ISL80101 Intersil Corporation, ISL80101 Datasheet - Page 8

• Manufacturer Part Number: ISL80101
• Description: High Performance 1A LDO
• Manufacturer: Intersil Corporation

www.DataSheet4U.com
Output Voltage Selection
An external resistor divider is used to scale the output
voltage relative to the internal reference voltage. This
voltage is then fed back to the error amplifier. The output
voltage can be programmed to any level between 0.8V
and 5V. An external resistor divider, R
set the output voltage as shown in Equation 3. The
recommended value for R
chosen according to Equation 4:
Power Dissipation
The junction temperature must not exceed the range
specified in the Recommended Operating Conditions. The
power dissipation can be calculated by using Equation 5:
The maximum allowed junction temperature, T
and the maximum expected ambient temperature,
T
temperature rise (ΔT
V
R
P
ΔT
A(MAX)
OUT
1
D
J
=
=
=
R
(
=
V
T
2
IN
J MAX
0.5V
×
(
will determine the maximum allowed junction
⎛
⎝
–
V
--------------- - 1
0.5V
V
OUT
×
OUT
)
⎛
⎜
⎝
–
R
------ -
R
T
–
1
2
)
A MAX
×
+
(
⎞
⎠
I
1
OUT
⎞
⎟
⎠
J
)
) as shown in Equation 6:
+
V
2
IN
8
is 500Ω to 1kΩ. R
×
I
GND
1
and R
1
2
is then
, is used to
J(MAX)
(EQ. 3)
(EQ. 4)
(EQ. 5)
(EQ. 6)
ISL80101
To calculate the maximum ambient operating
temperature, use the junction-to-ambient thermal
resistance (θ
Substitute P
operating temperature can be found by solving for T
using Equation 8:
Heatsinking The DFN Package
The DFN package uses the copper area on the PCB as a
heat-sink. The EPAD of this package must be soldered to
the copper plane (GND plane) for heat sinking. Figure 6
shows a curve for the θ
different copper area sizes.
P
T
FIGURE 6. 3mmx3mm-10 PIN DFN ON 4-LAYER PCB
A
D MAX
(
=
46
44
42
40
38
36
34
T
JMAX
2
)
=
(
EPAD-MOUNT COPPER LAND AREA ON PCB, mm
4
T
–
D
WITH THERMAL VIAS θ
COPPER LAND AREA ON PCB
JA
J MAX
P
(
for P
D MAX
) for the DFN package with Equation 5:
6
(
)
D(MAX)
–
8
)
T
×
A
θ
) θ
10
JA
JA
⁄
JA
of the DFN package for
and the maximum ambient
12
14
16
JA
vs EPAD-MOUNT
18
December 21, 2009
20
22
2
(EQ. 7)
(EQ. 8)
FN6931.0
24
A