LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
800mA Low Dropout
Positive Regulators Adjustable
and Fixed 2.85V, 3.3V, 5V
FEATURES
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DESCRIPTION
The LT
®
1117 is a positive low dropout regulator designed
to provide up to 800mA of output current. The device is
available in an adjustable version and fixed output voltages
of 2.85V, 3.3V and 5V. The 2.85V version is designed
specifically to be used in Active Terminators for the SCSI
bus. All internal circuitry is designed to operate down to 1V
input to output differential. Dropout voltage is guaranteed
at a maximum of 1.2V at 800mA, decreasing at lower load
currents. On chip trimming adjusts the reference/output
voltage to within ± 1%. Current limit is also trimmed in
order to minimize the stress on both the regulator and the
power source circuitry under overload conditions.
The low profile surface mount SOT-223 package allows the
device to be used in applications where space is limited. The
LT1117 requires a minimum of 10μF of output capacitance
for stability. Output capacitors of this size or larger are
normally included in most regulator designs.
Unlike PNP type regulators where up to 10% of the output
current is wasted as quiescent current, the quiescent current
of the LT1117 flows into the load, increasing efficiency.
Space Saving SOT-223 Surface Mount Package
3-Terminal Adjustable or Fixed 2.85V, 3.3V, 5V
Output Current of 800mA
Operates Down to 1V Dropout
Guaranteed Dropout Voltage at Multiple Current Levels
0.2% Line Regulation Max
0.4% Load Regulation Max
APPLICATIONS
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Active SCSI Terminators
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Battery Chargers
5V to 3.3V Linear Regulators
L,
LT, LTC, LTM, Linear Technology, OPTI-LOOP and the Linear logo are registered trademarks
of Linear Technology Corporation. UltraFast is a trademark of Linear Technology Corporation. All
other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Active Terminator for SCSI-2 Bus
1.4
110Ω
110Ω
LT1117-2.85
IN
4.75V TO
5.25V
OUT
GND
10μF
DROPOUT VOLTAGE (V)
110Ω
18 TO 27
LINES
1.2
1.0
T
J
= 25°C
0.8
0.6
0.4
0.2
INDICATES GUARANTEED TEST POINT
0
0
100 200 300 400 500 600 700 800
OUTPUT CURRENT (mA)
1117 TA02
Dropout Voltage (V
IN
– V
OUT
)
–40°C ≤ T
J
< 0°C
0°C ≤ T
J
≤ 125°C
+
+
22μF
T
J
= 125°C
110Ω
1117 TA01
1117fd
1
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage
Operating Voltage
LT1117, LT1117-3.3, LT1117-5 .........................15V
LT1117-2.85 .....................................................10V
Surge Voltage
LT1117, LT1117-3.3, LT1117-5 .........................20V
Operating JunctionTemperature Range
C Grade .................................................. 0°C to 125°C
I Grade ...............................................– 40°C to 125°C
Storage Temperature Range...................–65°C to 150°C
Lead Temperature ....................(See Soldering Methods)
PIN CONFIGURATION
FRONT VIEW
3
TAB IS
V
OUT
2
1
IN
OUT
ADJ/GND
TAB IS
V
OUT
FRONT VIEW
3
2
1
M PACKAGE
3-LEAD PLASTIC DD-PAK
T
JMAX
= 125°C,
θ
JC
= 10°C/W
IN
OUT
ADJ/GND
ST PACKAGE
3-LEAD PLASTIC SOT-223
T
JMAX
= 125°C,
θ
JC
= 15°C/W
ORDER INFORMATION
LEAD FREE FINISH
LT1117CST#PBF
LT1117IST#PBF
LT1117CST-2.85#PBF
LT1117IST-2.85#PBF
LT1117CST-3.3#PBF
LT1117IST-3.3#PBF
LT1117CST-5#PBF
LT1117IST-5#PBF
LT1117CM#PBF
LT1117CM-2.85#PBF
LT1117CM-3.3#PBF
LT1117CM-5#PBF
TAPE AND REEL
LT1117CST#TRPBF
LT1117IST#TRPBF
LT1117CST-2.85#TRPBF
LT1117IST-2.85#TRPBF
LT1117CST-3.3#TRPBF
LT1117IST-3.3#TRPBF
LT1117CST-5#TRPBF
LT1117IST-5#TRPBF
LT1117CM#TRPBF
LT1117CM-2.85#TRPBF
LT1117CM-3.3#TRPBF
LT1117CM-5#TRPBF
PART MARKING
1117
1117I
11172
1117I2
11173
1117I3
11175
1117I5
LT1117CM
LT1117CM-2.85
LT1117CM-3.3
LT1117CM-5
PACKAGE DESCRIPTION
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
TEMPERATURE RANGE
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
0°C to 125°C
0°C to 125°C
0°C to 125°C
1117fd
2
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
ORDER INFORMATION
LEAD BASED FINISH
LT1117CST
LT1117IST
LT1117CST-2.85
LT1117IST-2.85
LT1117CST-3.3
LT1117IST-3.3
LT1117CST-5
LT1117IST-5
LT1117CM
LT1117CM-2.85
LT1117CM-3.3
LT1117CM-5
TAPE AND REEL
LT1117CST#TR
LT1117IST#TR
LT1117CST-2.85#TR
LT1117IST-2.85#TR
LT1117CST-3.3#TR
LT1117IST-3.3#TR
LT1117CST-5#TR
LT1117IST-5#TR
LT1117CM#TR
LT1117CM-2.85#TR
LT1117CM-3.3#TR
LT1117CM-5#TR
PART MARKING
1117
1117I
11172
1117I2
11173
1117I3
11175
1117I5
LT1117CM
LT1117CM-2.85
LT1117CM-3.3
LT1117CM-5
PACKAGE DESCRIPTION
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic SOT-223
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
3-Lead Plastic DD-PAK
TEMPERATURE RANGE
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
–40°C to 125°C
0°C to 125°C
0°C to 125°C
0°C to 125°C
0°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C.
