LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
Low IQ, Low Dropout,
800mA, Source and Sink
Regulators Adjustable and
Fixed 2.5V, 2.85V, 5V Output
DESCRIPTION
FEATURES
n
n
n
n
n
n
n
n
Regulates While Sourcing or Sinking Current
Provides Termination for up to 27 SCSI Lines
600μA Quiescent Current
Ultralow Power Shutdown Mode
Current Limit and Thermal Shutdown Protection
Stable for Any CLOAD ≥ 0.22μF
Fast Settling Time
1V Dropout Voltage
APPLICATIONS
n
n
n
n
n
Active Negation SCSI Terminations
Computers
Disk Drives
CD-ROM
Supply Splitter
The LT®1118 family of low dropout regulators has the
unique capability of maintaining output regulation while
sourcing or sinking load current. The 2.85V output voltage
regulator is ideal for use as a Boulay termination of up
to 27 SCSI data lines. The regulator maintains regulation
while both sourcing and sinking current, enabling the use
of active negation drivers for improved noise immunity on
the data lines. Regulation of output voltage is maintained
for TERMPWR voltages as low as 4.0V. When unloaded,
quiescent supply current is a low 600μA, allowing continuous connection to the TERMPWR lines. An ultralow power
shutdown mode is also available on the SO-8 version. In
Shutdown the output is high impedance and supply current drops to less than 10μA.
Current limits in both sourcing and sinking modes, plus
on-chip thermal shutdown make the circuit tolerant of
output fault conditions.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
The LT1118 is available in 3-lead SOT-223 and 8-lead SO
packages.
TYPICAL APPLICATION
Load Transient Response
0.2V
IN
LT1118-2.85 OUT
$VOUT
GND
5V
2.2μF
0V
–0.2V
1μF
CERAMIC
800mA
ILOAD
1118 TA01
ILOAD
0mA
–400mA
1118 TA02
1118fd
1
LT1118/LT1118-2.5/
LT1118-2.85/LT1118-5
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Supply Voltage (VCC) ................................................15V
Input Voltage (Enable).................................– 0.2V to 7V
Output Voltage ............................... – 0.2V to VCC + 0.5V
Short-Circuit Duration ..................................... Indefinite
Operating Temperature Range...................... 0°C to 70°C
Storage Temperature Range...................– 65°C to 150°C
Lead Temperature (Soldering, 10 sec) .................. 300°C
PIN CONFIGURATION
TOP VIEW
TOP VIEW
GND 1
IN 1
8 GND
FRONT VIEW
8 EN
NC 2
7 IN
OUT 2
7 GND
EN 3
6 OUT
GND 3
6 GND
FB 4
5 IN
IN 4
5 NC
S8 PACKAGE
8-LEAD PLASTIC SO
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJA = 15°C/W
TJMAX = 125°C, θJA = 15°C/W
TAB IS
GND
3
IN
2
GND
1
OUT
ST PACKAGE
3-LEAD PLASTIC SOT-223
TJMAX = 125°C, θJC = 15°C/W
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1118CS8#PBF
LT1118CS8#TRPBF
1118
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-2.5#PBF
LT1118CS8-2.5#TRPBF
111825
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-2.85#PBF
LT1118CS8-2.85#TRPBF
111828
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-5#PBF
LT1118CS8-5#TRPBF
11185
8-Lead Plastic SO
0°C to 70°C
LT1118CST-2.5#PBF
LT1118CST-2.5#TRPBF
111825
3-Lead Plastic SOT-223
