BACKGROUND

Isolation products are used to provide electrical isolation to transfer signals between circuits of different voltage levels and/or between circuits that operate from different supply voltages and ground references. One type of isolator is called an opto-isolator or opto-coupler that provides an optical transmission path to transfer signals between circuits that can be electrically isolated from one another. Opto isolators are used in data communication, power supplies, and other systems where high voltage or high slew-rate common-mode signals appear between the input and output. Opto-isolators are often constructed as a transmitter and a receiver separated by glass and packaged together. Glass provides dc electrical isolation and optical transmission, but suffers from capacitive coupling between the transmitter and receiver and also adds cost to the device. Transformers provide isolation between magnetically coupled primary and secondary coils separated by an insulator to transfer data and/or power between two circuits that are separated by a high voltage or high slew-rate common-mode signal. Some transformers include a magnetic coupling material to enhance the magnetic coupling between the primary and secondary.

SUMMARY

In described examples, an integrated circuit includes a leadframe structure, which includes electrical conductors. A first coil structure is electrically connected to a first pair of the electrical conductors of the leadframe structure. The first coil structure is partially formed on a semiconductor die structure. A second coil structure is electrically connected to a second pair of the electrical conductors of the leadframe structure. The second coil structure is partially formed on the semiconductor die structure. A molded package structure encloses portions of the leadframe structure. The molded package structure exposes portions of the first and second pairs of the electrical conductors to allow external connection to the first and second coil structures. The molded package structure includes a cavity to magnetically couple portions of the first and second coil structures.

