MCP1802
300 mA, High PSRR, Low Quiescent Current LDO
Features:
Description:
•
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The MCP1802 is a family of CMOS low dropout (LDO)
voltage regulators that can deliver up to 300 mA of
current while consuming only 25 µA of quiescent
current (typical). The input operating range is specified
from 2.0V to 10.0V, making it an ideal choice for two to
six primary cell battery-powered applications, 9V
alkaline and one or two cell Li-Ion-powered
applications.
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•
•
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•
300 mA Maximum Output Current
Low Dropout Voltage, 200 mV typical @ 100 mA
25 µA Typical Quiescent Current
0.01 µA Typical Shutdown Current
Input Operating Voltage Range: 2.0V to10.0V
Standard Output Voltage Options:
- (0.9V, 1.8V, 2.5V, 3.0V, 3.3V, 5.0V, 6.0V)
Output voltage accuracy:
- ±2% (VR > 1.5V), ±30 mV (VR 1.5V)
Stable with Ceramic output capacitors
Current Limit Protection
Shutdown pin
High PSRR: 70 dB typical @ 10 kHz
Applications:
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Battery-powered Devices
Battery-powered Alarm Circuits
Smoke Detectors
CO2 Detectors
Pagers and Cellular Phones
Wireless Communications Equipment
Smart Battery Packs
Low Quiescent Current Voltage Reference
PDAs
Digital Cameras
Microcontroller Power
Solar-Powered Instruments
Consumer Products
Battery Powered Data Loggers
Related Literature:
• AN765, “Using Microchip’s Micropower LDOs”,
DS00765, Microchip Technology Inc., 2002
• AN766, “Pin-Compatible CMOS Upgrades to
BiPolar LDOs”, DS00766,
Microchip Technology Inc., 2002
• AN792, “A Method to Determine How Much
Power a SOT23 Can Dissipate in an Application”,
DS00792, Microchip Technology Inc., 2001
2010 Microchip Technology Inc.
The MCP1802 is capable of delivering 100 mA with
only 200 mV (typical) of input to output voltage
differential (VOUT = 3.0V). The output voltage tolerance
of the MCP1802 at +25°C is typically ±0.4% with a
maximum of ±2%. Line regulation is ±0.01% typical at
+25°C.
The LDO output is stable with a minimum of 1 µF of
output capacitance. Ceramic, tantalum or aluminum
electrolytic capacitors can all be used for input and
output. Overcurrent limit with current foldback provides
short-circuit protection. A shutdown (SHDN) function
allows the output to be enabled or disabled. When
disabled, the MCP1802 draws only 0.01 µA of current
(typical).
The MCP1802 is available in a SOT-23-5 package.
Package Types
SOT-23-5
NC
VOUT
5
1
VIN
4
2
3
VSS SHDN
DS22053C-page 1
MCP1802
Functional Block Diagram
MCP1802
+VIN
VOUT
VIN
SHDN
+VIN
Shutdown
Control
Voltage
Reference
+
Current Limiter
Error Amplifier
GND
Typical Application Circuit
MCP1802
VIN
1
VIN
VOUT
5
3.3V @ 40 mA
COUT mA
1 µF Ceramic
SOT-23-5
9V
Battery
2
GND
3
SHDN NC
VOUT
+
CIN
4
1 µF
Ceramic
DS22053C-page 2
2010 Microchip Technology Inc.
MCP1802
1.0
ELECTRICAL
CHARACTERISTICS
† Notice: Stresses above those listed under “Maximum
Ratings” 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 operational listings of this specification
is not implied. Exposure to maximum rating conditions
for extended periods may affect device reliability.
