XR215A Datasheet, PDF (26/32 Pages) Exar Corporation – Monolithic Phase-Locked Loop

XR-215A
Tracking Filter/Discriminator
The wide tracking range of the XR-215A allows the
system to track an input signal over a 3:1 frequency
range, centered about the VCO free running frequency.
The tracking range is maximum when the binary range-
select (pin 10) is open circuited. The circuit connections
for this application are shown in Figure 25. Typical
tracking range for a given input signal amplitude is shown
in Figure 26. Recommended values of external
components are:
1kW < R₀ < 4kW and 30 C₀ < C₁ < 300 C₀ where the timing
capacitor C₀ is determined by the center frequency
requirements (see Figure 8.)
5K
0.1mF
+12V
5K
0.1mF
2K
2K
Signal
Input
Vs
0.1mF
Ro
U1
6
Phase
Comp.
11
12
VCO
10
V_EE
9 13
14
C₀
5 16 V_CC
4
XR-215A
15
Op
8
Amp.
2 31 7
300pF
R_P 20K
C₁ C₁
2K
Cc
VCO
Output
10K
10K
R_F
Discriminator
Output
50 50
Figure 25. Circuit Connection For Tracking Filter Applications
Rev. 1.01
26