0°C to 70°C
LT1118CST-2.85#PBF
LT1118CST-2.85#TRPBF
111828
3-Lead Plastic SOT-223
0°C to 70°C
LT1118CST-5#PBF
LT1118CST-5#TRPBF
11185
3-Lead Plastic SOT-223
0°C to 70°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT1118CS8
LT1118CS8#TR
1118
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-2.5
LT1118CS8-2.5#TR
111825
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-2.85
LT1118CS8-2.85#TR
111828
8-Lead Plastic SO
0°C to 70°C
LT1118CS8-5
LT1118CS8-5#TR
11185
8-Lead Plastic SO
0°C to 70°C
LT1118CST-2.5
LT1118CST-2.5#TR
111825
3-Lead Plastic SOT-223
0°C to 70°C
LT1118CST-2.85
LT1118CST-2.85#TR
111828
3-Lead Plastic SOT-223
0°C to 70°C
LT1118CST-5
LT1118CST-5#TR
11185
3-Lead Plastic SOT-223
0°C to 70°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/
1118fd
2
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
Quiescent Current (VIN)
VEN = 5V
Quiescent Current in Shutdown (VIN)
Enable Input Thresholds
TYP
MAX
l
0.6
1
mA
VEN = 0V
l
1
10
μA
Input Low Level
Input High Level
l
l
0.4
1.4
1.4
2
V
V
Enable Input Current
0V ≤ VEN ≤ 5V
l
–1
25
μA
Feedback Voltage
No Load (25°C) (LT1118)
All Operating Conditions (Note 3)
l
1.213
1.200
1.225
1.225
1.237
1.250
V
V
No Load (25°C) (LT1118-2.5)
All Operating Conditions (Note 3)
l
2.47
2.45
2.5
2.5
2.53
2.55
V
V
No Load (25°C) (LT1118-2.85)
All Operating Conditions (Note 3)
l
2.82
2.79
2.85
2.85
2.88
2.91
V
V
No Load (25°C) (LT1118-5)
All Operating Conditions (Note 3)
l
4.95
4.90
5
5
5.05
5.10
V
V
Line Regulation (Note 4)
IL = 0mA, 4.2V ≤ VIN ≤ 15V (LT1118)
IL = 0mA, 4.2V ≤ VIN ≤ 15V (LT1118-2.5)
IL = 0mA, 4.75V ≤ VIN ≤ 15V (LT1118-2.85)
IL = 0mA, 6.5V ≤ VIN ≤ 15V (LT1118-5)
l
l
l
l
6
6
6
10
mV
mV
mV
mV
Load Regulation (Note 4)
0mA ≤ IL ≤ 800mA (LT1118)
– 400mA ≤ IL ≤ 0mA
l
l
6
6
mV
mV
0mA ≤ IL ≤ 800mA (LT1118-2.5)
– 400mA ≤ IL ≤ 0mA
l
l
12
12
mV
mV
0mA ≤ IL ≤ 800mA (LT1118-2.85)
– 400mA ≤ IL ≤ 0mA
l
l
12
12
mV
mV
0mA ≤ IL ≤ 800mA (LT1118-5)
– 400mA ≤ IL ≤ 0mA
l
l
25
25
mV
mV
Output Voltage
MIN
UNITS
Dropout Voltage (Note 5)
IL = 100mA
IL = 800mA
0.85
1
1.1
1.3
V
V
FB Pin Bias Current
LT1118
0.35
1
μA
Minimum Output Voltage
LT1118
Ripple Rejection
fRIPPLE = 120Hz, VIN – VOUT = 2V
VRIPPLE = 0.5VP-P
Load Transient Settling Time,
ΔV = 1%
0mA ≤ IL ≤ 800mA, CLOAD = 1μF
–400mA ≤ IL ≤ 0mA, CLOAD = 1μF
Output Short-Circuit Current
VOUT = 0V, Sourcing
VOUT = VIN, Sinking
l
2.1
60
800
V
80
dB
5
5
μs
μs
1200
–700
–400
mA
mA
Thermal Shutdown Junction Temperature
No Load
170
°C
Enable Turn-On Delay
No Load
50
μs
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: Unless otherwide specified, testing done at VCC = 5V
(LT1118-2.5, LT1118-2.85) or VCC = 7V (LT1118-5). VEN = VCC.
Output CLOAD = 1μF, ILOAD = 0.
Note 3: All operating conditions include the combined effects of load
current, input voltage and temperature over each parameter’s full range.
Note 4: Load and line regulation are tested at a constant junction
temperature by low duty cycle pulse testing.
Note 5: Dropout voltage is defined as the minimum input to output voltage
measured while sourcing the specified current.
