Datasheet

Data Sheet ADP1752/ADP1753
Rev. F | Page 17 of 20
In cases where the board temperature is known, the thermal
characterization parameter, Ψ
JB
, can be used to estimate the
junction temperature rise. Maximum junction temperature (T
J
)
is calculated from the board temperature (T
B
) and power
dissipation (P
D
) using the following formula:
T
J
= T
B
+ (P
D
× Ψ
JB
) (7)
Figure 42 through Figure 45 show junction temperature calcula-
tions for different board temperatures, load currents, V
IN
to
V
OUT
differentials, and areas of PCB copper.
140
120
100
80
60
40
20
0
0.25
0.75
1.25 1.75 2.25 2.75
JUNCTION TEMPERATURE, T
J
(°C)
V
IN
– V
OUT
(V)
MAX JUNCTION
TEMPERATURE
LOAD = 800mA
LOAD = 100mA
LOAD = 50mA
LOAD = 10mA
LOAD = 400mA
LOAD = 200mA
07718-141
Figure 42. 500 mm
2
of PCB Copper, T
B
= 25°C, LFCSP
140
120
100
80
60
40
20
0
0.25 0.75 1.25 1.75 2.25
2.75
JUNCTION TEMPERATURE, T
J
(°C)
V
IN
– V
OUT
(V)
MAX JUNCTION
TEMPERATURE
LOAD = 800mA
LOAD = 400mA
LOAD = 200mA
LOAD = 100mA
LOAD = 50mA
LOAD = 10mA
07718-142
Figure 43. 500 mm
2
of PCB Copper, T
B
= 50°C, LFCSP
140
120
100
80
60
40
20
0
0.25 0.75 1.25
1.75
2.25 2.75
JUNCTION TEMPERATURE, T
J
(°C)
V
IN
– V
OUT
(V)
MAX JUNCTION
TEMPERATURE
LOAD = 800mA
LOAD = 400mA
LOAD = 200mA
LOAD = 100mA
LOAD = 50mA
LOAD = 10mA
07718-143
Figure 44. 1000 mm
2
of PCB Copper, T
B
= 25°C, LFCSP
140
120
100
80
60
40
20
0
0.25 0.75
1.25 1.75 2.25 2.75
JUNCTION TEMPERATURE, T
J
(°C)
V
IN
– V
OUT
(V)
MAX JUNCTION
TEMPERATURE
LOAD = 800mA
LOAD = 400mA
LOAD = 200mA
LOAD = 100mA
LOAD = 50mA
LOAD = 10mA
07718-144
Figure 45. 1000 mm
2
of PCB Copper, T
B
= 50°C, LFCSP