Absolute Maximum Ratings †
Input Voltage ................................................................. +12V
Output Current (Continuous) ..................... PD/(VIN-VOUT)mA
Output Current (Peak) ............................................... 500 mA
Output Voltage ............................... (VSS-0.3V) to (VIN+0.3V)
SHDN Voltage ..................................(VSS-0.3V) to (VIN+0.3V)
Continuous Power Dissipation:
5-Pin SOT-23-5 .................................................... 250 mW
ELECTRICAL CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all limits are established for VIN = VR + 1.0V, Note 1, COUT = 1 µF (X7R),
CIN = 1 µF (X7R), VSHDN = VIN, TA = +25°C
Parameters
Sym
Min
Typ
Max
Input Operating Voltage
VIN
Input Quiescent Current
Iq
Units
Conditions
2.0
—
10.0
V
—
25
50
µA
IL = 0 mA
Input / Output Characteristics
ISHDN
—
0.01
0.10
µA
SHDN = 0V
IOUT_mA
300
300
260
260
—
—
—
—
—
—
—
—
mA
VR 2V, VIN = VR +1.0V
1.5V VR 2.0V, VIN=3.0V
1.0V VR 1.5V, VIN = VR +1.5V
0.9V VR 1.0V, VIN=2.5V
Shutdown Current
Maximum Output Current
Note 1
ILIMIT
—
380
—
mA
if VR 1.75V, then VIN = VR + 2.0V
IOUT_SC
—
50
—
mA
if VR 1.75V, then VIN = VR + 2.0V
VOUT
VR-2.0%
VR
VR+2.0%
V
VR-30 mV
VR
VR+30 mV
TCVOUT
—
100
—
ppm/°C
Line Regulation
VOUT/
(VOUTXVIN)
-0.2
±0.01
+0.2
%/V
(VR + 1V) VIN 10V, Note 1
VR 1.75V, IOUT = 30 mA
VR 1.75V, IOUT = 10 mA
Load Regulation
VOUT/VOUT
—
—
15
—
50
100
mV
IL = 1.0 mA to 100 mA, Note 4
IL = 1.0 mA to 300 mA,
VDROPOUT
—
60
90
mV
—
200
250
IL = 30 mA, 3.1V VR 6.0V
IL = 100 mA, 3.1V VR 6.0V
—
80
120
IL = 30 mA, 2.0V VR 3.1V
—
240
350
—
2.07 - VR
2.10 - VR
IL = 100 mA, 2.0V VR < 3.1V
IL = 30 mA,VR 2.0V
Current Limiter
Output Short Circuit Current
Output Voltage Regulation
VOUT Temperature
Coefficient
Dropout Voltage, Note 5
Power Supply Ripple
Rejection Ratio
3:
4:
5:
V
IOUT = 30 mA, -40°C TA +85°C,
Note 3
—
2.23 - VR
2.33 - VR
PSRR
—
70
—
dB
f = 10 kHz, IL = 50 mA, VINAC = 1V
pk-pk, CIN = 0 µF,
if VR 1.5V, then VIN = 2.5V
eN
—
0.46
—
μV/√Hz
IOUT = 100 mA, f = 1 kHz, COUT =
1 μF (X7R Ceramic), VOUT = 2.5V
Output Noise
Note 1:
2:
VR 1.45V, IOUT = 30 mA, Note 2
VR 1.45V, IOUT = 30 mA
IL = 100 mA, VR < 2.0V
The minimum VIN must meet two conditions: VIN2.0V and VIN (VR + 1.0V).
VR is the nominal regulator output voltage. For example: VR = 1.8V, 2.5V, 3.0V, 3.3V, or 5.0V.
The input voltage VIN = VR + 1.0V or ViIN = 2.0V (whichever is greater); IOUT = 100 µA.
TCVOUT = (VOUT-HIGH - VOUT-LOW) *106 / (VR * Temperature), VOUT-HIGH = highest voltage measured over the
temperature range. VOUT-LOW = lowest voltage measured over the temperature range.
Load regulation is measured at a constant junction temperature using low duty cycle pulse testing. Changes in output
voltage due to heating effects are determined using thermal regulation specification TCVOUT.
Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its measured
value with an applied input voltage of VR + 1.0V or 2.0V, whichever is greater.
