LM1117MP-3.3 [ETC]
IC-SM LDO RGULATOR ; IC- SM LDO RGULATOR\n
| 型号： | LM1117MP-3.3 |
| 厂家： | 
ETC |
| 描述： | IC-SM LDO RGULATOR
|
| 文件： | 总18页 (文件大小：405K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
February 1999
LM1117
800mA Low-Dropout Linear Regulator
General Description
Features
n Available in 2.85V, 3.3V, 5V, and Adjustable Versions
n Space Saving SOT-223 Package
The LM1117 is a series of low dropout voltage regulators
with a dropout of 1.2V at 800mA of load current. It has the
same pin-out as National Semiconductor’s industry standard
LM317.
n Current Limiting and Thermal Protection
n Output Current
800mA
The LM1117 is available in an adjustable version, which can
set the output voltage from 1.25V to 13.8V with only two ex-
ternal resistors. In addition, it is also available in three fixed
voltages, 2.85V, 3.3V, and 5V.
n Temperature Range
n Line Regulation
n Load Regulation
0˚C to 125˚C
0.2% (Max)
0.4% (Max)
The LM1117 offers current limiting and thermal shutdown. Its
circuit includes a zener trimmed bandgap reference to as-
Applications
n 2.85V Model for SCSI-2 Active Termination
±
sure output voltage accuracy to within 1%.
n Post Regulator for Switching DC/DC Converter
n High Efficiency Linear Regulators
n Battery Charger
The LM1117 series is available in SOT-223, TO-220, and
TO-252 D-PAK packages. A minimum of 10µF tantalum ca-
pacitor is required at the output to improve the transient re-
sponse and stability.
n Battery Powered Instrumentation
Typical Application
Active Terminator for SCSI-2 Bus
DS100919-5
Fixed Output Regulator
DS100919-28
© 1999 National Semiconductor Corporation
DS100919
www.national.com
Ordering Information
Temperature Range
Package
Packaging Marking
Transport Media
NSC Drawing
0˚C to +125˚C
LM1117MPX-ADJ
LM1117MPX-2.85
LM1117MPX-3.3
LM1117MPX-5.0
LM1117T-ADJ
3-lead SOT-223
N03A
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
Rails
MA04A
N04A
N05A
N06A
3-lead TO-220
3-lead TO-252
LM1117T-ADJ
LM1117T-2.85
LM1117T-3.3
LM1117T-5.0
LM1117DT-ADJ
LM1117DT-2.85
LM1117DT-3.3
LM1117DT-5.0
T03B
LM1117T-2.85
Rails
LM1117T-3.3
Rails
LM1117T-5.0
Rails
LM1117DTX-ADJ
LM1117DTX-2.85
LM1117DTX-3.3
LM1117DTX-5.0
Tape and Reel
Tape and Reel
Tape and Reel
Tape and Reel
TD03B
Block Diagram
DS100919-1
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2
Connection Diagrams
SOT-223
DS100919-4
Top View
TO-220
DS100919-2
Top View
TO-252
DS100919-38
Top View
3
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Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
TO-220 (T) Package
260˚C, 10 sec
260˚C, 4 sec
2000V
SOT-223 (IMP) Package
ESD Tolerance (Note 3)
Operating Ratings (Note 1)
Maximum Input Voltage (VIN to GND)
LM1117-ADJ, LM1117-3.3,
LM1117-5.0
Input Voltage (VIN to GND)
20V
LM1117-ADJ, LM1117-3.3,
LM1117-5.0
15V
Power Dissipation (Note 2)
Internally Limited
Junction Temperature (TJ
(Note 2)
)
LM1117-2.85
10V
150˚C
Junction Temperature Range (T
(Note 2)
)
J
0˚C to 125˚C
Storage Temperature Range
-65˚C to 150˚C
Lead Temperature
Electrical Characteristics
Typicals and limits appearing in normal type apply for T = 25˚C. Limits appearing in Boldface type apply over the entire junc-
J
tion temperature range for operation, 0˚C to 125˚C.
