MCP1702
250 mA Low Quiescent Current LDO Regulator
Features:
Description:
•
•
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•
The MCP1702 is a family of CMOS low dropout (LDO)
voltage regulators that can deliver up to 250 mA of
current while consuming only 2.0 µA of quiescent
current (typical). The input operating range is specified
from 2.7V to 13.2V, 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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•
•
•
•
•
2.0 µA Quiescent Current (typical)
Input Operating Voltage Range: 2.7V to 13.2V
250 mA Output Current for Output Voltages 2.5V
200 mA Output Current for Output Voltages < 2.5V
Low Dropout (LDO) Voltage
- 625 mV typical @ 250 mA (VOUT = 2.8V)
0.4% Typical Output Voltage Tolerance
Standard Output Voltage Options:
- 1.2V, 1.5V, 1.8V, 2.5V, 2.8V,
3.0V, 3.3V, 4.0V, 5.0V
Output Voltage Range 1.2V to 5.5V in 0.1V
Increments (50 mV increments available upon
request)
Stable with 1.0 µF to 22 µF Output Capacitor
Short-Circuit Protection
Overtemperature Protection
Applications:
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•
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•
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•
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•
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Battery-powered Devices
Battery-powered Alarm Circuits
Smoke Detectors
CO2 Detectors
Pagers and Cellular Phones
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 SOT-23 Can Dissipate in an Application”,
DS00792, Microchip Technology Inc., 2001
2010 Microchip Technology Inc.
The MCP1702 is capable of delivering 250 mA with
only 625 mV (typical) of input to output voltage
differential (VOUT = 2.8V). The output voltage tolerance
of the MCP1702 is typically ±0.4% at +25°C and ±3%
maximum over the operating junction temperature
range of -40°C to +125°C. Line regulation is ±0.1%
typical at +25°C.
Output voltages available for the MCP1702 range from
1.2V to 5.0V. The LDO output is stable when using only
1 µF of output capacitance. Ceramic, tantalum or
aluminum electrolytic capacitors can all be used for
input
and
output.
Overcurrent
limit
and
overtemperature shutdown provide a robust solution
for any application.
Package options include the SOT-23A, SOT-89-3, and
TO-92.
Package Types
3-Pin SOT-23A
3-Pin SOT-89
VIN
VIN
3
MCP1702
MCP1702
1
2
1
2
GND VOUT
3
GND VIN VOUT
3-Pin TO-92
1 23
Bottom
View
GND VIN VOUT
DS22008E-page 1
MCP1702
Functional Block Diagrams
MCP1702
VOUT
VIN
Error Amplifier
+VIN
Voltage
Reference
+
Overcurrent
Overtemperature
GND
Typical Application Circuits
MCP1702
VOUT
3.3V
VOUT
VIN
VIN
9V
Battery
DS22008E-page 2
+
CIN
1 µF Ceramic
GND
COUT
1 µF Ceramic
IOUT
50 mA
2010 Microchip Technology Inc.
MCP1702
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 †
VDD...............................................................................+14.5V
All inputs and outputs w.r.t. .............(VSS-0.3V) to (VIN+0.3V)
Peak Output Current ...................................................500 mA
Storage temperature .....................................-65°C to +150°C
Maximum Junction Temperature ................................... 150°C
ESD protection on all pins (HBM;MM) 4 kV; 400V
DC CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all limits are established for VIN = VOUT(MAX) + VDROPOUT(MAX), Note 1,
ILOAD = 100 µA, COUT = 1 µF (X7R), CIN = 1 µF (X7R), TA = +25°C.
Boldface type applies for junction temperatures, TJ of -40°C to +125°C. (Note 7)
Parameters
Sym
Min
Typ
Max
Units
Conditions
VIN
2.7
—
13.2
V
Note 1
Iq
—
2.0
5
µA
IL = 0 mA
IOUT_mA
250
—
—
mA
For VR 2.5V
50
100
—
mA
For VR < 2.5V, VIN 2.7V
100
130
—
mA
For VR < 2.5V, VIN 2.95V
150
200
—
mA
For VR < 2.5V, VIN 3.2V
200
250
—
mA
For VR < 2.5V, VIN 3.45V
IOUT_SC
—
400
—
mA
VIN = VIN(MIN) (Note 1), VOUT = GND,
Current (average current) measured
10 ms after short is applied.
