Introduction

STV6120

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Doc ID 022527 Rev 1

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Introduction

The STV6120 dual tuner has four identical wideband RF inputs. The switch matrix 4:2

allows the selection of the appropriate RF input for each down-conversion path. After the

matrix, there is a high-frequency low-pass filter followed by two down mixers. Each mixer,

which down-converts the signal to baseband, is followed by a low-pass filter and amplifying

The local oscillator signals are provided by two integrated fractional-N PLLs. Each PLL

contains an on-chip voltage controlled oscillator, which meets stringent phase noise

requirements. The PLL loop filters are partially integrated. The local oscillator frequencies

are programmable between 250 and 2150 MHz.

The comparison frequency for the phase-frequency detector is generated by dividing the

crystal oscillator reference frequency. The crystal frequency will be in the range 16 MHz

to 30 MHz depending on the application.

The design of the STV6120 has been carefully implemented to avoid the problems

associated with having two tuners integrated on a single chip.

Features

Benefits

Quad tuner inputs

Fits universal quad and Quattro LNB requirements

or if fewer inputs are used, very high isolation

4:2 switch matrix

Low-cost, high-performance BoM integration

allowing flexibility between legacy systems and

SCR (unicable) systems

Single flexible Xtal

Wide choice of crystal frequencies with robust

clock buffer to drive second tuners and

demodulators allowing eBoM savings

Fine-grained power management

Allows power savings and settings optimized for

actual use conditions

Wide input frequency range

Allows flexible and novel frequency planning and in

some cases BoM cost optimization

Intrinsic performance

Excellent compromise between linearity and noise

figure allowing the most difficult signals to be

extracted in the most congested and noisy

conditions

Fractional-N PLL

Low phase noise for low packet error rate under

extreme conditions (e.g., low symbol rates), fast

locking