ICS673-01 Datasheet, PDF (8/9 Pages) Integrated Circuit Systems – PLL Building Block

ICS673-01
PLL Building Block
Avoiding PLL Lockup (continued)
power, very small (SOT-23), low cost, and has
high input impedance.
The trigger voltage of the comparator is set by
the voltage divider formed by R2 and R3. The
voltage should be set to a value higher than the
VCO input is expected to run during normal
operation. Typically, this might be 0.5 V below
VDD. Hysteresis should be added to the circuit
by connecting resistor R4.
ICS673-01
PD
CHGP VCOIN
CAP
C2
VDD
R2
RZ
C1
-
+
R3
R4
Figure 5. Using an External Comparator to Reset the VCO.
MDS 673-01 D
8
Revision 022500
Printed 11/15/00
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