Rainbow Electronics AT86RF211 - Manual (Page 8)

8
AT86RF211
1942C–WIRE–06/02
Figure 7. Synthesizer Loop Filter Schematic
Note: The PLL loop filter can be designed to optimize the phase noise around the carrier.
Three configurations can be suggested, regarding the application and channel spacing:
- Narrow band: (14.7 k
Ω
+ 2.2 nF) // 220 pF
- Typical: (3.3 k
Ω
+ 5.6 nF) // 560 pF
- High datarates: (10 k
Ω
+ 1 nF) // 100 pF
VCO
P F D
&
C H P
Fref
FILT1 VCOIN