14

LTC1433/LTC1434

0.25

Ω. In most of the applications, the requirements for

these capacitors are fairly similar.

Figure 14 shows the complete circuit along with its effi-

ciency curve.

Latchup Prevention (Figure 15)

In applications where the input supply can momentarily

dip below the output voltage, it is recommended that a

diode will prevent the output capacitor from forward

biasing the parasitic diode of the internal monolithic power

MOSFET, preventing a large amount of current from

flowing into the substrate to create a potential latchup

condition.

Figure 14. Design Example Circuit and its Efficiency Curve

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

SSW

NC

BSW

NC

SGND

RUN/SS

LBO

LBI

POR

LTC1433

PGND

100

µF*

10V

0.1

µF

0.1

µF

100

µF*

10V

D1: MBRS130LT3

L1: SUMIDA CD54-220

*AVX TPSD107M010R0100

5V

400mA

D1

L1

22

µH

POWER-ON

RESET

6V

680pF

5.1k

10k

6800pF

50pF

LOAD CURRENT (A)

0.001

60

70

80

0.01

0.1

1

1433/34 F14

50

40

100

90

L = 22

µH

+

LTC1434

+

D1

D2

SW

L

1433/34 F15

Figure 15