Board Design Guidelines for SmartFusion2 SoC and IGLOO2 FPGAs
AC393 Application Note Revision 14.0 17
2.4 Limiting Surge Current During Device Reset
After device power-up, if the application asserts the DEVRST_N pin and there are no decoupling
capacitors on the board, additional surge current on VDD may be observed during assertion of
DEVRST_N or during a digest check operation. This section describes how to minimize additional surge
current during SmartFusion2/IGLOO2 device reset operation. This additional surge current does not
occur during device power-up; it is applicable only when DEVRST_N is asserted.
VDDI6 Connect to VSS through a 10 kΩ resistor
VDDI7 Connect to VSS through a 10 kΩ resistor – Connect to VSS through a 10 kΩ resistor
VDDI8 Connect to VSS through a
10 k
Ω resistor
– – – Connect to VSS through a 10 k
Ω
resistor
–
VDDI9 Connect to
VSS
through a
10 k
Ω
resistor
– – – – – Connect to
VSS
through a
10 k
Ω
resistor
––
1. The unused VDDI# pins must be connected to VSS through a 10 KΩ resistor. The VDDI# pins can be grouped and connected to
one 10 KΩ resistor or a 10 K Ω resistor can be used for each VDDI# bank, it completely depends on the board layout. For the
previous design the unused VDDI# pins were DNC, and cannot create functionality issue. Microsemi recommends connecting to
Ground to improve the board reliability.
Table 9 • Recommendation for Bank Supplies for VF256 and TQ144 Packages
1
Bank Supply
Names
VF256 TQ144
M2S025T/
M2GL025T
M2S010T/
M2GL010T
M2S005S/
M2GL005S
M2S010S/
M2GL010S
M2S005S/
M2GL005S
VDDI0 Connect to VSS through a 10 k
Ω resistor
VDDI1 Must connect
to VDDI1
Must connect
to VDDI1
Must connect
to VDDI1
––
VDDI2 Must connect
to VDDI2
Must connect
to VDDI2
Must connect
to VDDI2
Must connect
to VDDI2
Must connect
to VDDI2
VDDI3 Connect to VSS through a 10 k
Ω resistor
VDDI4 Must connect
to VDDI4
Must connect
to VDDI4
Must connect
to VDDI4
Must connect
to VDDI4
Must connect
to VDDI4
VDDI5 Connect to VSS through a 10 k
Ω resistor – Connect to VSS
through a 10 k
Ω
resistor
VDDI6 Connect to VSS through a 10 k
Ω resistor
VDDI7 Connect to VSS through a 10 kΩ resistor – Connect to VSS
through a 10 k
Ω
resistor
–
1. The unused VDDI# pins must be connected to VSS through a 10 KΩ resistor. The VDDI# pins can be grouped and connected to
one 10 KΩ resistor or a 10 K Ω resistor can be used for each VDDI# bank, it completely depends on the board layout. For the
previous design the unused VDDI# pins were DNC, and cannot create functionality issue. Microsemi recommends connecting to
Ground to improve the board reliability.
Table 8 • Recommendation for Bank Supplies for VF400 and FCS325 Packages
1
(continued)
To Next Page
Loading...