
Functional Overview
186
December 2003 Revised March 2005
SPRS231D
3.14 Power Supply Connection Examples
3.14.1
Core and I/O Voltage Supply Connections
The OMAP5912 device is extremely flexible regarding the implementation of the core and I/O voltage supplies
of the device.
In a typical system, all of the core voltage supplies (CV
DDx
) may be connected together and powered from
one common supply. Likewise, all of the I/O voltage supplies (DV
DDx
) may be connected together and
powered from a common supply. Figure 34 illustrates this common system configuration.
1.5-V
Voltage
Supply
CV
DD
CV
DD1
CV
DD2
CV
DD3
CV
DDA
CV
DDDLL
CV
DDRTC
2.75-V
Voltage
Supply
DV
DD1
DV
DD2
DV
DD3
DV
DD4
DV
DD5
DV
DD7
DV
DD8
DV
DD9
DV
DDRTC
DV
DD6
Supply
Voltage
1.8-V
OMAP5912
V
SS
NOTE: In this example, SDRAM (DV
DD4
) and FLASH (DV
DD5
) I/O voltage supplies are connected to 1.8 V and the other I/O voltage
supplies are connected to 2.75 V. But all the I/O voltage supplies (DV
DDx
) are dual-voltage capable and all power combinations
are possible.
Figure 34. Supply Connections for a Typical System
In the previous example, all CV
DDx
pins are connected in common. However, the OMAP5912 has dedicated
CV
DD
pins that supply power to different sections of the chip. This feature can be useful in prototyping phases
to troubleshoot power management features and perform advanced power analysis. By isolating each CV
DDx
bus from the power source through isolation jumpers or current sense resistors, the current draw into different
domains may be measured separately. This type of supply isolation must only be done during prototyping as
production system designs should connect all the CV
DDx
pins together, preferably to a common board plane.
NOTE:
There is no specific power sequencing for the different voltage supplies as long as all CV
DDx
and DV
DDx
voltages are ramped to valid operating levels within 500 ms of one another.
Additionally, if certain I/O pins are unused in a specific system application, the DV
DDx
supply
pins that power these I/O must still be connected to valid operating voltage levels.