The MCP1827/MCP1827S is a 1.5A Low Dropout
(LDO) linear regulator that provides high current and
low output voltages. The MCP1827 comes in a fixed or
adjustable output voltage version, with an output
voltage range of 0.8V to 5.0V. The 1.5A output current
capability, combined with the low output voltage
capability, make the MCP1827 a good choice for new
sub-1.8V output voltage LDO applications that have
high current demands. The MCP1827S is a 3-pin fixed
voltage version. The MCP1827/MCP1827S is based
upon the MCP1727 LDO device.
The MCP1827/MCP1827S is stable using ceramic
output capacitors that inherently provide lower output
noise and reduce the size and cost of the entire
regulator solution. Only 1 µF of output capacitance is
needed to stabilize the LDO.
Using CMOS construction, the quiescent current
consumed by the MCP1827/MCP1827S is typically
less than 120 µA over the entire input voltage range,
making it attractive for portable computing applications
that demand high output current. The MCP1827
versions have a Shutdown (S
HDN) pin. When shut
down, the quiescent current is reduced to less than
0.1 µA.
On the MCP1827 fixed output versions the
scaled-down output voltage is internally monitored and
a power good (PWRGD) output is provided when the
output is within 92% of regulation (typical). The
PWRGD delay is internally fixed at 200 µs (typical).
The overtemperature and short circuit current-limiting
provide additional protection for the LDO during system
fault conditions.
† Notice: Stresses above those listed under “Maximum Rat-
ings” may cause permanent damage to the device. This is a
stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
Adjust Pin Leakage CurrentI
Adjust Temperature CoefficientTCV
ADJ
ADJ
OUT
Fixed-Output Characteristics (Fixed Output Only)
Note 1:The minimum V
must meet two conditions: V
IN
2:VR is the nominal regulator output voltage for the fixed cases. VR = 1.2V, 1.8V, etc. VR is the desired set point output
voltage for the adjustable cases. V
3:TCV
= (V
OUT
OUT-HIGH
temperature range. V
– V
OUT-LOW
R
) *106 / (VR * ΔTemperature). V
OUT-LOW
is the lowest voltage measured over the temperature range.
4:Load regulation is measured at a constant junction temperature using low duty-cycle pulse testing. Load regulation is
tested over a load range from 1 mA to the maximum specified output current.
5:Dropout voltage is defined as the input-to-output voltage differential at which the output voltage drops 2% below its
nominal value that was measured with an input voltage of V
6:The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e., T
dissipation will cause the device operating junction temperature to exceed the maximum +150°C rating. Sustained
junction temperatures above 150°C can impact device reliability.
7:The junction temperature is approximated by soaking the device under test at an ambient temperature equal to the
desired junction temperature. The test time is small enough such that the rise in the junction temperature over the
ambient temperature is not significant.
Electrical Specifications: Unless otherwise noted, V
I
= 1 mA, CIN = C
OUT
-40°C to +125°C
= 4.7 µF (X7R Ceramic), TA = +25°C. Boldface type applies for junction temperatures, TJ (Note 7) of
OUT
ParametersSymMinTypMaxUnitsConditions
Voltage RegulationV
OUT
Dropout Characteristics
Dropout VoltageV
IN-VOUT
Power Good Characteristics
PWRGD Input Voltage Operat-
V
PWRGD_VIN
ing Range
PWRGD Threshold Voltage
(Referenced to V
OUT
)
PWRGD Threshold HysteresisV
PWRGD Output Voltage LowV
PWRGD LeakageP
PWRGD Time DelayT
Detect Threshold to PWRGD
V
PWRGD_TH
PWRGD_HYS
PWRGD_L
WRGD_LK
PG
T
VDET-PWRGD
Active Time Delay
Shutdown Input
Logic High Input V
Logic Low Input V
Input Leakage CurrentSHDN
SHDN
SHDN-HIGH
SHDN-LOW
ILK
AC Performance
Output Delay From SHDN
Output Noisee
Note 1:The minimum V
must meet two conditions: V
IN
T
OR
N
2:VR is the nominal regulator output voltage for the fixed cases. VR = 1.2V, 1.8V, etc. VR is the desired set point output
voltage for the adjustable cases. V
3:TCV
= (V
OUT
temperature range. V
OUT-HIGH
– V
OUT-LOW
R
) *106 / (VR * ΔTemperature). V
OUT-LOW
is the lowest voltage measured over the temperature range.
