WESTCODE An IXYS Company

Soft Recovery Diode Types M0225YH300 to M0225YH450

7.0 Computer Modelling Parameters

7.1 Device Dissipation Calculations

I AV = − VT 0 +

VT 0 + 4 ⋅ ff 2 ⋅ rT ⋅WAV

2 ⋅ ff 2 ⋅ rT

Where VT0 =1.9V, rT = 4.16mΩ

ff = form factor (normally unity for fast diode applications)

WAV

=

∆T

Rth

∆T = Tj(MAX ) − TK

7.2 Calculation of VF using ABCD Coefficients

The forward characteristic IF Vs VF, on page 6 is represented in two ways;

(i) the well established VT0 and rT tangent used for rating purposes and

(ii) a set of constants A, B, C, and D forming the coefficients of the representative equation for VF

in terms of IF given below:

VF = A + B ⋅ ln(IF ) + C ⋅ I F + D ⋅ IF

The constants, derived by curve fitting software, are given in this report for both hot and cold

characteristics. The resulting values for VF agree with the true device characteristic over a current

range, which is limited to that plotted.

25°C Coefficients

A -0.98548669

B 0.7956059

C 3.12049×10-3

D -0.02422947

150°C Coefficients

0.604350122

0.01967453

1.245792×10-3

0.1197498

8.0 Frequency Ratings

The curves illustrated in figures 8 to 16 are for guidance only and are superseded by the maximum

ratings shown on page 1.

9.0 Square wave ratings

These ratings are given for load component rate of rise of forward current of 100 and 500 A/µs.

10.0 Duty cycle lines

The 100% duty cycle is represented on all the ratings by a straight line. Other duties can be included

as parallel to the first.

Data Sheet. Types M0225YH300 to M0225YH450 Issue 1

Page 5 of 11

June, 2004