VOUT
VR-3.0%
VR±0.4%
VR+3.0%
V
VR-2.0%
VR±0.4%
VR+2.0%
V
VR-1.0%
VR±0.4%
VR+1.0%
V
TCVOUT
—
50
—
ppm/°C
Line Regulation
VOUT/
(VOUTXVIN)
-0.3
±0.1
+0.3
%/V
Load Regulation
VOUT/VOUT
-2.5
±1.0
+2.5
%
Input / Output Characteristics
Input Operating Voltage
Input Quiescent Current
Maximum Output Current
Output Short Circuit Current
Output Voltage Regulation
VOUT Temperature
Coefficient
Note 1:
2:
3:
4:
5:
6:
7:
Note 2
1% Custom
Note 3
(VOUT(MAX) + VDROPOUT(MAX))
VIN 13.2V, (Note 1)
IL = 1.0 mA to 250 mA for VR 2.5V
IL = 1.0 mA to 200 mA for VR 2.5V,
VIN = 3.45V (Note 4)
The minimum VIN must meet two conditions: VIN2.7V and VIN VOUT(MAX) + VDROPOUT(MAX).
VR is the nominal regulator output voltage. For example: VR = 1.2V, 1.5V, 1.8V, 2.5V, 2.8V, 3.0V, 3.3V, 4.0V, or 5.0V. The
input voltage VIN = VOUT(MAX) + VDROPOUT(MAX) or VIN = 2.7V (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 VOUT(MAX) + VDROPOUT(MAX) or 2.7V, whichever is greater.
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., TA, TJ, JA). Exceeding the maximum allowable power
dissipation will cause the device operating junction temperature to exceed the maximum 150°C rating. Sustained
junction temperatures above 150°C can impact the device reliability.
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.
2010 Microchip Technology Inc.
DS22008E-page 3
MCP1702
DC CHARACTERISTICS (CONTINUED)
Electrical Specifications: Unless otherwise specified, all limits are established for VIN = VOUT(MAX) + VDROPOUT(MAX), Note 1,
ILOAD = 100 µA, COUT = 1 µF (X7R), CIN = 1 µF (X7R), TA = +25°C.
Boldface type applies for junction temperatures, TJ of -40°C to +125°C. (Note 7)
Parameters
Dropout Voltage
(Note 1, Note 5)
Output Delay Time
Output Noise
Power Supply Ripple
Rejection Ratio
Thermal Shutdown
Protection
Note 1:
2:
3:
4:
5:
6:
7:
Sym
Min
Typ
Max
Units
Conditions
—
330
650
mV
IL = 250 mA, VR = 5.0V
—
525
725
mV
IL = 250 mA, 3.3V VR < 5.0V
—
625
975
mV
IL = 250 mA, 2.8V VR < 3.3V
—
750
1100
mV
IL = 250 mA, 2.5V VR < 2.8V
—
—
—
mV
VR < 2.5V, See Maximum Output
Current Parameter
TDELAY
—
1000
—
µs
VIN = 0V to 6V, VOUT = 90% VR
RL = 50 resistive
eN
—
8
—
PSRR
—
44
—
dB
TSD
—
150
—
°C
VDROPOUT
µV/(Hz)1/2 IL = 50 mA, f = 1 kHz, COUT = 1 µF
f = 100 Hz, COUT = 1 µF, IL = 50 mA,
VINAC = 100 mV pk-pk, CIN = 0 µF,
VR = 1.2V
The minimum VIN must meet two conditions: VIN2.7V and VIN VOUT(MAX) + VDROPOUT(MAX).
VR is the nominal regulator output voltage. For example: VR = 1.2V, 1.5V, 1.8V, 2.5V, 2.8V, 3.0V, 3.3V, 4.0V, or 5.0V. The
input voltage VIN = VOUT(MAX) + VDROPOUT(MAX) or VIN = 2.7V (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 VOUT(MAX) + VDROPOUT(MAX) or 2.7V, whichever is greater.
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., TA, TJ, JA). Exceeding the maximum allowable power
dissipation will cause the device operating junction temperature to exceed the maximum 150°C rating. Sustained
junction temperatures above 150°C can impact the device reliability.
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.