PARAMETER
Reference Voltage
Output Voltage
LT1117
LT1117-2.85
CONDITIONS
I
OUT
= 10mA, (V
IN
– V
OUT
) = 2V, T
J
= 25°C
10mA ≤ I
OUT
≤ 800mA, 1.4V ≤ (V
IN
– V
OUT
) ≤ 10V
I
OUT
= 10mA, V
IN
= 4.85V, T
J
= 25°C
0 ≤ I
OUT
≤ 800mA, 4.25V ≤ V
IN
≤ 10V
0 ≤ I
OUT
≤ 500mA, V
IN
= 3.95V
I
OUT
= 10mA, V
IN
= 5V, T
J
= 25°C
0 ≤ I
OUT
≤ 800mA, 4.75V ≤ V
IN
≤ 10V
I
OUT
= 10mA, V
IN
= 7V, T
J
= 25°C
0 ≤ I
OUT
≤ 800mA, 6.5V ≤ V
IN
≤ 12V
I
OUT
= 10mA, 1.5V ≤ V
IN
– V
OUT
≤ 15V (Note 2)
I
OUT
= 0mA, 4.25V ≤ V
IN
≤ 10V (Note 2)
I
OUT
= 0mA, 4.75V ≤ V
IN
≤ 15V (Note 2)
I
OUT
= 0mA, 6.5V ≤ V
IN
≤ 15V (Note 2)
(V
IN
– V
OUT
) = 3V, 10mA ≤ I
OUT
≤ 800mA (Note 2)
V
IN
= 4.25V, 0 ≤ I
OUT
≤ 800mA (Note 2)
V
IN
= 4.75V, 0 ≤ I
OUT
≤ 800mA (Note 2)
V
IN
= 6.5V, 0 ≤ I
OUT
≤ 800mA (Note 2)
I
OUT
= 100mA, 0°C ≤ T
J
≤ 125°C (Note 3)
I
OUT
= 500mA, 0°C ≤ T
J
≤ 125°C (Note 3)
I
OUT
= 800mA, 0°C ≤ T
J
≤ 125°C (Note 3)
I
OUT
= 100mA, – 40°C ≤ T
J
< 0°C (Note 3)
I
OUT
= 500mA, – 40°C ≤ T
J
< 0°C (Note 3)
I
OUT
= 800mA, – 40°C ≤ T
J
< 0°C (Note 3)
Current Limit
Minimum Load Current
LT1117
(V
IN
– V
OUT
) = 5V, T
J
= 25°C
(V
IN
– V
OUT
) = 15V (Note 4)
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ELECTRICAL CHARACTERISTICS
MIN
1.238
1.225
2.820
2.790
2.790
3.267
3.235
4.950
4.900
TYP
1.250
1.250
2.850
2.850
2.850
3.300
3.300
5.000
5.000
0.035
1
1
1
0.1
1
1
1
1.00
1.05
1.10
1.00
1.05
1.10
MAX
1.262
1.270
2.880
2.910
2.910
3.333
3.365
5.050
5.100
0.2
6
6
10
0.4
10
10
15
1.10
1.15
1.20
1.20
1.25
1.30
1200
5
UNITS
V
V
V
V
V
V
V
V
V
%
mV
mV
mV
%
mV
mV
mV
V
V
V
V
V
V
mA
mA
1117fd
LT1117-3.3
LT1117-5
Line Regulation
LT1117
LT1117-2.85
LT1117-3.3
LT1117-5
LT1117
LT1117-2.85
LT1117-3.3
LT1117-5
Load Regulation
Dropout Voltage
800
950
1.7
3
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
ELECTRICAL CHARACTERISTICS
PARAMETER
Quiescent Current
LT1117-2.85
LT1117-3.3
LT1117-5
CONDITIONS
V
IN
≤ 10V
V
IN
≤ 15V
V
IN
≤ 15V
T
A
= 25°C, 30ms Pulse
f
RIPPLE
= 120Hz, (V
IN
– V
OUT
) = 3V, V
RIPPLE
= 1V
P-P
10mA ≤ I
OUT
≤ 800mA, 1.4V ≤ (V
IN
– V
OUT
) ≤ 10V
T
A
= 125°C, 1000Hrs
(% of V
OUT
), 10Hz ≤ f ≤ 10kHz
(Junction-to-Case, at Tab)
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The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
J
= 25°C.
