Output Transition Time cal in PT ？

Dear All
以下是PT report_delay_cal跑出來的結果
另外底下有lib內片段的資料
請問output transition是如何計算出來的呢
這結果是astro計算出來的2倍，真不知是怎麼搞的
感謝了
From pin: ***/U31/A
To pin:***/U31/Y
Main Library Units:1ns1pF1kOhm
Library: 'ss_1p62v_125c'
Library Units:1ns1pF1kOhm
Library Cell: 'NOR3XLM'
arc sense:negative_unate
arc type:cell
CalculationRiseRiseFallFallSlewRail
Thresholds:DelaySlewDelaySlewDerateVoltageTemp.
-----------------------------------------------------------------------
from-pin5030->705070->300.5001.620125.0
to-pin5030->705070->300.5001.620125.0
RC network on pin '***/U31/Y' :
------------------------------------------------------
Number of elements = 10 Capacitances + 9 Resistances
Total capacitance= 0.029190 pF
Total capacitance= 0.029190 (in library unit)
Total resistance= 0.176340 Kohm
RiseFall
------------------------------------------------------------------
Input transition time= 0.2492180.231808(in library unit)
Effective capacitance= 0.0291900.029190(in pF)
Effective capacitance= 0.0291900.029190(in library unit)
Drive resistance= 32.5742336.689080(in Kohm)
Output transition time = 1.7896660.368313(in library unit)
Cell delay= 1.0439930.283440(in library unit)


rise_transition(delay_template_7x7) {
index_1 ("0.1000, 0.1880, 0.3560, 0.6720, 1.2660, 2.3860, 4.5000");
index_2 ("0.0002, 0.0007, 0.0024, 0.0078, 0.0245, 0.0773, 0.2435");
values ( \
"0.067, 0.077, 0.110, 0.202, 0.492, 1.455, 4.505", \
"0.066, 0.077, 0.110, 0.202, 0.492, 1.457, 4.506", \
"0.066, 0.077, 0.110, 0.202, 0.492, 1.457, 4.506", \
"0.066, 0.077, 0.110, 0.201, 0.492, 1.453, 4.510", \
"0.067, 0.078, 0.110, 0.202, 0.491, 1.455, 4.509", \
"0.067, 0.078, 0.111, 0.203, 0.491, 1.451, 4.508", \
"0.069, 0.080, 0.113, 0.205, 0.493, 1.455, 4.495");
}

你还要查查delay_template_7x7的定义，index1和2哪个是cap哪个是tran。
猜测index_1 是cap，然后fanout cap=0.029190 落在表外了，用外推推出的值

感謝小编的回答，以下是template的definevar1 = trans
var2 = cap
transition time實在是對不起來，不知哪邊有問題

lu_table_template(delay_template_7x7) {
variable_1 : input_net_transition;
variable_2 : total_output_net_capacitance;
index_1 ("1000, 1001, 1002, 1003, 1004, 1005, 1006");
index_2 ("1000, 1001, 1002, 1003, 1004, 1005, 1006");
}

跟slew derate有关。对于lib中定义上升时间为30-70%的，一般会加slew derate为1/2来模拟10-90%的slew，亦即在查表得到slew的值上乘以2

"這結果是astro計算出來的2倍"是因为astro中没有设这个derate吗?

感謝小编回答
一般derate是lib自帶出來的(至少在PT中是這樣)

ASTRO也是吃同樣的LIB，我想在DERATE這方面應該也是沒問題

待我詳查感謝