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Symbol
Parameter
Conditions
Units
VREF
Reference Voltage
LM1117-ADJ
IOUT=10mA, VIN-VOUT=2V, TJ=25˚C
10mA≤I OUT≤ 800mA, 1.4V≤
VIN-VOUT≤10V
1.238
1.225
1.250
1.250
1.262
1.270
V
V
VOUT
Output Voltage
LM1117-2.85
IOUT =10mA, VIN=4.85V, TJ=25˚C
O≤I OUT≤800mA, 4.25V≤ VIN≤10V
O≤IOUT ≤500mA, VIN=4.10V
2.820
2.790
2.790
2.850
2.850
2.850
2.880
2.910
2.910
V
V
V
LM1117-3.3
I
OUT=10mA, VIN=5V TJ=25˚C
O≤I OUT≤800mA, 4.75V≤ VIN≤10V
3.267
3.235
3.300
3.300
3.333
3.365
V
V
LM1117-5.0
I
OUT=10mA, VIN=7V, TJ=25˚C
4.950
4.900
5.000
5.000
5.050
5.100
V
V
O≤I OUT≤ 800mA, 6.5V≤ VIN≤12V
∆VOUT
Line Regulation
(Note 6)
LM1117-ADJ
IOUT=10mA, 1.5V≤ VIN-VOUT≤13.75V
0.035
0.2
6
%
LM1117-2.85
I
OUT=0mA, 4.25V≤ VIN≤10V
LM1117-3.3
OUT=0mA, 4.75V≤ VIN≤15V
LM1117-5.0
OUT=0mA, 6.5V≤ VIN≤15V
1
1
mV
mV
mV
%
I
6
I
1
10
0.4
10
10
∆V OUT
Load Regulation
(Note 6)
LM1117-ADJ
VIN-V OUT=3V, 10≤IOUT≤800mA
0.2
1
LM1117-2.85
V IN=4.25V, 0≤IOUT≤800mA
mV
mV
LM1117-3.3
V IN=4.75V, 0≤IOUT≤800mA
1
LM1117-5.0
V IN=6.5V, 0≤IOUT≤800mA
1
15
mV
V
V
IN-V OUT Dropout Voltage
(Note 7)
IOUT=100mA
1.10
1.15
1.20
1200
1.20
1.25
1.30
1500
I
I
OUT=500mA
OUT=800mA
V
V
ILIMIT
Current Limit
VIN-VOUT=5V, TJ=25˚C
800
mA
Minimum Load
Current (Note 8)
LM1117-ADJ
VIN=15V
1.7
5
mA
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4
Electrical Characteristics (Continued)
Typicals and limits appearing in normal type apply for T = 25˚C. Limits appearing in Boldface type apply over the entire junc-
J
tion temperature range for operation, 0˚C to 125˚C.
Min
(Note 5)
Typ
(Note 4)
Max
(Note 5)
Symbol
Parameter
Conditions
Units
Quiescent Current
LM1117-2.85
IN≤10V
LM1117-3.3
IN≤15V
LM1117-5.0
IN≤15V
TA=25˚C, 30ms Pulse
RIPPLE=120Hz, V IN-VOUT=3V
V
5
5
10
10
mA
mA
V
V
5
10
mA
%/W
dB
Thermal Regulation
Ripple Regulation
0.01
75
0.1
f
60
VRIPPLE=1VPP
Adjust Pin Current
60
120
5
µA
Adjust Pin Current
Change
10≤ IOUT≤ 800mA,
1.4V≤ VIN-VOUT≤ 10V
0.2
0.5
µA
%
%
%
Temperature Stability
Long Term Stability
RMS Output Noise
TA=125˚C, 1000Hrs
0.3
(% of VOUT), 10Hz≤f≤10kHz
0.003
Thermal Resistance
Junction-to-Case
3-Lead SOT-223
3-Lead TO-220
3-Lead TO-252
15.0
3.0
10
˚C/W
˚C/W
˚C/W
Thermal Resistance
Junction-to-Ambient
(No heat sink;
3-Lead SOT-223
3-Lead TO-220
3-Lead TO-252(Note 9)
136
79
92
˚C/W
˚C/W
˚C/W
No air flow)
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is in-
tended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.
