Datasheet

VIN = 12V
LM21305
SW
COMP
FREQ
EN
FB
PGOOD
PGND
2V5
AVIN
AGND
5V0
CBOOT
PVIN
C
IN3
L
R
F
C
5V0
C
2V5
C
F
C
c
R
c
C
FRQ
R
FRQ
R
FB1
R
FB2
C
BOOT
C
OUT1
VOUT
R
EN
R
PG
C
OUT2
C
IN2
C
IN1
LM21305
www.ti.com SNVS639F –DECEMBER 2009–REVISED MARCH 2013
Application Circuit Example
Figure 32. LM21305 Application Circuit Example
Table 1. Bill Of Materials (500kHz Switching Frequency)
V
OUT
1.2V 1.8V 2.5V 3.3V 5V Package
C
IN1
TANT 47 µF 25V TANT 47 µF 25V TANT 47 µF 25V TANT 47 µF 25V TANT 47 µF 25V CASE D
C
IN2
10 µF 25V 10 µF 25V 10 µF 25V 10 µF 25V 10 µF 25V 1210
C
IN3
1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 1206
C
F
1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 1.0 µF 25V 0603
C
2V5
, C
BOOT
0.1 µF 16V 0.1 µF 16V 0.1 µF 16V 0.1 µF 16V 0.1 µF 16V 0603
C
5V0
1.0 µF 16V 1.0 µF 16V 1.0 µF 16V 1.0 µF 16V 1.0 µF 16V 0603
C
FRQ
100 pF 50V 100 pF 50V 100 pF 50V 100 pF 50V 100 pF 50V 0603
C
c
3300 pF 25V 3300 pF 25V 4700 pF 25V 4700 pF 25V 4700 pF 25V 0603
C
OUT1
,
47 µF 6.3V X5R 47 µF 6.3V X5R 47 µF 6.3V X5R 47 µF 10V X5R 47 µF 10V X5R 1210
C
OUT2
L 1.5 µH 10A 2.2 µH 10A 2.2 µH 10A 3.3 µH 10A 3.3 µH 10A SMD
R
F
1Ω 1% 1Ω 1% 1Ω 1% 1Ω 1% 1Ω 1% 0603
R
FRQ
, R
PG
100 kΩ 1% 100 kΩ 1% 100 kΩ 1% 100 kΩ 1% 100 kΩ 1% 0603
R
FB2
, R
EN
10 kΩ 1% 10 kΩ 1% 10 kΩ 1% 10 kΩ 1% 10 kΩ 1% 0603
R
c
3.32 kΩ 1% 4.22 kΩ 1% 5.10 kΩ 1% 7.15 kΩ 1% 8.2 kΩ 1% 0603
R
FB1
10 kΩ 1% 20 kΩ 1% 31.6 kΩ 1% 45.3 kΩ 1% 73.2 kΩ 1% 0603
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