Hi.. I'm need help for power spectra density coding??

length(y)

nfft = 2^nextpow2(length(y_delta));

Fs=100;

Pxx = abs(fft(y,nfft)).^2/length(y)/Fs;

subplot(2,2,1),

plot(Pxx,'DisplayName','Pxx','YDataSource','Pxx');

Hpsd = dspdata.psd(Pxx(1:length(Pxx)/2),'Fs',Fs);

plot(Hpsd);

this is my program for PSD.. y is my name of data.. the problem is the graph will plot the x axis as frequency and y axis in dB.. the problem is, i want to maintain my amplitude value at y axis without changing it into dB.. how i can do that? anyone can help me?