LT3474/LT3474-1
APPLICATIONS INFORMATION
Diode Selection
Table 4 lists several Schottky diodes and their
manufacturers.
The catch diode (D1 from Figure 1) conducts current only
during switch off time. Average forward current in normal
operation can be calculated from:
Table 4. Schottky Diodes
V
I
V at 0.5A
V at 1A
R
AVE
F
F
PART NUMBER
On Semiconductor
MBR0520L
MBR0540
(V)
(A)
(mV)
(mV)
IOUT V – V
(
)
IN
OUT
ID AVG
=
(
)
V
20
40
20
40
0.5
0.5
1
385
510
IN
620
530
550
The only reason to consider a diode with a larger current
rating than necessary for nominal operation is for the
worst-case condition of shorted output. The diode cur-
rent will then increase to one half the typical peak switch
current.
MBRM120E
MBRM140
Diodes Inc.
B0530W
1
30
20
30
40
0.5
1
430
B120
500
500
530
Peakreversevoltageisequaltotheregulatorinputvoltage.
Use a diode with a reverse voltage rating greater than the
input voltage.
B130
1
B140 HB
1
International Rectifier
10BQ030
30
1
420
If using the PWM mode of the LT3474, select a diode with
low reverse leakage.
3474fd
14
Linear [ Linear ]
