As computer systems grew more complex, engineers sought simpler ways to interconnect the thousands of transistors they employed. Government agencies funded micro-module and multi-chip hybrid integrated circuit projects in search of a practical solution to this technological problem.
A hybrid integrated circuit, HIC, hybrid microcircuit, or simply hybrid, is a miniaturized electronic circuit constructed of individual devices, such as semiconductor devices (transistors & diodes) and passive components (resistors, inductors, transformers & capacitors), bonded to a substrate or printed circuit board (PCB). Hybrid circuits are often hermetically sealed by encapsulating the finished part in either epoxy or plastic.
A hybrid circuit serves as a component on a PCB in the same way as a monolithic integrated circuit; the difference between the two types of devices is in how they are constructed and manufactured:
Hybrid Integrated Circuits are manufactured using thick or thin film passive components (resistors, capacitors) built onto a ceramic substrate. Active devices (monolithic Integrated Circuits, discrete transistors, choke coils, Etc.) are separately fabricated and soldered onto the same substrate. The active and passive compnents are electrically connected by way of metal interconnects built onto the ceramic substrate.
The advantage of hybrid circuits is that components which cannot be included in a monolithic IC can be used, and a greater variety of electronic devices can be used on a single package.
Example of an Advanced Hybrid Integrated Circuit Package