
Electrical Characteristics
MCIMX31/MCIMX31L Technical Data, Rev. 4.1
Freescale Semiconductor
11
Table 6 provides the thermal resistance data for the 14
× 14 mm, 0.5 mm pitch package.
NOTES
1. 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.
2. Per JEDEC JESD51-2 with the single layer board horizontal. Board meets JESD51-9
specification.
3. Per JEDEC JESD51-6 with the board horizontal.
4. 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.
5. Thermal resistance between the die and the case top surface as measured by the cold plate method
(MIL SPEC-883 Method 1012.1).
6. 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.
Table 7 provides the thermal resistance data for the 19
× 19 mm, 0.8 mm pitch package.
Table 6. Thermal Resistance Data—14
× 14 mm Package
Rating
Board
Symbol
Value
Unit
Notes
Junction to Ambient (natural convection)
Single layer board (1s)
RθJA
56
°C/W
1, 2, 3
Junction to Ambient (natural convection)
Four layer board (2s2p)
RθJA
30
°C/W
1, 3
Junction to Ambient (@200 ft/min)
Single layer board (1s)
RθJMA
46
°C/W
1, 2, 3
Junction to Ambient (@200 ft/min)
Four layer board (2s2p)
RθJMA
26
°C/W
1, 3
Junction to Board
—
RθJB
17
°C/W
1, 4
Junction to Case
—
RθJC
10
°C/W
1, 5
Junction to Package Top (natural convection)
—
Ψ
JT
2°C/W
1, 6
Table 7. Thermal Resistance Data—19
× 19 mm Package
Rating
Board
Symbol
Value
Unit
Notes
Junction to Ambient (natural convection)
Single layer board (1s)
RθJA
46
°C/W
1, 2, 3
Junction to Ambient (natural convection)
Four layer board (2s2p)
RθJA
29
°C/W
1, 2, 3
Junction to Ambient (@200 ft/min)
Single layer board (1s)
RθJMA
38
°C/W
1, 2, 3
Junction to Ambient (@200 ft/min)
Four layer board (2s2p)
RθJMA
25
°C/W
1, 2, 3
Junction to Board
—
RθJB
19
°C/W
1, 3
Junction to Case (Top)
—
RθJCtop
10
°C/W
1, 4
Junction to Package Top (natural convection)
—
Ψ
JT
2°C/W
1, 5
Because
of
an
order
from
the
United
States
International
Trade
Commission,
BGA-packaged
product
lines
and
part
numbers
indicated
here
currently
are
not
available
from
Freescale
for
import
or
sale
in
the
United
States
prior
to
September
2010:
i.MX31
Product
Family