The MC44818 is a tuning circuit for TV and VCR tuner applications. It contains, on one chip, all the functions required for PLL control of a VCO. This integrated circuit also contains a high frequency prescaler and thus can handle frequencies up to 1.3 GHz. The MC44818 is a pin compatible drop in replacement for the MC44817, where the only difference is the MC44818 has a fixed divideby8 prescaler (cannot be bypassed) and the MC44817 uses the three wire bus.