2010 Microchip Technology Inc.
DS22053C-page 3
MCP1802
ELECTRICAL CHARACTERISTICS (CONTINUED)
Electrical Specifications: Unless otherwise specified, all limits are established for VIN = VR + 1.0V, Note 1, COUT = 1 µF (X7R),
CIN = 1 µF (X7R), VSHDN = VIN, TA = +25°C
Parameters
Sym
Min
Typ
Max
Units
Conditions
Logic High Input
VSHDN-HIGH
1.6
—
—
V
—
Logic Low Input
VSHDN-LOW
—
—
0.25
V
—
Shutdown Input
Note 1:
2:
3:
4:
5:
The minimum VIN must meet two conditions: VIN2.0V and VIN (VR + 1.0V).
VR is the nominal regulator output voltage. For example: VR = 1.8V, 2.5V, 3.0V, 3.3V, or 5.0V.
The input voltage VIN = VR + 1.0V or ViIN = 2.0V (whichever is greater); IOUT = 100 µA.
TCVOUT = (VOUT-HIGH - VOUT-LOW) *106 / (VR * Temperature), VOUT-HIGH = highest voltage measured over the
temperature range. VOUT-LOW = lowest voltage measured over the temperature range.
Load regulation is measured at a constant junction temperature using low duty cycle pulse testing. Changes in output
voltage due to heating effects are determined using thermal regulation specification TCVOUT.
Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its measured
value with an applied input voltage of VR + 1.0V or 2.0V, whichever is greater.
TEMPERATURE SPECIFICATIONS
Parameters
Sym
Min
Typ
Max
Units
Conditions
Temperature Ranges
Operating Temperature Range
Storage Temperature Range
TA
-40
—
+85
°C
Tstg
-55
—
+125
°C
JA
JC
—
—
256
81
—
—
°C/W
Thermal Package Resistance
Thermal Resistance, SOT-23-5
DS22053C-page 4
EIA/JEDEC JESD51-7
FR-4 0.063 4-Layer Board
2010 Microchip Technology Inc.
MCP1802
2.0
TYPICAL PERFORMANCE CURVES
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: VR = 3.3V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VR + 1.0V, SOT-23-5.
Note: Junction Temperature (TJ) is approximated by soaking the device under test to an ambient temperature equal to the desired junction temperature.
The test time is small enough such that the rise in Junction temperature over the Ambient temperature is not significant.
80
VOUT = 0.9V
IOUT = 0 µA
25.00
+25°C
24.00
+90°C
23.00
22.00
21.00
0°C
VOUT = 0.9V
VIN = 2.0V
70
GND Current (µA)
Quiescent Current (µA)
26.00
60
50
40
30
20
10
-45°C
20.00
0
2
4
6
8
10
0
30
60
Input Voltage (V)
FIGURE 2-1:
Voltage.
+90°C
27.00
26.00
25.00
-45°C
+25°C
24.00
4
5
7
Ground Current vs Load
80
0°C
6
70
VOUT = 3.3V
VIN = 4.3V
60
40
30
20
8
9
10
0
25
50
+25°C
29.00
30.00
VOUT = 6.0V
IOUT = 0 µA
+90°C
28.00
27.00
0°C
-45°C
FIGURE 2-5:
Current.
Quiescent Current (µA)
Quiescent Current (µA)
31.00
75
100
125
150
Load Current (mA)
Quiescent Current vs. Input
30.00
VOUT = 6.0V
VIN = 7.0V
50
Input Voltage (V)
FIGURE 2-2:
Voltage.
150
90
GND Current (µA)
Quiescent Current (µA)
FIGURE 2-4:
Current.
VOUT = 3.3V
IOUT = 0 µA
28.00
120
Load Current (mA)
Quiescent Current vs. Input
29.00
90
26.00
25.00
28.00
Ground Current vs Load
VOUT = 6.0V
VIN = 7.0V
IOUT = 0mA
26.00
24.00
VOUT = 0.9V
VIN = 2.0V
VOUT = 3.3V
VIN = 4.3V
22.00
20.00
7
7.5
8
8.5
9
9.5
10
Input Voltage (V)
FIGURE 2-3:
Voltage.
