|
|
PDF LT3080 Data sheet ( Hoja de datos )
| Número de pieza | LT3080 | |
| Descripción | Adjustable1.1A Single Resistor Low Dropout Regulator | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT3080 (archivo pdf) en la parte inferior de esta página. Total 26 Páginas | ||
|
No Preview Available !
LT3080
Adjustable1.1A Single
Resistor Low Dropout
Regulator
FEATURES
n Outputs May be Paralleled for Higher Current and
Heat Spreading
n Output Current: 1.1A
n Single Resistor Programs Output Voltage
n 1% Initial Accuracy of SET Pin Current
n Output Adjustable to 0V
n Low Output Noise: 40μVRMS (10Hz to 100kHz)
n Wide Input Voltage Range: 1.2V to 36V
n Low Dropout Voltage: 350mV (Except SOT-223
Package)
n <1mV Load Regulation
n <0.001%/V Line Regulation
n Minimum Load Current: 0.5mA
n Stable with 2.2μF Minimum Ceramic Output Capacitor
n Current Limit with Foldback and Overtemperature
Protected
n Available in 8-Lead MSOP, 3mm × 3mm DFN,
5-Lead DD-Pak, TO-220 and 3-Lead SOT-223
APPLICATIONS
n High Current All Surface Mount Supply
n High Efficiency Linear Regulator
n Post Regulator for Switching Supplies
n Low Parts Count Variable Voltage Supply
n Low Output Voltage Power Supplies
DESCRIPTION
The LT®3080 is a 1.1A low dropout linear regulator that can
be paralleled to increase output current or spread heat in
surface mounted boards. Architected as a precision cur-
rent source and voltage follower allows this new regulator
to be used in many applications requiring high current,
adjustability to zero, and no heat sink. Also the device
brings out the collector of the pass transistor to allow low
dropout operation —down to 350 millivolts— when used
with multiple supplies.
A key feature of the LT3080 is the capability to supply a
wide output voltage range. By using a reference current
through a single resistor, the output voltage is programmed
to any level between zero and 36V. The LT3080 is stable
with 2.2μF of capacitance on the output, and the IC uses
small ceramic capacitors that do not require additional
ESR as is common with other regulators.
Internal protection circuitry includes current limiting and
thermal limiting. The LT3080 regulator is offered in the
8-lead MSOP (with an exposed pad for better thermal
characteristics), a 3mm × 3mm DFN, 5-lead DD-Pak,
TO-220 and a simple-to-use 3-lead SOT-223 version.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and VLDO
and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
TYPICAL APPLICATION
Variable Output Voltage 1.1A Supply
VIN
1.2V TO 36V
IN
VCONTROL
1μF
LT3080
+
–
OUT
SET
RSET
VOUT = RSET • 10μA
3080 TA01a
VOUT
2.2μF
www.DataSheet.in
Set Pin Current Distribution
N = 13792
9.80 9.90 10.00 10.10 10.20
SET PIN CURRENT DISTRIBUTION (μA)
3080 G02
3080fb
1
1 page  
TYPICAL PERFORMANCE CHARACTERISTICS
Dropout Voltage
(Minimum IN Voltage)
400
350
ILOAD = 1.1A
300
250
200 ILOAD = 500mA
150
100 ILOAD = 100mA
50
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3080 G10
Dropout Voltage (Minimum
VCONTROL Pin Voltage)
1.6
TJ = –50°C
1.4
1.2
TJ = 125°C
1.0
TJ = 25°C
0.8
0.6
0.4
0.2
0
0 0.2 0.4 0.6 0.8 1.0 1.2
OUTPUT CURRENT (A)
3080 G11
LT3080
Dropout Voltage (Minimum
VCONTROL Pin Voltage)
1.6
1.4 ILOAD = 1.1A
1.2
1.0 ILOAD = 1mA
0.8
0.6
0.4
0.2
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3080 G12
Current Limit
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2 VIN = 7V
VOUT = 0V
0
–50 –25 0
25 50 75 100 125 150
TEMPERATURE (°C)
3080 G13
Load Transient Response
150
100
50
0
–50
–100
1.2
0.9
VIN = VCONTROL = 3V
VOUT = 1.5V
0.6 COUT = 10μF CERAMIC
CSET = 0.1μF
0.3
0
0 5 10 15 20 25 30 35 40 45 50
TIME (μs)
3080 G16
www.DataSheet.in
Current Limit
1.6
TJ = 25°C
1.4
SOT-223, DD-PAK
1.2 AND TO-220
1.0
0.8
0.6
MSOP
0.4 AND
DFN
0.2
0
0 6 12 18 24 30 36*
INPUT-TO-OUTPUT DIFFERENTIAL (V)
*SEE NOTE 9 IN ELECTRICAL
CHARACTERISTICS TABLE
3080 G14
Line Transient Response
