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600 AMD Geode™ LX Processors Data Book
Electrical Specifications
33234H
The data bus on the DDR SDRAM has a low voltage swing
when actively terminated (terminated topology). The termi-
nated topology supports higher data transfer rates and is
less constrained, but it consumes more power. Many
designs should be able to operate reliably without active
termination (unterminated topology). The design con-
straints are smaller memory subsystems and tight control
on routing. See the application note, AMD Geode™ LX
Processor and CS5535/CS5536 Companion Device Layout
Recommendations (publication ID #32739), for more infor-
mation.
When series termination resistors are used, as specified in
the AMD Geode™ LX Processor and CS5535/CS5536
Companion Device Layout Recommendations, the actual
power provided by the V
MEMLX
supply is split between the
processor and the series and parallel termination (see Fig-
ure 7-1). Therefore, it is impossible to specify the power
used by the processor’s memory subsystem with one hun-
dred percent accuracy. A conservative estimate, is that
32.5% of the power is consumed by the processor and
67.5% by the termination resistors. See the AMD Geode™
LX Processor Determining Memory Interface I/O Power
Consumption document (publication ID #40554) for the
detailed analysis. This number is used for the results in DC
Current tables (Tables 7-3, 7-4, and 7-5).
Figure 7-1. V
MEMLX
Power Split
V
MEMLX
V
MEMDIMM
V
TT
Connector
or
Device
MEM
LX
R
P1
R
P2
R
S
Table 7-3. AMD Geode LX 900@1.5W Processor DC Currents
LX 900@1.5W (600 MHz), No EEPROM, V
CORE
= 1.4V, TDP
T
= 5.3W, TDP
U
= 5.1W (Note 1)
Symbol Parameter Typ Avg Max Unit Comments
I
CC3ON
- CRT Display Power State:
On (S0/C0)
85 100 mA
I
CC3ON
- TFT Display 37 45
I
COREON
1420 3140
I
MEMON
- Terminated 150 165 Note 2, Note 3
I
MEMON
- Unterminated 90 100 Note 3
I
MEMDDR2ON
80 95
I
CC3IDLE
- CRT Display Power State:
Active Idle (S0/C1)
85 mA
I
CC3IDLE
- TFT Display 37
I
COREIDLE
1250
I
MEMIDLE
- Terminated 150 Note 2, Note 3
I
MEMIDLE
- Unterminated 80 Note 3
I
CC3SLP
- CRT Display Power State:
Sleep (S1)
4mA
I
CC3SLP
- TFT Display 4
I
CORESLP
600
I
MEMSLP
- Terminated 100 Note 2, Note 3
I
MEMSLP
- Unterminated 35 Note 3
Note 1. The AMD Geode LX 900@1.5W processor operates at 600 MHz. Model numbers reflect performance as described
here: http://www.amd.com/connectivitysolutions/geodelxbenchmark
.
T = Terminated and U = Unterminated.
Note 2. Calculations are based on a 32.5/67.5 split between V
MEMLX
used by the AMD Geode LX processor and series
termination resistors. See Section 7.4.3 on page 599 for more details.
Note 3. V
MEM
is 2.6V for the LX 900@1.5W processor.