MCP1754 Microchip Technology Inc., MCP1754 Datasheet - Page 21

• Manufacturer Part Number: MCP1754
• Description: 150 Ma, 16v, High Performance Ldo
• Manufacturer: Microchip Technology Inc.

5.0
5.1
The MCP1754/MCP1754S is most commonly used as
a voltage regulator. It’s low quiescent current and low
dropout voltage make it ideal for many battery-powered
applications.
FIGURE 5-1:
5.1.1
5.2
5.2.1
The internal power dissipation of the MCP1754/
MCP1754S is a function of input voltage, output
voltage and output current. The power dissipation, as
a result of the quiescent current draw, is so low, it is
insignificant (56.0 µA x V
can be used to calculate the internal power dissipation
of the LDO.
EQUATION
The
temperature specified for the MCP1754/MCP1754S is
+150
of the MCP1754/MCP1754S, the total internal power
dissipation is multiplied by the thermal resistance from
junction to ambient (Rθ
junction to ambient for the SOT23A pin package is
estimated at 336
© 2011 Microchip Technology Inc.
I
50 mA
P
V
V
OUT
LDO
IN(MAX)
OUT(MIN)
P
V
1.8V
°
Input Voltage Range = 3.6V to 4.8V
LDO
C
OUT
maximum
.
= LDO Pass device internal power dissipation
To estimate the internal junction temperature
APPLICATION CIRCUITS &
ISSUES
Typical Application
Power Calculations
=
= Maximum input voltage
Package Type = SOT23
APPLICATION INPUT CONDITIONS
POWER DISSIPATION
V
(
= LDO minimum output voltage
V
IN
V
OUT
IN MAX )
C
1 µF Ceramic
maximum = 4.8V
(
OUT
Typical Application Circuit.
GND
V
°
typical = 1.8V
C/W.
OUT
continuous
MCP1754S
I
OUT
JA
)
–
). The thermal resistance from
V
IN
OUT MIN
= 50 mA maximum
). The following equation
(
V
IN
operating
)
) I
V
3.6V to 4.8V
×
IN
1 µF Ceramic
OUT MAX )
C
IN
(
junction
)
MCP1754/MCP1754S
EQUATION
The maximum power dissipation capability for a
package can be calculated given the junction-to-
ambient thermal resistance and the maximum ambient
temperature for the application. The following equation
can be used to determine the package maximum
internal power dissipation.
EQUATION
EQUATION
EQUATION
T
temperature
P
Rθ
T
P
T
T
Rθ
T
P
Rθ
T
T
T
AMAX
A(MAX)
A
J(MAX)
J(MAX)
J(RISE)
J
J(RISE)
TOTAL
D(MAX)
D(MAX)
JA
JA
JA
= Junction Temperature
= Ambient temperature
= Thermal resistance from junction to ambient
= Thermal resistance from junction to ambient
= Thermal resistance from junction to ambient
= Maximum ambient temperature
T
= Total device power dissipation
= Maximum continuous junction
= Maximum continuous junction
= Maximum ambient temperature
J MAX
= Maximum device power dissipation
= Rise in device junction temperature over
= Maximum device power dissipation
= Rise in device junction temperature over
P
(
temperature
D MAX
the ambient temperature
the ambient temperature
T
(
J RISE
(
)
T
=
)
J
=
)
P
=
TOTAL
=
(
---------------------------------------------------
T
T
J RISE
P
J MAX
(
(
D MAX
(
×
Rθ
Rθ
)
)
+
–
)
JA
JA
×
T
T
A
A MAX
Rθ
+
(
T
DS22276A-page 21
JA
AMAX
)
)