Triple-Band Tuners Compatible With DAB, T-DMB Standards

A pair of tuners for triple-band, dual-mode mobile TV and digital radio applications receive VHF Band III and L-Band broadcasts, as well as FM band. The MAX2170 and MAX2171 from Maxim Integrated Products handle digital audio broadcast (DAB) and terrestrial digital multimedia broadcast (T-DMB) with a minimum of external components. The L-Band front end (with a 3-dB noise figure) eliminates the need for an external low-noise amplifier, reducing both cost and size. When tuning VHF frequencies, the on-chip tracking filter rejects out-of-band interference. This tracking filter doubles as an FM band-select tuner.

The only difference between the devices is the R-divider ratio of the frequency stabilizer. The MAX2170 has a fixed divide-by-1 ratio, while the MAX2171’s value is 3. They both run off of a 24.576-MHz crystal. The devices operate from a 2.7- to 3.3-V supply and draw 150 mW (typical) in L-Band low-power mode. They contain all of the blocks needed to implement a low-IF TV/radio tuner, except a crystal and the optional L-Band filtering required by some applications. Sensitivity is −101 dBm at L-Band, −99 dBm at VHF, and −109 dBm at FM band. Operating temperature range is −40°C to 85°C. The devices come in a 6- by 6-mm, 40-pin QFN package.