Application Circuit Diagram; Passive Loop Filter; Cdcm7005 With A Passive Loop Filter Configuration - Texas Instruments CDCM7005 User Manual

Application Circuit Diagram

5.1 Application Circuit Diagram
5.1.1

Passive Loop Filter

Figure 5−1. CDCM7005 With a Passive Loop Filter Configuration
V
CC
5-2
The following applications sections the two loop filter configurations are
discussed.
The passive loop filter is a second order filter (two poles, one zero). The zero
is required for the overall loop stability. R1, C1, and C2 generate the dominant
pole of the system. A second pole is introduced by R2 and C3.
VC(X)O
491.52 MHz
PECL_OUT_B
PECL_OUT
CDCM7005
PRI_REF
SEC_REF
CTRL_LE
CTRL_DATA
SPI
STATUS_REF
CTRL_CLK
V
STATUS_VC(X)O
CC
130 Ω
130 Ω
VC(X)O_IN
VC(X)O_IN_B
R R
82 Ω 82 Ω
Low-Pass Filter
160 Ω
V_CTRL
C3
100 nF
R1
4.7 kΩ
CP_OUT
C1
22 µF
PLL_LOCK
10 nF 10 nF
YnA
10 nF
YnB
R R
150 Ω 150 Ω
R2
C2
100 nF