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RC6505
PRODUCT SPECIFICATION
2
P
Pin Assignments
Pin Descriptions
Pin Number
1
2
3
4
5
6
7
8
9
10
11
12
13
Pin Name
IF_IN-
IF_IN+
OUT
INP
VRT
GND_BUF
BUF_OUT+
BUF_OUT-
VCC_BUF
BUF_IN+
NC
BUF_IN-
RFGND
Description
IF Input Complement.
IF Input.
Output of OPA.
Non-Inverting Input of OPA.
Output Reference Voltage for Top of A/D Input Range.
Ground for Output Buffer.
Differential Buffer/Driver Output.
Differential Buffer/Driver Output Complement.
Supply Voltage for Output Buffer.
Differential Buffer/Driver Input.
No Connect or Ground.
Differential Buffer/Driver Input Complement.
Ground for High Frequency Crystal Oscillator.
1
2
3
4
5
6
7
8
9
10
11
12
IF_IN-
IF_IN+
OUT
INP
VRT
GND_BUF
BUF_OUT+
BUF_OUT-
VCC_BUF
BUF_IN+
NC
BUF_IN-
VCC_IF1
NC
GND_IF1
GND_IF2
IF_OUT+
IF_OUT-
VCCIF2
VCC_RF
XTL2
XTL1
XOSCOA
RFGND
24
23
22
21
20
19
18
17
16
15
14
13
65-6505-02
Functional Description
The RC6505 as shown in the block diagram performs several
analog signal processing typically required in modern wide-
band digital receivers. These include:
IF Sections
Bias Voltage Generation
Crystal Oscillator
IF Gain Section
The front end IF section provides greater than 48dB of stable
gain at IF frequencies.
The input has high impedance while maintaining a low noise
figure. The input and output sections are on different sup-
plies to minimize parasitic couplings and prevent oscilla-
tions. The differential signal fed at IF_IN + /IF_IN- is
available at IF_OUT+ /IF_OUT- after amplification.
This output can be filtered externally and fed back into the
IC at pins BUF_IN+ & BUF_IN- to enhance the drive capa-
bility of the output and also to reduce any ‘kick-back’ from
the A/D sampling.
Bias Reference Voltage
The RC6505 has a built-in 3.25V references and an opera-
tional amplifier (OPA) with the ability to drive 10mA of
load. The OPA will serve as a voltage follower to provide
certain flexibility on application. Note that, the 3.25V refer-
ence has sourcing capability only.
Crystal Oscillator
This section has a crystal oscillator that can be used to gener-
ate timing signals like an A/D clock. The output level of
Crystal Oscillator will be TTL compatible at the XOSCOA
terminal.