DS22008E-page 4
2010 Microchip Technology Inc.
MCP1702
TEMPERATURE SPECIFICATIONS (Note 1)
Parameters
Sym
Min
TJ
Typ
Max
Units
Conditions
-40
+125
°C
Steady State
Transient
Temperature Ranges
Operating Junction Temperature Range
Maximum Junction Temperature
TJ
—
+150
°C
Storage Temperature Range
TA
-65
+150
°C
JA
—
336
—
°C/W
JC
—
110
—
°C/W
JA
—
153.3
—
°C/W
JC
—
100
—
°C/W
JA
—
131.9
—
°C/W
JC
—
66.3
—
°C/W
Thermal Package Resistance (Note 2)
Thermal Resistance, 3L-SOT-23A
Thermal Resistance, 3L-SOT-89
Thermal Resistance, 3L-TO-92
Note 1:
2:
EIA/JEDEC JESD51-7
FR-4 0.063 4-Layer Board
EIA/JEDEC JESD51-7
FR-4 0.063 4-Layer Board
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., TA, TJ, JA). Exceeding the maximum allowable power
dissipation will cause the device operating junction temperature to exceed the maximum 150°C rating. Sustained
junction temperatures above 150°C can impact the device reliability.
Thermal Resistance values are subject to change. Please visit the Microchip web site for the latest packaging
information.
2010 Microchip Technology Inc.
DS22008E-page 5
MCP1702
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 = 2.8V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VOUT(MAX) + VDROPOUT(MAX).
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.
120.00
VOUT = 1.2V
4.00
GND Current (µA)
Quiescent Current (µA)
5.00
+130°C
3.00
0°C
+90°C
+25°C
2.00
1.00
-45°C
Temperature = +25°C
100.00
VOUT = 1.2V
VIN = 2.7V
80.00
60.00
40.00
20.00
0.00
0.00
2
4
6
8
10
12
14
0
40
80
Input Voltage (V)
FIGURE 2-1:
Voltage.
Quiescent Current vs. Input
FIGURE 2-4:
Current.
+130°C
3.00
+25°C
+90°C
2.00
0°C
1.00
-45°C
0.00
200
Temperature = +25°C
100.00
VOUT = 5.0V
VIN = 6.0V
80.00
60.00
40.00
VOUT = 2.8V
VIN = 3.8V
20.00
0.00
3
5
7
9
11
13
0
50
100
Input Voltage (V)
FIGURE 2-2:
Voltage.
Quiescent Current vs.Input
FIGURE 2-5:
Current.
Quiescent Current (µA)
+130°C
3.00
+90°C
2.00
+25°C
200
250
0°C
-45°C
Ground Current vs. Load
3.00
VOUT = 5.0V
4.00
150
Load Current (mA)
5.00
Quiescent Current (µA)
160
Ground Current vs. Load
120.00
VOUT = 2.8V
GND Current (µA)
Quiescent Current (µA)
5.00
4.00
120
Load Current (mA)
VOUT = 2.8V
VIN = 3.8V
2.50
IOUT = 0 mA
VOUT = 5.0V
VIN = 6.0V
2.00
1.50
VOUT = 1.2V
VIN = 2.7V
1.00
0.50
0.00
1.00
6
7
8
9
10
11
12
13
14
Input Voltage (V)
FIGURE 2-3:
Voltage.
DS22008E-page 6
Quiescent Current vs.Input
-45
-20
5
30
55
80
105
130
Junction Temperature (°C)
FIGURE 2-6:
Quiescent Current vs.
Junction Temperature.
2010 Microchip Technology Inc.
MCP1702
Note: Unless otherwise indicated: VR = 2.8V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VOUT(MAX) + VDROPOUT(MAX).
VOUT = 1.2V
ILOAD = 0.1 mA
1.23
-45°C
0°C
1.22
1.21
1.20
+130°C
+90°C
+25°C
1.19
1.23
Output Voltage (V)
Output Voltage (V)
1.24
1.18
VOUT = 1.2V
0°C
1.22
-45°C
1.21
+25°C
1.20
+90°C
+130°C
1.19
1.18
2
4
6
8
10
12
14
0
20
Input Voltage (V)
FIGURE 2-7:
Voltage.