4:Load regulation is measured at a constant junction temperature using low duty-cycle pulse testing. Load regulation is
tested over a load range from 1 mA to the maximum specified output current.
5:Dropout voltage is defined as the input-to-output voltage differential at which the output voltage drops 2% below its
nominal value that was measured with an input voltage of V
6:The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e., T
dissipation will cause the device operating junction temperature to exceed the maximum +150°C rating. Sustained
junction temperatures above 150°C can impact device reliability.
7:The junction temperature is approximated by soaking the device under test at an ambient temperature equal to the
desired junction temperature. The test time is small enough such that the rise in the junction temperature over the
ambient temperature is not significant.
Electrical Specifications: Unless otherwise noted, V
I
= 1 mA, CIN = C
OUT
-40°C to +125°C
= 4.7 µF (X7R Ceramic), TA = +25°C. Boldface type applies for junction temperatures, TJ (Note 7) of
OUT
ParametersSymMinTypMaxUnitsConditions
Power Supply Ripple Rejection
PSRR—60—dBf = 100 Hz, C
Ratio
Thermal Shutdown TemperatureT
Thermal Shutdown Hysteresis
Note 1:The minimum V
must meet two conditions: V
IN
ΔT
SD
SD
2:VR is the nominal regulator output voltage for the fixed cases. VR = 1.2V, 1.8V, etc. VR is the desired set point output
voltage for the adjustable cases. V
3:TCV
= (V
OUT
OUT-HIGH
temperature range. V
– V
OUT-LOW
R
) *106 / (VR * ΔTemperature). V
OUT-LOW
is the lowest voltage measured over the temperature range.
4:Load regulation is measured at a constant junction temperature using low duty-cycle pulse testing. Load regulation is
tested over a load range from 1 mA to the maximum specified output current.
5:Dropout voltage is defined as the input-to-output voltage differential at which the output voltage drops 2% below its
nominal value that was measured with an input voltage of V
6:The maximum allowable power dissipation is a function of ambient temperature, the maximum allowable junction
temperature and the thermal resistance from junction to air. (i.e., T
dissipation will cause the device operating junction temperature to exceed the maximum +150°C rating. Sustained
junction temperatures above 150°C can impact device reliability.
7:The junction temperature is approximated by soaking the device under test at an ambient temperature equal to the
desired junction temperature. The test time is small enough such that the rise in the junction temperature over the
ambient temperature is not significant.
= V
IN
= V
OUT(MAX)
+ V
DROPOUT(MAX)
Note 1, VR=1.8V for Adjustable Output,
—150—°CI
—10—°CI
≥ 2.3V and V
IN
((R1/R2)+1). Figure 4-1.
ADJ *
≥ V
IN
OUT(MAX)
OUT-HIGH
IN = VOUTMAX
, TJ, θJA). Exceeding the maximum allowable power
A
+ V
DROPOUT(MAX).
is the highest voltage measured over the
+ V
DROPOUT(MAX)
I
= 10 mA,
OUT
V
= 30 mV pk-pk,
INAC
C
= 0 µF
IN
= 100 µA, V
OUT
V
= 2.8V
IN
= 100 µA, V
OUT
V
= 2.8V
IN
.
OUT
= 10 µF,
= 1.8V,
OUT
= 1.8V,
OUT
TEMPERATURE SPECIFICATIONS
Electrical Specifications: Unless otherwise indicated, all limits apply for V
ParametersSymMinTypMaxUnitsConditions
Temperature Ranges
Operating Junction Temperature RangeT
Maximum Junction TemperatureT
Storage Temperature RangeT
—31.2—°C/W4-Layer JC51 Standard Board
—31.4—°C/W4-Layer JC51 Standard Board
—29.3—°C/W4-Layer JC51 Standard Board
—29.4—°C/W4-Layer JC51 Standard Board
Note:The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note: Unless otherwise indicated, V
Ceramic (X7R), I
Note: Junction Temperature (T
= 1 mA, Temperature = +25°C, VIN = V
OUT
) is approximated by soaking the device under test to an ambient temperature equal to
J
the desired Junction temperature. The test time is small enough such that the rise in Junction temperature over the
Ambient temperature is not significant.
