Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
Advanced AMS1117
Monolithic 1A LOW DROPOUT VOLTAGE REGULATOR
Systems
FEATURES APPLICATIONS
Three Terminal Adjustable or Fixed Voltages* High Efficiency Linear Regulators
1.5V, 1.8V, 2.5V, 2.85V, 3.3V and 5.0V
Post Regulators for Switching Supplies
Output Current of 1A 5V to 3.3V Linear Regulator
Operates Down to 1V Dropout Battery Chargers
Line Regulation: 0.2% Max. Active SCSI Terminators
Load Regulation: 0.4% Max. Power Management for Notebook
SOT-223 and TO-252 package available Battery Powered Instrumentation
GENERAL DESCRIPTION
The
The AMS1117 series of adjustable and fixed voltage regulators are designed to provide 1A output current and to operate
down to 1V input-to-output differential. The dropout voltage of the device is guaranteed maximum 1.3V at maximum output
current, decreasing at lower load currents.
On-chip trimming adjusts the reference voltage to 1%. Current limit is also trimmed, minimizing the stress under overload
conditions on both the regulator and power source circuitry.
The AMS1117 devices are pin compatible with other three-terminal SCSI regulators and are offered in the low profile surface
mount SOT-223 package and in the TO-252 (DPAK) plastic package.
ORDERING INFORMATION:
PACKAGE TYPE OPERATING JUNCTION
TO-252 SOT-223 TEMPERATURE RANGE
AMS1117CD AMS1117 -40 to 125° C
AMS1117CD-1.5 AMS1117-1.5 -40 to 125° C
AMS1117CD-1.8 AMS1117-1.8 -40 to 125° C
AMS1117CD-2.5 AMS1117-2.5 -40 to 125° C
AMS1117CD-2.85 AMS1117-2.85 -40 to 125° C
AMS1117CD-3.3 AMS1117-3.3 -40 to 125° C
AMS1117CD-5.0 AMS1117-5.0 -40 to 125° C
*For additional available fixed voltages contact factory.
PIN CONNECTIONS
FIXED VERSION
ADJUSTABLE VERSION
1- Ground
2- VOUT
3- VIN
1- Adjust
2- VOUT
3- VIN
SOT-223 Top View
12 3
TAB IS
OUTPUT
TO-252 FRONT VIEW
1
2
3
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
ABSOLUTE MAXIMUM RATINGS (Note 1)
Power Dissipation Internally limited
Soldering information
Input Voltage 15V
Lead Temperature (10 sec) 300°C
Operating
Junction Temperature Range
Thermal Resistance
Control Section -40°C to 125°C
TO-252 package ϕ JA= 80°C/W
Power Transistor -40°C to 150°C
SOT-223 package ϕ JA= 90°C/W*
Storage temperature - 65°C to +150°C
* With package soldering to copper area over backside
ground plane or internal power plane ϕ JA can vary from
46°C/W to >90°C/W depending on mounting technique and
the size of the copper area.
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified.
Parameter
Device Conditions Min Typ Max Units
Reference Voltage
(Note 2) AMS1117 IOUT = 10 mA
10mA IOUT 1A, 1.5V (VIN - VOUT) 12V 1.238
1.225 1.250
1.250 1.262
1.270 V
V
Output Voltage
(Note 2) AMS1117-1.5 0 IOUT 1A , 3.0V VIN 12V 1.485
1.476 1.500
1.500 1.515
1.524 V
V
AMS1117-1.8 0 IOUT 1A , 3.3V VIN 12V 1.782
1.773 1.800
1.800 1.818
1.827 V
V
AMS1117-2.5 0 IOUT 1A , 4.0V VIN 12V 2.475
2.460 2.500
2.500 2.525
2.560 V
V
AMS1117-2.85 0 IOUT 1A , 4.35V VIN 12V 2.82
2.79 2.850
2.850 2.88
2.91 V
V
AMS1117-3.3 0 IOUT 1A , 4.75V VIN 12V 3.267
3.235 3.300
3.300 3.333
3.365 V
V
AMS1117-5.0 0 IOUT 1A , 6.5V VIN 12V 4.950
4.900 5.000
5.000 5.050
5.100 V
V
Line Regulation AMS1117 ILOAD = 10 mA , 1.5V (VIN - VOUT) 12V 0.015
0.035 0.2
0.2 %
%
AMS1117-1.5 3.0V VIN 12V 0.3
0.6 5
6 mV
mV
AMS1117-1.8 3.3V VIN 12V 0.3
0.6 5
6 mV
mV
AMS1117-2.5 4.0V VIN 12V 0.3
0.6 6
6 mV
mV
AMS1117-2.85 4.35V VIN 12V 0.3
0.6 6
6 mV
mV
AMS1117-3.3 4.75V VIN 12V 0.5
1.0 10
10 mV
mV
AMS1117-5.0 6.5V VIN 12V 0.5
1.0 10
10 mV
mV
Load Regulation
(Notes 2, 3)
AMS1117 (VIN - VOUT) =3V, 10mA IOUT 1A 0.1
0.2 0.3
0.4 %
%
AMS1117-1.5 VIN = 5V, 0 IOUT 1A 3
6 10
20 mV
mV
AMS1117-1.8 VIN = 5V, 0 IOUT 1A 3
6 10
20 mV
mV
AMS1117-2.5 VIN = 5V, 0 IOUT 1A 3
6 12
20 mV
mV
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
ELECTRICAL CHARACTERISTICS
Electrical Characteristics at IOUT = 0 mA, and TJ = +25°C unless otherwise specified.
