The STV6110A satellite tuner is a directconversion
(zero IF) receiver dedicated to digital
TV broadcasting.
On the RF input is a low noise amplifier (LNA),
with buffer to supply the RF output for
loop-through, and a continuously variable gain
LNA to ensure an optimal signal level for the two
mixers. Each mixer, which down-converts the
signal to baseband, is followed by a low-pass filter
and amplifier. The baseband gain can be varied
by programming a register via the I2C bus.
The LO signals are provided by an integrated PLL
which contains an on-chip voltage controlled
oscillator (VCO) meeting stringent phase noise
requirements. The PLL loop filter is integrated.
The LO frequencies are programmable.
The comparison frequency for the phasefrequency
detector (PFD) is generated by dividing
the crystal oscillator reference frequency. The
crystal frequency can be from 16 MHz to 32 MHz
depending on application.