Datasheet

LPC4350_30_20_10 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 4.2 — 18 August 2014 87 of 155
NXP Semiconductors
LPC4350/30/20/10
32-bit ARM Cortex-M4/M0 microcontroller
9. Thermal characteristics
The average chip junction temperature, T
j
(C), can be calculated using the following
equation:
(1)
• T
amb
= ambient temperature (C),
• R
th(j-a)
= the package junction-to-ambient thermal resistance (C/W)
• P
D
= sum of internal and I/O power dissipation
The internal power dissipation is the product of I
DD
and V
DD
. 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.
T
j
T
amb
P
D
R
th j a–
+=
Table 7. Thermal characteristics
V
DD
= 2.2 V to 3.6 V; T
amb
=  40  C to +85  C unless otherwise specified;
Symbol Parameter Conditions Min Typ Max Unit
T
j(max)
maximum junction
temperature
--125 C
Table 8. Thermal resistance (LQFP packages)
Symbol Parameter Conditions Thermal resistance
in C/W ±15 %
LQFP144
R
th(j-a)
thermal resistance from
junction to ambient
JEDEC (4.5 in  4 in); still air 38
Single-layer (4.5 in  3 in);
still air
50
R
th(j-c)
thermal resistance from
junction to case
11
Table 9. Thermal resistance value (BGA packages)
Symbol Parameter Conditions Thermal resistance in C/W ±15 %
LBGA256 TFBGA180 TFBGA100
R
th(j-a)
thermal resistance from
junction to ambient
JEDEC (4.5 in  4 in); still air 29 38 46
8-layer (4.5 in  3 in); still air 24 30 37
R
th(j-c)
thermal resistance from
junction to case
14 11 11