|
|
PDF LT3081 Data sheet ( Hoja de datos )
| Número de pieza | LT3081 | |
| Descripción | 1.5A Single Resistor Rugged Linear Regulator | |
| Fabricantes | Linear Technology | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT3081 (archivo pdf) en la parte inferior de esta página. Total 30 Páginas | ||
|
No Preview Available !
Features
n Extended Safe Operating Area
n Maximum Output Current: 1.5A
n Stable with or without Input/Output Capacitors
n Wide Input Voltage Range: 1.2V to 36V
n Single Resistor Sets Output Voltage
n Output Current Monitor: IMON = IOUT/5000
n Junction Temperature Monitor: 1µA/°C
n Output Adjustable to 0V
n 50µA SET Pin Current: 1% Initial Accuracy
n Output Voltage Noise: 27µVRMS
n Parallel Multiple Devices for Higher Current or
Heat Spreading
n Programmable Current Limit
n Reverse-Battery and Reverse-Current Protection
n <1mV Load Regulation Typical Independent of VOUT
n <0.001%/V Line Regulation Typical
n Available in Thermally-Enhanced 12-Lead 4mm × 4mm
DFN and 16-Lead TSSOP, 7-Lead DD-Pak and 7-Lead
TO-220
Applications
n All Surface Mount Power Supply
n Rugged Industrial Power Supply
n Post Regulator for Switching Supplies
n Low Output Voltage Supply
n Intrinsic Safety Applications
LT3081
1.5A Single Resistor
Rugged Linear Regulator
with Monitors
Description
The LT®3081 is a 1.5A low dropout linear regulator de-
signed for rugged industrial applications. Key features of
the IC are the extended safe operating area (SOA), output
current monitor, temperature monitor and programmable
current limit. The LT3081 can be paralleled for higher
output current or heat spreading. The device withstands
reverse input and reverse output-to-input voltages without
reverse current flow.
The LT3081’s precision 50µA reference current source
allows a single resistor to program output voltage to
any level between zero and 34.5V. The current reference
architecture makes load regulation independent of output
voltage. The LT3081 is stable with or without input and
output capacitors.
The output current monitor (IOUT/5000) and die junction
temperature output (1µA/°C) provide system monitoring
and debug capability. In addition, a single resistor pro-
grams current limit.
Internal protection circuitry includes reverse-battery and
reverse-current protection, current limiting and thermal
limiting. The LT3081 is offered in the 16-lead TSSOP (with
exposed pad for improved thermal performance), 7-lead
TO-220, 7-lead DD-Pak, and an 12-lead 4mm × 4mm DFN.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Typical Application
LT3081
Wide Safe Operating Area Supply
VIN
IN
ILOAD/5000
1µA/°C
50µA
+
–
IMON
TEMP
SET
1k 1k 30.1k
OUT
ILIM
4.53k
10µF*
*OPTIONAL
IOUT
1.5V
1A
300Ω*
3081 TA01a
For more information www.linear.com/LT3081
SET Pin Current
50.5
50.4
IL = 5mA
50.3
50.2
50.1
50.0
49.9
49.8
49.7
49.6
49.5
–50 –25
0 25 50 75 100
TEMPERATURE (°C)
125 150
3081 TA01b
3081fc
1
1 page  
LT3081
Typical Performance Characteristics TJ = 25°C unless otherwise specified.
