Data Sheet

ADCA5191

APPLICATIONS INFORMATION

analog.com

Rev. 0 | 18 of 24

THERMAL CONSIDERATIONS

The ADCA5191 is packaged in a thermally efficient, 32-lead

8.5°C/W, where the case is defined by the exposed pad on the

bottom of the package. For the best thermal performance, it is

recommended to add as many thermal vias as possible under the

exposed pad of the LFCSP and to fill these vias with a paste that

has high thermal conductivity. It is also recommended that the array

of vias under the ADCA5191 interface to an external heat sink such

as a pedestal on the system chassis.

SOLDERING INFORMATION AND

RECOMMENDED PCB LAND PATTERN

Figure 38 shows the recommended land pattern for the ADCA5191.

To minimize thermal impedance, the exposed pad on the 5 mm ×

5 mm LFCSP is soldered to a ground plane. To improve thermal

dissipation, 45 thermal vias are arranged in an array under the

exposed pad. The array consists of alternating rows of six vias and

seven vias, maximizing the number of vias within the area. The

area under the pad is also tied to ground on the bottom layer of the

PCB. If multiple ground layers exist, tie these layers together by the

vias. The external layer of the PCB must be a minimum of 1 oz.

copper. The minimum average plated hole wall thickness of the vias

must not be less than 0.001 inches, and it is recommended that the

vias be filled with a conductive paste, such as Tatsuta AE3030, and

plated over.

For further information on optimizing the thermal performance while

using the ADCA5191, refer to the AN-1604 Application Note, Ther-

mal Management Calculations for RF Amplifiers in LFCSP and

Flange Packages.

Figure 38. Recommended PCB Layout (Dimensions Shown in Inches)