9A Highly Integrated SupIRBuckTM
Single‐Input V-o1lt3a-ge, Synchronous Buck Regulator
PD‐97661
IR3899
THERMAL DERATING CURVES
Measurement done on Evaluation board of IRDC3899.PCB is 4 layer board with 2 oz Copper, FR4 material, size 2.23"x2"
PVin = 12V, Vout=1.2V, Vcc = Internal LDO (6.4V), Fs = 600kHz
10.5
10
9.5
9
8.5
Lout-0.51uH,0.29mΩ(Vitec 59PR9876N)
8
25 30 35 40 45 50 55 60 65 70 75 80 85
Tamb(ºC)
0 LFM 200 LFM
PVin = 12V, Vout=3.3V, Vcc = Internal LDO (6.4V), Fs = 600kHz
10.5
10
9.5
9
8.5
8
7.5
7
6.5
Lout-1.2uH,2.9mΩ(Delta MPL105-1R2)
6
25 30 35 40 45 50 55 60 65 70 75 80 85
Tamb(ºC)
0 LFM 200 LFM
Note: International Rectifier Corporation specifies current rating of SupIRBuck devices conservatively. The continuous current
load capability might be higher than the rating of the device if input voltage is 12V typical and switching frequency is below 750
kHz.The above derating curves are generated at 12V input ,600kHz with 0-200LFM air flow and ambient temperature up to
85°C.Detailed thermal derating information can be found in the Application Note AN-1174 “Thermal Derating of DC-DC
Convertors using IR3899/98/97”. However, the maximum current is limited by the internal current limit and designers need to
consider enough guard bands between load current and minimum current limit to guarantee that the device does not trip at
steady state condition.
13 JANUARY 18, 2013 |DATA SHEET | 3.6