SET Pin Current
50.5
50.4
ILOAD = 5mA
50.3
50.2
50.1
50.0
49.9
49.8
49.7
49.6
49.5
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3081 G01
Offset Voltage
N = 3195
–2 –1 0 1
VOS DISTRIBUTION (mV)
2
3081 G04
SET Pin Current
N = 3195
49 49.5 50 50.5 51
SET PIN CURRENT DISTRIBUTION (µA)
3081 G02
Offset Voltage (VOUT – VSET)
1.0 ILOAD = 5mA
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
0
6 12 18 24 30
INPUT-TO-OUTPUT DIFFERENTIAL (V)
36
3081 G05
Offset Voltage (VOUT – VSET)
2.0 ILOAD = 5mA
1.5
1.0
0.5
0
–0.5
–1.0
–1.5
–2.0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3081 G03
Offset Voltage (VOUT – VSET)
0.2
0
–0.2
–0.4 TJ = 25°C
–0.6
TJ = 125°C
–0.8
–1.0
–1.2
–1.4
0
0.25 0.5 0.75 1 1.25 1.5
LOAD CURRENT (A)
3081 G06
Load Regulation
300 ∆ILOAD = 5mA TO 1.5A
250
0
–0.5
200 –1.0
150 –1.5
100 –2.0
50 –2.5
0
–50 –25
–3.0
0 25 50 75 100 125 150
TEMPERATURE (°C)
3081 G07
Minimum Load Current
3.0
2.5
2.0
1.5
VIN – VOUT = 36V
1.0
VIN – VOUT = 2V
0.5
0
–50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
3081 G08
For more information www.linear.com/LT3081
Dropout Voltage
1.5
1.4
TJ = –50°C
1.3
TJ = 25°C
1.2 TJ = 125°C
1.1
1.0
0
0.25 0.5 0.75 1
LOAD CURRENT (A)
1.25 1.5
3081 G09
3081fc
5
5 Page 
LT3081
Applications Information
Introduction
The LT3081 regulator is easy to use and has all the pro-
tection features expected in high performance regulators.
Included are short-circuit protection, reverse-input protec-
tion and safe operating area protection, as well as thermal
shutdown with hysteresis. Safe operating area (SOA) for
the LT3081 is extended, allowing for use in harsh indus-
trial and automotive environments where sudden spikes
in input voltage lead to high power dissipation.
The LT3081 fits well in applications needing multiple rails.
This new architecture adjusts down to zero with a single
resistor, handling modern low voltage digital ICs as well
as allowing easy parallel operation and thermal manage-
ment without heat sinks. Adjusting to zero output allows
shutting off the powered circuitry.
A precision “0” TC 50μA reference current source connects
to the noninverting input of a power operational amplifier.
The power operational amplifier provides a low impedance
buffered output to the voltage on the noninverting input.
A single resistor from the noninverting input to ground
sets the output voltage. If this resistor is set to 0Ω, zero
output voltage results. Therefore, any output voltage can
be obtained between zero and the maximum defined by
the input power supply is obtainable.
The benefit of using a true internal current source as the
reference, as opposed to a bootstrapped reference in older
regulators, is not so obvious in this architecture. A true
reference current source allows the regulator to have gain
and frequency response independent of the impedance on
the positive input. On older adjustable regulators, such as
the LT1086 loop gain changes with output voltage and
bandwidth changes if the adjustment pin is bypassed to
ground. For the LT3081, the loop gain is unchanged with
output voltage changes or bypassing. Output regulation
is not a fixed percentage of output voltage, but is a fixed
fraction of millivolts. Use of a true current source allows
all of the gain in the buffer amplifier to provide regulation,
and none of that gain is needed to amplify up the reference
to a higher output voltage.
The LT3081 has many additional features that facilitate
monitoring and control. Current limit is externally pro-
grammable via a single resistor between the ILIM pin and
OUT. Shorting this resistor out disables all output current
to the load, only bias currents remain.
The IMON pin produces a current output proportional to
load current. For every 1A of load current, the IMON pin
sources 200µA of current. This can be sensed using an
external resistor to monitor load requirements and detect
potential faults. The IMON pin can operate at voltages above
OUT, so it operates even during a short-circuit condition.
One additional monitoring function is the TEMP pin, a cur-
rent source that is proportional to average die temperature.
For die temperatures above 0°C, the TEMP pin sources a
current equal to 1µA/°C. This pin operates normally during
output short-circuit conditions.
Programming Linear Regulator Output Voltage
The LT3081 generates a 50μA reference current that flows
out of the SET pin. Connecting a resistor from SET to
ground generates a voltage that becomes the reference
point for the error amplifier (see Figure 1). The reference
voltage equals 50µA multiplied by the value of the SET
pin resistor. Any voltage can be generated and there is
no minimum output voltage for the regulator.
IN
CIN
LT3081
50µA
+
–
SET
CSET RSET
COUT
OUT
VOUT = 50µA • RSET
RLOAD
3081 F01
Figure 1. Basic Adjustable Regulator
For more information www.linear.com/LT3081
3081fc
11
11 Page | ||
| Páginas | Total 30 Páginas | |
| PDF Descargar | [ Datasheet LT3081.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 |