Quiescent Current vs. Input
2010 Microchip Technology Inc.
-45
-22.5
0
22.5
45
67.5
90
Junction Temperature (°C)
FIGURE 2-6:
Quiescent Current vs.
Junction Temperature.
DS22053C-page 5
MCP1802
Note: Unless otherwise indicated: VR = 3.3V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VR + 1.0V, SOT-23-5.
VOUT = 0.9V
ILOAD = 1 mA
0.920
0.915
-45°C
0.910
0°C
+25°C
0.905
0.900
0.920
0°C
0.915
Output Voltage (V)
Output Voltage (V)
0.925
0.910
0.905
+25
0.900
-45°C
0.895
+90°C
0.890
0.885
+90°C
0.895
0.880
2
3
4
5
6
7
8
9
0
10
25
50
Output Voltage vs. Input
3.34
Output Voltage (V)
VOUT = 3.3V
ILOAD = 1 mA
0°C
3.33
FIGURE 2-10:
Current.
3.32
3.31
+25°C
-45°C
3.30
3.29
3.28
100
125
150
+90°C
Output Voltage vs. Load
3.34
3.33
Output Voltage (V)
FIGURE 2-7:
Voltage.
75
Load Current (mA)
Input Voltage (V)
3.27
-45°C
3.32
VIN = 4.3V
VOUT = 3.3V
0°C
3.31
3.30
+25°C
3.29
3.28
+90°C
3.27
3.26
3.26
3.25
4
5
6
7
8
9
0
10
25
Output Voltage vs. Input
6.06
VOUT = 6.0V
ILOAD = 1 mA
6.04
0°C
6.02
+25°C
6.00
-45°C
5.98
+90°C
5.96
5.94
FIGURE 2-11:
Current.
75
100
125
150
Output Voltage vs. Load
6.06
6.04
Output Voltage (V)
FIGURE 2-8:
Voltage.
50
Load Current (mA)
Input Voltage (V)
Output Voltage (V)
VIN = 2.0V
VOUT = 0.9V
VIN = 7.0V
VOUT = 6.0V
+25°C
0°C
6.02
-45°C
6.00
5.98
+90°C
5.96
5.94
5.92
7
7.5
8
8.5
9
9.5
10
0
Input Voltage (V)
FIGURE 2-9:
Voltage.
DS22053C-page 6
Output Voltage vs. Input
25
50
75
100
125
150
Load Current (mA)
FIGURE 2-12:
Current.
Output Voltage vs. Load
2010 Microchip Technology Inc.
MCP1802
Note: Unless otherwise indicated: VR = 3.3V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VR + 1.0V, SOT-23-5.
Dropout Voltage (V)
0.30
VOUT = 3.3V
0.25
0.20
+90°C
0.15
+25°C
0.10
-45°C
0.05
+0°C
0.00
0
25
50
75
100
125
150
Load Current (mA)
FIGURE 2-13:
Current.
FIGURE 2-16:
Dynamic Line Response.
160
0.30
VOUT = 6.0V
Short Circuit Current (mA)
Dropout Voltage (V)
Dropout Voltage vs. Load
0.25
0.20
+90°C
+25°C
0.15
0.10
-45°C
0.05
+0°C
0.00
0
25
50
75
100
125
VOUT = 3.3V
ROUT < 0.1Ω
140
120
100
80
60
40
20
0
0
150
1
2
3
FIGURE 2-14:
Current.
Dropout Voltage vs. Load
4
5
6
7
8
9
10
Input Voltage (V)
Load Current (mA)
FIGURE 2-17:
Input Voltage.
Short Circuit Current vs.
Load Regulation (%)
-1.40
VOUT = 0.9V
IOUT = 0.1 mA to 150 mA
-1.50
-1.60
VIN = 10V
VIN = 8V
VIN = 6V
VIN = 4V
-1.70
-1.80
VIN = 2V
-1.90
-45
-22.5
0
22.5
45
67.5
90
Temperature (°C)
FIGURE 2-15:
Dynamic Line Response.