Note 2: The maximum power dissipation is a function of T
J(max)
, θ , and T . The maximum allowable power dissipation at any ambient temperature is P = (T -
JA
J
A
D
(max)–T )/θ . All numbers apply for packages soldered directly into a PC board.
A
JA
Note 3: For testing purposes, ESD was applied using human body model, 1.5kΩ in series with 100pF.
Note 4: Typical Values represent the most likely parametric norm.
Note 5: All limits are guaranteed by testing or statistical analysis.
Note 6: Load and line regulation are measured at constant junction room temperature.
Note 7: The dropout voltage is the input/output differential at which the circuit ceases to regulate against further reduction in input voltage. It is measured when the
output voltage has dropped 100mV from the nominal value obtained at V =V
IN
+1.5V.
OUT
Note 8: The minimum output current required to maintain regulation.
2
Note 9: Minimum pad size of 0.038in
5
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Typical Performance Characteristics
Dropout Voltage (VIN-V
)
Short-Circuit Current
OUT
DS100919-22
DS100919-23
Load Regulation
LM1117-ADJ Ripple Rejection
DS100919-24
DS100919-6
LM1117-ADJ Ripple Rejection vs. Current
Temperature Stability
DS100919-25
DS100919-7
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6
Typical Performance Characteristics (Continued)
Adjust Pin Current
LM1117-2.85 Load Transient Response
DS100919-26
DS100919-8
LM1117-5.0 Load Transient Response
LM1117-2.85 Line Transient Response
DS100919-9
DS100919-10
LM1117-5.0 Line Transient Response
DS100919-11
7
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APPLICATION NOTE
1.0 External Capacitors/Stability
Figure 2, shows a typical application using a fixed output
regulator. The Rt1 and Rt2 are the line resistances. It is ob-
vious that the V LOAD is less than the VOUT by the sum of the
voltage drops along the line resistances. In this case, the
load regulation seen at the RLOAD would be degraded from
the data sheet specification. To improve this, the load should
be tied directly to the output terminal on the positive side and
directly tied to the ground terminal on the negative side.
1.1 Input Bypass Capacitor
An input capacitor is recommended. A 10µF tantalum on the
input is a suitable input bypassing for almost all applications.
1.2 Adjust Terminal Bypass Capacitor
The adjust terminal can be bypassed to ground with a by-
pass capacitor (CADJ) to improve ripple rejection. This by-
pass capacitor prevents ripple from being amplified as the
output voltage is increased. At any ripple frequency, the im-
pedance of the CADJ should be less than R1 to prevent the
ripple from being amplified:
<
R1
(2π*fRIPPLE*CADJ
)
The R1 is the resistor between the output and the adjust pin.
Its value is normally in the range of 100-200Ω. For example,
>
with R1=124Ω and fRIPPLE=120Hz, the CADJ should be
11µF.
1.3 Output Capacitor
DS100919-18
The output capacitor is critical in maintaining regulator stabil-
ity, and must meet the required conditions for both minimum
amount of capacitance and ESR (Equivalent Series Resis-
tance). The minimum output capacitance required by the
LM1117 is 10µF, if a tantalum capacitor is used. Any increase
of the output capacitance will merely improve the loop stabil-
ity and transient response. The ESR of the output capacitor
should be less than 0.5Ω. In the case of the adjustable regu-
lator, when the CADJ is used, a larger output capacitance
(22µf tantalum) is required.
FIGURE 2. Typical Application using Fixed Output
Regulator
When the adjustable regulator is used (Figure 3), the best
performance is obtained with the positive side of the resistor
R1 tied directly to the output terminal of the regulator rather
than near the load. This eliminates line drops from appearing
effectively in series with the reference and degrading regula-
tion. For example, a 5V regulator with 0.05Ω resistance be-
tween the regulator and load will have a load regulation due
to line resistance of 0.05Ω x IL. If R1 (=125Ω) is connected
near the load, the effective line resistance will be 0.05Ω
(1+R2/R1) or in this case, it is 4 times worse. In addition, the
ground side of the resistor R2 can be returned near the
ground of the load to provide remote ground sensing and im-
prove load regulation.
2.0 Output Voltage
The LM1117 adjustable version develops a 1.25V reference
voltage, VREF, between the output and the adjust terminal.
