D
Vout
+
Iout
Cout
ǒ
1
fS(Iout)
–
I
P
L
Vout
)
Vd–Vin
Ǔ
)
I
P
ESR
14
TPS61040, TPS61041
SLVS413I – OCTOBER 2002 – REVISED DECEMBER 2016
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(1)
See
Third-Party Products
disclaimer.
where
•
I
P
= Peak current as described in
Peak Current Control
•
L = Selected inductor value
•
I
out
= Nominal load current
•
fS (I
out
) = Switching frequency at the nominal load current as calculated previously
•
Vd = Rectifier diode forward voltage (typically 0.3 V)
•
C
out
= Selected output capacitor
•
ESR = Output capacitor ESR value
(7)
See
Table 4
and the
Typical Application
for choosing the output capacitor.
Table 4. Recommended Input and Output Capacitors
DEVICE
CAPACITOR
VOLTAGE RATING
COMPONENT SUPPLIER
(1)
COMMENTS
TPS6104x
4.7
μ
F/X5R/0805
6.3 V
Tayo Yuden JMK212BY475MG
C
IN
/C
OUT
10
μ
F/X5R/0805
6.3 V
Tayo Yuden JMK212BJ106MG
C
IN
/C
OUT
1
μ
F/X7R/1206
25 V
Tayo Yuden TMK316BJ105KL
C
OUT
1
μ
F/X5R/1206
35 V
Tayo Yuden GMK316BJ105KL
C
OUT
4.7
μ
F/X5R/1210
25 V
Tayo Yuden TMK325BJ475MG
C
OUT
(1)
See
Third-Party Products
disclaimer.
8.2.2.5 Input Capacitor Selection
For good input voltage filtering, low ESR ceramic capacitors are recommended. A 4.7-
μ
F ceramic input capacitor
is sufficient for most of the applications. For better input voltage filtering this value can be increased. See
Table 4
and typical applications for input capacitor recommendations.
8.2.2.6 Diode Selection
To achieve high efficiency a Schottky diode should be used. The current rating of the diode should meet the
peak current rating of the converter as it is calculated in
Peak Current Control
. Use the maximum value for I
LIM
for this calculation. See
Table 5
and the typical applications for the selection of the Schottky diode.
Table 5. Recommended Schottky Diode for Typical LCD Bias Supply (see
Figure 23
)
DEVICE
REVERSE VOLTAGE
COMPONENT SUPPLIER
(1)
COMMENTS
TPS6104x
30 V
ON Semiconductor MBR0530
20 V
ON Semiconductor MBR0520
20 V
ON Semiconductor MBRM120L
High efficiency
30 V
Toshiba CRS02
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