Pin description – Rainbow Electronics MAX2105 User Manual
Page 9
MAX2102/MAX2105
Direct-Conversion Tuner ICs for
Digital DBS Applications
_______________________________________________________________________________________
9
Pin Description
RF Ground. Connect directly to the ground plane.
GND
9, 11,
19, 24
Automatic Gain-Control Input. Bypass this pin with a 1000pF capacitor close to the pin, to minimize cou-
pling.
AGC
10
Q Channel Baseband Output
QOUT
13
Baseband +5V Supply. Bypass with a 10pF capacitor from this pin to pin 12 (GND), as close to the IC as
possible. Connect an additional 0.1µF capacitor in parallel with the 10pF capacitor (placement less critical).
V
CC
14
Q Channel Offset-Correction Noninverting Input. Connect a 0.22µF (typ) capacitor between QDC and QDC.
This capacitor must be placed as close to the IC as possible (see
Layout Considerations
section).
QDC
15
Ground (substrate)
GND
5
RF +5V Supply. Bypass with a 22pF capacitor from this pin to pin 9 (GND), as close to the IC as possible.
V
CC
6
RF Noninverting Input. Couple through a 22pF capacitor directly to a 50
Ω
signal source.
RFIN
7
RF Inverting Input. Connect to a 22pF series capacitor and a 51
Ω
resistor to ground.
RFIN
8
RF +5V Supply. Bypass with a 22pF capacitor from this pin to pin 11 (GND), as close to the IC as possible.
V
CC
4
Baseband Ground
GND
3, 12
PIN
I Channel Baseband Output
IOUT
2
Baseband +5V Supply. Bypass with a 10pF capacitor from this pin to pin 3 (GND), as close to the IC as
possible. Connect an additional 0.1µF capacitor in parallel with the 10pF capacitor (placement less critical).
V
CC
1
FUNCTION
NAME
Q Channel Offset-Correction Inverting Input. Connect a 0.22µF (typ) capacitor between QDC and QDC. This
capacitor must be placed as close to the IC as possible (see
Layout Considerations
section).
QDC
16
I Channel Offset-Correction Inverting Input. Connect a 0.22µF (typ) capacitor between IDC and IDC. This
capacitor must be placed as close to the IC as possible (see
Layout Considerations
section).
IDC
17
I Channel Offset-Correction Noninverting Input. Connect a 0.22µF (typ) capacitor between IDC and IDC.
This capacitor must be placed as close to the IC as possible (see
Layout Considerations
section).
IDC
18
RF +5V Supply. Bypass with a 10pF capacitor from this pin to pin 19 (GND) as close to the IC as possible.
V
CC
20
Local-Oscillator Complementary Input Port (Figure 1)
LO
21
Local-Oscillator Input Port (Figure 1)
LO
22
RF +5V Supply. Bypass with a 10pF capacitor from this pin to pin 24 (GND) as close to the IC as possible.
V
CC
23
Prescaler Ground. To disable the prescaler, leave this pin open.
PSGND
25
Prescaler Output. Drives CMOS load. Connect 2k
Ω
from this pin to GND (if the prescaler is enabled).
PSOUT
26
Prescaler Modulus Control. Leave open when the prescaler is disabled.
MOD
27
Prescaler +5V Supply.
Must be connected even if the prescaler is disabled.
Bypass with a 1000pF
capacitor.
V
CC
28