22
603 Hardware Specifications, REV 2
Preliminary—Subject to Change without Notice
1.7.2 PLL Power Supply Filtering
The AVdd power signal is provided on the 603 to provide power to the clock generation phase-lock loop. To
ensure stability of the internal clock, the power supplied to the AVdd input signal should be filtered using a
circuit similar to the one shown in Figure 12. The circuit should be placed as close as possible to the AVdd
pin to ensure it filters out as much noise as possible.
Figure 12. PLL Power Supply Filter Circuit
1.7.3 Decoupling Recommendations
Due to the 603’s dynamic power management feature, large address and data buses, and high operating
frequencies, the 603 can generate transient power surges and high frequency noise in its power supply,
especially while driving large capacitive loads. This noise must be prevented from reaching other
components in the 603 system, and the 603 itself requires a clean, tightly regulated source of power.
Therefore, it is recommended that the system designer place a decoupling capacitor with a low ESR
(effective series resistance) rating at each Vdd and OVdd pin of the 603.
These capacitors should range in value from 220 pF to 10
µ
F to provide both high and low frequency
filtering, and should be placed as close as possible to their associated Vdd pin. Surface-mount tantulum or
ceramic devices are preferred. It is also recommended that these decoupling capacitors receive their power
from Vdd and GND power planes in the PCB, utilizing short traces to minimize inductance in the traces.
Power and ground connections must be made to all external Vdd and GND pins of the 603.
1.7.4 Connection Recommendations
To ensure reliable operation, it is highly recommended to connect unused inputs to an appropriate signal
level. Unused active-low inputs should be connected to Vdd. Unused active-high inputs should be connected
to GND.
1.7.5 Thermal Management Information for the Motorola Package
This section provides a thermal management example for the 603; this example is based on a typical desktop
configuration using a 240 lead, 32 mm x 32 mm, Motorola wire-bond CQFP package. The heat sink used
for this data is a pinfin configuration from Thermalloy, part number 2338.
1.7.5.1 Thermal Characteristics for the Motorola Wire-Bond CQFP Package
The thermal characteristics for a wire-bond CQFP package are as follows:
Thermal resistance (junction-to-case)
= R
θ
jc
or
θ
jc
= 2.2
°
C/Watt (junction-to-case)
1.7.5.2 Thermal Management Example
The following example is based on a typical desktop configuration using a Motorola wire-bond CQFP
package. The heat sink used for this data is a pinfin heat sink #2338 attached to the wire-bond CQFP
package with thermal grease.
Vdd
AVdd
10 Ohms
10 uF
0
.
1 uF
GND