2010 Microchip Technology Inc.
FIGURE 2-18:
Temperature.
Load Regulation vs.
DS22053C-page 7
MCP1802
Note: Unless otherwise indicated: VR = 3.3V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VR + 1.0V, SOT-23-5.
VOUT = 3.3V
IOUT = 0.1 mA to 150 mA
-0.10
-0.20
VIN = 8V
VIN = 6V
VIN = 10V
-0.30
-0.40
VIN = 4.3V
-0.50
0.020
Line Regulation (%/V)
Load Regulation (%)
0.00
-0.60
0.015
VOUT = 3.3V
VIN = 4.3V to 10V
150 mA
100 mA
0.010
10 mA
0.005
0.000
-0.005
1 mA
-0.010
-45
-22.5
0
22.5
45
67.5
90
-45
-22.5
Temperature (°C)
FIGURE 2-19:
Temperature.
0.00
VIN = 8V
VIN = 9V
-0.20
22.5
45
67.5
90
Line Regulation vs.
0.020
Line Regulation (%/V)
Load Regulation (%)
FIGURE 2-22:
Temperature.
VOUT = 6.0V
IOUT = 0.1 mA to 150 mA
-0.10
0
Temperature (°C)
Load Regulation vs.
0.10
VIN = 10V
VIN = 7V
-0.30
0.015
VOUT = 6.0V
VIN = 7.0V to 10.0V
150 mA
100 mA
0.010
50 mA
0.005
0.000
-0.005
-0.010
1 mA
10 mA
-0.015
-45
-22.5
0
22.5
45
67.5
90
-45
-22.5
Temperature (°C)
FIGURE 2-20:
Temperature.
FIGURE 2-23:
Temperature.
VIN = 2.0 to 10.0V
VOUT = 0.9V
150 mA
0.010
100 mA
PSRR (dB)
0.015
50 mA
0.005
0.000
-0.005
1 mA
10 mA
-0.010
-45
-22.5
0
22.5
45
67.5
Temperature (°C)
FIGURE 2-21:
Temperature.
DS22053C-page 8
0
22.5
45
67.5
90
Temperature (°C)
Load Regulation vs.
0.020
Line Regulation (%/V)
50 mA
Line Regulation vs.
90
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
0.01
Line Regulation vs.
VR=3.3V
VIN=4.3V
VINAC = 100 mV p-p
CIN=0 μF
IOUT=100 µA
0.1
FIGURE 2-24:
1
10
Frequency (KHz)
100
1000
PSRR vs. Frequency.
2010 Microchip Technology Inc.
MCP1802
PSRR (dB)
Note: Unless otherwise indicated: VR = 3.3V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VR + 1.0V, SOT-23-5.
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
0.01
VR= 6.0V
VIN= 7.0V
VINAC = 100 mV p-p
CIN= 0 μF
IOUT= 100 µA
0.1
1
10
Frequency (KHz)
100
1000
FIGURE 2-25:
PSRR vs Frequency.
FIGURE 2-28:
Dynamic Load Response.
FIGURE 2-26:
Power Up Timing.
FIGURE 2-29:
SHDN.
Power Up Timing From
Noise ( µV/Hz)
10
Dynamic Load Response.
2010 Microchip Technology Inc.
IOUT = 100 mA
1
0.1
2.5V
0.01
0.001
0.01
FIGURE 2-27:
5.0V
FIGURE 2-30:
0.1
1
10
Frequency (KHz)
100
1000
Noise Graph.
DS22053C-page 9
MCP1802
NOTES:
DS22053C-page 10
2010 Microchip Technology Inc.
MCP1802
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
Pin No.
SOT-23-5
Name
1
VIN
2
GND
3
SHDN
3.1
4
NC
5
VOUT
Function
Unregulated Supply Voltage
Ground Terminal
Shutdown
No connection
Regulated Voltage Output
Unregulated Input Voltage (VIN)
Connect VIN to the input unregulated source voltage.