2.85
+130°C
+90°C
2.81
2.80
2.79
0°C
-45°C
+25°C
2.78
2.77
80
100
Output Voltage vs. Load
VOUT = 2.8V
2.82
+130°C
+90°C
2.81
2.80
2.79
+25°C
2.78
0°C
-45°C
2.77
3
4
5
6
7
8
9
10 11 12 13 14
0
50
Input Voltage (V)
FIGURE 2-8:
Voltage.
Output Voltage vs. Input
+90°C
FIGURE 2-11:
Current.
150
200
VOUT = 5.0V
5.03
+130°C
5.02
5.00
-45°C
0°C
4.98
250
Output Voltage vs. Load
5.04
Output Voltage (V)
5.04
100
Load Current (mA)
VOUT = 5.0V
ILOAD = 0.1 mA
5.06
Output Voltage (V)
60
2.83
2.83
2.82
FIGURE 2-10:
Current.
Output Voltage (V)
Output Voltage (V)
Output Voltage vs. Input
VOUT = 2.8V
ILOAD = 0.1 mA
2.84
40
Load Current (mA)
+25°C
+130°C
5.02
+90°C
5.01
5.00
4.99
0°C
4.98
4.97
4.96
-45°C
+25°C
4.96
6
7
8
9
10
11
12
13
14
0
Output Voltage vs. Input
2010 Microchip Technology Inc.
100
150
200
250
Load Current (mA)
Input Voltage (V)
FIGURE 2-9:
Voltage.
50
FIGURE 2-12:
Current.
Output Voltage vs. Load
DS22008E-page 7
MCP1702
Note: Unless otherwise indicated: VR = 2.8V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VOUT(MAX) + VDROPOUT(MAX).
Dropout Voltage (V)
1.40
VOUT = 1.8V
1.30
+130°C
+90°C
1.20
+25°C
1.10
1.00
0°C
0.90
-45°C
0.80
0.70
0.60
100
120
140
160
180
200
Load Current (mA)
Dropout Voltage (V)
FIGURE 2-13:
Current.
Dropout Voltage vs. Load
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
FIGURE 2-16:
Dynamic Line Response.
FIGURE 2-17:
Dynamic Line Response.
VOUT = 2.8V
+130°C
+90°C
+25°C
+0°C
-45°C
0
25
50
75 100 125 150 175 200 225 250
Load Current (mA)
Dropout Voltage vs. Load
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
VOUT = 5.0V
+130°C
+90°C
+25°C
+0°C
-45°C
0
25
50
75 100 125 150 175 200 225 250
600.00
Short Circuit Current (mA)
Dropout Voltage (V)
FIGURE 2-14:
Current.
VOUT = 2.8V
ROUT < 0.1
500.00
400.00
300.00
200.00
100.00
0.00
4
DS22008E-page 8
Dropout Voltage vs. Load
8
10
12
14
Input Voltage (V)
Load Current (mA)
FIGURE 2-15:
Current.
6
FIGURE 2-18:
Input Voltage.
Short Circuit Current vs.
2010 Microchip Technology Inc.
MCP1702
0.20
0.15
0.10
0.05
0.00
-0.05
-0.10
-0.15
-0.20
-0.25
-0.30
0.20
VIN = 6V
VIN = 4V
VIN = 10V
Line Regulation (%/V)
Load Regulation (%)
Note: Unless otherwise indicated: VR = 2.8V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VOUT(MAX) + VDROPOUT(MAX).
VIN = 12V
VIN = 13.2V
VOUT = 1.2V
ILOAD = 0.1 mA to 200 mA
VOUT = 1.2V
VIN = 2.7V to 13.2V
0.16
0.12
1 mA
0.08
0 mA
0.04
100 mA
0.00
-45
-20
5
30
55
80
105
130
-45
-20
5
Temperature (°C)
0.40
0.30
0.20
0.10
0.00
-0.10
-0.20
-0.30
-0.40
-0.50
-0.60
Load Regulation vs.
FIGURE 2-22:
Temperature.
VOUT = 2.8V
ILOAD = 1 mA to 250 mA
VIN = 6V
VIN = 10V
VIN = 3.8V
VIN = 13.2V
0.20
Line Regulation (%/V)
Load Regulation (%)
FIGURE 2-19:
Temperature.
55
80
105
130
0.16
Line Regulation vs.
