MCP1824S Microchip Technology Inc., MCP1824S Datasheet - Page 21

• Manufacturer Part Number: MCP1824S
• Description: 300 Ma, Low Voltage, Low Quiescent Current Ldo Regulator
• Manufacturer: Microchip Technology Inc.

5.0
5.1
The MCP1824/MCP1824S is used for applications that
require high LDO output current and a power good
output.
FIGURE 5-1:
5.1.1
5.2
5.2.1
The internal power dissipation within the MCP1824/
MCP1824S is a function of input voltage, output
voltage,
Equation 5-1
power dissipation for the LDO.
EQUATION 5-1:
Input Voltage Range
Off
3.3V
Where:
2007 Microchip Technology Inc.
P
Temperature Rise
On
V
LDO
V
V
OUT(MIN)
Package Type
P
DROPOUT (max)
V
V
IN(MAX)
V
APPLICATION CIRCUITS/
ISSUES
Typical Application
DISS
Power Calculations
OUT
IN
P
IN
output
=
SHDN
LDO
V
APPLICATION CONDITIONS
POWER DISSIPATION
maximum
IN
minimum
(
4.7 µF
C
V
(typical)
(typical)
can be used to calculate the internal
1
IN MAX )
(
I
= LDO Pass device internal
= Maximum input voltage
= LDO minimum output voltage
OUT
MCP1824-2.5
1
current
2
power dissipation
Typical Application Circuit.
)
3 4 5
–
GND
=
=
=
=
=
=
=
=
=
V
OUT MIN
and
SOT-223-5
3.3V ± 5%
3.465V
3.135V
0.350V
2.5V
300 mA maximum
0.240W
14.88°C
(
V
10 kΩ
quiescent
OUT
)
) I
R
×
1
= 2.5V @ 300 mA
OUT MAX )
PWRGD
(
current.
C
10 µF
2
)
MCP1824/MCP1824S
In addition to the LDO pass element power dissipation,
there is power dissipation within the MCP1824/
MCP1824S as a result of quiescent or ground current.
The power dissipation as a result of the ground current
can be calculated using the following equation:
EQUATION 5-2:
The total power dissipated within the MCP1824/
MCP1824S is the sum of the power dissipated in the
LDO pass device and the P(I
CMOS construction, the typical I
MCP1824S is 120 µA. Operating at a maximum V
3.465V results in a power dissipation of 0.12 milli-Watts
for a 2.5V output. For most applications, this is small
compared to the LDO pass device power dissipation
and can be neglected.
The
temperature specified for the MCP1824/MCP1824S is
+125°C
of the MCP1824/MCP1824S, the total internal power
dissipation is multiplied by the thermal resistance from
junction to ambient (Rθ
resistance from junction to ambient for the SOT-223-5
package is estimated at 62° C/W.
EQUATION 5-3:
Where:
T
P
T
J(MAX)
TOTAL
V
AMAX
Rθ
maximum
.
IN(MAX)
P
To estimate the internal junction temperature
JA
T
I(GND
J MAX
I
VIN
(
= Maximum continuous junction
= Total device power dissipation
= Thermal resistance from junction to
= Maximum ambient temperature
P
I GND
temperature
ambient
(
)
= Power dissipation due to the
= Maximum input voltage
= Current flowing in the V
=
continuous
)
P
quiescent current of the LDO
with no LDO output current
(LDO quiescent current)
TOTAL
=
JA
V
) of the device. The thermal
IN MAX
GND
(
×
Rθ
GND
) term. Because of the
)
JA
operating
×
+
I
DS22070A-page 21
for the MCP1824/
VIN
T
AMAX
IN
junction
pin
IN
of