LPC47M172_07 SMSC [SMSC Corporation], LPC47M172_07 Datasheet - Page 143

• Manufacturer Part Number: LPC47M172_07
• Description: Advanced I/O Controller with Motherboard GLUE Logic
• Manufacturer: SMSC [SMSC Corporation]

7.39
Note:
SMSC LPC47M172
See Table 13.4 for SCK_BJT_GATE timing.
Backfeed Cut and Latched Backfeed Cut Circuitry
The nBACKFEED_CUT requires an external pull-up to V_5P0_STBY.
nBACKFEED_CUT is a signal required by the S3 power state circuitry and is powered by the VTR supply.
It is a function PWRGD_PS and nSLP_S3 according to the table below. nBACKFEED_CUT is used to
switch between the main voltage regulator and the suspend voltage regulator for various sub-systems
when the system is transitioning into the S3 power state.
nBACKFEED_CUT
LATCHED_BF_CUT
PWRGD_PS
Table 7.43 - nBACKFEED_CUT and LATCHED_BF_CUT Pins
Name
SMSC I/O
MCH
0
0
1
1
Table 7.44 - nBACKFEED_CUT Truth Table
Figure 7.15 - SCK_BJT_Gate Circuit
INPUTS
OD8
OP14
SCK_BJT_GATE
DATASHEET
Buffer
NSLP_S3
V_5P0_STBY
Page 143
1k
Power
0
1
0
1
Well
VTR
VTR
RMB_SCK
Open-Drain Output used for
STR Circuitry
for STR Circuitry
Latched Backfeed Cut Output
Advanced I/O Controller with Motherboard GLUE Logic
nBACKFEED_CUT
Description
SMSC/Non-SMSC Register Sets (Rev. 01-11-07)
OUTPUT
Hi-Z
Hi-Z
Hi-Z
0
Datasheet