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PI6C49003A

PCIe® Gen 2 Networking Clock Generator

www.pericom.com

11/11/14

All trademarks are property of their respective owners.

Crystal Load Capacitors

If an input crystal is used, crystal should be connected from pins X1 to ground and X2 to ground to optimize the accuracy of the

output frequency.

For example, for a crystal with a 18pF load cap, each external crystal cap would be 18pF. (18 - 8) *2 =18.

Application Notes

Crystal circuit connection

The following diagram shows PI6LC4830-01 crystal circuit connection with a parallel crystal. For the CL=18pF crystal, it is suggest-

ed to use C1= 27pF, C2= 33pF. C1 and C2 can be adjusted to fine tune to the target ppm of crystal oscillator according to different

board layouts.

C1

27pF

Crystal�(C

C2

33pF

XTAL_IN

XTAL_OUT

SaRonix-eCera

CG2500003

Crystal Oscillator Circuit

Recommended Crystal Specification

Pericom recommends:

a)GC2500003XTAL49S/SMD(4.0mm),25M,CL=18pF,+/-30ppm,http://www.pericom.com/pdf/datasheets/se/GC_GF.pdf

b)FY2500081,SMD5x3.2(4P),25M,CL=18pF,+/-30ppm,http://www.pericom.com/pdf/datasheets/se/FY_F9.pdf

c)FL2500047,SMD3.2x2.5(4P),25M,CL=18pF,+/-20ppm,http://www.pericom.com/pdf/datasheets/se/FL.pdf

Configuration test load board termination for HCSL Outputs

Rs

33

5%

Rs

33

5%

Rp

49.9

1%

475

1%

Rp

49.9

1%

2pF

5%

2pF

5%

Clock#

Clock

TLA

TLB

PI6C49003A

Figure 4. Configuration Test Load Board Termination

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