VOUT = 2.8V
VIN = 3.8V to 13.2V
250 mA
200 mA
0.12
0.08
0 mA
100 mA
0.04
0.00
-45
-20
5
30
55
80
105
130
-45
-20
5
Temperature (°C)
Load Regulation vs.
0.40
0.30
FIGURE 2-23:
Temperature.
VOUT = 5.0V
ILOAD = 1 mA to 250 mA
VIN = 6V
0.20
0.10
VIN = 10V
VIN = 8V
0.00
30
55
80
105
130
Temperature (°C)
VIN = 13.2V
-0.10
0.16
Line Regulation (%/V)
FIGURE 2-20:
Temperature.
Load Regulation (%)
30
Temperature (°C)
0.14
Line Regulation vs.
VOUT = 5.0V
VIN = 6.0V to 13.2V
0.12
0 mA
200 mA
250 mA
0.10
0.08
100 mA
0.06
-45
-20
5
30
55
80
105
130
-45
-20
Temperature (°C)
FIGURE 2-21:
Temperature.
Load Regulation vs.
2010 Microchip Technology Inc.
5
30
55
80
105
130
Temperature (°C)
FIGURE 2-24:
Temperature.
Line Regulation vs.
DS22008E-page 9
MCP1702
Note: Unless otherwise indicated: VR = 2.8V, COUT = 1 µF Ceramic (X7R), CIN = 1 µF Ceramic (X7R), IL = 100 µA,
TA = +25°C, VIN = VOUT(MAX) + VDROPOUT(MAX).
0
-10
PSRR (dB)
-20
-30
-40
-50
-60
VR=1.2V
COUT=1.0 μF ceramic X7R
VIN=2.7V
CIN=0 μF
IOUT=1.0 mA
-70
-80
-90
0.01
0.1
1
10
Frequency (kHz)
100
1000
FIGURE 2-25:
Power Supply Ripple
Rejection vs. Frequency.
FIGURE 2-28:
Power Up Timing.
FIGURE 2-29:
Dynamic Load Response.
FIGURE 2-30:
Dynamic Load Response.
0
-10
PSRR (dB)
-20
-30
-40
-50
-60
VR=5.0V
COUT=1.0 μF ceramic X7R
VIN=6.0V
CIN=0 μF
IOUT=1.0 mA
-70
-80
-90
0.01
0.1
1
10
Frequency (kHz)
100
1000
FIGURE 2-26:
Power Supply Ripple
Rejection vs. Frequency.
100
VR=5.0V, VIN=6.0V
IOUT=50 mA
Noise (μV/Hz)
10
1
VR=2,8V, VIN=3.8V
0.1
VR=1.2V, VIN=2.7V
0.01
0.001
0.01
0.1
FIGURE 2-27:
DS22008E-page 10
1
10
Frequency (kHz)
100
1000
Output Noise vs. Frequency.
2010 Microchip Technology Inc.
MCP1702
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
PIN FUNCTION TABLE
Pin No.
SOT-23A
Pin No.
SOT-89
Pin No.
TO-92
Symbol
1
1
1
GND
Ground Terminal
2
3
3
VOUT
Regulated Voltage Output
3
2, Tab
2
VIN
Unregulated Supply Voltage
–
–
–
NC
No connection
3.1
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 (2.0 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.
3.2
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.
2010 Microchip Technology Inc.
Function
3.3
Unregulated Input Voltage Pin
(VIN)
Connect VIN to the input unregulated source voltage.
Like all LDO 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, 1 µF of capacitance will ensure stable
operation of the LDO circuit. For applications that have
load currents below 100 mA, the input capacitance
requirement can be lowered. 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.
DS22008E-page 11
MCP1702
4.0
DETAILED DESCRIPTION
4.1
Output Regulation
4.3
A portion of the LDO output voltage is fed back to the
internal error amplifier and compared with the precision
internal band gap 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
Overtemperature
The internal power dissipation within the LDO is a
function of input-to-output voltage differential and load
current. If the power dissipation within the LDO is
excessive, the internal junction temperature will rise
above the typical shutdown threshold of 150°C. At that
point, the LDO will shut down and begin to cool to the
typical turn-on junction temperature of 130°C. If the
power dissipation is low enough, the device will
continue to cool and operate normally. If the power
dissipation remains high, the thermal shutdown
protection circuitry will again turn off the LDO,
protecting it from catastrophic failure.
