, designed for 3000Vrms isolation applications with 2-channel unidirectional capability. This capacitive coupling isolator operates across 3V to 5.5V supply range and supports 25Mbps data rates with 25kV/µs common mode transient immunity. The part is active in production status and ROHS3 compliant, packaged in 8-SOIC surface mount configuration.

Equivalent and substitute parts are identified when design requirements permit flexibility in isolation voltage, data rate, temperature grade, or automotive qualification while maintaining core functional compatibility in the 8-SOIC package footprint.

Substiute Parts

ISO7321FCDR

Texas InstrumentsIn Stock: 8153ISO7321FCDR Datasheet

Current PartRFQ

ISO7321CDR

Texas InstrumentsIn Stock: 33514ISO7321CDR Datasheet

Parametric EquivalentRFQ

ISO7321CQDRQ1

Texas InstrumentsIn Stock: 17972ISO7321CQDRQ1 Datasheet

Parametric EquivalentRFQ

ISO7321FCQDRQ1

Texas InstrumentsIn Stock: 4050ISO7321FCQDRQ1 Datasheet

Parametric EquivalentRFQ

SI8621BC-B-ISR

Skyworks Solutions Inc.In Stock: 9671SI8621BC-B-ISR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the ISO7321FCDR are classified into two categories based on parametric equivalence and manufacturer recommendation:

Parametric Equivalents (Texas Instruments ISO7321 Series): ISO7321CDR, ISO7321CQDRQ1, and ISO7321FCQDRQ1 maintain identical electrical specifications across isolation voltage (3000Vrms), data rate (25Mbps), common mode transient immunity (25kV/µs), propagation delay (57ns), and supply voltage range (3V ~ 5.5V). These parts differ only in temperature grade qualification and automotive certification status. All three share the same 8-SOIC package footprint and capacitive coupling technology.

Manufacturer Recommended Substitute (Skyworks Solutions SI8621BC-B-ISR): This part provides enhanced performance characteristics including higher isolation voltage (3750Vrms), increased data rate (150Mbps), and improved common mode transient immunity (35kV/µs). The SI8621BC-B-ISR maintains 2-channel unidirectional configuration, 8-SOIC package compatibility, and overlapping supply voltage range (2.5V ~ 5.5V). This substitute is applicable when design margins or performance headroom justify the higher specification device.

Parameter Comparison

Engineering Selection Recommendations

ISO7321CDR: Direct parametric equivalent for non-automotive applications. Identical electrical performance and package footprint. Select when standard industrial temperature grade and non-automotive qualification are acceptable. Higher inventory availability (33,455 units) supports supply chain continuity.

ISO7321CQDRQ1 and ISO7321FCQDRQ1: Automotive-qualified alternatives with AEC-Q100 certification. Select these variants when designs require automotive-grade components or operate in automotive environments. Both maintain identical electrical specifications to the ISO7321FCDR. ISO7321CQDRQ1 provides standard automotive qualification; ISO7321FCQDRQ1 provides automotive qualification with extended temperature margin.

SI8621BC-B-ISR: Enhanced performance substitute from Skyworks Solutions. Select when design requirements include higher data rate capability (150Mbps vs. 25Mbps), improved common mode transient immunity (35kV/µs vs. 25kV/µs), or lower propagation delay (13ns vs. 57ns). This part supports extended supply voltage range down to 2.5V. Cross-manufacturer substitution requires PCB layout and signal integrity validation due to different manufacturer design characteristics.

Frequently Asked Questions (FAQ)

Q: Can ISO7321CDR directly replace ISO7321FCDR without design changes? A: Yes. ISO7321CDR is a parametric equivalent with identical isolation voltage, data rate, propagation delay, and supply voltage specifications. Both use 8-SOIC package with identical pinout. No design changes are required for direct substitution in non-automotive applications.

Q: What is the difference between ISO7321CQDRQ1 and ISO7321FCQDRQ1? A: Both are automotive-qualified variants (AEC-Q100) with identical electrical specifications. The primary distinction is temperature grade designation in the part number suffix. Both maintain 3000Vrms isolation, 25Mbps data rate, and -40°C to 125°C operating range. Selection depends on specific automotive qualification requirements and design documentation.

Q: When should SI8621BC-B-ISR be selected over ISO7321 variants? A: SI8621BC-B-ISR provides superior performance with 150Mbps data rate (6x higher), 35kV/µs CMTI (40% higher), and 13ns propagation delay (77% lower). Select this Skyworks part when system design requires higher bandwidth, faster signal transitions, or improved noise immunity. Extended supply range (2.5V minimum) supports lower voltage applications. Cross-manufacturer substitution requires signal integrity analysis and layout validation.

Q: Are all substitute parts compatible with the same PCB layout? A: All listed substitutes use identical 8-SOIC (0.154", 3.90mm Width) package with matching pinout. PCB footprints are mechanically compatible. However, SI8621BC-B-ISR from Skyworks may require signal integrity re-evaluation due to different propagation delay characteristics and manufacturer-specific design parameters.

Q: What is the moisture sensitivity level difference between parts? A: ISO7321 series parts specify MSL 2 (1 Year). SI8621BC-B-ISR specifies MSL 2A (4 Weeks). MSL 2A requires shorter shelf life management and more stringent moisture control during storage and assembly. Verify component handling procedures align with the more restrictive MSL 2A requirement if SI8621BC-B-ISR is selected.

Q: Can these parts be used interchangeably in automotive applications? A: ISO7321CQDRQ1 and ISO7321FCQDRQ1 carry AEC-Q100 automotive qualification and are suitable for automotive designs. ISO7321FCDR and ISO7321CDR are standard industrial grade and require design review before automotive application. SI8621BC-B-ISR is standard grade without automotive qualification; automotive use requires separate qualification assessment.