LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
800mA Low Dropout
Positive Regulators
Adjustable and Fixed 2.85V,
3.3V, 5V
DESCRIPTIO
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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
FEATURES
s
s
s
s
s
s
s
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
APPLICATIO S
s
s
s
s
s
Active SCSI Terminators
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Battery Chargers
5V to 3.3V Linear Regulators
TYPICAL APPLICATIO
Dropout Voltage (V
IN
– V
OUT
)
1.4
1.2
DROPOUT VOLTAGE (V)
Active Terminator for SCSI-2 Bus
110Ω
110Ω
LT1117-2.85
IN
4.75V TO
5.25V
OUT
GND
10µF
110Ω
18 TO 27
LINES
1.0
T
J
= 25°C
0.8
0.6
0.4
0.2
T
J
= 125°C
+
+
22µF
110Ω
INDICATES GUARANTEED TEST POINT
LT1117 • TA01
0
0
100 200 300 400 500 600 700 800
OUTPUT CURRENT (mA)
LT1117 • TPC01
U
U
U
–40°C
≤
T
J
< 0°C
0°C
≤
T
J
≤
125°C
1
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
ABSOLUTE
AXI U
RATI GS
Input Voltage
Operating Voltage
LT1117, LT1117-3.3, LT1117-5 ...................... 15V
LT1117-2.85 ................................................... 10V
Surge Voltage
LT1117, LT1117-3.3, LT1117-5 ...................... 20V
PACKAGE/ORDER I FOR ATIO
FRONT VIEW
3
TAB IS
V
OUT
2
1
IN
OUT
ADJ/GND
ST PACKAGE
3-LEAD PLASTIC SOT-223
T
J MAX
= 125°C,θ
JC
= 15°C/W
ORDER PART
NUMBER
LT1117CST
LT1117CST-2.85
LT1117CST-3.3
LT1117CST-5
LT1117IST
LT1117IST-2.85
LT1117IST-3.3
LT1117IST-5
ST PART MARKING
1117
1117I
11172 1117I2
11173 1117I3
11175 1117I5
Consult factory for Military grade parts.
ELECTRICAL CHARACTERISTICS
The
q
denotes 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
10
≤
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, 6.50V
≤
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)
q
q
q
q
q
q
q
q
q
LT1117-3.3
LT1117-5
Line Regulation
LT1117
LT1117-2.85
LT1117-3.3
LT1117-5
2
U
U
W
W W
U
W
(Note 1)
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)
ORDER PART
NUMBER
LT1117CM
LT1117CM-2.85
LT1117CM-3.3
LT1117CM-5
FRONT VIEW
3
TAB IS
V
OUT
2
1
M PACKAGE
3-LEAD PLASTIC DD
IN
OUT
ADJ/GND
T
J MAX
= 125°C,θ
JC
= 10°C/W
DD PART MARKING
1117
11172
11173
11175
MIN
1.238
1.225
2.820
2.790
2.790
3.267
3.235
4.950
4.900
TYP
MAX
UNITS
V
V
V
V
V
V
V
V
V
%
mV
mV
mV
1.250 1.262
1.250 1.270
2.850 2.880
2.850 2.910
2.850 2.910
3.300 3.333
3.300 3.365
5.000 5.050
5.000 5.100
0.035
1
1
1
0.2
6
6
10
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
ELECTRICAL CHARACTERISTICS
The
q
denotes specifications which apply over the full operating temperature range, otherwise specifications are at T
J
= 25°C.
PARAMETER
Load Regulation
LT1117
LT1117-2.85
LT1117-3.3
LT1117-5
CONDITIONS
(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
Quiescent Current
LT1117
LT1117-2.85
LT1117-3.3
LT1117-5
(V
IN
– V
OUT
) = 5V, T
J
= 25°C,
(V
IN
– V
OUT
) = 15V (Note 4)
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)
q
q
q
q
q
q
q
q
q
q
q
MIN
TYP
0.1
1
1
1
1.00
1.05
1.10
1.00
1.05
1.10
MAX
0.4
10
10
15
1.10
1.15
1.20
1.20
1.25
1.30
1200
5
10
10
10
0.1
120
5
UNITS
%
mV
mV
mV
V
V
V
V
V
V
mA
mA
mA
mA
mA
%/W
dB
µA
µA
%
%
%
°C/W
Dropout Voltage
800
950
1.7
5
5
5
0.01
Thermal Regulation
Ripple Rejection
Adjust Pin Current
Adjust Pin Current Change
Temperature Stability
Long Term Stability
RMS Output Noise
Thermal Resistance
60
75
55
0.2
0.5
0.3
0.003
15
Note 1:
Absolute Maximum Ratings are those values beyond which the life
to the device may be imparied.
