The LC7456A receives the composite video signal from the V / C (Video Chroma) signal processor and extracts the closed caption data. This data and a clock signal, generated by an on-chip PLL, are then sent to the decoder IC. The LC7456A is a CMOS version of the LA7945 IC also currently in production. The differences between the LA7945 and the LC7456A are a change from Bipolar to CMOS technology, a smaller package size (22 pins to 16 pins), and a reduction in the external circuitry requierd. An LC8640XX series microcontroller is needed to perform the decoding after the LC7456A has extracted the caption data from the composite video signal.