LT8337/LT8337-1

20

Rev. 0

For more information www.analog.com

L1: WURTH ELEKTRONIK 74438357015

L2: WURTH ELEKTRONIK 74479290125

FB1: WURTH ELEKTRONIK 742792040

* THE EMI PERFORMANCE IS SHOWN IN THE TYPICAL PERFORMANCE CHARACTERISTICS SECTION.

12V

1.5A

0.1µF

50V

X7R

0.1µF

50V

X7R

OUTPUT EMI FILTER

FB1

22µF

25V

X7R

×4

1µF

50V

X7R

×2

SYNC/MODE

PG

SW

BST

EN/UVLO

FB

GND

LT8337

83371 TA02a

RT

L1

1.5µH

0.1µF

1M

90.9k

1µF

47.5k

2MHz

4.7pF

49.9k

1M

332k

4.5V TO 10V

22µF

25V

X7R

47µF

35V

10µF

25V

X7R

INPUT EMI FILTER

L2

0.25µH

+

The exposed pad on the bottom of the package should

be soldered to the ground plane to reduce the package

thermal resistance. To keep the thermal resistance low,

extend the ground plane as much as possible, and add

many thermal vias to additional power ground planes

within the circuit board.

Thermal Considerations

Care should be taken in the layout of the PCB to ensure

good heat sinking of the LT8337/LT8337-1. The power

ground plane should consist of large copper layers with

thermal vias; these layers spread heat dissipated by the

IC. Placing additional vias can reduce thermal resistance

further. The maximum load current should be derated

as the junction temperature approaches its maximum

temperature rating. Power dissipation within the IC can

APPLICATIONS INFORMATION

be estimated by calculating the total power loss from an

efficiency measurement and subtracting the inductor loss.

The junction temperature can be calculated by multiply-

ing the total IC power dissipation by the thermal resis-

tance from junction to ambient and adding the ambient

temperature. The IC includes internal overtemperature

protection that is intended to protect the device during

momentary overload conditions. The overtemperature

protection shuts down the IC when the junction tem-

perature exceeds 170°C (typ). The internal soft-start is

triggered when the junction temperature drops below

165°C (typ). The maximum rated junction temperature

is exceeded when this protection is active. Continuous

operation above the specified absolute maximum operat-

ing junction temperature (see Absolute Maximum Ratings

section) may impair device reliability or permanently dam-

age the device.

TYPICAL APPLICATIONS