Overcurrent
The MCP1702 internal circuitry monitors the amount of
current flowing through the P-Channel pass transistor.
In the event of a short-circuit or excessive output
current, the MCP1702 will turn off the P-Channel
device for a short period, after which the LDO will
attempt to restart. If the excessive current remains, the
cycle will repeat itself.
MCP1702
VOUT
VIN
Error Amplifier
+VIN
Voltage
Reference
+
Overcurrent
Overtemperature
GND
FIGURE 4-1:
DS22008E-page 12
Block Diagram.
2010 Microchip Technology Inc.
MCP1702
5.0
FUNCTIONAL DESCRIPTION
The MCP1702 CMOS LDO linear regulator is intended
for applications that need the lowest current
consumption while maintaining output voltage
regulation. The operating continuous load range of the
MCP1702 is from 0 mA to 250 mA (VR 2.5V). The
input operating voltage range is from 2.7V to 13.2V,
making it capable of operating from two or more
alkaline cells or single and multiple Li-Ion cell batteries.
5.1
Input
The input of the MCP1702 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 (up to
100 mA), a 1 µF ceramic capacitor will be sufficient to
ensure circuit stability. Larger values can be used to
improve circuit AC performance.
5.2
Output
The maximum rated continuous output current for the
MCP1702 is 250 mA (VR 2.5V). For applications
where VR < 2.5V, the maximum output current is
200 mA.
A minimum output capacitance of 1.0 µF is required for
small signal stability in applications that have up to
250 mA output current capability. The capacitor type
can be ceramic, tantalum or aluminum electrolytic. The
esr range on the output capacitor can range from 0 to
2.0.
The output capacitor range for ceramic capacitors is
1 µF to 22 µF. Higher output capacitance values may
be used for tantalum and electrolytic capacitors. Higher
output capacitor values pull the pole of the LDO
transfer function inward that results in higher phase
shifts which in turn cause a lower crossover frequency.
The circuit designer should verify the stability by
applying line step and load step testing to their system
when using capacitance values greater than 22 µF.
5.3
Output Rise Time
When powering up the internal reference output, the
typical output rise time of 500 µs is controlled to
prevent overshoot of the output voltage. There is also a
start-up delay time that ranges from 300 µs to 800 µs
based on loading. The start-up time is separate from
and precedes the Output Rise Time. The total output
delay is the Start-up Delay plus the Output Rise time.
2010 Microchip Technology Inc.
DS22008E-page 13
MCP1702
6.0
APPLICATION CIRCUITS AND
ISSUES
6.1
The MCP1702 is most commonly used as a voltage
regulator. Its low quiescent current and low dropout
voltage makes it ideal for many battery-powered
applications.
VIN
(2.8V to 3.2V)
GND
VIN
VOUT
CIN
1 µF Ceramic
COUT
1 µF Ceramic
FIGURE 6-1:
6.1.1
TJ(MAX)
=
PTOTAL
=
Typical Application Circuit.
Input Voltage Range = 2.8V to 3.2V
VIN maximum = 3.2V
VOUT typical = 1.8V
Total device power dissipation
Thermal resistance from
junction to ambient
=
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
APPLICATION INPUT CONDITIONS
Package Type = SOT-23A
Maximum continuous junction
temperature
RJA
TAMAX
MCP1702
IOUT
150 mA
T J MAX = P TOTAL R JA + T AMAX
Where:
Typical Application
VOUT
1.8V
EQUATION 6-2:
Where:
PD(MAX)
=
Maximum device power
dissipation
TJ(MAX)
=
Maximum continuous junction
temperature
IOUT = 150 mA maximum
6.2
Power Calculations
6.2.1
TA(MAX)
RJA
Maximum ambient temperature
=
Thermal resistance from
junction to ambient
POWER DISSIPATION
The internal power dissipation of the MCP1702 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
(2.0 µA x VIN). The following equation can be used to
calculate the internal power dissipation of the LDO.
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
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
Thermal resistance from
junction to ambient
RJA
EQUATION 6-5:
T J = T J RISE + T A
The maximum continuous operating junction
temperature specified for the MCP1702 is +125°C. To
estimate the internal junction temperature of the
MCP1702, 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-23A pin package is estimated at
336°C/W.
