MBR1100

http://onsemi.com

3

Figure 5. Typical Capacitance

20

40

0

150

50

40

30

20

15

30

50

100

60

100

10

70

80

90

70

60

90

80

NOTE 3 — MOUNTING DATA:

Data shown for thermal resistance junction−to−ambient

guideline values for preliminary engineering or in case the

tie point temperature cannot be measured.

Mounting

Method

Lead Length, L (in)

1/8

1/4

1/2

3/4

1

52

65

72

85

°C/W

2

67

80

87

100

°C/W

3

—

50

°C/W

Mounting Method 1

P.C. Board with

1−1/2

″ x 1−1/2″

copper surface.

Mounting Method 3

P.C. Board with

1−1/2

″ x 1−1/2″

copper surface.

BOARD GROUND

PLANE

Mounting Method 2

LL

LL

L = 3/8″

NOTE 4 — THERMAL CIRCUIT MODEL:

(For heat conduction through the leads)

)

Use of the above model permits junction to lead thermal

resistance for any mounting configuration to be found. For

a given total lead length, lowest values occur when one side

of the rectifier is brought as close as possible to the heat sink.

Terms in the model signify:

(Subscripts A and K refer to anode and cathode sides,

respectively.) Values for thermal resistance components are:

NOTE 5 — 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 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.