Dual-Frequency Synthesizer IC Suits Tuner Applications

The ACS2301, a dual-frequency synthesizer IC, is designed to support cable modems, set-top boxes, television, and cable telephony tuner applications. The device is manufactured using a CMOS process, which has fewer steps than BiCMOS processing, for lower end-user costs. It’s designed for use in dual-conversion tuners, which handle two Ifs and have two on-board VCOs. The chip is equipped with two fully programmable RF dividers at 2.0 and 1.1 GHz. It divides each VCO frequency by a known division ratio and compares it to a stable reference frequency. It then generates a dc tuning voltage that the VCOs use to provide very stable, low-noise LO signals. Operation is from 0.4 GHz to 2.0 GHz with RF input sensitivity of –10 to 20 dBm.