M1010-01 Datasheet, PDF (4/8 Pages) Integrated Circuit Systems – VCSO BASED CLOCK JITTER ATTENUATOR

Integrated
Circuit
Systems, Inc.
External Loop Filter
To provide stable PLL operation, the M1010-01 requires
the use of an external loop filter. This is implemented by
connecting passive external components to the device
as shown in Figure 4 below.
The M1010-01 utilizes a differential analog signal path
to minimize noise coupling from the system. Because of
this, the loop filter implementation requires two identical
complementary RC filters as shown here.
R_LOOP C_LOOP
R_POST
R_LOOP C_LOOP
R_POST
C_POST
C_POST
M1010-01
VCSO BASED CLOCK JITTER ATTENUATOR
Preliminary Information
PLL bandwidth is affected by the “M” value and the
“Mfin” value, as well as the VCSO frequency.
The various SEL1:0 settings can be used to actively
change PLL loop bandwidth in a given application. See
“SEL2:0 Look-up Table (LUT)” on pg. 3.
See Table 5, Example Loop Filter Component
Values for M1010-01-155.5200, on pg. 4.
PLL Simulator Tool Available
A free PC software utility is available on the ICS website
(www.icst.com). The M2000 Timing Modules PLL
Simulator is a downloadable application that simulates
PLL jitter and wander transfer characteristics. This
enables the user to set appropriate external loop
component values in a given application.
OP_IN nOP_IN
49
OP_OUT nOP_OUT nVC VC
85
67
Figure 4: External Loop Filter
Example Loop Filter Component Values for M1010-01-155.5200¹
VCSO Parameters: K_VCO = 200kHz/V, R_IN = 2050kΩ, VCSO Bandwidth = 700kHz.
Device Configuration
Example External Loop Filter Component Value
Nominal Performance Using These Values
F_Ref F_VCSO Mfin M, R R loop
(MHz) (MHz)
Value²
C loop
R post C post PLL Loop Damping
Passband Peak
Bandwidth Factor Amplitude @ Center
(dB)
Freq.
19.44 155.52 8
1 118.0kΩ 1.0µF
100kΩ 1000pF
270Hz
6.5
0.05
10Hz
2 118.0kΩ 22.0µF 200kΩ 1000pF
134Hz
6.8
0.04
4Hz
1 59.0kΩ 1.0µF
100kΩ 1000pF
610Hz
6.5
0.05
20Hz
77.76 155.52 2
2 59.0kΩ 2.2µF
100kΩ 1000pF
267Hz
6.8
0.04
10Hz
8 118.0kΩ 2.2µF
200kΩ 1000pF
134Hz
6.8
0.04
10Hz
1 40.2kΩ 1.0µF
40.2kΩ 1000pF
740Hz
6.3
0.05
20Hz
155.52 155.52 1
4 59.0kΩ 1.0µF
100kΩ 1000pF
267Hz
6.8
0.04
10Hz
8 76.8kΩ 2.0µF
200kΩ 1000pF
180Hz
6.3
0.05
8Hz
Table 5: Example Loop Filter Component Values for M1010-01-155.5200
Note 1: K_VCO , VCSO Bandwidth, M Divider Value, and External Loop Filter Component Values determine Loop Bandwidth, Damping Factor,
and Passband Peaking. For PLL Simulator software, go to www.icst.com.
Note 2: For loop timing applications, the recommended value for the product of “Mfin” x “M” is 8 or higher.
M1010-01 Datasheet Rev 0.4
4 of 8
Revised 29Sep2003
Integrated Circuit Systems, Inc. ● Communications Modules ● www.icst.com ● tel [phone]