As shown in Figure 1, this voltage is applied across resistor
R1 to generate a constant current I1. The current IADJ from
the adjust terminal could introduce error to the output. But
since it is very small (60µA) compared with the I1 and very
constant with line and load changes, the error can be ig-
nored. The constant current I1 then flows through the output
set resistor R2 and sets the output voltage to the desired
level.
For fixed voltage devices, R1 and R2 are integrated inside
the devices.
DS100919-19
FIGURE 3. Best Load Regulation using Adjustable
Output Regulator
4.0 Protection Diodes
DS100919-17
Under normal operation, the LM1117 regulators do not need
any protection diode. With the adjustable device, the internal
resistance between the adjust and output terminals limits the
current. No diode is needed to divert the current around the
regulator even with capacitor on the adjust terminal. The ad-
FIGURE 1. Basic Adjustable Regulator
3.0 Load Regulation
The LM1117 regulates the voltage that appears between its
output and ground pins, or between its output and adjust
pins. In some cases, line resistances can introduce errors to
the voltage across the load. To obtain the best load regula-
tion, a few precautions are needed.
±
just pin can take a transient signal of 25V with respect to
the output voltage without damaging the device.
When a output capacitor is connected to a regulator and the
input is shorted to ground, the output capacitor will discharge
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8
APPLICATION NOTE (Continued)
into the output of the regulator. The discharge current de-
pends on the value of the capacitor, the output voltage of the
regulator, and rate of decrease of V IN. In the LM1117 regu-
lators, the internal diode between the output and input pins
can withstand microsecond surge currents of 10A to 20A.
With an extremely large output capacitor (≥1000 µF), and
with input instantaneously shorted to ground, the regulator
could be damaged.
DS100919-37
FIGURE 5. Cross-sectional view of Integrated Circuit
Mounted on a printed circuit board. Note that the case
temperature is measured at the point where the leads
contact with the mounting pad surface
In this case, an external diode is recommended between the
output and input pins to protect the regulator, as shown in
Figure 4.
The LM1117 regulators have internal thermal shutdown to
protect the device from over-heating. Under all possible op-
erating conditions, the junction temperature of the LM1117
must be within the range of 0˚C to 125˚C. A heatsink may be
required depending on the maximum power dissipation and
maximum ambient temperature of the application. To deter-
mine if a heatsink is needed, the power dissipated by the
regulator, PD , must be calculated:
IIN = IL + IG
PD = (VIN-VOUT)I + VIN G
I
L
Figure 6 shows the voltages and currents which are present
in the circuit.
DS100919-15
FIGURE 4. Regulator with Protection Diode
5.0 Heatsink Requirements
When an integrated circuit operates with an appreciable cur-
rent, its junction temperature is elevated. It is important to
quantify its thermal limits in order to achieve acceptable per-
formance and reliability. This limit is determined by summing
the individual parts consisting of a series of temperature
rises from the semiconductor junction to the operating envi-
ronment. A one-dimensional steady-state model of conduc-
tion heat transfer is demonstrated in Figure 5. The heat gen-
erated at the device junction flows through the die to the die
attach pad, through the lead frame to the surrounding case
material, to the printed circuit board, and eventually to the
ambient environment. Below is a list of variables that may af-
fect the thermal resistance and in turn the need for a heat-
sink.
DS100919-16
FIGURE 6. Power Dissipation Diagram
R
θJC(Component Vari-
ables)
RθCA (Application Vari-
ables)
Leadframe Size &
Material
Mounting Pad Size,
Material, & Location
No. of Conduction Pins
Placement of Mounting
Pad
Die Size
PCB Size & Material
Traces Length & Width
Adjacent Heat Sources
Die Attach Material
Molding Compound Size
and Material
Volume of Air
Ambient Temperatue
Shape of Mounting Pad
9
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needed since the package alone will dissipate enough heat
to satisfy these requirements. If the calculated value for θJA
falls below these limits, a heatsink is required.
