Power Distribution System (PDS) Design!

Allen

Introduction:
       FPGA designers are faced with a unique task when it comes to designing power distribution
systems (PDS). Most other large, dense ICs (such as large microprocessors) come with very
specific bypass capacitor requirements. Since these devices are only designed to implement
; j1 P8 A0 F  Hspecific tasks in their hard silicon, their power supply demands are fixed and only fluctuate
within a certain range. FPGAs do not share this property. Since FPGAs can implement an
2 r. Z% u, U* t* k+ t7 [7 ^+ walmost infinite number of applications at undetermined frequencies and in multiple clock
( Q' A8 a5 H9 F# M# Y4 u' A2 udomains, it can be very complicated to predict what their transient current demands will be.
6 P- R, l. N% I9 T( U1 ?* mSince exact transient current behavior cannot be known for a new FPGA design, the only
choice when designing the first version of an FPGA PDS is to go with a conservative worstcase
design.
. M% ?7 v0 U' C+ ETransient current demands in digital devices are the cause of ground bounce, the bane of highspeed
digital designs. In low-noise or high-power situations, the power supply decoupling
network must be tailored very closely to these transient current needs, otherwise ground
bounce and power supply noise will exceed the limits of the device. The transient currents in an
FPGA are different from design to design. This application note provides a comprehensive
method for designing a bypassing network to suit the individual needs of a specific FPGA
* A7 c4 x6 G( @$ o7 Z) ddesign.
The first step in this process is to examine the utilization of the FPGA to get a rough idea of its
transient current requirements. Next, a conservative decoupling network is designed to fit these
1 I( P8 D( J0 i  brequirements. The third step is to refine the network through simulation and modification of
capacitor numbers and values. In the fourth step, the full design is built and in the fifth step it is
measured. Measurements are made consisting of oscilloscope and possibly spectrum analyzer
5 `3 X3 f# E1 [" |0 V5 y: @readings of power supply noise. Depending on the measured results, further iterations through
' f9 d$ J0 A* tthe part selection and simulation steps could be necessary to optimize the PDS for the specific
application. A sixth optional step is also given for cases where a peRFectly optimized PDS is
needed.

ugi929

很经典的东西，收藏了

weekway

多谢楼主了！在这儿总能找到需要的资料！

zdz98

有没有中文的,看英文累啊............不过还是先谢谢楼主了.

Iric071

哥們,還有麼 ,繼續發阿...河合

forevercgh

LZ摘录的一段已经蛮有吸引了，资料不错，谢谢