Continue to Site

# Library compiler builds DFF problem

Status
Not open for further replies.

#### red_0220

##### Junior Member level 1
Hi all, I plan to change data of cell library ,
but something I don't understand.

This is D-Flip Flop(DFF) data of cell library :

cell(QDFFLTX1) {
.
.
.
pin(D) {
nextstate_type : data;
direction : input ;
capacitance : 0.001165;
internal_power() {
when : "!CK";
power(POWER_7x1) {
index_1 ("0.009652,0.016106,0.025992,0.046675,0.088958,0.216628,0.447814");
values("0.003651,0.003635,0.003626,0.003611,0.003614,0.003725,0.004117");
}
}
.
.
.
pin(CK) {
direction : input ;
capacitance : 0.001915;
max_transition : 0.217000;
clock : true;
internal_power() {
power(POWER_7x1) {
index_1("0.009651,0.016105,0.025992,0.046675,0.088957,0.216628,0.447814");
values("0.004066,0.004029,0.004007,0.004000,0.004050,0.004346,0.005062");
}
}

What do the value mean?
And how can I measure by hspice?

Hi,

Detailed description for the different fields in a timing library can be found in the library compiler user guide which can be downloaded from solvenet. Regarding the numbers in the tables, they are input pin internal power tables for the CK and D pins. Input pin internal power is defined as the energy dissipated when the signal at the input pin toggles (from 1to0 or 0to1) and the output pin is stable(not changing). For a flop and on the input pins (CK and D) this energy would be to charge the gate capacitance and any internal node switching enenrgy. The index is the ramp rate of the signal applied to the pin.

Hope this helps!

thanks~

If I want to get value of pin(D)

May I be multiplied by VDD and D signal from 0 to 1 (or 1 to 0) average of current ?

(
HSPICE example:
.MEAS TRAN avgval AVG I(vdd) FROM=58ns ,TO=60ns
Than It multiplied by VDD.
)

Status
Not open for further replies.