AMD LX 600@0.7W, LX 700@0.8W, LX 800@0.9W, LX 900@1.5W Figure 7-1. VMEMLX Power Split , Table 7-3. AMD Geode LX 900@1.5W Processor DC Currents, I

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 VMEMLX 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. VMEMLX Power Split

VMEMLX VMEMDIMM

VTT

Connector

Device

MEM

RP1

RP2

Table 7-3. AMD Geode LX 900@1.5W Processor DC Currents

LX 900@1.5W (600 MHz), No EEPROM, VCORE = 1.4V, TDPT = 5.3W, TDPU = 5.1W (Note 1)

Symbol Parameter Typ Avg Max Unit Comments

ICC3ON - CRT Display Power State:

On (S0/C0)

85 100 mA

ICC3ON - TFT Display 37 45

ICOREON 1420 3140

IMEMON - Terminated 150 165 Note 2, Note 3

IMEMON - Unterminated 90 100 Note 3

IMEMDDR2ON 80 95

ICC3IDLE - CRT Display Power State:

Active Idle (S0/C1)

85 mA

ICC3IDLE- TFT Display 37

ICOREIDLE 1250

IMEMIDLE - Terminated 150 Note 2, Note 3

IMEMIDLE - Unterminated 80 Note 3

ICC3SLP - CRT Display Power State:

Sleep (S1)

4mA

ICC3SLP - TFT Display 4

ICORESLP 600

IMEMSLP - Terminated 100 Note 2, Note 3

IMEMSLP - 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 VMEMLX used by the AMD Geode LX processor and series

termination resistors. See Section 7.4.3 on page 599 for more details.

Note 3. VMEM is 2.6V for the LX 900@1.5W processor.