1118fd
3
LT1118/LT1118-2.5/
LT1118-2.85/LT1118-5
TYPICAL PERFORMANCE CHARACTERISTICS
Dropout Voltage vs Output Current
Ripple Rejection vs Frequency
80
800mA
1.2
400mA
1
0.8
TJ = 125°C
0.6
0.4
10mA
60
40
NO LOAD
20
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
TJ = 75°C
TJ = 25°C
DROPOUT VOLTAGE (V)
Ripple Rejection vs Frequency
80
1.4
10mA
60
40
NO LOAD
20
0.2
SOURCING CURRENT
0
0
0
200
400
600
OUTPUT CURRENT (mA)
800
10
100
SINKING CURRENT
1k
10k
FREQUENCY (Hz)
0
100k
100
10
1k
10k
FREQUENCY (Hz)
100k
1118 G02
1118 G01
Output Impedance vs Frequency
1118 G03
Feedback Current vs Temperature
10
Ripple Rejection vs Load Current
450
80
CIN = CLOAD = 1μF
400
NO CURRENT
350
100mA SOURCE
CURRENT (nA)
ZOUT (Ω)
10mA SOURCE
0.1
0.01
100mA SINK
103
300
250
200
150
100
10mA SINK
0.001
102
RIPPLE REJECTION (dB)
1
106
0
–55 –35 –15
5 25 45 65 85 105 125
TEMPERATURE (°C)
1118 G04
20
0
–400
–200
0
200
400
LOAD CURRENT (mA)
600
800
1118 G06
1118 G05
Input Current
vs Output Sink Current
Ground Pin Current
vs Output Source Current
2000
800
1750
700
GROUND PIN CURRENT (μA)
INPUT CURRENT (μA)
40
50
104
105
FREQUENCY (Hz)
1500
1250
1000
750
500
250
0
60
600
500
400
300
200
100
0
50
100 150 200 250 300 350 400
OUTPUT SINK CURRENT (mA)
1118 G07
0
0
400
200
600
OUTPUT SOURCING CURRENT (mA)
800
1118 G08
1118fd
4
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
PIN FUNCTIONS
IN: Input Supply Pin. This pin should be decoupled with
a 1μF or larger low ESR capacitor. The two IN pins on the
SO-8 package must be directly connected on the printed
circuit board to prevent voltage drops between the two
inputs. When used as a SCSI active termination, IN connects to term power. When used as a supply splitter, IN is
also the positive supply output.
OUT: Regulated Output Voltage. Output can source or sink
current. Current limit for sourcing and sinking current is
provided to protect the device from fault conditons. The
output must have a low ESR output filter capacitor. COUT
≥ 0.22μF to guarantee stability. A 0.1μF ceramic capacitor
may be needed in parallel with COUT if the ESR of the main
COUT is too high.
GND: Ground Pin. The multiple GND pins on the SO-8
package are internally connected, but lowest load regulation
errors will result if these pins are tightly connected on the
printed circuit board. This will also aid heat dissipation at
high power levels.
FB: Feedback Pin. The feedback pin is used to program
the output voltage of the adjustable S8 part. The output
voltage range that can be achieved is 2.1V to 6.5V. The
output voltage is determined by the selection of feedback
resistors defined by the following formula:
EN: TTL/CMOS Logic Input. A high level allows normal
operation. A low level reduces supply current to zero. This
pin is internally connected to VIN on 3-lead ST packaged
devices.
VOUT = VFB (1 + R1/R2) + IFBR1
LT1118 Adjustable
VIN
IN
OUT
1μF
1μF
LT1118
EN
GND
(
VOUT = VFB 1 +
)
R1
+ IFB R1
R2
R1
FB
R2
1118 TA06
OPERATION
Output Capacitor
The LT1118 family of voltage regulators require an output
capacitor for stability. The regulators are stable with output capacitors larger than 0.2μF. Load transient response
is very sensitive to output capacitor value and dielectric
choice. Low ESR ceramic capacitors are the best choice
for fast settling to load transients. Output capacitors
between 0.2μF and 1μF give good performance in most
applications. Larger tantalum output capacitors may be
used to reduce load transient amplitudes. Larger capacitors should be paralleled with a 0.1μF ceramic capacitor
to maintain quick settling time performance and to insure
stability of the regulator control loop. Capacitors larger
than 10μF may be safely used with the regulators, but
little transient settling performance improvement results
from their use.
