S1M8831A Samsung Semiconductor, Inc., S1M8831A Datasheet - Page 31

• Manufacturer Part Number: S1M8831A
• Description: Fractional-n Rf/integer-n If Dual Pll Frequency Synthesizer
• Manufacturer: Samsung Semiconductor, Inc.

FRACTIONAL-N RF/INTEGER-N IF DUAL PLL
PCB LAYOUT GUIDE
In doing PCB layouts for S1M8831A/33, we recommend that you apply the following design guide to your
handsets, thus improving the phase noise and reference spurious performances of the phones.
1. The S1M8831A/33 has external four power supply pins to supply on-chip bias, each for analog and digital
2. VCO power lines should be well separated from those of PLL because VCO is generally a very sensitive
3. For more improvement of reference spurious performance, it is recommended that the LPF ground be tied to
blocks of RF and IF PLLs. Basically in doing PCB layout, it is important that power supply lines should be
separated from one another and thus coupling noises through the voltage supply lines can be minimized.
If you have some troubles with the direction to separate, you can choose the following recommendations for
your convenience;
It minimizes coupling noise effects from a digital switching noise into analog blocks. We also recommend
that a passive RC low pass filter (R(22 ), C(100nF)) be utilized for suppressing high frequency noise on the
analog power supply line and reducing any digital noise couplings.
device from power line noises and PLL is a digital noise generator.
the PLL ground, not the VCO ground.
Tying analog power lines, V
Tying digital power lines, V
A point connecting the analog and digital power lines should be near to battery line as close as possible.
P1
CC
and V
RF and V
P2
, is possible.
CC
IF, is possible.
S1M8831A/33
31