= 1.8V (Adjustable), VIN = 2.8V, C
OUT
OUT
+ 0.6V, R
= 4.7 µF Ceramic (X7R), CIN = 4.7 µF
OUT
= 10 kΩ To VIN.
PWRGD
= 2.3V to 6.0V
= 1.2V adj
FIGURE 2-1:Quiescent Current vs. Input
Voltage (1.2V Adjustable).
FIGURE 2-2:Ground Current vs. Load
Current (1.2V Adjustable).
FIGURE 2-4:Line Regulation vs.
Temperature (1.2V Adjustable).
FIGURE 2-5:Load Regulation vs.
Temperature (Adjstable Version).
FIGURE 2-3:Quiescent Current vs.
Junction Temperature (1.2V Adjustable).
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:PIN FUNCTION TABLE
MCP1827/MCP1827S
3-Pin Fixed
Output
—
122V
233GNDGround
344V
—
——
PadPadPadEPExposed Pad of the Package (ground potential)
3.1Input Voltage Supply (VIN)
Connect the unregulated or regulated input voltage
source to V
several inches away from the LDO, or the input source
is a battery, it is recommended that an input capacitor
be used. A typical input capacitance value of 1 µF to
10 µF should be sufficient for most applications.
3.2Shutdown Control Input (SHDN)
The SHDN input is used to turn the LDO output voltage
on and off. When the SHDN input is at a logic-high
level, the LDO output voltage is enabled. When the
input is pulled to a logic-low level, the LDO
SHDN
output voltage is disabled. When the SHDN input is
pulled low, the PWRGD output also goes low and the
LDO enters a low quiescent current shutdown state
where the typical quiescent current is 0.1 µA.
5-Pin Fixed
Output
11SHDNShutdown Control Input (active-low)
5
. If the input voltage source is located
IN
Adjustable
Output
—
5ADJVoltage Adjust/Sense Input
NameDescription
IN
OUT
PWRGDPower Good Output
Input Voltage Supply
Regulated Output Voltage
3.4Power Good Output (PWRGD)
The PWRGD output is an open-drain output used to
indicate when the LDO output voltage is within 92%
(typically) of its nominal regulation value. The PWRGD
threshold has a typical hysteresis value of 2%. The
PWRGD output is delayed by 200 µs (typical) from the
time the LDO output is within 92% + 3% (max
hysteresis) of the regulated output value on power-up.
This delay time is internally fixed.
3.5Output Voltage Adjust Input (ADJ)
For adjustable applications, the output voltage is
connected to the ADJ input through a resistor divider
that sets the output voltage regulation value. This
provides the user the capability to set the output
voltage to any value they desire within the 0.8V to 5.0V
range of the device.
3.3Ground (GND)
Connect the GND pin of the LDO to a quiet circuit
ground. This will help the LDO power supply rejection
ratio and noise performance. The ground pin of the
LDO only conducts the quiescent current of the LDO
(typically 120 µA), so a heavy trace is not required.
For applications have switching or noisy inputs tie the
GND pin to the return of the output capacitor. Ground
planes help lower inductance and voltage spikes
caused by fast transient load currents and are
recommended for applications that are subjected to
fast load transients.
The V
LDO. A minimum output capacitance of 1.0 µF is
required for LDO stability. The MCP1827/MCP1827S is
stable with ceramic, tantalum and aluminum-electrolytic capacitors. See Section 4.3 “Output Capacitor”
for output capacitor selection guidance.
pin is the regulated output voltage of the
OUT
OUT
)
3.7Exposed Pad (EP)
The DDPAK and TO-220 package have an exposed tab
on the package. A heat sink may be mount to the tab to
aid in the removal of heat from the package during
operation. The exposed tab is at the ground potential of
the LDO.