Parameter
Device Conditions Min Typ Max Units
Load Regulation
(Notes 2, 3)
AMS1117-2.85 VIN = 5V, 0 IOUT 1A 3
6 12
20 mV
mV
AMS1117-3.3 VIN = 5V, 0 IOUT 1A 3
7 15
25 mV
mV
AMS1117-5.0 VIN = 8V, 0 IOUT 1A 5
10 20
35 mV
mV
Dropout Voltage
(VIN - VOUT) AMS1117-1.5/-1.8/-2.5/-
2.85/-3.3/-5.0 VOUT , VREF = 1%, IOUT = 1A (Note 4)
1.1 1.3
V
Current Limit
AMS1117-1.5/-1.8/-2.5/-
2.85/-3.3/-5.0 (VIN - VOUT) = 5V
900 1,100 1,500 mA
Minimum Load
Current AMS1117 (VIN - VOUT) = 12V (Note 5) 5 10 mA
Quiescent Current AMS1117-1.5/-1.8/-2.5/-
2.85/-3.3/-5.0
VIN 12V
5
10
mA
Ripple Rejection AMS1117 f =120Hz , COUT = 22µF Tantalum, IOUT = 1A,
(VIN-VOUT ) = 3V, CADJ =10µF 60 75 dB
AMS1117-1.5/-1.8/-2.5/-
2.85 f =120Hz , COUT = 22µF Tantalum, IOUT = 1A,
VIN = 6V 60
72
dB
AMS1117-3.3 f =120Hz , COUT = 22µF Tantalum, IOUT = 1A
VIN = 6.3V 60 72
dB
AMS1117-5.0 f =120Hz , COUT = 22µF Tantalum, IOUT = 1A
VIN = 8V 60 68
dB
Thermal Regulation AMS1117 TA = 25°C, 30ms pulse 0.008 0.04 %W
Adjust Pin Current AMS1117 10mA IOUT 1A , 1.5V (VIN - VOUT) 12V 55
120 µA
µA
Adjust Pin Current
Change AMS1117 10mA IOUT 1A , 1.5V (VIN - VOUT) 12V 0.2
5
µA
Temperature Stability 0.5 %
Long Term Stability TA =125°C, 1000Hrs 0.3 1 %
RMS Output Noise
(% of VOUT )
TA = 25°C , 10Hz f 10kHz 0.003
%
Thermal Resistance
Junction-to-Case
15 °C/W
Parameters identified with boldface type apply over the full operating temperature range.
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. For guaranteed specifications and test conditions, see the
Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed.
Note 2: Line and Load regulation are guaranteed up to the maximum power dissipation of 1.2 W. Power dissipation is determined by the input/output differential
and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range.
Note 3: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constant junction
temperature by low duty cycle pulse testing. Load regulation is measured at the output lead ~1/8” from the package.
Note 4: Dropout voltage is specified over the full output current range of the device.
Note 5: Minimum load current is defined as the minimum output current required to maintain regulation. When 1.5V (VIN - VOUT) 12V the device is
guaranteed to regulate if the output current is greater than 10mA.
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
APPLICATION HINTS
The AMS1117 series of adjustable and fixed regulators are easy
to use and are protected against short circuit and thermal
overloads. Thermal protection circuitry will shut-down the
regulator should the junction temperature exceed 165°C at the
sense point.
Pin compatible with older three terminal adjustable regulators,
these devices offer the advantage of a lower dropout voltage,
more precise reference tolerance and improved reference stability
with temperature.
Stability
The circuit design used in the AMS1117 series requires the use of
an output capacitor as part of the device frequency compensation.