Like all low dropout linear regulators, low source
impedance is necessary for the stable operation of the
LDO. The amount of capacitance required to ensure
low source impedance will depend on the proximity of
the input source capacitors or battery type. For most
applications, 0.1 µF of capacitance will ensure stable
operation of the LDO circuit. The type of capacitor used
can be ceramic, tantalum or aluminum electrolytic. The
low ESR characteristics of the ceramic will yield better
noise and PSRR performance at high frequency.
3.2
Ground Terminal (GND)
Regulator ground. Tie GND to the negative side of the
output and the negative side of the input capacitor.
Only the LDO bias current (25 µA typical) flows out of
this pin; there is no high current. The LDO output
regulation is referenced to this pin. Minimize voltage
drops between this pin and the negative side of the
load.
2010 Microchip Technology Inc.
3.3
Shutdown 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
SHDN input is pulled to a logic-low level, the LDO
output voltage is disabled and the LDO enters a low
quiescent current shutdown state where the typical
quiescent current is 0.01 µA. The SHDN pin does not
have an internal pull-up or pull-down resistor. The the
SHDN pin must be connected to either VIN or GND to
prevent the device from becoming unstable.
3.4
Regulated Output Voltage (VOUT)
Connect VOUT to the positive side of the load and the
positive terminal of the output capacitor. The positive
side of the output capacitor should be physically
located as close to the LDO VOUT pin as is practical.
The current flowing out of this pin is equal to the DC
load current.
DS22053C-page 11
MCP1802
NOTES:
DS22053C-page 12
2010 Microchip Technology Inc.
MCP1802
4.0
DETAILED DESCRIPTION
4.1
Output Regulation
A portion of the LDO output voltage is fed back to the
internal error amplifier and compared with the precision
internal bandgap reference. The error amplifier output
will adjust the amount of current that flows through the
P-Channel pass transistor, thus regulating the output
voltage to the desired value. Any changes in input
voltage or output current will cause the error amplifier
to respond and adjust the output voltage to the target
voltage (refer to Figure 4-1).
4.2
Overcurrent
The MCP1802 internal circuitry monitors the amount of
current flowing through the P-Channel pass transistor.
In the event that the load current reaches the current
limiter level of 380 mA (typical), the current limiter
circuit will operate and the output voltage will drop. As
the output voltage drops, the internal current foldback
circuit will further reduce the output voltage causing the
output current to decrease. When the output is shorted,
a typical output current of 50 mA flows.
4.3
Shutdown
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
SHDN input is pulled to a logic-low level, the LDO
output voltage is disabled and the LDO enters a low
quiescent current shutdown state where the typical
quiescent current is 0.01 µA. The SHDN pin does not
have an internal pull-up or pull-down resistor. Therefore
the SHDN pin must be pulled either high or low to
prevent the device from becoming unstable. The
internal device current will increase when the device is
operational and current flows through the pull-up or
pull-down resistor to the SHDN pin internal logic. The
SHDN pin internal logic is equivalent to an inverter
input.
2010 Microchip Technology Inc.
4.4
Output Capacitor
The MCP1802 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 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
MCP1802 to improve dynamic performance and power
supply ripple rejection performance. Aluminum-electrolytic capacitors are not recommended for low
temperature applications of 25°C.
4.5
Input Capacitor
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 0.1 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.
DS22053C-page 13
MCP1802
MCP1802
+VIN
VOUT
VIN
SHDN
Shutdown
Control
+VIN
Voltage
Reference
+
Current Limiter
Error Amplifier
GND
FIGURE 4-1:
DS22053C-page 14
Block Diagram.
2010 Microchip Technology Inc.
MCP1802
5.0
FUNCTIONAL DESCRIPTION
The MCP1802 CMOS low dropout linear regulator is
intended for applications that need the low current
consumption while maintaining output voltage
regulation. The operating continuous load range of the
MCP1802 is from 0 mA to 300 mA. The input operating
voltage range is from 2.0V to 10.0V, making it capable
of operating from three or more alkaline cells or single
and multiple Li-Ion cell batteries.