MCP1827/MCP1827S
V
OUTVADJ
R1R2+
R
2
------------------
⎝⎠
⎛⎞
=
Where:
V
OUT
=LDO Output Voltage
V
ADJ
=ADJ Pin Voltage
(typically 0.41V)
SHDN
GND
ADJ
2
1µF
V
OUT
4.7 µF
V
IN
On
Off
R
1
R
2
C
1
C2
MCP1827-ADJ
1
3
4
5
R1R
2
V
OUTVADJ
–
V
ADJ
--------------------------------
⎝⎠
⎛⎞
=
Where:
V
OUT
=LDO Output Voltage
V
ADJ
=ADJ Pin Voltage
(typically 0.41V)
4.0DEVICE OVERVIEW
The MCP1827/MCP1827S is a high output current,
Low Dropout (LDO) voltage regulator. The low dropout
voltage of 330 mV typical at 1.5A of current makes it
ideal for battery-powered applications. Unlike other
high output current LDOs, the MCP1827/MCP1827S
only draws a maximum of 220 µA of quiescent current.
The MCP1827 has a shutdown control input and a
power good output.
4.1LDO Output Voltage
The 5-pin MCP1827 LDO is available with either a fixed
output voltage or an adjustable output voltage. The
output voltage range is 0.8V to 5.0V for both versions.
The 3-pin MCP1827S LDO is available as a fixed
voltage device.
4.1.1ADJUST INPUT
The adjustable version of the MCP1827 uses the ADJ
pin (pin 5) to get the output voltage feedback for output
voltage regulation. This allows the user to set the
output voltage of the device with two external resistors.
The nominal voltage for ADJ is 0.41V.
Figure 4-1 shows the adjustable version of the
MCP1827. Resistors R
divider network necessary to set the output voltage.
With this configuration, the equation for setting V
EQUATION 4-1:
and R2 form the resistor
1
OUT
is:
EQUATION 4-2:
4.2Output Current and Current
Limiting
The MCP1827/MCP1827S LDO is tested and ensured
to supply a minimum of 1.5A of output current. The
MCP1827/MCP1827S has no minimum output load, so
the output load current can go to 0 mA and the LDO will
continue to regulate the output voltage to within
tolerance.
The MCP1827/MCP1827S also incorporates an output
current limit. If the output voltage falls below 0.7V due
to an overload condition (usually represents a shorted
load condition), the output current is limited to 2.2A
(typical). If the overload condition is a soft overload, the
MCP1827/MCP1827S will supply higher load currents
of up to 3A. The MCP1827/MCP1827S should not be
operated in this condition continuously as it may result
in failure of the device. However, this does allow for
device usage in applications that have higher pulsed
load currents having an average output current value of
1.5A or less.
Output overload conditions may also result in an
over-temperature shutdown of the device. If the
junction temperature rises above 150°C, the LDO will
shut down the output voltage. See Section 4.8“Overtemperature Protection” for more information
on overtemperature shutdown.
FIGURE 4-1:Typical adjustable output
voltage application circuit.
The allowable resistance value range for resistor R2 is
from 10 kΩ to 200 kΩ. Solving the equation for R
yields the following equation:
The MCP1827/MCP1827S requires a minimum output
capacitance of 1 µF for output voltage stability. Ceramic
capacitors are recommended because of their size,
cost and environmental robustness qualities.
Aluminum-electrolytic and tantalum capacitors can be
used on the LDO output as well. The Equivalent Series
Resistance (ESR) of the electrolytic output capacitor
must be no greater than 1 ohm. The output capacitor
should be located as close to the LDO output as is
practical. Ceramic materials X7R and X5R have low
temperature coefficients and are well within the
acceptable ESR range required. A typical 1 µF X7R
0805 capacitor has an ESR of 50 milli-ohms.
Larger LDO output capacitors can be used with the
1
MCP1827/MCP1827S to improve dynamic
performance and power supply ripple rejection
performance. A maximum of 22 µF is recommended.
Aluminum-electrolytic capacitors are not recommended for low-temperature applications of ≤ 25°C.