The addition of 22µF solid tantalum on the output will ensure
stability for all operating conditions.
When the adjustment terminal is bypassed with a capacitor to
improve the ripple rejection, the requirement for an output
capacitor increases. The value of 22µF tantalum covers all cases
of bypassing the adjustment terminal. Without bypassing the
adjustment terminal smaller capacitors can be used with equally
good results.
To further improve stability and transient response of these
devices larger values of output capacitor can be used.
Protection Diodes
Unlike older regulators, the AMS1117 family does not need any
protection diodes between the adjustment pin and the output and
from the output to the input to prevent over-stressing the die.
Internal resistors are limiting the internal current paths on the
AMS1117 adjustment pin, therefore even with capacitors on the
adjustment pin no protection diode is needed to ensure device
safety under short-circuit conditions.
Diodes between the input and output are not usually needed.
Microsecond surge currents of 50A to 100A can be handled by the
internal diode between the input and output pins of the device. In
normal operations it is difficult to get those values of surge
currents even with the use of large output capacitances. If high
value output capacitors are used, such as 1000µF to 5000µF and
the input pin is instantaneously shorted to ground, damage can
occur. A diode from output to input is recommended, when a
crowbar circuit at the input of the AMS1117 is used (Figure 1).
AMS1117
IN OUT
ADJ +COUT
2
F
VOUT
R1
R2
CADJ
10
µ
F
D1
VIN
Figure 1.
Output Voltage
The AMS1117 series develops a 1.25V reference voltage
between the output and the adjust terminal. Placing a resistor
between these two terminals causes a constant current to flow
through R1 and down through R2 to set the overall output
voltage. This current is normally the specified minimum load
current of 10mA. Because IADJ is very small and constant it
represents a small error and it can usually be ignored.
AMS1117
IN OUT
ADJ R1
R2
VOUT
VREF
VIN
IADJ
50µA
VOUT = VREF (1+ R2/R1)+IADJR2
Figure 2. Basic Adjustable Regulator
Load Regulation
True remote load sensing it is not possible to provide, because
the AMS1117 is a three terminal device. The resistance of the
wire connecting the regulator to the load will limit the load
regulation. The data sheet specification for load regulation is
measured at the bottom of the package. Negative side sensing is a
true Kelvin connection, with the bottom of the output divider
returned to the negative side of the load.
The best load regulation is obtained when the top of the resistor
divider R1 is connected directly to the case not to the load. If R1
were connected to the load, the effective resistance between the
regulator and the load would be:
RP x ( R2+R1 ) , RP = Parasitic Line Resistance
R1
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
APPLICATION HINTS
Connected as shown , RP is not multiplied by the divider ratio
AMS1117
IN OUT
ADJ
RL
R1*
R2*
VIN
RP
PARASITIC
LINE RESISTANCE
*CONNECT R1 TO CASE
CONNECT R2 TO LOAD
Figure 3. Connections for Best Load Regulation
In the case of fixed voltage devices the top of R1 is connected
Kelvin internally, and the ground pin can be used for negative
side sensing.
Thermal Considerations
The AMS1117 series have internal power and thermal limiting
circuitry designed to protect the device under overload conditions.
However maximum junction temperature ratings of 125°C should
not be exceeded under continuous normal load conditions.
Careful consideration must be given to all sources of thermal
resistance from junction to ambient. For the surface mount
package SOT-223 additional heat sources mounted near the
device must be considered. The heat dissipation capability of the
PC board and its copper traces is used as a heat sink for the
device. The thermal resistance from the junction to the tab for the
AMS1117 is 15°C/W. Thermal resistance from tab to ambient
can be as low as 30°C/W.
The total thermal resistance from junction to ambient can be as
low as 45°C/W. This requires a reasonable sized PC board with
at least on layer of copper to spread the heat across the board and
couple it into the surrounding air.
Experiments have shown that the heat spreading copper layer
does not need to be electrically connected to the tab of the device.
The PC material can be very effective at transmitting heat
between the pad area, attached to the pad of the device, and a
ground plane layer either inside or on the opposite side of the
board. Although the actual thermal resistance of the PC material
is high, the Length/Area ratio of the thermal resistance between
layers is small. The data in Table 1, was taken using 1/16” FR-4
board with 1 oz. copper foil, and it can be used as a rough
guideline for estimating thermal resistance.
For each application the thermal resistance will be affected by
thermal interactions with other components on the board. To
determine the actual value some experimentation will be
necessary.
The power dissipation of the AMS1117 is equal to:
PD = ( VIN - VOUT )( IOUT )
Maximum junction temperature will be equal to:
TJ = TA(MAX) + PD(Thermal Resistance (junction-to-ambient))
Maximum junction temperature must not exceed 125°C.
