An Integrated Video IF Amplifier and PLL Detection System

A second-generation Phase Locked Loop (PLL) synchronous detector has been successfully combined with a high gain IF amplifier and automatic gain and frequency control (AGC and AFC), to form a high performance video IF system on a 105 x 114 mil die in a 28 pin package. Integration of these functions together in the same package required in excess of 80dB of isolation at 45MHz. Research indicated that the dominant coupling mode would be mutual inductance within the package wirebonds and leadframe, and that side-to-side isolation was superior to end-to-end isolation. This experience was applied to the die layout and placement resulting in a system which is able to acquire lock below viewable signal levels.