Rainbow Electronics MAX3580 - Manual (Page 14)

MAX3580
Direct-Conversion TV Tuner
14 ______________________________________________________________________________________
Shutdown Control (Register Address 0x08)
SHDN_BG: Main Bandgap
0 = Enabled
1 = Disabled
The main bandgap can and will be shut down
once all other blocks are shut down (i.e., all bits in this
shutdown register and bits VCO_ in the VCO
Control Register and bits DC_MO_ in the DC
Offset Control Register are shut down).
SHDN_PD: Baseband Power Detector
0 = Enabled
1 = Disabled
SHDN_RF: RF LNA/VGA:
0 = Enabled
1 = Disabled
SHDN_MIX: I/Q Mixer and LO Drivers
0 = Enabled
1 = Disabled
SHDN_BB: Baseband Filters and VGA
0 = Enabled
1 = Disabled
SHDN_SYN: Fractional PLL
0 = Enabled
1 = Disabled
SHDN_REF: Controls the Crystal Oscillator Buffered
Output
0 = Enabled
1 = Disabled
The XTAL oscillator activation results from the
SHDN_SYN, SHDN_REF bits: If either one is on,
the XTAL oscillator runs. The XTAL oscillator is
shut down only if both bits are off.
VCO Control (Register Address 0x09)
VCO<1:0>: Selects 1 of 3 VCO Bands. 00 turns off
VCO block completely.
BS<2:0>: Selects 1 of 8 VCO Sub-Bands
VAS: VCO Band Autoselect
0 = VCO band select controlled by bits VCO<1:0>
1 = Controlled by autotuner
ADL: VCO ADC Latch Enable Bit
1 = Latches ADC value
0 = Default
ADE: Enable VCO Tune Voltage DAC Read
1 = Enables ADC read
0 = Default
Baseband Control (Register Address 0x0A)
PD_TH<2:0>: Detection Threshold for Baseband
Power Detector
BB_BW<3:0>: Baseband Filter Bandwidth. Optimum
values for 7MHz and 8MHz wide RF channels can
be taken from the ROM table.
DC Offset Control (Register Address 0x0B)
DC_TH<1:0>: DC Offset Correction Thresholds.
Keeps output within:
00 = Output within ±0.55V of balanced state
11 = Output within ±0.75V of balanced state
DC_SP<1:0>: DC Offset Correction Speed (or Highpass
Corner Frequency).
11 = Fast (~500Hz)
01 = Slow (~20Hz)
00 = Off/hold DAC values
DC_MO<1:0>: Mode of Operation
00 = Off
10/01 = Sets I/Q channel DACs direct from register
11 = Normal operation
DC_DAC<8>: MSB for DC Offset DAC
BB_BIA: Baseband Filter Op-Amp Bias Settings
0 = Low
1 = High
* Not production tested.