Measures For Heat Release In Designing The Board - Renesas R-IN32M3 Series User Manual

R-IN32M3 Series: Board design edition
25.2.1

Measures for Heat Release in Designing the Board

(1) Thermal Vias
Placing as many vias to the power supply and GND areas as possible below the center of the package increases the
number of paths for the flow of heat in the z direction. We recommend placing one via for each power supply and GND
ball.
(2) Power Supply and GND Planes
Secure as large an area as is possible for the power supply and GND planes of the board. This enables the broad diffusion
of heat through vias in the direction of the surface plane. Dividing paths for heat dissipation from plane to plane
decreases the effectiveness of heat dissipation. Therefore, place the GND pattern in such a way that the paths are divided
as little as is possible. We recommend L2 for the GND layer.
○: Recommended example
L1
L2 (GND)
L3
L4
AGND
GND p attern for securin g the maximu m
area for heat dissipa tion pa ths
R18UZ0021EJ0400
Dec. 28, 2018
△: Example of less effective heat dissipation
L1
L2 (GND)
L3
L4
GND
AGND
GND p attern where paths for heat
dissipation are blocked by AGND
25. Thermal Design <R>
Thermal vi as
GND
Paths for heat
dissipation
Page 59 of 64