ISO7421D

Overview

The ISO7421D is a low-power, dual-channel digital isolator manufactured by Texas Instruments. It features two independent channels with one forward and one reverse direction, supporting data rates up to 50 Mb/s. The device operates within a supply voltage range of 3 V to 5.5 V and draws approximately 2 mA of quiescent current per channel. It provides an isolation voltage rating of 2500 Vrms using capacitive coupling technology. Key electrical specifications include a maximum propagation delay of 9 ns and a common-mode transient immunity of 25 kV/µs. The component is housed in an 8-pin SOIC package and is rated for operation between -40°C and +125°C.

Feature Summary

• Provides galvanic isolation between circuits using capacitive coupling technology
• Supports bidirectional signal transmission across two independent channels
• Ensures high noise immunity with specified common-mode transient rejection capabilities
• Operates reliably across extended industrial temperature ranges

Applications

• Isolation interfaces for mixed-signal microcontrollers
• Digital-to-analog converter signal isolation
• Transformer driver circuit protection
• Voltage regulator feedback loop isolation

Procurement Notes

Verify the specific suffix 'D' corresponds to the SOIC-8 tube packaging configuration as listed in official documentation. Confirm that the required data rate and isolation voltage meet system specifications before ordering. Ensure compatibility with the intended operating temperature range and supply voltage constraints defined in the datasheet.

Selection Notes

Select this component when dual-channel isolation is required for general-purpose digital signals. Consider the 50 Mb/s data rate limit and 2500 Vrms isolation rating against application needs. Evaluate the 8-pin SOIC footprint availability against board space constraints. Compare power consumption requirements against other isolator families if lower quiescent current is critical.

Part Context

The ISO7421D belongs to the ISO742x family of low-power dual-channel digital isolators from Texas Instruments. This series is designed to replace traditional optocouplers in modern electronic designs. The family offers improved performance metrics regarding speed and power efficiency while maintaining robust isolation characteristics for industrial and commercial applications.

Replacement Considerations

Check for updated revisions of the ISO7421 series. Verify pinout compatibility with existing designs if substituting with similar devices from other manufacturers.