Intel 855GME

188
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
Hub Interface
8.1.4.2 Separate GMCH Voltage Divider Circuits for HLVREF and PSWING
This option allows for tuning the voltage references HLVREF and PSWING individually. The
reference voltage for both HLVREF and PSWING must meet the voltage specification in Table 70.
Normal care needs to be taken to minimize crosstalk to other signals (< 10-15 mV). Figure 91
depicts the individual HLVREF and PSWING voltage reference divider circuits for GMCH.
Table 70 presents the recommended resistor values for HLVREF and PSWING divider circuits for
GMCH.
Table 69. Recommended Resistor Values for Single VREF/VSWING Divider Circuit
Recommended Resistor Values VCCHI
Option 1 R1 = 80.6
Ω± 1% R2 = 51.1 Ω±1% R3 = 40.2 Ω±1% 1.5 V
Option 2 R1 = 255
Ω± 1% R2 = 162 Ω±1% R3 = 127 Ω±1% 1.5 V
Option 3 R1 = 226
Ω± 1% R2 = 147 Ω±1% R3 = 113 Ω±1% 1.5 V
C1 and C3 = 0.1 µF (near divider)
C5, C6 = 0.01 µF (near component)
Figure 91. Individual HLVREF and PSWING Voltage Reference Divider Circuits for GMCH
Table 70. Recommended Resistor Values for HLVREF and PSWING Divider Circuits for GMCH
Signal Name Recommended Resistor Values VCCHI Capacitor
HLVREF
(350 mV)
R4 = 287
Ω±1%
R5 = 100
Ω±1%
VCCHI=1.35 V
C3 = 0.1 µF (near divider);
C6 = 0.01 µF (near component)
PSWING
(800 mV)
R6 = 68.1
Ω±1%
R7 = 100
Ω±1%
VCCHI=1.35 V
C1 = 0.1 µF (near divider)
C5 = 0.01 µF (near component)
V
CC
HI
R4
R5
C1 C3
R6
R7
HLVREF
PSWING
C5
C6
GMCH