M2006-02A Datasheet Rev 1.0

5 of 8

Revised 28Jul2004

Integr ated Circuit Systems , Inc. ● Ne tw o r ki ng & C o mmun ica t io ns ● ww w. icst.com ● tel (508 ) 85 2-54 00

M2006-02A

Prod uct Data Sh eet

Integrated

Circuit

Systems, Inc.

External Loop Filter

To provide stable PLL operation, and thereby a low jitter

output clock, the M2006-02A requires the use of an

external loop filter. This is provided via the provided

filter pins (see Figure 4).

Due to the differential signal path design, the

implementation requires two identical complementary

RC filters as shown here.

Figure 4: External Loop Filter

PLL bandwidth is affected by loop filter component

values, “Mfec” and “Mfin” values, and the “PLL Loop

Constants” listed in AC Characteristics on pg. 7.

The various “Non-FEC ratio” settings can be used to

actively change PLL loop bandwidth in a given

application. See “FEC PLL Ratio Dividers Look-up

Table (LUT)” on pg. 3.

See Example External Loop Filter Component Values table.

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.

Go to the SAW PLL Simulator Software web page at

www.icst.com/products/calculators/m2000filterSWdesc.htm

C

POST

C

POST

VC

nVC

R

POST

nOP_OUT

OP_OUT

R

POST

R

LOOP

R

LOOP

C

LOOP

C

LOOP

OP_IN

nOP_IN

6

7

5

49

8

Device Configuration

Example External Loop Filter Component Values

Nominal Performance Using These Values

(MHz)

F

pins

FEC_ SEL3:0

pins

R loop

C loop

R post

C post

PLL Loop

Bandwidth

Damping

Factor

Passband

19.44

622.08

0 0

1 1 0 0

11.5

k

Ω

2.2

µF

34

k

Ω

470

pF

1k

Hz

6.0

0.05

77.76

0 1

1 1 1 0

155.52

1 0

1 1 1 1

622.08

1 1

0 1 1 0

5.11

k

Ω

4.7

µF

6.0

0.06

167.3317

1 0

0 0 0 1

113.0

k

Ω

0.22

µF

6.0

0.06

669.3266

1 1

28.0

k

Ω

1.0

µF

6.3

0.05

155.52

669.3266

1 0

1 0 0 1

121.0

k

Ω

0.22

µF

6.0

0.05

622.08

1 1

30.1

k

Ω

1.0

µF

6.5

0.05

Table 8: Example External Loop Filter Component Values

Note 1: K

Passband Peaking. For PLL Simulator software, go to www.icst.com.

Symbol Parameter

Rating

Unit

V

I

Inputs

V

V

O

Outputs

V

V

CC

Power Supply Voltage

4.6

V

T

S

Storage Temperature

Table 9: Absolute Maximum Ratings

Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the

device. These ratings are stress specifications only. Functional operation of product at these conditions

or any conditions beyond those listed in Recommended Conditions of Operation, DC Characteristics, or

AC Characteristics is not implied. Exposure to absolute maximum rating conditions for extended periods

may affect product reliability.