regarding CCS library

[VLSI@91]

can anyone tell me how are these transition values calculated? does these values depend on resistance and capacitance values? here is the snap shot of CCS library file(i.e the values present in the index)

cell_fall ("xyz") {
index_1 ("0.0076758, 0.0154251, 0.0309978, 0.0622924, 0.125181, 0.251561, 0.50553, 1.0159");
index_2 ("0.000353652, 0.00146662, 0.00366656, 0.0091664, 0.022916, 0.05729, 0.143225");
values ("0.0812256, 0.0934280, 0.1119136, 0.1512316, 0.2437192, 0.4739112, 1.0492549", \
"0.0846568, 0.0968465, 0.1153510, 0.1546916, 0.2471952, 0.4772467, 1.0518043", \
"0.0916162, 0.1038143, 0.1223046, 0.1616508, 0.2541862, 0.4841215, 1.0608125", ....)
cell_rise ("del_1_8_7") {
index_1 ("0.0076758, 0.0154251, 0.0309978, 0.0622924, 0.125181, 0.251561, 0.50553, 1.0159");
index_2 ("0.000353652, 0.00146662, 0.00366656, 0.0091664, 0.022916, 0.05729, 0.143225");
values ("0.0814071, 0.0949213, 0.1171349, 0.1679353, 0.2917976, 0.6003212, 1.3746957", \
"0.0848904, 0.0984052, 0.1206107, 0.1714088, 0.2950569, 0.6038173, 1.3759728", \
"0.0918296, 0.1053378, 0.1275378, 0.1783569, 0.3019112, 0.6105945, 1.3818049",...)
fall_transition ("del_1_8_7") {
index_1 ("0.0076758, 0.0154251, 0.0309978, 0.0622924, 0.125181, 0.251561, 0.50553, 1.0159");
index_2 ("0.000353652, 0.00146662, 0.00366656, 0.0091664, 0.022916, 0.05729, 0.143225");
values ("0.0270282, 0.0394019, 0.0632482, 0.1242832, 0.2867956, 0.6994650, 1.7449550", \
"0.0270243, 0.0394241, 0.0632522, 0.1242825, 0.2864429, 0.7007818, 1.7391046", \
"0.0270430, 0.0394602, 0.0633354, 0.1242409, 0.2869259, 0.7024533, 1.7450782",...)
rise_transition ("del_1_8_7") {
index_1 ("0.0076758, 0.0154251, 0.0309978, 0.0622924, 0.125181, 0.251561, 0.50553, 1.0159");
index_2 ("0.000353652, 0.00146662, 0.00366656, 0.0091664, 0.022916, 0.05729, 0.143225");
values ("0.0299951, 0.0473579, 0.0819551, 0.1724126, 0.4066016, 0.9952064, 2.4622058", \
"0.0301367, 0.0473040, 0.0820432, 0.1725090, 0.4066503, 0.9933618, 2.4677627", \
"0.0301424, 0.0472923, 0.0820650, 0.1725071, 0.4068602, 0.9936619, 2.4690523",...)

also what are these values corresponding to the indices indicate? do the transition values correspond to delay? if so then what does cell_rise/fall values represent?

Thanks in advance

 

[rca]

CCS provide the waveform of the current transform, then this is very much complicate to interprete or generate.

 

[artmalik]

Ok, CCS timing is done with respect to the current source. so the delay is calculate when the current source is able to charge the output till 50% of vdd. for the transition time it is till the trip points integral of current over time till it reaches the threshold voltages. Actually you should try to compare the library NLDM with CCS through DC compiler and it will be able to do all the checks. Debugging by looking at the libraries is not practical.

 

[VLSI@91]

thank you. will try out with DC compiler