
SPC563M64
Electrical characteristics
Doc ID 14642 Rev 6
3.3.1
General notes for specifications at maximum junction temperature
An estimation of the chip junction temperature, TJ, can be obtained from the equation:
Equation 1
TJ = TA + (RθJA * PD)
where:
TA = ambient temperature for the package (
oC)
RθJA = junction-to-ambient thermal resistance (
oC/W)
PD = power dissipation in the package (W)
The thermal resistance values used are based on the JEDEC JESD51 series of standards
to provide consistent values for estimations and comparisons. The difference between the
values determined for the single-layer (1s) board compared to a four-layer board that has
two signal layers, a power and a ground plane (2s2p), demonstrate that the effective thermal
resistance is not a constant. The thermal resistance depends on the:
●
Construction of the application board (number of planes)
●
Effective size of the board which cools the component
●
Quality of the thermal and electrical connections to the planes
●
Power dissipated by adjacent components
Connect all the ground and power balls to the respective planes with one via per ball. Using
fewer vias to connect the package to the planes reduces the thermal performance. Thinner
Table 13.
Thermal characteristics for 208-pin LBGA(1)
1.
Thermal characteristics are targets based on simulation that are subject to change per device characterization.
Symbol
C
Parameter
Conditions
Value
Unit
RθJA
CC
D
Junction-to-ambient, natural
convection(2),(3)
2.
Junction temperature is a function of die size, on-chip power dissipation, package thermal resistance, mounting site (board)
temperature, ambient temperature, air flow, power dissipation of other components on the board, and board thermal
resistance.
3.
Per SEMI G38-87 and JEDEC JESD51-2 with the single-layer board horizontal.
One layer board - 1s
39
°C/W
RθJMA
CC
D Junction-to-ambient natural convecti
on(2),(4)
4.
Per JEDEC JESD51-6 with the board horizontal.
Four layer board - 2s2p
24
°C/W
RθJA
CC
D Junction-to-ambient (@200 ft/min)
(2),(4)Single layer board
31
°C/W
RθJMA
CC
D Junction-to-ambient (@200 ft/min)
(2),(4)Four layer board 2s2p
20
°C/W
RθJB
CC
D Junction-to-board(5)
5.
Thermal resistance between the die and the printed circuit board per JEDEC JESD51-8. Board temperature is measured
on the top surface of the board near the package.
Four layer board - 2s2p
13
°C/W
RθJC
CC
D Junction-to-case(6)
6.
Indicates the average thermal resistance between the die and the case top surface as measured by the cold plate method
(MIL SPEC-883 Method 1012.1) with the cold plate temperature used for the case temperature.
6°C/W
ΨJT
CC
D
Junction-to-package top natural
convection(7)
7.
Thermal characterization parameter indicating the temperature difference between package top and the junction
temperature per JEDEC JESD51-2. When Greek letters are not available, the thermal characterization parameter is written
as Psi-JT.
2°C/W