Worst case transient response of the LT1118 regulators
occurs at zero output current. In order to obtain the fastest
transient settling performance, the regulator output may
be preloaded with a small current. The preload current
reduces the regulator output impedance, reducing output
voltage settling time.
Thermal Considerations
The LT1118 regulators are packaged in plastic SOT-223 and
fused lead S8 packages. These small footprint packages
are unable to convectively dissipate the heat generated
when the regulator is operating at high current levels. In
order to control die operating temperatures, the PC board
layout should allow for maximum possible copper area at
the ground pins of the LT1118. The ground pins and the
tab on the SOT-223 package are electrically and thermally
1118fd
5
LT1118/LT1118-2.5/
LT1118-2.85/LT1118-5
OPERATION
connected to the die substrate. Table 1 shows measured
thermal resistance from junction to ambient for the LT1118
connected to various sized PC board ground planes. The
power dissipated in the LT1118 varies with input voltage
and loading. When the regulator is sourcing current the
power which must be dissipated by the package is:
PD = (VIN – VOUT) • ILOAD
When the regulator is sinking load current, power dissipation is nearly independent of VIN and can be calculated
as:
PD = VOUT • ILOAD
Heat sinking to the IC package must consider the worst
case power dissipation which may occur.
Table 1. Measured Thermal Resistance from Junction to Ambient
for the LT1118
S8 Package
SOT-223
Free Air
1 Sq Inch Copper
120°C/W
55°C/W
95°C/W
53°C/W
4 Sq Inch Copper
35°C/W
38°C/W
TYPICAL APPLICATIONS
SCSI Active Terminator
110Ω
•
•
•
• 110Ω
TERMPWR
110Ω
LT1118-2.85 OUT
IN
5V
•
•
• 110Ω
•
GND
+
27 LINES
110Ω
2.2μF
1μF
1118 TA03
Power Supply Splitter
VIN
5V
5V
1μF
IN
LT1118-2.5
GND
ANALOG
COMMON
2.5V
OUT
1μF
1118 TA04
1118fd
6
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
PACKAGE DESCRIPTION
ST Package
3-Lead Plastic SOT-223
(Reference LTC DWG # 05-08-1630)
.248 – .264
(6.30 – 6.71)
.129 MAX
.114 – .124
(2.90 – 3.15)
.059 MAX
.264 – .287
(6.70 – 7.30)
.248 BSC
.130 – .146
(3.30 – 3.71)
.039 MAX
.059 MAX
.090
BSC
.181 MAX
.033 – .041
(0.84 – 1.04)
.0905
(2.30)
BSC
RECOMMENDED SOLDER PAD LAYOUT
10° – 16°
.010 – .014
(0.25 – 0.36)
10°
MAX
.071
(1.80)
MAX
10° – 16°
.024 – .033
(0.60 – 0.84)
.0008 – .0040
(0.0203 – 0.1016)
.012
(0.31)
MIN
.181
(4.60)
BSC
ST3 (SOT-233) 0502
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(Reference LTC DWG # 05-08-1610)
.050 BSC
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
8
.245
MIN
7
6
5
.160 ±.005
.150 – .157
(3.810 – 3.988)
NOTE 3
.228 – .244
(5.791 – 6.197)
.030 ±.005
TYP
1
RECOMMENDED SOLDER PAD LAYOUT
.010 – .020
× 45°
(0.254 – 0.508)
.008 – .010
(0.203 – 0.254)
0°– 8° TYP
.016 – .050
(0.406 – 1.270)
NOTE:
1. DIMENSIONS IN
.053 – .069
(1.346 – 1.752)
.014 – .019
(0.355 – 0.483)
TYP
INCHES
(MILLIMETERS)
2. DRAWING NOT TO SCALE
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)