5.1
5.2
Output
The maximum rated continuous output current for the
MCP1802 is 300 mA.
A minimum output capacitance of 1.0 µF is required for
small signal stability in applications that have up to
300 mA output current capability. The capacitor type
can be ceramic, tantalum or aluminum electrolytic.
Input
The input of the MCP1802 is connected to the source
of the P-Channel PMOS pass transistor. As with all
LDO circuits, a relatively low source impedance (10)
is needed to prevent the input impedance from causing
the LDO to become unstable. The size and type of the
capacitor needed depends heavily on the input source
type (battery, power supply) and the output current
range of the application. For most applications a 0.1 µF
ceramic capacitor will be sufficient to ensure circuit
stability. Larger values can be used to improve circuit
AC performance.
2010 Microchip Technology Inc.
DS22053C-page 15
MCP1802
NOTES:
DS22053C-page 16
2010 Microchip Technology Inc.
MCP1802
6.0
APPLICATION CIRCUITS &
ISSUES
6.1
The MCP1802 is most commonly used as a voltage
regulator. Its low quiescent current and low dropout
voltage make it ideal for many battery-powered
applications.
MCP1802
SHDN
GND
VOUT
1.8V
IOUT
50 mA
COUT
1 µF Ceramic
FIGURE 6-1:
6.1.1
VIN
VOUT
VIN
2.4V to 5.0V
CIN
1 µF
Ceramic
TJ(MAX)
=
Maximum continuous junction
temperature
PTOTAL
=
Total device power dissipation
RJA
=
Thermal resistance from
junction to ambient
TAMAX
=
Maximum ambient temperature
The maximum power dissipation capability for a
package can be calculated given the junction-toambient 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 6-3:
T J MAX – T A MAX
P D MAX = --------------------------------------------------R JA
Typical Application Circuit.
APPLICATION INPUT CONDITIONS
Package Type =
Input Voltage Range =
SOT-23-5
Where:
PD(MAX)
=
Maximum device power
dissipation
TJ(MAX)
=
Maximum continuous junction
temperature
TA(MAX)
=
Maximum ambient temperature
RJA
=
Thermal resistance from
junction to ambient
2.4V to 5.0V
VIN maximum =
5.0V
VOUT typical =
1.8V
IOUT =
6.2
T J MAX = P TOTAL R JA + T AMAX
Where:
Typical Application
NC
EQUATION 6-2:
50 mA maximum
Power Calculations
6.2.1
POWER DISSIPATION
The internal power dissipation of the MCP1802 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
(25.0 µA x VIN). The following equation can be used to
calculate the internal power dissipation of the LDO.
EQUATION 6-1:
P LDO = VIN MAX – V OUT MIN I OUT MAX
Where:
PLDO
=
LDO Pass device internal power
dissipation
VIN(MAX)
=
Maximum input voltage
VOUT(MIN)
=
LDO minimum output voltage
The maximum continuous operating temperature
specified for the MCP1802 is +85°C. To estimate the
internal junction temperature of the MCP1802, the total
internal power dissipation is multiplied by the thermal
resistance from junction to ambient (RJA). The thermal
resistance from junction to ambient for the SOT-23-5
package is estimated at 256°C/W.
2010 Microchip Technology Inc.
EQUATION 6-4:
T J RISE = P D MAX R JA
Where:
TJ(RISE)
=
Rise in device junction
temperature over the ambient
temperature
PTOTAL
=
Maximum device power
dissipation
RJA
=
Thermal resistance from
junction to ambient
EQUATION 6-5:
T J = T J RISE + T A
Where:
TJ
=
Junction Temperature
TJ(RISE)
=
Rise in device junction
temperature over the ambient
temperature
TA
=
Ambient temperature
DS22053C-page 17
MCP1802
6.3
Voltage Regulator
Internal power dissipation, junction temperature rise,
junction temperature and maximum power dissipation
are calculated in the following example. The power
dissipation, as a result of ground current, is small
enough to be neglected.
