Datasheet

74HCT9046A_6 © NXP B.V. 2009. All rights reserved.
Product data sheet Rev. 06 — 15 September 2009 36 of 43
NXP Semiconductors
74HCT9046A
PLL with band gap controlled VCO
(1) R3’ = fictive resistance
R3’ =
C1 = 100 pF
C2 = 470 nF
C3 = 39 nF
R1 = 30 kΩ
R2 = 30 kΩ
R3' = 2550 Ω
R
bias
=43kΩ
R4 = 600 Ω
Fig 34. Frequency synthesizer
mbd098
R4
C2
R2R1
VCO
R3'
PHASE
COMPARATOR
PC2
DIVIDE BY 10
"190"
OSCILLATOR
"HCU04"
13
100 kHz
14
3
4
f
OUT
PROGRAMMABLE
DIVIDER
"4059"
9
11 12 6 7 5
1 MHz
K
p
K
n
K
f
K
o
C1
C3
(1)
R
bias
15
Φ
u
R
bias
17
------------
Fig 35. Type 2, second order frequency step response
012 4
1.6
1.0
0.6
0
0.8
mga959
3
1.4
1.2
0.4
0.2
5678
ω
n
t
∆Φ
e
(t)
∆Φ
e
/ω
n
∆ω
e
(t)
∆ω
e
/ω
n
−0.6
0
0.4
1.0
0.2
−0.4
−0.2
0.6
0.8
= 5.0
ζ
0.5
0.707
1.0
= 0.3
ζ
= 2.0
ζ