MAX2102 Ver la hoja de datos (PDF) - Maxim Integrated
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MAX2102 Datasheet PDF : 16 Pages
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Direct-Conversion Tuner ICs for
Digital DBS Applications
VCC
47µF
100Ω
LOAD
0.1µF
VCC
VCC
RF
INPUT
(50Ω
SOURCE)
51Ω
AGC
CONTROL
1000pF
22pF
22pF
22pF
0.1µF
1 VCC
10pF 2
IOUT
3 GND
4 VCC
5 GND
6
VCC
22pF
7 RFIN
8 RFIN
9 GND
10
AGC
11 GND
28
VCC
27
MOD
PSOUT 26
PSGND 25
1000pF
MAX2102
MAX2105
GND 24
VCC 23
LO 22
10pF
22pF
22pF
LO 21
VCC 20
10pF
19
GND
IDC 18
47µF
100Ω
LOAD
0.1µF
VCC
0.1µF
12
GND
13 QOUT
10pF
14 VCC
17
IDC
16
QDC
QDC 15
VCC
2kΩ
MODULUS
CONTROL
PRESCALER
OUTPUT
VCC
LO
22Ω
INPUT
(50Ω
SOURCE)
56Ω
33Ω
VCC
0.22µF
0.22µF
Figure 1. Typical Operating Circuit
Detailed Description
The MAX2102/MAX2105 down-convert signals in the
range 950MHz to 2150MHz directly to baseband I/Q
signals. They are targeted for digital DBS tuner applica-
tions where a direct downconversion provides a cost
savings over prior-art, multiple-conversion approaches.
However, the MAX2102/MAX2105 are applicable to any
system requiring a broadband I/Q downconversion.
Internally, the MAX2102 and MAX2105 consist of a
broadband front-end variable gain stage, a quadrature
downconverter, an oscillator buffer, high-linearity I and
Q baseband amplifiers, and offset correction amplifiers.
The MAX2102 features a front-end AGC dynamic range
of over 50dB, while the MAX2105 provides a front-end
AGC dynamic range of over 41dB. Specifically, the
AGC control can be adjusted so that a sine wave at
RFIN ranging in power from -69dBm to -19dBm
(MAX2102) or -60dBm to -19dBm (MAX2105) will pro-
duce a sine wave at IOUT and QOUT at 500mVp-p lev-
els. The noise figure is lowest when the AGC is at its
maximum gain setting (see Typical Operating
Characteristics). The VSWR at RFIN is unaffected by
the AGC setting.
The local-oscillator (LO) buffer accepts an external LO
signal at LO, LO, and internally limits the signal to pro-
vide a consistent on-chip LO level. The LO input drive
level should be maintained within the specified limits
(see Applications Information section).
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