The MAX2121B low-cost, direct-conversion tuner IC is
designed for satellite set-top and VSAT applications.
The device directly converts the satellite signals from the
LNB to baseband using a broadband I/Q downconverter.
The operating frequency range extends from 925MHz to
2250MHz.
The device includes an LNA and an RF variable-gain amplifier,
I and Q downconverting mixers, and digitally controlled
baseband filters (40MHz to 124MHz) and variable-gain
amplifiers. Together, the RF and baseband variable-gain
amplifiers provide more than 80dB of gain control range.
The device includes fully monolithic VCOs, as well as a
complete fractional-N frequency synthesizer. Additionally,
an on-chip crystal oscillator is provided along with a buffered
output for driving additional tuners and demodulators.
Synthesizer programming and device configuration
are accomplished with a 2-wire serial interface. The IC
features a VCO autoselect (VAS) function that automatically
selects the proper VCO. For multituner applications,
the device can be configured to have one of two 2-wire
interface addresses. A low-power standby mode is available
whereupon the signal path is shut down while leaving
the reference oscillator, digital interface, and buffer circuits
active, providing a method to reduce power in single
and multituner applications.
The device is the most advanced broadband/VSAT DBS
tuner available. The low noise figure eliminates the need
for an external LNA. A small number of passive components
are needed to form a complete broadband satellite
tuner DVB-S2 RF front-end solution. The tuner is available
in a very small, 5mm x 5mm, 28-pin TQFN package.
Applications
- DBS Tuner
- Navigation Systems
- Satellite Set-Top Box
- VSATs
