Zxbm1021, Thermal performance, Rthja = 45°c/w – Diodes ZXBM1021 User Manual
Page 21: Rthja = 108°c/w
ZXBM1021
Document number: DS36322 Rev. 2 - 2
21 of 25
April 2014
© Diodes Incorporated
ZXBM1021
Thermal Performance
(1) Package type: QFN4040-20
Note:
11. The power dissipation de-rating curve for ZXBM1021 in U-QFN4040-
20 package is based on 2”x2” F substrate, 2oz copper, 1. mm thick
PCB with minimum recommended pad layout on the top layer with thermal vias to all copper bottom layer and the ‘junction to ambient’
thermal resistance (Rthja) of 45°C/W.
(2) Package type: QSOP-20
Note:
12. The power dissipation de-rating curve for ZXBM1021 in QSOP-
20 package is based on 2”x2” F substrate, 2oz copper, 1. mm thick PCB
all copper top layer (pad layout included) without any vias or the bottom layer copper and the ‘junction to ambient’ thermal resistance (Rthja)
of 108°C/W.
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-50
-25
0
25
50
75
100
125
150
Maximum
Pow
er
(W)
Ambient Operating Temperature (
o
C)
U-QFN4040-20 Derating Curve
Rthja = 45°C/W
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-50
-25
0
25
50
75
100
125
150
Maximum
Pow
er
(W)
Ambient Operating Temperature (
o
C)
QSOP-20 Derating Curve
Rthja = 108°C/W