Datasheet

Complete, Direct-Conversion
Tuner for DVB-S2 Applications
Pin Description
PIN NAME FUNCTION
1 VCC_RF2
DC Power Supply for LNA. Connect to a +3.3V low-noise supply. Bypass to GND with a 1nF capacitor
connected as close as possib l e to the pi n. D o not shar e capaci tor gr ound vi as w ith other g r ound connections.
2 VCC_RF1
DC Power Supply for LNA. Connect to a +3.3V low-noise supply. Bypass to GND with a 1nF capacitor
connected as close as possib l e to the pi n. D o not shar e capaci tor gr ound vi as w ith other g r ound connections.
3 GND Ground. Connect to board’s ground plane for proper operation.
4 RFIN Wideband 75Ω RF Input. Connect to an RF source through a DC-blocking capacitor.
5 GC1
RF Gain-Control Input. High-impedance analog input with a 0.5V to 2.7V operating range.
V
GC1
= 0.5V corresponds to the maximum gain setting.
6 VCC_LO
DC Power Supply for LO Generation Circuits. Connect to a +3.3V low-noise supply. Bypass to GND with
a 1nF capacitor connected as close as possible to the pin. Do not share capacitor ground vias with
other ground connections.
7 VCC_VCO
DC Power Supply for VCO Circuits. Connect to a +3.3V low-noise supply. Bypass to GND with a 1nF
capacitor connected as close as possible to the pin. Do not share capacitor ground vias with other
ground connections.
8 VCOBYP
Internal VCO Bias Bypass. Bypass to GND with a 100nF capacitor connected as close as possible to
the pin. Do not share capacitor ground vias with other ground connections.
9 VTUNE
High-Impedance VCO Tune Input. Connect the PLL loop filter output directly to this pin with as short of a
connection as possible.
10 GNDTUNE Ground for VTUNE. Connect to the PCB ground plane.
11 GNDSYN Ground for Synthesizer. Connect to the PCB ground plane.
12 CPOUT
C h ar g e - P um p O u tp u t . C o n n e c t t h i s o u t p u t t o t he P L L l o o p fi l t e r i n p u t w i t h th e s h or t e s t c o n n e ct i o n
p o ss i b l e .
13 VCC_SYN
DC Power Supply for Synthesizer Circuits. Connect to a +3.3V low-noise supply. Bypass to GND with a
1nF capacitor connected as close as possible to the pin. Do not share capacitor ground vias with other
ground connections.
14 XTAL
Crystal-Oscillator Interface. Use with an external parallel-resonance-mode crystal through a series 1nF
capacitor. See the Typical Application Circuit.
15 REFOUT Crystal-Oscillator Buffer Output. A DC-blocking capacitor must be used when driving external circuitry.
16 VCC_DIG
DC Power Supply for Digital Logic Circuits. Connect to a +3.3V low-noise supply. Bypass to GND with a
1nF capacitor connected as close as possible to the pin. Do not share capacitor ground vias with other
ground connections.
17 QOUT+
18 QOUT-
Quadrature Baseband Differential Output. AC-couple with 47nF capacitors to the demodulator input.
19 IOUT+
20 IOUT-
In-Phase Baseband Differential Output. AC-couple with 47nF capacitors to the demodulator input.
21 IDC+
22 IDC-
I-Channel Baseband DC Offset Correction. Connect a 47nF ceramic chip capacitor from IDC- to IDC+.
23 QDC+
24 QDC-
Q- C hannel Baseb and D C O ffset C or r ecti on. C onnect a 47nF cer am i c chi p cap aci tor fr om QD C - to QD C + .
25 VCC_BB
DC Power Supply for Baseband Circuits. Connect to a +3.3V low-noise supply. Bypass to GND with
a 1nF capacitor connected as close as possible to the pin. Do not share capacitor ground vias with
other ground connections.
MAX2112
8
Maxim Integrated