4.4Input Capacitor
T
PG
T
VDET_PWRGD
V
PWRGD_TH
V
OUT
PWRGD
V
OL
V
OH
V
IN
SHDN
V
OUT
30 µs
70 µs
T
OR
PWRGD
T
PG
Low input source impedance is necessary for the LDO
output to operate properly. When operating from
batteries, or in applications with long lead length
(> 10 inches) between the input source and the LDO,
some input capacitance is recommended. A minimum
of 1.0 µF to 4.7 µF is recommended for most
applications.
For applications that have output step load
requirements, the input capacitance of the LDO is very
important. The input capacitance provides the LDO
with a good local low-impedance source to pull the
transient currents from in order to respond quickly to
the output load step. For good step response
performance, the input capacitor should be of
equivalent (or higher) value than the output capacitor.
The capacitor should be placed as close to the input of
the LDO as is practical. Larger input capacitors will also
help reduce any high-frequency noise on the input and
output of the LDO and reduce the effects of any
inductance that exists between the input source
voltage and the input capacitance of the LDO.
MCP1827/MCP1827S
FIGURE 4-2:Power Good Timing.
4.5Power Good Output (PWRGD)
The PWRGD output is used to indicate when the output
voltage of the LDO is within 92% (typical value, see
Section 1.0 “Electrical Characteristics” for Minimum
and Maximum specifications) of its nominal regulation
value.
As the output voltage of the LDO rises, the PWRGD
output will be held low until the output voltage has
exceeded the power good threshold plus the hysteresis
value. Once this threshold has been exceeded, the
power good time delay is started (shown as T
Electrical Characteristics table). The power good time
delay is fixed at 200 µs (typical). After the time delay
period, the PWRGD output will go high, indicating that
the output voltage is stable and within regulation limits.
If the output voltage of the LDO falls below the power
good threshold, the power good output will transition
low. The power good circuitry has a 170 µs delay when
detecting a falling output voltage, which helps to
increase noise immunity of the power good output and
avoid false triggering of the power good output during
fast output transients. See Figure 4-2 for power good
timing characteristics.
When the LDO is put into Shutdown mode using the
input, the power good output is pulled low
SHDN
immediately, indicating that the output voltage will be
out of regulation. The timing diagram for the power
good output when using the shutdown input is shown in
Figure 4-3.
The power good output is an open-drain output that can
be pulled up to any voltage that is equal to or less than
the LDO input voltage. This output is capable of sinking
1.2 mA (V
PWRGD
< 0.4V maximum).
PG
in the
FIGURE 4-3:Power Good Timing from
Shutdown.
4.6Shutdown Input (SHDN)
The SHDN input is an active-low input signal that turns
the LDO on and off. The SHDN
percentage of the input voltage. The typical value of
this shutdown threshold is 30% of VIN, with minimum
and maximum limits over the entire operating
temperature range of 45% and 15%, respectively.
The SHDN
input will ignore low-going pulses (pulses
meant to shut down the LDO) that are up to 400 ns in
pulse width. If the shutdown input is pulled low for more
than 400 ns, the LDO will enter Shutdown mode. This
small bit of filtering helps to reject any system noise
spikes on the shutdown input signal.
On the rising edge of the SHDN
circuitry has a 30 µs delay before allowing the LDO
output to turn on. This delay helps to reject any false
turn-on signals or noise on the SHDN
the 30 µs delay, the LDO output enters its soft-start
period as it rises from 0V to its final regulation value. If
the SHDN input signal is pulled low during the 30 µs
delay period, the timer will be reset and the delay time
will start over again on the next rising edge of the
input. The total time from the SHDN input going
SHDN
high (turn-on) to the LDO output being in regulation is
typically 100 µs. See Figure 4-4 for a timing diagram of
the SHDN
input.
FIGURE 4-4:Shutdown Input Timing
Diagram.
