
M1010-01 Datasheet Rev 0.4
4
of 8
Revised 29Sep2003
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Integrated
Circuit
Systems, Inc.
M1010-01
VCSO B
ASED
C
LOCK
J
ITTER
A
TTENUATOR
P r e l i m i n a r y I n f o r m a t i o n
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
Figure 4: External Loop Filter
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.
C
POST
C
POST
VC
nVC
R
POST
nOP_OUT
OP_OUT
R
POST
R
LOOP
C
LOOP
OP_IN
nOP_IN
6
7
5
4
9
8
Example Loop Filter Component Values for M1010-01-155.5200
1
VCSO Parameters: K
VCO
= 200kHz/V, R
IN
= 2050k
, VCSO Bandwidth = 700kHz.
Device Configuration
Example External Loop Filter Component Value
F
Ref
(MHz)
(MHz)
Value
2
Nominal Performance Using These Values
PLL Loop
Bandwidth
Factor
F
VCSO
Mfin
M, R
R loop
C loop
R post
C post
Damping
Passband Peak
Amplitude
@ Center
(dB)
Freq
.
0.05
0.04
0.05
0.04
0.04
0.05
0.04
0.05
19.44
155.52
8
1
2
1
2
8
1
4
8
118.0
k
118.0
k
59.0
k
59.0
k
118.0
k
40.2
k
59.0
k
76.8
k
1.0
μ
F
22.0
μ
F
1.0
μ
F
2.2
μ
F
2.2
μ
F
1.0
μ
F
1.0
μ
F
2.0
μ
F
100
k
200
k
100
k
100
k
200
k
40.2
k
100
k
200
k
1000
pF
1000
pF
1000
pF
1000
pF
1000
pF
1000
pF
1000
pF
1000
pF
270
Hz
134
Hz
610
Hz
267
Hz
134
Hz
740
Hz
267
Hz
180
Hz
6.5
6.8
6.5
6.8
6.8
6.3
6.8
6.3
10
Hz
4
Hz
20
Hz
10
Hz
10
Hz
20
Hz
10
Hz
8
Hz
77.76
155.52
2
155.52
155.52
1
Table 5: Example Loop Filter Component Values for M1010-01-155.5200
Note 1: K
, 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.