FOD2742C

Overview

The FOD2742C is an optically isolated error amplifier manufactured by Fairchild Semiconductor, now part of onsemi. It integrates a precision programmable shunt reference (KA431) with an NPN phototransistor output in an 8-SOIC package. Key electrical parameters include a 2500 Vrms isolation voltage, a forward voltage of 1.5 V, and a current transfer ratio ranging from 100% to 200%. The device operates within a temperature range of -25°C to +85°C, supports a maximum collector current of 50 mA, and features a reference voltage of 2.495 V.

Feature Summary

• Integrates a precision programmable shunt reference with an optocoupler for compact error amplification
• Provides high-voltage electrical isolation between input and output circuits
• Utilizes an NPN phototransistor output stage for signal transmission

Applications

• Switching power supply feedback loops
• Battery management systems
• Industrial control circuitry requiring galvanic isolation

Procurement Notes

Verify the manufacturer status carefully, as Fairchild Semiconductor has been acquired by onsemi. Confirm that the specific revision or suffix matches your design requirements, noting that legacy parts may have limited availability or end-of-life statuses. Ensure compliance with RoHS directives if applicable to your region. Cross-reference datasheets from both Fairchild and onsemi archives to confirm pinout consistency and parameter tolerances before finalizing procurement.

Selection Notes

Select this component when a combined reference and isolation function is required to reduce board space. The integrated KA431 reference simplifies external component count compared to discrete solutions. Consider the SOIC-8 package constraints for thermal management and PCB layout. Verify that the 2500 Vrms isolation rating meets the safety standards of the target application environment.

Part Context

The FOD2742 series belongs to the family of optically isolated amplifiers designed for precise voltage regulation in isolated environments. It replaces traditional designs that require separate reference ICs and optocouplers. The integration of the KA431 shunt reference allows for accurate error amplification directly within the isolated domain, enhancing system reliability and reducing complexity in power conversion topologies.

Replacement Considerations

Check for direct equivalents such as the FOD2742A or FOD2742B, which share similar architectures but may differ in current transfer ratio specifications. Verify compatibility with onsemi's updated product lines following the Fairchild acquisition.