MIN
TYP
5
5
5
0.01
60
75
55
0.2
0.5
0.3
0.003
15
120
5
MAX
10
10
10
0.1
UNITS
mA
mA
mA
%/W
dB
μA
μA
%
%
%
°C/W
Thermal Regulation
Ripple Rejection
Adjust Pin Current
Adjust Pin Current Change
Temperature Stability
Long Term Stability
RMS Output Noise
Thermal Resistance
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
See thermal regulation specification for changes in output voltage
due to heating effects. Load regulation and line regulation are measured at
a constant junction temperature by low duty cycle pulse testing.
Note 3:
Dropout voltage is specified over the full output current range
of the device. Dropout voltage is defined as the minimum input/output
differential measured at the specified output current. Test points and limits
are also shown on the Dropout Voltage curve.
Note 4:
Minimum load current is defined as the minimum output current
required to maintain regulation.
TYPICAL PERFORMANCE CHARACTERISTICS
Minimum Operating Current
(Adjustable Device)
4
MINIMUM OPERATING CURRENT (mA)
1.25
OUTPUT VOLTAGE DEVIATION (%)
T
J
= 125°C
T
J
= 25°C
0.75
Short-Circuit Current
0.10
0.05
0
–0.05
–0.10
–0.15
Load Regulation
ΔI
LOAD
= 800mA
SHORT CIRCUIT CURRENT (A)
1.00
3
T
J
= 125°C
T
J
= 25°C
2
T
J
= –55°C
1
0.50
0.25
0
0
10
15
5
INPUT/OUTPUT DIFFERENTIAL (V)
20
1117 G01
0
0
5
10
INPUT/OUTPUT DIFFERENTIAL (V)
15
1117 G02
–0.20
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
1117 G03
1117fd
4
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
TYPICAL PERFORMANCE CHARACTERISTICS
LT1117 Ripple Rejection
100
90
80
RIPPLE REJECTION (dB)
70
60
50
40
30
20
10
0
C
ADJ
= 200μF AT f < 60Hz
C
ADJ
= 25μF AT f > 60Hz
I
OUT
= 0.5A
10
100
1k
10k
FREQUENCY (Hz)
100k
1117 G04
LT1117 Ripple Rejection
vs Current
100
V
RIPPLE
≤
0.5V
P-P
RIPPLE REJECTION (dB)
90
80
V
OUT
= 5V
C
ADJ
= 25μF
C
OUT
= 25μF
2.0
OUTPUT VOLTAGE CHANGE (%)
Temperature Stability
V
RIPPLE
≤ 3V
P-P
f
RIPPLE
= 120Hz
V
RIPPLE
≤ 3V
P-P
f
RIPPLE
= 20kHz
V
RIPPLE
≤ 0.5V
P-P
(V
IN
– V
OUT)
≥ 3V
1.0
70
60
50
40
30
20
10
0
0
0
(V
IN
– V
OUT)
≥ V
DROPOUT
–1.0
0.2
0.4
0.6
OUTPUT CURRENT (A)
0.8
1117 G05
–2.0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1117 G06
Adjust Pin Current
100
OUTPUT VOLTAGE
DEVIATION (V)
90
ADJUST PIN CURRENT (μA)
80
70
60
50
40
LOAD CURRENT
(A)
30
20
10
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
1117 G07
LT1117-2.85
Load Transient Response
0.3
0.2
0.1
0
–0.1
–0.2
0.5
0
–0.5
0
10 20 30 40 50 60 70 80 90 100
TIME (μs)
1117 G08
LT1117-5
Load Transient Response
0.3
OUTPUT VOLTAGE
DEVIATION (V)
LOAD CURRENT
(A)
C
IN
= 10μF
0.2 C
OUT
= 10μF TANTALUM
V
IN
= 6.5V
PRELOAD = 0.1A
0.1
0
–0.1
–0.2
0.5
0
–0.5
0
10 20 30 40 50 60 70 80 90 100
TIME (μs)
1117 G09
C
IN
= 10μF
C
OUT
= 10μF TANTALUM
V
IN
= 4.25V
PRELOAD = 0.1A
LT1117-2.85
Line Transient Response
60
OUTPUT VOLTAGE
DEVIATION (mV)
OUTPUT VOLTAGE
DEVIATION (mV)
C
IN
= 1μF
40 C
OUT
= 10μF TANTALUM
I
OUT
= 0.1A
20
0
–20
–40
INPUT VOLTAGE
(V)
5.25
4.25
3.25
0
20 40 60 80 100 120 140 160 180 200
TIME (μs)
1117 G10
LT1117-5
Line Transient Response
60
40
20
0
–20
–40
INPUT VOLTAGE
(V)
7.50
6.50
5.50
0
20 40 60 80 100 120 140 160 180 200
TIME (μs)
1117 G11
C
IN
= 1μF
C
OUT
= 10μF TANTALUM
I
OUT
= 0.1A
1117fd
5
嵌入式系统
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