SLUAAO2 March 2023 CSD13201W10 , CSD13202Q2 , CSD13302W , CSD13303W1015 , CSD13306W , CSD13380F3 , CSD13381F4 , CSD13383F4 , CSD13385F5 , CSD15380F3 , CSD15571Q2 , CSD16301Q2 , CSD16321Q5 , CSD16322Q5 , CSD16323Q3 , CSD16325Q5 , CSD16327Q3 , CSD16340Q3 , CSD16342Q5A , CSD16401Q5 , CSD16403Q5A , CSD16404Q5A , CSD16406Q3 , CSD16407Q5 , CSD16408Q5 , CSD16409Q3 , CSD16410Q5A , CSD16411Q3 , CSD16412Q5A , CSD16413Q5A , CSD16414Q5 , CSD16415Q5 , CSD16556Q5B , CSD16570Q5B , CSD17301Q5A , CSD17302Q5A , CSD17303Q5 , CSD17304Q3 , CSD17305Q5A , CSD17306Q5A , CSD17307Q5A , CSD17308Q3 , CSD17309Q3 , CSD17310Q5A , CSD17311Q5 , CSD17312Q5 , CSD17313Q2 , CSD17318Q2 , CSD17322Q5A , CSD17327Q5A , CSD17381F4 , CSD17382F4 , CSD17483F4 , CSD17484F4 , CSD17501Q5A , CSD17505Q5A , CSD17506Q5A , CSD17507Q5A , CSD17510Q5A , CSD17522Q5A , CSD17527Q5A , CSD17551Q3A , CSD17551Q5A , CSD17552Q3A , CSD17552Q5A , CSD17553Q5A , CSD17555Q5A , CSD17556Q5B , CSD17559Q5 , CSD17570Q5B , CSD17571Q2 , CSD17573Q5B , CSD17575Q3 , CSD17576Q5B , CSD17577Q3A , CSD17577Q5A , CSD17578Q3A , CSD17578Q5A , CSD17579Q3A , CSD17579Q5A , CSD17581Q3A , CSD17581Q5A , CSD17585F5 , CSD18501Q5A , CSD18502KCS , CSD18502Q5B , CSD18503KCS , CSD18503Q5A , CSD18504KCS , CSD18504Q5A , CSD18509Q5B , CSD18510KCS , CSD18510KTT , CSD18510Q5B , CSD18511KCS , CSD18511KTT , CSD18511Q5A , CSD18512Q5B , CSD18513Q5A , CSD18514Q5A , CSD18531Q5A , CSD18532KCS , CSD18532NQ5B , CSD18532Q5B , CSD18533KCS , CSD18533Q5A , CSD18534KCS , CSD18534Q5A , CSD18535KCS , CSD18535KTT , CSD18536KCS , CSD18536KTT , CSD18537NKCS , CSD18537NQ5A , CSD18540Q5B , CSD18541F5 , CSD18542KCS , CSD18542KTT , CSD18543Q3A , CSD18563Q5A , CSD19501KCS , CSD19502Q5B , CSD19503KCS , CSD19505KCS , CSD19505KTT , CSD19506KCS , CSD19506KTT , CSD19531KCS , CSD19531Q5A , CSD19532KTT , CSD19532Q5B , CSD19533KCS , CSD19533Q5A , CSD19534KCS , CSD19534Q5A , CSD19535KCS , CSD19535KTT , CSD19536KCS , CSD19536KTT , CSD19537Q3 , CSD19538Q2 , CSD19538Q3A , CSD22202W15 , CSD22204W , CSD22205L , CSD22206W , CSD23202W10 , CSD23203W , CSD23280F3 , CSD23285F5 , CSD23381F4 , CSD23382F4 , CSD25202W15 , CSD25211W1015 , CSD25213W10 , CSD25304W1015 , CSD25310Q2 , CSD25402Q3A , CSD25404Q3 , CSD25480F3 , CSD25481F4 , CSD25483F4 , CSD25484F4 , CSD25485F5 , CSD25501F3 , CSD75207W15 , CSD75208W1015 , CSD83325L , CSD85301Q2 , CSD85302L , CSD85312Q3E , CSD86311W1723 , CSD87312Q3E , CSD87313DMS , CSD87501L , CSD87502Q2 , CSD87503Q3E , CSD88537ND , CSD88539ND

6 Estimating SOA for Different Pulse Widths

What if the pulse width is different from those shown in the SOA graph? Normally, the pulse widths of the SOA curves in TI MOSFET data sheets are in decile values (for example, 10 µs, 100 µs, 1 ms, 10 ms, 100 ms) but an application can require a pulse width which is in between these curves. A log-log plot of I_DS vs. t_PW values from the CSD17570Q5B data sheet SOA curves is shown in Figure 6-1.

Figure 6-1 CSD17570Q5B SOA Current vs. Pulse Width at V_DS = 12 V

As detailed in section 2.3.2 in the TI application report, Robust Hot Swap Design, the SOA current capability at different pulse widths can be estimated using the SOA currents at the pulse widths above and below the required pulse width as follows:

Equation 3.

I_{D S} (t_{P W}) = a \times {(t_{P W})}^{m}

Equation 4.

m = \frac{l n (\frac{I_{D S} (t_{P W 1})}{I_{D S} (t_{P W 2})})}{l n (\frac{t_{P W 1}}{t_{P W 2}})}

Equation 5.

a = \frac{I_{D S} (t_{P W 1})}{{(t_{P W 1})}^{m}}

From the original example, if the pulse width is increased to 20 ms, then the current capability is reduced and is estimated as follows:

Equation 6.

I_{D S} (10 m s) = 7.3 A

Equation 7.

I_{D S} (100 m s) = 4.1 A

Equation 8.

m = \frac{\ln (\frac{7.3 A}{4.1 A})}{l n (\frac{10 m s}{100 m s})} = - 0.25

Equation 9.

a = \frac{7.3 A}{{(10 m s)}^{- 0.25}} = 12.9

Equation 10.

I_{D S} (20 m s) = 12.9 \times {(20 m s)}^{- 0.25} = 6.1 A

For a 20 ms pulse at V_DS = 12 V, the capability is I_DS = 6.1 A at T_C = 25°C. At T_C = 100°C the rating is reduced to I_DS = 2.4 A.