APPLICATION NOTE (Continued)
The next parameter which must be calculated is the maxi-
mum allowable temperature rise, TR(max):
As a design aid, Table 1 shows the value of the θJA of SOT-
223 and TO-252 for different heatsink area. The copper pat-
terns that we used to measure these θJAs are shown at the
end of the Application Notes Section. Figure 7 and Figure 8
reflects the same test results as what are in the Table 1
TR(max)=TJ(max)-TA(max)
where TJ(max) is the maximum allowable junction tempera-
ture (125˚C), and TA(max) is the maximum ambient tem-
perature which will be encountered in the application.
Figure 9 and Figure 10 shows the maximum allowable power
dissipation vs. ambient temperature for the SOT-223 and
TO-252 device. Figures Figure 11 and Figure 12 shows the
maximum allowable power dissipation vs. copper area (in2)
for the SOT-223 and TO-252 devices. Please see AN1028
for power enhancement techniques to be used with SOT-223
and TO-252 packages.
Using the calculated values for TR(max) and PD, the maxi-
mum allowable value for the junction-to-ambient thermal re-
sistance (θJA) can be calculated:
θJA = TR(max)/PD
If the maximum allowable value for θJA is found to be
≥136˚C/W for SOT-223 package or ≥79˚C/W for TO-220
package or ≥92˚C/W for TO-252 package, no heatsink is
TABLE 1. θJA Different Heatsink Area
Copper Area
Layout
Thermal Resistance
Top Side (in2)*
Bottom Side (in2)
(θJA,˚C/W) SOT-223
(θJA,˚C/W) TO-252
1
2
0.0123
0.066
0.3
0
0
136
123
84
103
87
60
54
52
47
84
70
63
57
57
89
72
61
55
53
3
0
4
0.53
0.76
1
0
75
5
0
69
6
0
66
7
0
0.2
0.4
0.6
0.8
1
115
98
8
0
9
0
89
10
11
12
13
14
15
16
0
82
0
79
0.066
0.175
0.284
0.392
0.5
0.066
0.175
0.284
0.392
0.5
125
93
83
75
70
*Tab of device attached to topside copper
DS100919-34
FIGURE 8. θJA vs. 2oz Copper Area for TO-252
DS100919-13
FIGURE 7. θJA vs. 1oz Copper Area for SOT-223
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10
APPLICATION NOTE (Continued)
DS100919-35
FIGURE 12. Maximum Allowable Power Dissipation vs.
2oz Copper Area for TO-252
DS100919-12
FIGURE 9. Maximum Allowable Power Dissipation vs.
Ambient Temperature for SOT-223
DS100919-36
FIGURE 10. Maximum Allowable Power Dissipation vs.
Ambient Temperature for TO-252
DS100919-14
FIGURE 11. Maximum Allowable Power Dissipation vs.
1oz Copper Area for SOT-223
11
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APPLICATION NOTE (Continued)
DS100919-20
FIGURE 13. Top View of the Thermal Test Pattern in Actual Scale
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12
APPLICATION NOTE (Continued)
DS100919-21
FIGURE 14. Bottom View of the Thermal Test Pattern in Actual Scale
13
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Typical Application Circuits
DS100919-30
DS100919-31
Adjusting Output of Fixed Regulators
Regulator with Reference
DS100919-27
5V Logic Regulator with Electronic Shutdown*
DS100919-29
1.25V to 10V Adjustable Regulator with Improved
Ripple Rejection
DS100919-32
Battery Backed-Up Regulated Supply
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14
Typical Application Circuits (Continued)
DS100919-33
Low Dropout Negative Supply
15
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Physical Dimensions inches (millimeters) unless otherwise noted
3-Lead SOT-223 Package
Order Number LM1117MPX-ADJ, LM1117MPX-2.85, LM1117MPX-3.3, or LM1117MPX-5.0
NSC Package Number MA04A
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16
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
3-Lead TO-220 Package
Order Number LM1117T-ADJ, LM1117T-2.85, LM1117T-3.3, or LM1117T-5.0
NSC Package Number T03B
17
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Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
3-Lead TO-252 Package
Order Number LM1117DT-ADJ, LM1117DT-2.85, LM1117DT-3.3, or LM1117DT-5.0
NSC Package Number TD03B
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VICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF NATIONAL SEMI-
CONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or sys-
tems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose fail-
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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