关于新版PADS系统自带库的问题.

今天安装了PADS9.4.1发现系统自带了不少7251 7351元器件库,但是发现
CNA7251,CNB7251,CNC7251,CNP7251,,,
  THA7351,THB7351,THC7351,THP7351,,,
不知道这些A,B,C,P代表什么意思,
知道的大侠指点下吧！

百度了一下找到了答案,谢谢"白山黑水",以下是从"白山黑水"新浪博客复制过来的,给有同样需要的人.
I'm looking for description about these libraries which category of component each library
covers or any other specifics, and what begining letter stands for.

In LP Viewer found PLB library files:

PCBM-STARTER.PLB09
BGA7351B.PLB09
SMN7351B.PLB09
SMM7351B.PLB09
SML7351B.PLB09
CNA7251.PLB09
CNB7251.PLB09
CNC7251.PLB09
CNP7251.PLB09
THA7251.PLB09
THB7251.PLB09
THC7251.PLB09
THP7251.PLB09


Answer
PCBM-STARTER = BGA & SMN combined with Mfr data added.

CN = Connectors

TH = Through-hole

SM = Surface Mount

A = Most Annular Ring for Through-hole
B = Nominal Annular Ring for Through-hole
C = Least Annular Ring for Through-hole
P = Proportional (The Annular Ring grows larger as the hole gets bigger for Through-hole)

SML = Least SMT Pad
SMN = Nominal SMT Pad
SMM = Most SMT Pad

BGA only comes in "Nominal" format

这里的Most ,Nominal , Least说的是封装在制作时的一个思维标准。Most 用于密度小的板子（pad 尺寸最大），Nominal用于密度适中的（pad尺寸中等），Least适用于密度大板子（pad尺寸最小）。