4.7Dropout Voltage and Undervoltage
Lockout
4.8Overtemperature Protection
The MCP1827/MCP1827S LDO has temperature-sensing circuitry to prevent the junction temperature from exceeding approximately 150
junction temperature does reach 150°C, the LDO
output will be turned off until the junction temperature
cools to approximately 140
°C, at which point the LDO
output will automatically resume normal operation. If
the internal power dissipation continues to be
excessive, the device will again shut off. The junction
temperature of the die is a function of power
dissipation, ambient temperature and package thermal
resistance. See Section 5.0 “Application Cir-cuits/Issues” for more information on LDO power
dissipation and junction temperature.
°C. If the LDO
Dropout voltage is defined as the input-to-output
voltage differential at which the output voltage drops
2% below the nominal value that was measured with a
+ 0.6V differential applied. The
V
R
MCP1827/MCP1827S LDO has a very low dropout
voltage specification of 330 mV (typical) at 1.5A of output current. See Section 1.0 “Electrical Characteris-tics” for maximum dropout voltage specifications.
The MCP1827/MCP1827S LDO operates across an
input voltage range of 2.3V to 6.0V and incorporates
input Undervoltage Lockout (UVLO) circuitry that keeps
the LDO output voltage off until the input voltage
reaches a minimum of 2.18V (typical) on the rising
edge of the input voltage. As the input voltage falls, the
LDO output will remain on until the input voltage level
reaches 2.04V (typical).
Since the MCP1827/MCP1827S LDO undervoltage
lockout activates at 2.04V as the input voltage is falling,
the dropout voltage specification does not apply for
output voltages that are less than 1.9V.
For high-current applications, voltage drops across the
PCB traces must be taken into account. The trace
resistances can cause significant voltage drops
between the input voltage source and the LDO. For
applications with input voltages near 2.3V, these PCB
trace voltage drops can sometimes lower the input
voltage enough to trigger a shutdown due to
undervoltage lockout.
with no LDO output current
(LDO quiescent current)
T
JMAX()PTOTALRθJA
×T
AMAX
+=
T
J(MAX)
= Maximum continuous junction
temperature
P
TOTAL
= Total device power dissipation
Rθ
JA
= Thermal resistance from junction to
ambient
T
AMAX
= Maximum ambient temperature
5.0APPLICATION
CIRCUITS/ISSUES
5.1Typical Application
The MCP1827/MCP1827S is used for applications that
require high LDO output current and a power good
output.
FIGURE 5-1:Typical Application Circuit.
5.1.1APPLICATION CONDITIONS
Package Type = TO-220-5
Input Voltage Range = 3.3V ± 5%
V
maximum = 3.465V
IN
V
minimum = 3.135V
IN
V
DROPOUT (max)
V
(typical) = 2.5V
OUT
P
(typical) = 1.2W
DISS
Temperature Rise = 35.2
5.2Power Calculations
= 0.550V
I
= 1.5A maximum
OUT
°C
In addition to the LDO pass element power dissipation,
there is power dissipation within the
MCP1827/MCP1827S 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
MCP1827/MCP1827S is the sum of the power dissipated in the LDO pass device and the P(I
Because of the CMOS construction, the typical I
the MCP1827/MCP1827S is 120 µA. Operating at a
maximum of 3.465V results in a power dissipation of
0.49 milli-Watts. For most applications, this is small
compared to the LDO pass device power dissipation
and can be neglected.
The maximum continuous operating junction
temperature specified for the MCP1827/MCP1827S is
°C. To estimate the internal junction temperature
+125
of the MCP1827/MCP1827S, the total internal power
dissipation is multiplied by the thermal resistance from
junction to ambient (Rθ
) of the device. The thermal
JA
resistance from junction to ambient for the TO-220-5
package is estimated at 29.3
° C/W.
GND
) term.
for
GND
5.2.1POWER DISSIPATION
The internal power dissipation within the
MCP1827/MCP1827S is a function of input voltage,
output voltage, output current and quiescent current.
Equation 5-1 can be used to calculate the internal
power dissipation for the LDO.
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.
Equation 5-4 can be used to determine the package
maximum internal power dissipation.
EQUATION 5-4:
EQUATION 5-5:
5.3Typical Application
Internal power dissipation, junction temperature rise,
junction temperature and maximum power dissipation
is calculated in the following example. The power
dissipation as a result of ground current is small
enough to be neglected.