75
50
25
0
–25
–50 VOUT = 1.5V
ILOAD = 10mA
6 COUT = 2.2μF
CERAMIC
5 CSET = 0.1μF
4 CERAMIC
3
2
0 10 20 30 40 50 60 70 80 90 100
TIME (μs)
3080 G17
Load Transient Response
75 VOUT = 1.5V
50 CSET = 0.1μF
25 VIN = VCONTROL = 3V
0
–25 COUT = 10μF CERAMIC
–50 COUT = 2.2μF CERAMIC
400
300
200
100
0
0 5 10 15 20 25 30 35 40 45 50
TIME (μs)
3080 G15
Turn-On Response
5
4
3
2
1 RSET = 100k
0
CSET = 0
RLOAD = 1Ω
2.0 COUT = 2.2μF CERAMIC
1.5
1.0
0.5
0
0 1 2 3 4 5 6 7 8 9 10
TIME (μs)
3080 G27
3080fb
5
5 Page 
LT3080
APPLICATIONS INFORMATION
(5 milliohms for the two devices in parallel) only adds about
10 millivolts of output regulation drop at an output of 2A.
Even with an output voltage as low as 1V, this only adds
1% to the regulation. Of course, more than two LT3080’s
can be paralleled for even higher output current. They are
spread out on the PC board, spreading the heat. Input
resistors can further spread the heat if the input-to-output
difference is high.
Thermal Performance
In this example, two LT3080 3mm × 3mm DFN devices
are mounted on a 1oz copper 4-layer PC board. They are
placed approximately 1.5 inches apart and the board is
mounted vertically for convection cooling. Two tests were
set up to measure the cooling performance and current
sharing of these devices.
The first test was done with approximately 0.7V input-
to-output and 1A per device. This gave a 700 milliwatt
dissipation in each device and a 2A output current. The
temperature rise above ambient is approximately 28°C
and both devices were within plus or minus 1°C. Both the
thermal and electrical sharing of these devices is excel-
lent. The thermograph in Figure 5 shows the temperature
distribution between these devices and the PC board
reaches ambient temperature within about a half an inch
from the devices.
The power is then increased with 1.7V across each device.
This gives 1.7 watts dissipation in each device and a device
temperature of about 90°C, about 65°C above ambient
as shown in Figure 6. Again, the temperature matching
between the devices is within 2°C, showing excellent
tracking between the devices. The board temperature has
reached approximately 40°C within about 0.75 inches of
each device.
While 90°C is an acceptable operating temperature for these
devices, this is in 25°C ambient. For higher ambients, the
temperature must be controlled to prevent device tempera-
ture from exceeding 125°C. A 3-meter-per-second airflow
across the devices will decrease the device temperature
about 20°C providing a margin for higher operating ambi-
ent temperatures.
Both at low power and relatively high power levels de-
vices can be paralleled for higher output current. Current
sharing and thermal sharing is excellent, showing that
acceptable operation can be had while keeping the peak
temperatures below excessive operating temperatures on
a board. This technique allows higher operating current
linear regulation to be used in systems where it could
never be used before.
Quieting the Noise
The LT3080 offers numerous advantages when it comes
to dealing with noise. There are several sources of noise
in a linear regulator. The most critical noise source for any
LDO is the reference; from there, the noise contribution
Figure 5. Temperature Rise at 700mW Dissipation
www.DataSheet.in
Figure 6. Temperature Rise at 1.7W Dissipation
3080fb
11
11 Page | ||
| Páginas | Total 26 Páginas | |
| PDF Descargar | [ Datasheet LT3080.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT3080 | Adjustable1.1A Single Resistor Low Dropout Regulator | Linear Technology |
| LT3080-1 | Parallelable 1.1A Adjustable Single Resistor Low Dropout Regulator | Linear Technology |
| LT3081 | 1.5A Single Resistor Rugged Linear Regulator | Linear Technology |
| LT3082 | 200mA Single Resistor Low Dropout Linear Regulator | Linear Technology |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |