XR2211 Exar Corporation, XR2211 Datasheet - Page 8

• Manufacturer Part Number: XR2211
• Description: FSK Demodulator/ Tone Decoder
• Manufacturer: Exar Corporation

DESIGN EQUATIONS
(All resistance in , all frequency in Hz and all capacitance in farads, unless otherwise specified)
(See Figure 3 for definition of components)
1. VCO Center Frequency, f
2. Internal Reference Voltage, V
3. Loop Low-Pass Filter Time Constant, :
where:
if R
4. Loop Damping, :
Note: For derivation/explanation of this equation, please see TAN-011.
5. Loop-tracking
bandwidth,
XR-2211
F
f
0
Rev. 3.01
f
is
f
LL
V
R
or C
R
R
f
REF
O
PP
0
1
f
1
F
C
f
reactance is
1
R
· R
0
1
R
· C
V
f
PP
1250· C
0
R
2
1
f
CC
R
Tracking
Bandwidth
0
1
( seconds )
· R
1
· C
f
O
R
F
– 650 mV in volts
1
F
0
O
:
, then R
f
2
f
REF
(measured at pin 10):
PP
f
LH
= R1
8