MBRF1045 Datasheet, PDF (3/6 Pages) Motorola, Inc – SWITCHMODE™ Schottky Power Rectifirers

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 minority
carrier injection and stored charge. Satisfactory circuit
analysis work may be performed by using a model consisting
of an ideal diode in parallel with a variable capacitance. (See
Figure 5.)
Rectification efficiency measurements show that operation
will be satisfactory up to several megahertz. For example,
relative waveform rectification efficiency is approximately 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 capacitance, which
lowers the dc output voltage.
MBRF1045
1500
1000
700
MAXIMUM
500
TYPICAL
300
200
150
0.05 0.1 0.2 0.5 1 2
5 10 20 50
VR, REVERSE VOLTAGE (VOLTS)
Figure 5. Capacitance
VCC
12 Vdc
+150 V, 10 mAdc
2.0 kΩ
12 V
2.0 µs
1.0 kHz
100
2N2222
D.U.T.
+ _{4.0 µF}
CURRENT
AMPLITUDE
ADJUST
0 – 10 AMPS
100
CARBON
2N6277
1.0 CARBON
1N5817
Figure 6. Test Circuit for dv/dt and Reverse Surge Current
Rectifier Device Data
3