Datasheet

LPC178X_7X All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 5 — 9 September 2014 70 of 122
NXP Semiconductors
LPC178x/7x
32-bit ARM Cortex-M3 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
Table 10. Thermal characteristics
V
DD
= 3.0 V to 3.6 V; T
amb
=  40  C to +85  C unless otherwise specified;
Symbol Parameter Min Typ Max Unit
T
j(max)
maximum junction
temperature
- - 125 C
Table 11. Thermal resistance (LQFP packages)
T
amb
=  40  C to +85  C unless otherwise specified.
Symbol Conditions Thermal resistance in C/W ±15 %
LQFP208 LQFP144
ja JEDEC (4.5 in  4 in)
0 m/s 27.4 31.5
1 m/s 25.7 28.1
2.5 m/s 24.4 26.2
Single-layer (4.5 in  3 in)
0 m/s 35.4 43.2
1 m/s 31.2 35.7
2.5 m/s 29.2 32.8
jc - 8.8 7.8
jb - 15.4 13.8
Table 12. Thermal resistance value (TFBGA packages)
T
amb
=  40  C to +85  C unless otherwise specified.
Symbol Conditions Thermal resistance in C/W ±15 %
TFBGA208 TFBGA180
ja JEDEC (4.5 in  4 in)
0 m/s 41 45.5
1 m/s 35 38.3
2.5 m/s 31 33.8
8-layer (4.5 in  3 in)
0 m/s 34.9 38
1 m/s 30.9 33.5
2.5 m/s 28 29.8
jc - 8.3 8.9
jb - 13.6 12
T
j
T
amb
P
D
R
th j a–
+=