1-GHz Low-Power Digital Cable Silicon Tuner
The BCM3422 is a highly integrated, advanced direct conversion, single-chip silicon tuner. It integrates the global tuning function including selectivity and supports 64-QAM, 256-QAM, and 1024-QAM digital cable applications. The input signal is first driven to the LNA with wideband AGC and then filtered and fed to the image rejection mixer. The LO signal feeds the second input of the mixer which down-converts the RF signal to a low 4-MHz IF frequency. The IF signal is then filtered (channel selectivity) and shaped to be connected to fit the channel decoder inputs. There is no need for an external SAW filter. Additionally, the Voltage Controlled Oscillator (VCO) is fully integrated with no external tank component.
The BCM3422 is specifically designed for use with Broadcom's industry-leading single-chip cable modem and set-top box devices. With a low BOM cost and a proven reference design, the BCM3422 provides a better alternative to traditional can tuners. Its low power operation is suited well for applications that require battery backup capability such as VoIP cable modems. The BCM3422's extended bandwidth to 1 GHz makes it ideal for next-generation cable devices.
- Single-chip direct conversion silicon tuner completes system design with Broadcom cable modem or set-top box
- DOCSIS®/EuroDOCSIS™ 1.0/1.1/2.0/3.0
- Extreme integration level leads to highly cost-effective BOM
- Eliminates significant external components:
-Surface Acoustic Wave (SAW) IF filters
-RSSI measurement components
-IF amplifiers
-Oscillator components
