The SP5511 is a single-chip frequency synthesiser designed for TV tuning systems. Control data is entered in the standard I2C BUS format. In 18-lead plastic DIL package, the SP5511 has three addressable current-limited output ports (P0-P3) and four bi-directional output ports (P0-P2) and four addressable bi-directional open-collector ports (P4-P7) of which P6 is also a 3-bit 5-level ADC input. The information on these ports can be read via the I2C BUS. The SP5511S is a variant in a 16-lead miniature plastic package, without P0-P2 but functionally identical in other respects to the SP5511. The device has four programmable I2C BUS addresses, allowing two or more synthesisers to be used in a system.