Overview

The LC72720N and LC72720NM are single-chip system ICs that implement the signal processing required by the European Broadcasting Union RDS (Radio Data System) standard and by the US NRSC (National Radio System Committee) RDBS (Radio Broadcast Data System) standard. These ICs include band-pass filter, demodulator, synchronization, and error correction circuits as well as data buffer RAM on chip and perform effective error correction using a soft-decision error correction technique.

Features

• Error correction capability improved by soft-decision error correction

• The load on the microcontroller can be reduced by storing decoded data in the on-chip data buffer RAM.

• Two synchronization detection circuits provide continuous and stable detection of the synchronization timing.

• Data can be read out starting with the backwardprotection block data after a synchronization reset.

• Fully adjustment free

• Operating power-supply voltage: 4.5 to 5.5 V

• Operating temperature: –40 to +85°C

• Packages: DIP24S, MFP24

Functions

• Band-pass filter: Switched capacitor filter (SCF)

• Demodulator: RDS data clock regeneration and demodulated data reliability information

• Synchronization: Block synchronization detection (with variable backward and forward protection conditions)

• Error correction: Soft-decision/hard-decision error correction

• Buffer RAM: Adequate for 24 blocks of data (about 500 ms) and flag memory

• Data I/O: CCB interface (power on reset)