74hct9046a NXP Semiconductors, 74hct9046a Datasheet - Page 34

• Manufacturer Part Number: 74hct9046a
• Description: Pll With Bandgap Controlled Vco
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Rewriting the equation for natural frequency results in:
The maximum overshoot occurs at N
When C2 = 470 nF, it follows:
Hence the current source bias resistance
R
With
For extra ripple suppression a capacitor C3 can be connected in parallel with R4, with an extra
For stability reasons
2003 Oct 30
R4
R3
1
1
2
b
PLL with band gap controlled VCO
= 17
(1) R3'
=
=
=
=
=
K
------------------------------- -
0.4 2.24 10
----------------------------------------- -
--------------------------- -
0.5 5000
------- -
C2
= 0.707 (0.5
R3'
p
------- -
C2
5000
0.707
2
1
2550 = 43 k .
=
=
K
=
n
OSCILLATOR
=
v
fictive resistance
R
------ -
17
2
--------------------------- -
470 10
b
2
"HCU04"
--------------------------- -
0.00028
1 MHz
K
470 10
0.0012
30
n
=
0.00028
6
3
–
2
=
–
9
should be 0.1
9
0.0012
=
=
n
600
) it follows:
2550
DIVIDE BY 10
C1 = 100 pF.
C2 = 470 nF.
C3 = 39 nF.
"190"
max
2
, hence C3
= 30; hence K
100 kHz
u
Fig.34 Frequency synthesizer.
14
3
R1 = 30 k .
R2 = 30 k .
R3' = 2550 .
R
R4 = 600 .
b
COMPARATOR
PROGRAMMABLE
= 43 k .
PHASE
DIVIDER
0.1C2 or C3 = 39 nF.
PC2
"4059"
n
K n
K p
=
34
1
30
:
R3'
15
(1)
R
b
13
C3
K f
C2
R4
9
R1
11
R2
12 6
VCO
K o
C1
74HCT9046A
3
7
MBD098
= R4
Product specification
5
4
C3.
f OUT