falls to a low voltage. During this time, the soft-start voltage

is forced to track the output so that once the short is re-

moved, the LM2852 can restart gracefully from whatever

voltage the output reached during the short circuit event. The

range of soft-start capacitors is therefore restricted to values

1nF to 50nF.

COMPENSATION

The LM2852 provides a highly integrated solution to power

supply design. The compensation of the LM2852, which is

type-three, is included on-chip. The benefit to integrated

compensation is straightforward, simple power supply de-

sign. Since the output filter capacitor and inductor values

impact the compensation of the control loop, the range of L,

C and C

OUTPUT FILTER VALUES

Table 1 details the recommended inductor and capacitor

ranges for the LM2852 that are suggested for various typical

output voltages. Values slightly different than those recom-

mended may be used, however the phase margin of the

power supply may be degraded.

TABLE 1. Output Filter Values

Frequency

Option

V

PVIN (V)

L (µH)

C (µF)

C

Ω)

Min

Max

Min

Max

Min

Max

LM2852Y

(500kHz)

0.8

3.3

10

15

100

220

70

200

0.8

5.0

10

15

100

120

70

200

1.0

3.3

10

15

100

180

70

200

1.0

5.0

10

15

100

180

70

200

1.2

3.3

10

15

100

180

70

200

1.2

5.0

15

22

100

120

70

200

1.5

3.3

10

15

100

120

70

200

1.5

5.0

22

22

100

120

70

200

1.8

3.3

10

15

100

120

100

200

1.8

5.0

22

33

100

120

100

200

2.5

3.3

6.8

10

68

120

95

275

2.5

5.0

15

22

68

120

95

275

3.3

5.0

15

22

68

100

100

275

LM2852X

(1500kHz)

0.8

3.3

110

The 1500kHz version is

designed for ceramic output

capacitors which typically

Ω.)

0.8

5.0

1.0

3.3

1.0

5.0

1.2

3.3

1.2

5.0

1.5

3.3

1.5

5.0

1.8

3.3

1.8

5.0

2.5

3.3

2.5

5.0

3.3

5.0

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