MBR2045CT

http://onsemi.com

5

0.01

0.1

1.0

10

100

0.05

0.03

0.02

0.01

0.1

t, TIME (ms)

0.5

0.3

0.2

1.0

TIME

equivalent square power pulse.

r(t) = normalized value of transient thermal resistance at time, t, i.e.:

1000

Figure 9. Thermal Response

0.07

0.7

HIGH FREQUENCY OPERATION

Since current flow in a Schottky rectifier is the result of

majority carrier conduction, it is not subject to junction

diode forward and reverse recovery transients due to minor-

ity carrier injection and stored charge. Satisfactory circuit

analysis work may be performed by using a model consist-

ing of an ideal diode in parallel with a variable capacitance.

(See Figure 10.)

Rectification efficiency measurements show that opera-

tion will be satisfactory up to several megahertz. For exam-

ple, relative waveform rectification efficiency is approxi-

mately 70 percent at 2.0 MHz, e.g., the ratio of dc power to

RMS power in the load is 0.28 at this frequency, whereas

perfect rectification would yield 0.406 for sine wave inputs.

However, in contrast to ordinary junction diodes, the loss in

waveform efficiency is not indicative of power loss; it is

simply a result of reverse current flow through the diode ca-

pacitance, which lowers the dc output voltage.

2.0 ms

1.0 kHz

12 V

100

12 Vdc

2N2222

CURRENT

AMPLITUDE

ADJUST

0−10 AMPS

100

CARBON

2N6277

1.0 CARBON

1N5817

D.U.T.

2.0 kW

+150 V, 10 mAdc

4.0 mF

+

1000

500

300

0

050

700

Figure 10. Typical Capacitance

10

20

30

200

40

Figure 11. Test Circuit for dv/dt and Reverse Surge Current

f = 1 MHz

100

600

400

800

900