2
3
4
.004 – .010
(0.101 – 0.254)
.050
(1.270)
BSC
SO8 0303
1118fd
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
7
LT1118/LT1118-2.5/
LT1118-2.85/LT1118-5
TYPICAL APPLICATION
Variable 2.1V to 6.5V Regulator with DIgital Control
12V
0.1μF
IN
1μF
R1
13.3k R2
6.19k
LT1118
EN
VOUT
OUT
GND
0.22μF
VCC
VDAC
FB
VOUT
R3
6.19k
DIN
LTC1257
GND
VREF
CLK
μP
LOAD
1118 TA05
VOUT = 1.225 1 +
R1
( R2 || R3 )
– VDAC
R1
R2
RELATED PARTS
PART NUMBER DESCRIPTION
COMMENTS
LT1129
700mA, Micropower, LDO
VIN: 4.2V to 30V, VOUT(MIN) = 3.8V, VDO = 0.40V, IQ = 50μA, ISD = 16μA;
DD, SOT-223, S8, TO220-5 and TSSOP20 Packages
LT1206
250mA/60MHz Current Feedback Amplifier High Output Current Drive Capability, Can Sink/Source
LT1210
1.1A, 35MHz Current Feedback Amplifer
High Output Current Drive Capability, Can Sink/Source
LT1763
500mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , S8 Package
LT1764/
LT1764A
3A, Low Noise, Fast Transient Response,
LDO
VIN: 2.7V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = < 1μA, Low Noise
< 40μVRMS , “A” Version Stable with Ceramic Capacitors, DD and TO220-5 Packages
LTC1844
150mA, Very Low Drop-Out LDO
VIN: 1.6V to 6.5V, VOUT(MIN) = 1.25V, VDO = 0.08V, IQ = 35μA, ISD = < 1μA,
Low Noise < 60μVRMS , ThinSOT™ Package
LT1962
300mA, Low Noise Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.27V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , MS8 Package
LT1963/
LT1963A
1.5A, Low Noise, Fast Transient Response, VIN: 2.1V to 20V, VOUT(MIN) = 1.21V, VDO = 0.34V, IQ = 1mA, ISD = < 1μA,
Low Noise < 40μVRMS , “A” Version Stable with Ceramic Capacitors;
LDO
DD, TO220-5, SOT-223 and S8 Packages
LT3021
500mA, Low Voltage VDO , VIN(MIN) = 0.9V,
LDO
VIN: 0.9V to 10V, VOUT(MIN) = 0.20V, VDO = 0.16V, IQ = 120μA, ISD = 3μA, DFN and
S8 Packages
LT3024
Dual, 100mA/500mA, Low Noise
Micropower, LDO
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 60μA, ISD = < 1μA, DFN and
TSSOP Packages
LT3028
Dual, 100mA/500mA, Low Noise
Micropower, LDO with Independent Inputs
VIN: 1.8V to 20V, VOUT(MIN) = 1.22V, VDO = 0.30V, IQ = 30μA, ISD = < 1μA,
Low Noise < 20μVRMS , DFN and TSSOP Packages
LT3080/
LT3080-1
1.1A Parallelable, Low Noise, Low Dropout 300mV Dropout Voltage (2-Supply Operation), Low Noise: 40μVRMS, VIN: 1.2V to 36V, VOUT:
0V to 35.7V, Current-Based Reference with 1-Resistor VOUT Set; Directly Parallelable (No Op
Linear Regulator
Amp Required), Stable with Ceramic Caps, TO-220, SOT-223, MSOP and 3mm × 3mm DFN
Packages; LT3080-1 Version Has Integrated Internal Ballast Resistor
LT3085
500mA, Parallelable Low Noise Low
Dropout Linear Regulator
275mV Dropout Voltage (2 Supply Operation), Low Noise: 40μVRMS, VIN: 1.2V to 36V,
VOUT: 0V to 35.7V, Current Reference, MSOP-8 and 2mm × 3mm DFN-6 Packages
ThinSOT is a trademark of Linear Technology Corporation
1118fd
8
Linear Technology Corporation
LT 0209 REV D • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 1995
工商网监
湘ICP备2023018690号