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 PERFOR A CE CHARACTERISTICS
Minimum Operating Current
(Adjustable Device)
4
MINIMUM OPERATING CURRENT (mA)
1.25
OUTPUT VOLTAGE DEVIATION (%)
SHORT CIRCUIT CURRENT (A)
3
T
J
= 125°C
T
J
= 25°C
2
T
J
= –55°C
1
0
0
5
10
15
INPUT/OUTPUT DIFFERENTIAL (V)
20
U W
LT1117 • TPC02
Short-Circuit Current
0.10
T
J
= 125°C
T
J
= 25°C
0.75
0.05
0
– 0.05
– 0.10
– 0.15
Load Regulation
∆
I
LOAD
= 800mA
1.00
0.50
0.25
0
0
5
10
INPUT/OUTPUT DIFFERENTIAL (V)
15
– 0.20
–50
–25
0
25
50
75
TEMPERATURE (°C)
100
125
LT1117 • TPC03
LT1117 • TPC04
3
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
TYPICAL PERFOR A CE 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
(V
IN
– V
OUT)
≥
V
DROPOUT
V
RIPPLE
≤
3V
P-P
V
RIPPLE
≤
0.5V
P-P
RIPPLE REJECTION (dB)
(V
IN
– V
OUT)
≥
3V
f
RIPPLE
= 120Hz
V
RIPPLE
≤
3V
P-P
f
RIPPLE
= 20kHz
V
RIPPLE
≤
0.5V
P-P
OUTPUT VOLTAGE CHANGE (%)
Adjust Pin Current
100
OUPUT VOLTAGE
DEVIATION (V)
90
AJUST PIN CURRENT (µA)
0.2
0.1
0
–0.1
–0.2
80
70
60
50
40
OUPUT VOLTAGE
DEVIATION (V)
LOAD CURRENT
(A)
20
10
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1117 • TPC08
0.5
0
–0.5
0
10 20 30 40 50 60 70 80 90 100
TIME (µs)
LT1117 • TPC09
LOAD CURRENT
(A)
30
LT1117-2.8
Line Transient Response
OUPUT VOLTAGE
DEVIATION (mV)
OUPUT VOLTAGE
DEVIATION (mV)
C
IN
= 1µF
C
OUT
= 10µF TANTALUM
40
I
OUT
= 0.1A
20
0
–20
–40
60
60
40
20
0
–20
–40
INPUT VOLTAGE
(V)
7.50
6.50
5.50
INPUT VOLTAGE
(V)
5.25
4.25
3.25
0
20 40 60 80 100 120 140 160 180 200
TIME (µs)
LT1117 • TPC11
4
U W
LT1117 • TPC05
LT1117 Ripple Rejection vs Current
100
V
OUT
= 5V
90 C
ADJ
= 25µF
C
OUT
= 25µF
80
70
60
50
40
30
20
10
0
0
0.2
0.4
0.6
OUTPUT CURRENT (A)
0.8
2.0
Temperature Stability
1.0
0
–1.0
–2.0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1117 • TPC07
LT1117 • TPC06
LT1117-2.85
Load Transient Response
0.3
C
IN
= 10µF
C
OUT
= 10µF TANTALUM
V
IN
= 4.25V
PRELOAD = 0.1A
0.3
LT1117-5
Load Transient Response
C
IN
= 10µF
C
OUT
= 10µF TANTALUM
0.2
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)
LT1117 • TPC10
LT1117-5
Line Transient Response
C
IN
= 1µF
C
OUT
= 10µF TANTALUM
I
OUT
= 0.1A
0
20 40 60 80 100 120 140 160 180 200
TIME (µs)
LT1117 • TPC12
LT1117/LT1117-2.85
LT1117-3.3/LT1117-5
BLOCK DIAGRA
W
IN
+
–
THERMAL
LIMIT
ADJ
OUT
GND
FOR FIXED VOLTAGE DEVICE
LT1117 • BD01
APPLICATIO HI TS
The LT1117 family of 3-terminal regulators are easy to
use. They 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. These regulators are pin compatible
with older 3-terminal adjustable regulators, offer lower
dropout voltage and more precise reference tolerance.
Reference stability over temperature is improved over
older types of regulators.
Stability
The LT1117 family of regulators requires an output ca-
pacitor as part of the device frequency compensation. A
minimum of 10µF of tantalum or 50µF of aluminum
electrolytic is required. The ESR of the output capacitor
should be less than 0.5Ω. Surface mount tantalum capaci-
tors, which have very low ESR, are available from several
manufacturers.
When using the LT1117 adjustable device the adjust
terminal can be bypassed to improve ripple rejection.
When the adjust terminal is bypassed the required value of
the output capacitor increases. The device will require an
output capacitor of 22µF tantalum or 150µF aluminum
electrolytic when the adjust pin is bypassed.
Normally, capacitor values on the order of 100µF are used
in the output of many regulators to ensure good load
transient response with large load current changes. Out-
put capacitance can be increased without limit and larger
values of output capacitance further improve stability and
transient response.
Protection Diodes
In normal operation, the LT1117 family does not need any
protection diodes. Older adjustable regulators required
protection diodes between the adjust pin and the output
and between the output and input to prevent over stress-
ing the die. The internal current paths on the LT1117 adjust
pin are limited by internal resistors. Therefore, even with
capacitors on the adjust pin, no protection diode is needed
to ensure device safety under short-circuit conditions.
U U
5
Embedded System
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