ADP1711 Analog Devices, ADP1711 Datasheet - Page 11

• Manufacturer Part Number: ADP1711
• Description: 150 mA, Low Dropout, CMOS Linear Regulator
• Manufacturer: Analog Devices

Current and thermal limit protections are intended to protect
the device against accidental overload conditions. For reliable
operation, device power dissipation must be externally limited
so junction temperatures do not exceed 125°C.
THERMAL CONSIDERATIONS
To guarantee reliable operation, the junction temperature of the
ADP1710/ADP1711 must not exceed 125°C. To ensure the
junction temperature stays below this maximum value, the user
needs to be aware of the parameters that contribute to junction
temperature changes. These parameters include ambient
temperature, power dissipation in the power device, and thermal
resistances between the junction and ambient air (θ
number is dependent on the package assembly compounds used
and the amount of copper to which the GND pins of the package
are soldered on the PCB. Table 5 shows typical θ
5­lead TSOT package for various PCB copper sizes.
Table 5.
Copper Size (mm
0
50
100
300
500
1
The junction temperature of the ADP1710/ADP1711 can be
calculated from the following equation:
where:
T
P
where:
I
I
V
respectively.
Power dissipation due to ground current is quite small and can
be ignored. Therefore, the junction temperature equation
simplifies to the following:
As shown in Equation 4, for a given ambient temperature, input
to output voltage differential, and continuous load current,
there exists a minimum copper size requirement for the PCB to
ensure the junction temperature does not rise above 125°C. The
following figures show junction temperature calculations for
different ambient temperatures, load currents, V
differentials, and areas of PCB copper.
LOAD
GND
1
Device soldered to minimum size pin traces.
A
D
IN
is the ambient temperature.
is the power dissipation in the die, given by
and V
is the ground current.
T
P
T
is the load current.
D
J
J
= T
= T
= [(V
OUT
A
A
+ (P
+ {[(V
IN
are the input voltage and output voltage,
– V
D
2
× θ
)
IN
OUT
– V
JA
) × I
)
OUT
LOAD
) × I
] + (V
LOAD
] × θ
IN
× I
JA
GND
}
θ
170
152
146
134
131
JA
)
(°C/W)
JA
IN
values of the
JA
to V
). The θ
OUT
JA
Rev. 0 | Page 11 of 16
(2)
(3)
(4)
140
120
100
140
120
100
140
120
100
80
60
40
20
80
60
40
20
80
60
40
20
0
0
0
0.5
0.5
0.5
MAX T
MAX T
MAX T
Figure 23. 500 mm
Figure 24. 100 mm
1.0
1.0
1.0
1mA
10mA
1mA
10mA
1mA
10mA
Figure 25. 0 mm
J
J
J
(DO NOT OPERATE ABOVE THIS POINT)
(DO NOT OPERATE ABOVE THIS POINT)
(DO NOT OPERATE ABOVE THIS POINT)
1.5
1.5
1.5
30mA
80mA
30mA
80mA
30mA
80mA
2.0
2.0
2.0
2
V
V
V
2
2
of PCB Copper, T
IN
IN
IN
2.5
2.5
2.5
of PCB Copper, T
of PCB Copper, T
– V
– V
– V
OUT
OUT
OUT
ADP1710/ADP1711
100mA
125mA
100mA
125mA
100mA
125mA
3.0
3.0
3.0
(V)
(V)
(V)
3.5
3.5
3.5
(LOAD CURRENT)
(LOAD CURRENT)
(LOAD CURRENT)
A
A
A
= 25°C
150mA
150mA
150mA
= 25°C
= 25°C
4.0
4.0
4.0
4.5
4.5
4.5
5.0
5.0
5.0