ISO7021FD

Overview

The ISO7021FD is an ultra-low power, two-channel digital isolator from Texas Instruments designed for CMOS and LVCMOS digital I/O isolation. It features capacitive coupling technology with a 3000 Vrms insulation voltage rating. The device operates within a supply voltage range of 1.71 V to 5.5 V, consuming only 6.5 µA per channel in typical operation. It supports data rates up to 4 Mb/s with a propagation delay of 140 ns. Packaged in an SOIC-8 surface-mount format, it functions reliably across a temperature range of -55°C to +125°C.

Feature Summary

• Ultra-low power consumption suitable for energy-constrained applications
• ATE X and IECEx certification for hazardous area compliance
• Capacitive coupling isolation providing robust signal transmission

Applications

• Isolation of digital I/Os in industrial automation systems
• Signal isolation in battery-powered measurement devices
• Communication interfaces in hazardous environment instrumentation

Procurement Notes

Verify the specific suffix requirements against your design needs, as the FD variant indicates tube packaging. Confirm that the ATEX/IECEx certifications align with your target regulatory standards for hazardous locations. Ensure the SOIC-8 footprint matches your PCB layout constraints and thermal management strategy before finalizing procurement.

Selection Notes

Select this component when ultra-low quiescent current is critical, such as in battery-operated sensors. The 4 Mb/s data rate suits moderate-speed communication links. Consider the wide operating temperature range for harsh environments. Compare against higher-speed ISO7421 or ISO7821 models if data throughput requirements exceed 4 Mb/s.

Part Context

The ISO7021FD belongs to the ISO7021 family of digital isolators, which emphasizes minimal power usage. Unlike general-purpose isolators, this series targets applications where standby power significantly impacts system longevity. The FD package variant specifically denotes the tube configuration, distinguishing it from tape-and-reel options like the FDR suffix.

Replacement Considerations

Direct replacements include other ISO7021 variants with different packaging suffixes, such as ISO7021FDR for reel-based assembly. For higher performance requirements, consider upgrading to the ISO7421FED for increased data rates or the ISO7821FDWWR for superior isolation ratings.