LPC540xx
NXP Semiconductors
32-bit ARM Cortex-M4 microcontroller
9. Thermal characteristics
The average chip junction temperature, Tj (C), can be calculated using the following
equation:
Tj = Tamb + PD Rthj – a
(1)
• Tamb = ambient temperature (C),
• Rth(j-a) = the package junction-to-ambient thermal resistance (C/W)
• PD = sum of internal and I/O power dissipation
The internal power dissipation is the product of IDD and VDD. The I/O power dissipation of
the I/O pins is often small and many times can be negligible. However it can be significant
in some applications.
Table 11. Thermal resistance
Symbol Parameter
LQFP208 Package
Conditions
Max/Min
Unit
Rth(j-a)
thermal resistance from
JEDEC (4.5 in 4 in); still air
33 15 % C/W
junction to ambient
Single-layer (4.5 in 3 in); still air 41 15 % C/W
16 15 % C/W
Rth(j-c)
thermal resistance from
junction to case
LQFP100 Package
Rth(j-a) thermal resistance from
JEDEC (4.5 in 4 in); still air
48 15 % C/W
junction to ambient
Single-layer (4.5 in 3 in); still air 65 15 % C/W
19 15 % C/W
Rth(j-c)
thermal resistance from
junction to case
TFBGA180 Package
Rth(j-a) thermal resistance from
JEDEC (4.5 in 4 in); still air
8-layer (4.5 in 3 in); still air
41 15 % C/W
33 15 % C/W
14 15 % C/W
junction to ambient
Rth(j-c)
thermal resistance from
junction to case
TFBGA100 Package
Rth(j-a) thermal resistance from
JEDEC (4.5 in 4 in); still air
8-layer (4.5 in 3 in); still air
69 15 % C/W
60 15 % C/W
10 15 % C/W
junction to ambient
Rth(j-c)
thermal resistance from
junction to case
LPC540xx
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© NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet
Rev. 1.8 — 22 June 2018
87 of 168
NXP [ NXP ]
