74HCT9046AN Philips, 74HCT9046AN Datasheet - Page 27

• Manufacturer Part Number: 74HCT9046AN
• Description: PLL with bandgap controlled VCO
• Manufacturer: Philips

Philips Semiconductors
Filter design considerations for PC1 and PC2 of the HCT9046A
Figure 30 shows some examples of passive and active filters to be used with the phase comparators of the HCT9046A.
Transfer functions of phase comparators and filters are given in Table 4.
Table 4 Transfer functions of phase comparators and filters.
1999 Jan 11
PC1
PC2
COMPARATOR
PLL with bandgap controlled VCO
PHASE
a.
b.
c.
d.
e.
Fig.30
passive filter
without
damping
passive filter
with damping
active filter
with damping
passive filter
with damping
active filter
with damping
FILTER TYPE
A = 10
A = 10
F
F
F
F
F
j
j
j
j
j
TRANSFER FUNCTION
=
=
=
=
=
5
5
---------------------------- -
1 A
---------------------------- -
1 A
= limit DC gain
---------------------------- -
1 A
= DC gain amplitude
-------------------- -
1
--------------------------------------- -
1
1
1
1
+
+
27
+
+
+
1
1
j
j
+
+
+
j
j
j
+
j
j
j
1
j
2
2
2
1
1
1
1
+
2
1
-------------------- -
1
-------------------- -
1
-------------------- -
2
+
j
+
j
+
j
j
j
j
1
1
1
2
2
2
A = 10
R3' = R
R
K
K
1
2
3
1
2
3
b
PC1
PC2
= R3
= R4
= R4
= R3'
= R4
= R4
= 25 to 250 k
=
=
5
b
= DC gain amplitude
/17;
EXPLANATION
V
---------- - V r
------ - V r
4
5
C2;
C2;
C3;
C2;
C3;
C2;
CC
74HCT9046A
Product specification