Ripple Rejection
The ripple rejection values are measured with the adjustment pin
bypassed. The impedance of the adjust pin capacitor at the ripple
frequency should be less than the value of R1 (normally 100 to
200) for a proper bypassing and ripple rejection approaching
the values shown. The size of the required adjust pin capacitor is
a function of the input ripple frequency. If R1=100 at 120Hz
the adjust pin capacitor should be >13µF. At 10kHz only 0.16µF
is needed.
The ripple rejection will be a function of output voltage, in
circuits without an adjust pin bypass capacitor. The output ripple
will increase directly as a ratio of the output voltage to the
reference voltage (VOUT / VREF ).
Table 1.
COPPER AREA THERMAL RESISTANCE
TOP SIDE* BACK SIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 Sq. mm 2500 Sq. mm 2500 Sq. mm 45°C/W
1000 Sq. mm 2500 Sq. mm 2500 Sq. mm 45°C/W
225 Sq. mm 2500 Sq. mm 2500 Sq. mm 53°C/W
100 Sq. mm 2500 Sq. mm 2500 Sq. mm 59°C/W
1000 Sq. mm 1000 Sq. mm 1000 Sq. mm 52°C/W
1000 Sq. mm 0 1000 Sq. mm 55°C/W
* Tab of device attached to topside copper.
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Operating Current
(Adjustable Device) Short-Circuit Current
Load Regulation Ripple Rejection vs. Current
Adjust Pin CurrentTemperature Stability
0 5 10 15 20
0
3
6
9
12
INPUT/OUTPUT DIFFERENTIAL (V)
0 5 10 15
MINIMUM OPERATING CURRENT (mA)
INPUT/OUTPUT DIFFERENTIAL
0
0.25
0.50
0.75
1.00
1.25
SHORT CIRCUIT CURRENT (A)
-50 -25 0 25 50 75 100 125
-0.20
-0.15
-0.10
-0.05
0
0.05
0.10
TEMPERATURE (°C)
OUTPUT VOLTAGE DEVIATION (%)
00.25 0.5 0.75 1.0
0
10
20
30
40
50
60
70
80
90
100
OUTPUT CURRENT (A)
RIPPLE REJECTION (dB)
-50 -25 0 25 50 75 100 125 150
-2.0
-1.0
0
1.0
2.0
TEMPERATURE (°C)
OUTPUT VOLTAGE CHANGE (%)
TEMPERATURE (°C)
-50 -25 0 25 50 75 100 125 150
0
10
20
30
40
50
60
70
80
90
100
ADJUST PIN CURRENT (µA)
TJ = 125°C
TJ = 25°C
fRIPPLE = 120Hz
fRIPPLE = 20Hz
VRIPPLE3Vp-p
VRIPPLE0.5Vp-p
ILOAD = 1A
VOUT = 5V
CADJ = 25µF
COUT = 25µF
TJ = 125°C
TJ = 25°C
Advanced Monolithic Systems, Inc. www.advanced-monolithic.com Phone (925) 443-0722 Fax (925) 443-0723
AMS1117
PACKAGE DIMENSIONS inches (millimeters) unless otherwise noted.
TO-252 PLASTIC PACKAGE (D)
0.030
(0.762)
TYP
0.087-0.094
(2.21-2.39) 0.018-0.023
(0.46-0.58)
0.020±0.002
(0.510±0.0508)
0.018-0.023
(0.46-0.58) D (D3) AMS DRW# 011601
0.035-0.050
(0.89-1.27)
0.035-0.045
(0.89-1.14)
0.235-0.245
(5.969-6.223)
0.156-0.204
(3.96-5.18)
0.255-0.265
(6.48-6.73)
0.206-0.214
(5.23-5.44)
0.025
(0.635)
TYP
7.0°
0.380-0.410
(9.65-10.41)
0.045-0.060
(1.14-1.52)
3 LEAD SOT-223 PLASTIC PACKAGE
0.130-0.146
(3.30-3.71)
0.248-0.264
(6.30-6.71)
0.116-0.124
(2.95-3.15)
0.264-0.287
(6.71-7.29)
0.090
(2.29)
NOM
0.071
(1.80)
MAX
0.033-0.041
(0.84-1.04)
0.025-0.033
(0.64-0.84)
0.181
(4.60)
NOM
0.012
(0.31)
MIN
0.025-0.033
(0.64-0.84)
10°
MAX
10°-16°
10°-16°
0.010-0.014
(0.25-0.36)
(SOT-223 ) AMS DRW# 042292