6.3.1
Junction Temperature Estimate
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 in the following table.
TJ = TJRISE + TA(MAX)
POWER DISSIPATION EXAMPLE
Package
Package Type = SOT-23-5
Input Voltage
TJ = 81.42°C
Maximum Package Power Dissipation at +25°C
Ambient Temperature
SOT-23-5 (256°C/Watt = RJA)
PD(MAX) = (85°C - 25°C) / 256°C/W
VIN = 2.4V to 5.0V
PD(MAX) = 234 milli-Watts
LDO Output Voltages and Currents
VOUT = 1.8V
IOUT = 50 mA
Maximum Ambient Temperature
TA(MAX) = +40°C
Internal Power Dissipation
Internal Power dissipation is the product of the LDO
output current times the voltage across the LDO
(VIN to VOUT).
PLDO(MAX) = (VIN(MAX) - VOUT(MIN)) x IOUT(MAX)
PLDO = (5.0V - (0.98 x 1.8V)) x 50 mA
PLDO = 161.8 milli-Watts
6.4
Voltage Reference
The MCP1802 can be used not only as a regulator, but
also as a low quiescent current voltage reference. In
many microcontroller applications, the initial accuracy
of the reference can be calibrated using production test
equipment or by using a ratio measurement. When the
initial accuracy is calibrated, the thermal stability and
line regulation tolerance are the only errors introduced
by the MCP1802 LDO. The low cost, low quiescent
current and small ceramic output capacitor are all
advantages when using the MCP1802 as a voltage
reference.
Device 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 (RJA) is
derived from an EIA/JEDEC standard for measuring
thermal resistance for small surface mount packages.
The EIA/JEDEC specification is JESD51-7, “High
Effective Thermal Conductivity Test Board for Leaded
Surface Mount Packages”. 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 this subject.
TJ(RISE) = PTOTAL x RqJA
TJRISE = 161.8 milli-Watts x 256.0°C/Watt
TJRISE = 41.42°C
DS22053C-page 18
Ratio Metric Reference
25 µA Bias
CIN
1 µF
PIC®
Microcontroller
MCP1802
VIN
VOUT
GND
COUT
1 µF
VREF
ADO
AD1
Bridge Sensor
FIGURE 6-2:
Using the MCP1802 as a
Voltage Reference.
6.5
Pulsed Load Applications
For some applications, there are pulsed load current
events that may exceed the specified 300 mA
maximum specification of the MCP1802. The internal
current limit of the MCP1802 will prevent high peak
load demands from causing non-recoverable damage.
The 300 mA rating is a maximum average continuous
rating. As long as the average current does not exceed
300 mA nor the max power dissipation of the packaged
device, pulsed higher load currents can be applied to
the MCP1802. The typical current limit for the
MCP1802 is 380 mA (TA +25°C).
2010 Microchip Technology Inc.
MCP1802
7.0
PACKAGING INFORMATION
7.1
Package Marking Information
Example:
5-Lead SOT-23
Standard Options for SOT-23
XXNN
Symbol
Voltage *
Symbol
9X_8#
0.9
9X_Z#
3.0
9X_B#
1.2
9B_2#
3.3
9X_K#
1.8
9B_M#
5.0
9X_T#
2.5
9B_Z#
6.0
* Custom output voltages available upon request.
Contact your local Microchip sales office for more
information.
1
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
9XNN
Voltage *
1
Customer-specific information
Year code (last digit of calendar year)
Year code (last 2 digits of calendar year)
Week code (week of January 1 is week ‘01’)
Alphanumeric traceability code
Pb-free JEDEC designator for Matte Tin (Sn)
This package is Pb-free. The Pb-free JEDEC designator ( e3 )
can be found on the outer packaging for this package.
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.
2010 Microchip Technology Inc.
DS22053C-page 19
MCP1802
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