LINER LT1118_06

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
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FEATURES
■
■
■
■
■
■
■
■
DESCRIPTIO
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
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APPLICATIO S
■
■
■
■
■
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.
The LT1118 is available in 3-lead SOT-223 and 8-lead SO
packages.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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TYPICAL APPLICATIO
Load Transient Response
0.2V
IN
∆VOUT
LT1118-2.85 OUT
– 0.2V
GND
5V
2.2µF
0V
1µF
CERAMIC
800mA
ILOAD
1118 TA01
ILOAD
0mA
– 400mA
1118 TA02.tif
1118fc
1
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
W W
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ABSOLUTE
AXI U RATI GS
(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
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PACKAGE DESCRIPTIO
TOP VIEW
GND 1
FRONT VIEW
TOP VIEW
IN 1
8 GND
8 EN
NC 2
7 IN
OUT 2
7 GND
EN 3
6 OUT
GND 3
6 GND
FB 4
5 IN
IN 4
TAB IS
GND
5 NC
S8 PACKAGE
8-LEAD PLASTIC SO
S8 PACKAGE
8-LEAD PLASTIC SO
TJMAX = 125°C, θJC = 15°C/W
TJMAX = 125°C, θJC = 15°C/W
3
IN
2
GND
1
OUT
ST PACKAGE
3-LEAD PLASTIC SOT-223
TJMAX = 125°C, θJC = 15°C/W
ORDER
PART NUMBER
S8 PART
MARKING
ORDER
PART NUMBER
S8 PART
MARKING
ORDER
PART NUMBER
ST PART
MARKING
LT1118CS8
1118
LT1118CS8-2.5
LT1118CS8-2.85
LT1118CS8-5
111825
111828
11185
LT1118CST-2.5
LT1118CST-2.85
LT1118CST-5
111825
111828
11185
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marking: http://www.linear.com/leadfree/
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
The ● denotes 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)
VEN = 0V
●
Enable Input Thresholds
Input Low Level
Input High Level
●
●
0V ≤ VEN ≤ 5V
Enable Input Current
Feedback Voltage
Output Voltage
LT1118
LT1118-2.5
LT1118-2.85
LT1118-5
MIN
0.4
TYP
MAX
UNITS
0.6
1
mA
1
10
µA
1.4
1.4
2
V
V
●
–1
25
µA
No Load (25°C)
All Operating Conditions (Note 3)
●
1.213
1.200
1.225
1.225
1.237
1.250
V
V
No Load (25°C)
All Operating Conditions (Note 3)
●
2.47
2.45
2.5
2.5
2.53
2.55
V
V
No Load (25°C)
All Operating Conditions (Note 3)
●
2.82
2.79
2.85
2.85
2.88
2.91
V
V
No Load (25°C)
All Operating Conditions (Note 3)
●
4.95
4.90
5
5
5.05
5.1
V
V
1118fc
2
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
ELECTRICAL CHARACTERISTICS
The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Line Regulation (Note 4)
LT1118
LT1118-2.5
LT1118-2.85
LT1118-5
IL = 0mA, 4.2V ≤ VIN ≤ 15V
IL = 0mA, 4.2V ≤ VIN ≤ 15V
IL = 0mA, 4.75V ≤ VIN ≤ 15V
IL = 0mA, 6.5V ≤ VIN ≤ 15V
●
●
●
●
6
6
6
10
mV
mV
mV
mV
Load Regulation (Note 4)
LT1118
0mA ≤ IL ≤ 800mA
– 400mA ≤ IL ≤ 0mA
●
●
6
6
mV
mV
LT1118-2.5
0mA ≤ IL ≤ 800mA
– 400mA ≤ IL ≤ 0mA
●
●
12
12
mV
mV
LT1118-2.85
0mA ≤ IL ≤ 800mA
– 400mA ≤ IL ≤ 0mA
●
●
12
12
mV
mV
LT1118-5
0mA ≤ IL ≤ 800mA
– 400mA ≤ IL ≤ 0mA
●
●
25
25
mV
mV
0.85
1
1.1
1.3
V
V
0.35
1
µA
2.1
V
Dropout Voltage (Note 5)
IL = 100mA
IL = 800mA
FB Pin Bias Current
LT1118
Minimum Output Voltage
LT1118
●
Ripple Rejection
fRIPPLE = 120Hz, VIN – VOUT = 2V
VRIPPLE = 0.5VP-P
Load Transient Settling Time,
∆V = 1%
0mA ≤ IL ≤ 800mA, CLOAD = 1µF
– 400mA ≤ IL ≤ 0mA, CLOAD = 1µF
Output Short-Circuit Current
ISC+
ISC–
VOUT = 0V
VOUT = VIN
60
800
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.
1118fc
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LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
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TYPICAL PERFORMANCE CHARACTERISTICS
Ripple Rejection vs Frequency
Dropout Voltage vs Output Current
Ripple Rejection vs Frequency
80
1.4
80
800mA
TJ = 25°C
RIPPLE REJECTION (dB)
TJ = 75°C
DROPOUT VOLTAGE
1
0.8
TJ = 125°C
0.6
0.4
400mA
10mA
60
RIPPLE REJECTION (dB)
1.2
40
NO LOAD
20
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
10mA SOURCE
0.1
0.01
100mA SINK
103
300
250
200
150
100
10mA SINK
0.001
102
RIPPLE REJECTION (dB)
350
100mA SOURCE
CURRENT (nA)
ZOUT (mA)
1
106
0
–55 –35 –15
5
25 45
TEMP
65
85 105 125
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
600
500
400
300
200
100
250
0
60
0
0
50
100 150 200 250 300 350 400
OUTPUT SINK CURRENT (mA)
1118 G07
0
400
200
600
OUTPUT SOURCING CURRENT (mA)
800
1118 G08
1118fc
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LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
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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:
VOUT = VFB (1 + R1/R2) + IFBR1
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.
LT1118 Adjustable
VIN
IN
OUT
1µF
1µF
LT1118
EN
GND
(
VOUT = VFB 1 +
)
R1
+ IFB R1
R2
R1
FB
R2
1118 TA06
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OPERATIO
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
1118fc
5
LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
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OPERATIO
thermally 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
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TYPICAL APPLICATIO S
SCSI Active Terminator
110Ω
•
•
•
• 110Ω
TERMPWR
110Ω
IN
LT1118-2.85 OUT
5V
•
•
• 110Ω
•
GND
+
27 LINES
110Ω
2.2µF
1µF
1118 TA03
Power Supply Splitter
VIN
5V
5V
1µF
IN
ANALOG
COMMON
2.5V
LT1118-2.5 OUT
GND
1µF
1118 TA04
1118fc
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LT1118/LT1118-2.5
LT1118-2.85/LT1118-5
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PACKAGE DESCRIPTIO
ST Package
3-Lead Plastic SOT-223
(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)
(LTC DWG # 05-08-1610)
.189 – .197
(4.801 – 5.004)
NOTE 3
.045 ±.005
.050 BSC
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
1118fc
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
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TYPICAL APPLICATIO
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
LT1005
Logic Controlled Regulator
5V, 1A Main Output Plus 35mA Auxilliary Output
LT1117
800mA Low Dropout Regulator
Fixed 2.85V, 3.3V, 5V or Adjustable Outputs
LT1120A
Micropower Regulator with Comparator and Shutdown
20µA Supply Current, 2.5V Reference Output
LT1121
Micropower Low Dropout Regulator with Shutdown
Reverse Voltage and Reverse Current Protection
1118fc
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Linear Technology Corporation
LT/LWI 0706 REV C • PRINTED IN USA
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900 ● FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 1995