LTC3611 Просмотр технического описания (PDF) - Linear Technology

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LTC3611

10A, 32V Monolithic Synchronous Step-Down DC/DC Converter

Linear Technology 

LTC3611

APPLICATIONS INFORMATION

PGND

INTVCC

CVCC

4.7μF

6.3V

SW

CF

0.1μF

50V

64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49

VIN

SGND

VOUT

2.5V AT

10A

C5

COUT1

L1

1μH

22μF

100μF

6.3V

×2

(OPTIONAL)

GND

VIN

5V TO 32V

VIN

GND

CIN

4.7μF

C6 +

100μF

50V

50V

×2

(OPTIONAL)

1 PGND

2 PGND

3 PGND

4 SW

5 SW

6 SW

7 SW

8

SW

9 SW

10 SW

11 SW

12 PVIN

13 PVIN

14

PVIN

15

PVIN

16 PVIN

LTC3611

SGND 48

SGND 47

SGND 46

SGND 45

44

EXTVCC

43

VFB

SGND 42

ION 41

SGND 40

FCB 39

ITH 38

VRNG 37

PGOOD 36

35

VON

34

SGND

33

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

CIN = MURATA GRM32ER71H475K

COUT = MURATA GRM43SR60J107M

L1 = COOPER HCP0703-IRO

C5: MURATA GRM31CR60J226KE19

KEEP POWER AND SIGNAL GROUNDS SEPARATE.

CONNECT TO ONE POINT.

SW

2Ω

INTVCC

DB

CMDSH-3

CB1

0.22μF

SW

CSS

0.1μF

EXTVCC

C4

0.01μF

R1

9.5k

C1

1%

(OPTIONAL)

RON

182k

1%

CON

0.01μF

(OPTIONAL)

R5

12.5k

R3 39.2k

11k

RPG1

100k

INTVCC

RSS1

510k

VIN

(OPTIONAL)

0.01μF

R2

30.1k

1%

(OPTIONAL)

C2

VOUT

VIN

CC1

680pF

CC2

100pF

RVON

0Ω

VOUT

SGND

3611 F06

Figure 6. Design Example: 5V to 32V Input to 2.5V/10A at 550kHz

• Use a compact plane for the switch node (SW) to improve

cooling of the MOSFETs and to keep EMI down.

• Use planes for VIN and VOUT to maintain good voltage

filtering and to keep power losses low.

• Flood all unused areas on all layers with copper. Flood-

ing with copper reduces the temperature rise of power

components. Connect these copper areas to any DC

net (VIN, VOUT, GND or to any other DC rail in your

system).

When laying out a printed circuit board without a ground

plane, use the following checklist to ensure proper opera-

tion of the controller. These items are also illustrated in

Figure 7.

• Segregate the signal and power grounds. All small

signal components should return to the SGND pin at

one point, which is then tied to the PGND pin.

• Connect the input capacitor(s) CIN close to the IC. This

capacitor carries the MOSFET AC current.

• Keep the high dV/dT SW, BOOST and TG nodes away

from sensitive small-signal nodes.

• Connect the INTVCC decoupling capacitor CVCC closely

to the INTVCC and PGND pins.

• Connect the top driver boost capacitor CB closely to

the BOOST and SW pins.

• Connect the VIN pin decoupling capacitor CF closely to

the VIN and PGND pins.

3611fb

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