
CY28551-3
....................Document #: 001-05677 Rev. *D Page 19 of 28
.
PCIEXC(stoppable)
PCIEXT(stoppable)
PCIEXC(free running)
PCIEXT(free running)
PE_REQ#
Tdrive_PE_REQ# < 10ns
Figure 9. CLKREQ# De-Assertion
VTT_PWRGD# = Low
Delay >
0.25 ms
S1
Power Off
S0
VDD_A = 2.0V
Sample
Inputs straps
S2
Normal
Operation
Wait for <1.8 ms
Enable Outputs
S3
VTT_PWRGD# = toggle
VDD_A = off
Figure 10. VTT_PWRGD# Timing Diagram
FS_[D:A]
VTT_PWRGD#
PWRGD_VRM
VDD Clock Gen
Clock State
Clock Outputs
Clock VCO
0.2-0.3 ms
Delay
State 0
State 2
State 3
Wait for
VTT_PWRGD#
Sample Sels
Off
On
State 1
Device is not affected,
VTT_PWRGD# is ignored
Figure 11. VTT_PWRGD# Timing Diagram