74hct7046a NXP Semiconductors, 74hct7046a Datasheet - Page 29

• Manufacturer Part Number: 74hct7046a
• Description: Phase-locked-loop With Lock Detector
• Manufacturer: NXP Semiconductors

Philips Semiconductors
December 1990
SUBJECT
PLL conditions
PLL frequency
PLL locks on
noise rejection at
AC ripple content
with no signal at
the SIG
capture range
harmonics at
centre frequency
signal input
when PLL is
locked
Phase-locked-loop with lock detector
IN
input
PHASE
COMPARATOR
PC1
PC2
PC1, PC2
PC1
PC2
PC1
PC2
PC1
PC2
DESIGN CONSIDERATIONS
VCO adjusts to f
VCO adjusts to f
Loop filter component selection
(a) = R3 x C2
(a) 1 = R3 x C2;
yes
no
high
low
f
f
r
r
= 2f
= f
2 = R4 x C2;
3 = (R3 + R4) x C2
i
, small ripple content at
i
, large ripple content at
Fig. 26 Simple loop filter for PLL with offset; R3 R4 500 .
Fig. 25 Simple loop filter for PLL without offset; R3 500 .
o
o
29
with
with
(b) amplitude characteristic
(b) amplitude characteristic
DEMOUT
DEMOUT
DEMOUT
DEMOUT
= 90 and V
= 360 and V
= 0
= 90
VCOIN
VCOIN
74HC/HCT7046A
= 1/2 V
(c) pole-zero diagram
(c) pole-zero diagram
= min. (see Fig.8).
Product specification
CC
(see Fig.6).