DS22008E-page 14
Where:
TJ
=
Junction Temperature
TJ(RISE)
=
Rise in device junction
temperature over the ambient
temperature
TA
Ambient temperature
2010 Microchip Technology Inc.
MCP1702
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
POWER DISSIPATION EXAMPLE
Package
Package Type
=
SOT-23A
=
2.8V to 3.2V
Input Voltage
VIN
LDO Output Voltages and Currents
VOUT
=
1.8V
IOUT
=
150 mA
Maximum Ambient Temperature
TA(MAX)
=
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 below.
TJ
=
(VIN(MAX) - VOUT(MIN)) x
IOUT(MAX)
PLDO
=
(3.2V - (0.97 x 1.8V)) x 150 mA
PLDO
=
218.1 milli-Watts
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 SOT-23 Can Dissipate in an
Application”, (DS00792), for more information
regarding this subject.
TJ(RISE)
=
PTOTAL x RqJA
TJRISE
=
218.1 milli-Watts x 336.0°C/Watt
TJRISE
=
73.3°C
2010 Microchip Technology Inc.
PD(MAX)
=
(+125°C - 40°C) / 336°C/W
PD(MAX)
=
253 milli-Watts
SOT-89 (153.3°C/Watt = RJA)
PD(MAX)
=
(+125°C - 40°C) / 153.3°C/W
PD(MAX)
=
0.554 Watts
TO92 (131.9°C/Watt = RJA)
Internal Power dissipation is the product of the LDO
output current times the voltage across the LDO
(VIN to VOUT).
PLDO(MAX)
TJRISE + TA(MAX)
SOT-23 (336.0°C/Watt = RJA)
+40°C
Internal Power Dissipation
=
TJ = 113.3°C
Maximum Package Power Dissipation at +40°C
Ambient Temperature Assuming Minimal Copper
Usage.
6.4
PD(MAX)
=
(+125°C - 40°C) / 131.9°C/W
PD(MAX)
=
644 milli-Watts
Voltage Reference
The MCP1702 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 MCP1702 LDO. The low-cost, low quiescent
current and small ceramic output capacitor are all
advantages when using the MCP1702 as a voltage
reference.
Ratio Metric Reference
2 µA Bias
MCP1702
VIN
CIN
VOUT
1 µF
GND
PIC®
Microcontroller
COUT
1 µF
VREF
ADO
AD1
Bridge Sensor
FIGURE 6-2:
Using the MCP1702 as a
Voltage Reference.
DS22008E-page 15
MCP1702
6.5
Pulsed Load Applications
For some applications, there are pulsed load current
events that may exceed the specified 250 mA
maximum specification of the MCP1702. The internal
current limit of the MCP1702 will prevent high peak
load demands from causing non-recoverable damage.
The 250 mA rating is a maximum average continuous
rating. As long as the average current does not exceed
250 mA, pulsed higher load currents can be applied to
the MCP1702. The typical current limit for the
MCP1702 is 500 mA (TA +25°C).
DS22008E-page 16
2010 Microchip Technology Inc.
MCP1702
7.0
PACKAGING INFORMATION
7.1
Package Marking Information
3-Pin SOT-23A
Example:
Standard
Extended Temp
Symbol
Voltage *
Symbol
Voltage *
HA
HB
HC
HD
HE
1.2
1.5
1.8
2.5
2.8
HF
HG
HH
HJ
—
3.0
3.3
4.0
5.0
—
XXNN
HANN
Custom
GA
4.5
GC
2.1
GB
2.2
GD
4.1
* Custom output voltages available upon request.
Contact your local Microchip sales office for more information.
Standard
3-Lead SOT-89
Symbol
Voltage *
Symbol
Voltage *
HA
HB
HC
HD
HE
1.2
1.5
1.8
2.5
2.8
HF
HG
HK
HH
HJ
3.0
3.3
3.6
4.0
5.0
XXXYYWW
NNN
Custom
LA
2.1
H9
4.2
LB
3.2
—
—
* Custom output voltages available upon request.
Contact your local Microchip sales office for more information.
3-Lead TO-92
XXXXXX
XXXXXX
XXXXXX
YWWNNN
Legend: XX...X
Y
YY
WW
NNN
e3
*
Note:
Example:
Extended Temp
HA1014
256
Example:
1702
1202E
e3
TO^^
014256
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.
DS22008E-page 17
MCP1702
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