cx28250 Mindspeed Technologies, cx28250 Datasheet - Page 43

• Manufacturer Part Number: cx28250
• Description: Cx28250 Atm Physical Interface Phy Devices
• Manufacturer: Mindspeed Technologies

CX28250
ATM Physical Interface (PHY) Devices
2.1.3 PLL Filter Network
Figure 2-5. Schematic Detail of Analog Components
28250-DSH-002-C
Note:
1.
2.
3. Connections between filter networks and N6 should be as short as possible.
4. R1 and C1 are not populated. They are used for device verification, and are not needed in production.
All capacitors are 10% ceramic unless noted otherwise.
All resistors are 1%.
L6
Three external networks are required as shown in
these components are located as close to the CX28250 as possible.
analog ground pin. It is important that both filters are at the same ground
potential relative to the analog ground pins.
low frequency noise. These rings should have numerous ground vias tying them
directly to the ground plane.
ensure that the design will meet jitter specifications over the temperature range of
-40 to +85 C. The customer may relax this tolerance based on their own
requirements.
1 µF
604 Ω
Note that the ground side of the Tx filters are tied together and then run to an
There is also a 'guard ring' around these networks to provide immunity from
Mindspeed recommends using a 5% NPO grade capacitor for C27. This is to
R1
L10
Mindspeed Technologies
0.015µF
C1
68.1 Ω
470 pF
N6
2.2 µF
0.015µF
™
604 Ω
P11
270 pF
Figure
2.0 Functional Description
2-5. It is important that
M6
2.1 Line Interface
500035_049
2-7