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PRELIMINARY INFORMATION
describes products that are not in full production at the time of printing. Specifications are based on design goals
and limited characterization. They may change without notice. Contact Fairchild Semiconductor for current information.
P
www.fairchildsemi.com
Features
Demodulates 16 level to 2 level VSB signals
Versatile delayed AGC & Tuner Controls
60dB Gain from IF to baseband
45dB AGC range with a digital control
<1% distortion @ 2 Vpp baseband output
50dB typical IMD3
On-chip low phase noise VCO (100dBc/Hz @ 20KHz
from 200MHz)
Wideband Quadrature Prescalers
<2
°
Quadrature phase error
Programmable Video Filter-Amplifier
Direct input interface for SAW filters
9dB input Noise Figure at max gain
On-chip band gap reference and temperature
compensation
Available in 28 lead PLCC package
Description
The RC6516 is fully integrated IF Demodulator customized
for Vestigal Side Band (VSB) receivers. As shown in the
Block Diagram, the IC performs IF amplification with gain
control, synchronous demodulation of I & Q channels and
carrier recovery using a Frequency & Phase Lock Loop
(FPLL). The RC6516 directly provides delayed AGC control
for a front end tuner. The demodulated output is filtered and
amplified. The device accepts direct digital control inputs
from a microprocessor for gain control, calibration and shut
down functions. The IC is packaged in a 28-pin PLCC.
Block Diagram
GND2
XTAL1
AFC+
BANDGAP
REF
AGC CONTROL
SHUT DOWN
OF AFC DEFEAT
LOGIC
XTAL
CP
CP
LNA
LIM
+
–
VGA
RF
3.5dB
FILTER-BQD
LO
RF
LO
PD
PL
IF
VCO
+4
90
0
EN
EN
26
16dB
EEV
ds
20
ds
EN
VC01
VCC3(5V)
GND3
VC02
PDO
XTAL2
VCC1 (12V)
GND1
IN+
IF
IN–
G
ND
P
TAGC
C
AGC
DLY ADJ
G
UP
G
DN
RFLT
I
DAT
+
IMX+
IMX–
AFC–
AFC+
Q
ADJ
SHUT DOWN
AFC-SWT
NOTE: Arrows indicate current mode signals
VCC2(12V)
65-7563
RC6516
IF Demodulator for Vestigial S ide Band Rec eivers
Rev. 0.9.0