Datasheet
IBM PowerPC 750GX RISC Microprocessor
DD1.X
Figure 5-3. Dual PLL Power Supply Filter Circuits (Recommended if Dual-PLL is Enabled)1
Discrete Resistor
Ferrite Bead
2
Ω
A1V Pin
DD
C1
C2
AV
DD
AGND Pin2
Discrete Resistor
Ferrite Bead
2
Ω
A2V Pin
DD
C1
C2
AV
DD
AGND Pin2
Item
Resistor
C1
Description/Value
2 Ω
0.1 µF Ceramic
10.0 µF Ceramic
C2
Ferrite Bead
30 Ω (typical) - Murata BLM21P300S or similar
Notes:
1. The dual PLL power supply circuits shown in this figure are recommended for a design that uses the dual PLL feature. For
more information about the dual PLL feature, see Section 5.2, Low Voltage Operation at Lower Frequency, on page 46.
2. Connected to ground without a filter.
5.4 Decoupling Recommendations
Capacitor decoupling is required for the 750GX. Decoupling capacitors act to reduce high-frequency chip
switching noise and provide localized bulk charge storage to reduce major power-surge effects. Guidelines
for high-frequency noise decoupling will be provided in a separate application note. Bulk decoupling requires
a more complete understanding of the system and system power architecture, which is beyond the scope of
this document.
System Design Information
Page 52 of 73
750GX_ds_body.fm SA14-2765-02
September 2, 2005
IBM [ IBM ]