5.3.1POWER DISSIPATION EXAMPLE
Package
Package Type = TO-220-5
Input Voltage
V
= 3.3V ± 5%
IN
LDO Output Voltage and Current
V
= 2.5V
OUT
I
= 1.5A
OUT
Maximum Ambient Temperature
T
Internal Power Dissipation
P
LDO(MAX)
=60°C
A(MAX)
=(V
P
= ((3.3V x 1.05) – (2.5V x 0.975))
LDO
IN(MAX)
– V
OUT(MIN)
x 1.5A
P
=1.54 Watts
LDO
) x I
OUT(MAX)
EQUATION 5-6:
5.3.1.1Device Junction Temperature Rise
The internal junction temperature rise is a function of
internal power dissipation and the thermal resistance
from junction-to-ambient for the application. The
thermal resistance from junction-to-ambient (Rθ
derived from EIA/JEDEC standards for measuring
thermal resistance. The EIA/JEDEC specification is
JESD51. The standard describes the test method and
board specifications for measuring the thermal
resistance from junction to ambient. The actual thermal
resistance for a particular application can vary
depending on many factors such as copper area and
thickness. Refer to AN792, “A Method to Determine
How Much Power a SOT23 Can Dissipate in an
Application” (DS00792), for more information regarding
To estimate the internal junction temperature, the
calculated temperature rise is added to the ambient or
offset temperature. For this example, the worst-case
junction temperature is estimated below:
MCP1827/MCP1827S
=T
T
J
TJ = 45.12°C + 60.0°C
T
= 105.12°C
J
As you can see from the result, this application will be
operating within the maximum operating junction
temperature of 125°C.
JRISE
+ T
A(MAX)
5.3.1.3Maximum Package Power
Dissipation at 60°C Ambient
Temperature
TO-220-5 (29.3° C/W RθJA):
P
P
DDPAK-5 (31.2°C/Watt Rθ
P
P
From this table you can see the difference in maximum
allowable power dissipation between the TO-220-5
package and the DDPAK-5 package.
YYear code (last digit of calendar year)
YYYear code (last 2 digits of calendar year)
WWWeek code (week of January 1 is week ‘01’)
NNNAlphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
*This package is Pb-free. The Pb-free JEDEC designator ()
can be found on the outer packaging for this package.
Note:In the event the full Microchip part number cannot be marked on one line, it will
be carried over to the next line, thus limiting the number of available
characters for customer-specific information.
2. Dimensions D and E do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .005" per side.
3. Dimensioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Note:For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
UnitsINCHES
Dimension LimitsMINNOMMAX
Number of PinsN3
Pitche.100 BSC
Overall HeightA.160–.190
Standoff §A1.000–.010
Overall WidthE.380–.420
Exposed Pad WidthE1.245––
Molded Package LengthD. 330–.380
Overall LengthH.549–. 625
Exposed Pad LengthD1.270––
Lead Thicknessc.014–.029
Pad ThicknessC2.045–.065
Lower Lead Widthb.020–.039
Upper Lead Widthb1.045–.070
Foot LengthL.068–.110
Pad LengthL1––.067
Foot Angleφ0°–8°
2. Dimensions D and E do not include mold flash or protrusions. Mold flash or protrusions shall not exceed .005" per side.
3. Dimens ioning and tolerancing per ASME Y14.5M.
BSC: Basic Dimension. Theoretically exact value shown without tolerances.
Note:For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
UnitsINCHES
Dimension LimitsMINNOMMAX
Number of PinsN5
Pitche.067 BSC
Overall HeightA.160–.190
Standoff §A1.000–.010
Overall WidthE.380–.420
Exposed Pad WidthE1.245––
Molded Package LengthD.330–.380
Overall LengthH.549–.625
Exposed Pad LengthD1.270––
Lead Thicknessc.014–.029
Pad ThicknessC2.045–.065
Lead Widthb.020–.039
Foot LengthL.068–.110
Pad LengthL1––.067
Foot Angleφ0°–8°
Note the following details of the code protection feature on Microchip devices:
•Microchip products meet the specification contained in their particular Microchip Data Sheet.
•Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
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