DV
out
+
I
out
C
out
ǒ
1
fS(Iout)
–
I
P
L
Vout ) Vd–Vin
Ǔ
) I
P
ESR
14
TPS61040
,
TPS61041
SLVS413I –OCTOBER 2002–REVISED DECEMBER 2016
www.ti.com
Product Folder Links: TPS61040 TPS61041
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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 μF/X5R/0805 6.3 V Tayo Yuden JMK212BY475MG C
IN
/C
OUT
10 μF/X5R/0805 6.3 V Tayo Yuden JMK212BJ106MG C
IN
/C
OUT
1 μF/X7R/1206 25 V Tayo Yuden TMK316BJ105KL C
OUT
1 μF/X5R/1206 35 V Tayo Yuden GMK316BJ105KL C
OUT
4.7 μF/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-μF 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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