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MAX2165 Datasheet(Scheda tecnica) 18 Page - Maxim Integrated Products

Numero della parte MAX2165
Dettagli  Single-Conversion DVB-H Tuner
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Produttore  MAXIM [Maxim Integrated Products]
Homepage  http://www.maxim-ic.com
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Single-Conversion DVB-H Tuner
18
______________________________________________________________________________________
To close the RF gain-control loop, connect the 300µA
control current sink of the power detector (pin
OVLD_DET) to VCC with a 40k
Ω pullup resistor. The
resulting voltage is fed with an RC lowpass to the
RF_AGC input.
VCO Autotuner
The MAX2165 includes 3 VCOs with each VCO contain-
ing 8 VCO sub-bands. The appropriate VCO and VCO
sub-band for the desired local oscillator frequency can
be manually selected by programming the VCO[1:0]
and SB[2:0] bits in the VCO control register (Table 11).
Alternatively, the MAX2165 can be set to autonomously
choose a VCO and VCO sub-band. Automatic VCO
selection is enabled by setting the VAS bit in the VCO
Control register (Table 11). The autotuner begins
selecting the appropriate VCO once the fractional por-
tion of the N-divider has been programmed. Therefore,
when changing LO frequencies, all the N-divider regis-
ters (integer and fractional) must be programmed to
activate the autotuner function.
PLL lock detection can be achieved by monitoring the
MUX pin or by reading the LD bit in the Chip-Status
Readback register (Table 18).
Charge-Pump Current Selection
The PLL charge-pump current can also be either manu-
ally programmed or automatically selected by the VCO
autotuner. Program the CPS bit in the PLL configuration
register (Table 8) to 1 to enable automatic charge-
pump-current selection, or program CPS to 0 to enable
manual charge-pump-current selection. The autotuner
function must be enabled (VAS = 1) to enable automat-
ic charge-pump-current selection. When in manual
mode, the charge-pump current is programmed by the
ICP bit in the PLL Configuration register.
VCO Autotuner Delay Selection
During the autotuner selection process, the autotuner
must allow time for the PLL to settle before determining
if VCO selection was successful. This wait time is pro-
grammable through the ADLY[1:0] bits in the PLL
Configuration register (Table 8). Program the wait time
to be longer than the expected PLL settling time.
RF Notch Filter
The MAX2165 integrates an RF notch filter that can be
used to notch out large interfering signals in the
830MHz to 950MHz frequency range to prevent perfor-
mance degradation when operating in the presence of
large cellular phone signals. The notch frequency of the
filter is programmable through the TF_NTCH[3:0] bits in
the Tracking Filter register (Table 6). Optimal notch fil-
ter codes for two different notch frequencies are stored
in an on-chip ROM table. See the
Baseband Filter and
Tracking Filter section for additional details. When no
interfering cellular signals are present or when receiving
signals in the 783MHz to 860MHz frequency range, the
TF_NTCH[3:0] bits must be programmed to 111 to move
the notch out to the highest possible frequency to mini-
mize the filter’s in-band attenuation.
MSB
LSB
DATA BYTE
DESCRIPTION
ADDRESS
D7
D6
D5
D4
D3
D2
D1
D0
Reserved
0x0
X
X
X
X
X
X
X
X
Optimal tracking
filter notch settings
for operation
below 725MHz
and above
725MHz
0x1
TF_NTCH[3:0]
Tracking filter notch low
Recommended notch frequency settings for Rx
frequencies below 725MHz
TF_NTCH[3:0]
Tracking filter notch high
Recommended notch frequency settings for Rx
frequencies above 725MHz
Optimal tracking
settings at
780MHz and
470MHz
0x2
TF_BAL[3:0]
Optimal tracking filter settings at 780MHz
TF_BAL[3:0]
Optimal tracking filter settings at 470MHz
Optimal baseband
filter BW for 8MHz
channel
0x3
BB_BW[3:0]
8MHz wide
XX
XX
Table 21. ROM Table




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