GT-64260A Design Guide
Doc. No. MV-S300165-00, Rev. A
CONFIDENTIAL
Copyright © 2002 Marvell
Page 92
Document Classification: Proprietary Information
May 21, 2002, Preliminary
14.2 Electrical Specification
The CPU interface can be configured to support 3.3V or 2.5V IO voltage. This is configured at reset by sampling
the AD[31].
•
0 = 2.5V IO
•
1 = 3.3V IO
14.3 Termination Topology
The 60x and MPX standards do not require any termination. Simulate the board topology to determine if termina-
tion is needed.
14.4 Timing Requirements
The CPU interface can run up to 133 MHz. The timing is very tight and the designer must simulate the system to
work in the maximum frequency.
14.4.1 Calculating the Reference Point
The output delay values in the GT-64260A datasheet’s AC timing table is defined for a specific load. This value
includes the rise/fall time of the output. To calculate the signal fly time, the rise/fall time must be measured and a
reference measuring point must be set.
describes the test circuit for the GT-64260A (Cload = 15pf):
Figure 43: GT-64260A Test Circuit (Cload = 15pf)
shows the results of the test circuit simulation.
`
Cload
GT-64260A Output