|
|
PDF LT1129-3.3 Data sheet ( Hoja de datos )
| Número de pieza | LT1129-3.3 | |
| Descripción | Micropower Low Dropout Regulators | |
| Fabricantes | Linear | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LT1129-3.3 (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
FEATURES
n 400mV Dropout Voltage
n 700mA Output Current
n 50μA Quiescent Current
n No Protection Diodes Needed
n Adjustable Output from 3.8V to 30V
n 3.3V and 5V Fixed Output Voltages
n Controlled Quiescent Current in Dropout
n Shutdown
n 16μA Quiescent Current in Shutdown
n Stable with 3.3μF Output Capacitor
n Reverse Battery Protection
n No Reverse Output Current
n Thermal Limiting
n Surface Mount SOT-223 and DD-Pak Packages
APPLICATIONS
n Low Current Regulator
n Regulator for Battery-Powered Systems
n Post Regulator for Switching Supplies
n 5V to 3.3V Logic Regulator
LT1129/LT1129-3.3/LT1129-5
Micropower Low Dropout
Regulators with Shutdown
DESCRIPTION
The LT®1129/LT1129-3.3/LT1129-5 are micropower low
dropout regulators with shutdown. The devices are capable
of supplying 700mA of output current with a dropout
voltage of 400mV at maximum output. Designed for use
in battery-powered systems, the low quiescent current,
50μA operating and 16μA in shutdown, make them an ideal
choice. The quiescent current does not rise in dropout as
it does with many other low dropout PNP regulators.
Other features of the LT1129 /LT1129-3.3/LT1129-5 include
the ability to operate with small output capacitors. They
are stable with only 3.3μF on the output while most older
devices require between 10μF and 100μF for stability. Also
the input may be connected to ground or a reverse voltage
without reverse current flow from output to input. This
makes the LT1129/LT1129-3.3/LT1129-5 ideal for backup
power situations where the output is held high and the
input is at ground or reversed. Under these conditions,
only 16μA will flow from the output pin to ground. The
devices are available in 5-lead TO-220, 5-lead DD-Pak and
3-lead SOT-223 packages.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
VIN > 5.5V
5V Supply with Shutdown
5
IN
1
OUT
LT1129-5
4 SHDN
2
SENSE
GND
3
5V OUT
500mA
+
3.3μF
SOLID TANTALUM
VSHDN (PIN 4) OUTPUT
< 0.25
OFF
> 2.8
ON
NC ON
112935 TA01
Dropout Voltage
0.6
0.5
0.4
0.3
0.2
0.1
0
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
OUTPUT CURRENT (A)
112935 TA02
112935ff
1
1 page  
LT1129/LT1129-3.3/LT1129-5
ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
SYMBOL
CONDITIONS
MIN TYP MAX UNITS
Ripple Rejection
Current Limit
VIN – VOUT = 1V (Avg), VRIPPLE = 0.5VP-P,
fRIPPLE = 120Hz, ILOAD = 0.7A, TJ = 25°C
VIN – VOUT = 7V, TJ = 25°C
52 64
1.2 1.6
dB
A
Input Reverse Leakage Current
VIN = –20V, VOUT = 0V
l 1.0 mA
Reverse Output Current (Note 11)
LT1129-3.3
LT1129-5
LT1129 (Note 5)
VOUT = 3.3V, VIN = 0V
VOUT = 5V, VIN = 0V
VOUT = 3.8V, VIN = 0V
16 25
16 25
16 25
μA
μA
μA
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: The shutdown pin input voltage rating is required for a low
impedance source. Internal protection devices connected to the shutdown
pin will turn on and clamp the pin to approximately 7V or – 0.6V. This
range allows the use of 5V logic devices to drive the pin directly. For high
impedance sources or logic running on supply voltages greater than 5.5V,
the maximum current driven into the shutdown pin must be limited to less
than 20mA.
Note 3: For junction temperatures greater than 110°C, a minimum load
of 1mA is recommended. For TJ > 110°C and IOUT < 1mA, output voltage
may increase by 1%.
Note 4: Operating conditions are limited by maximum junction
temperature. The regulated output voltage specification will not apply
for all possible combinations of input voltage and output current. When
operating at maximum input voltage, the output current range must be
limited. When operating at maximum output current, the input voltage
range must be limited.
Note 5: The LT1129 is tested and specified with the adjust pin connected
to the output pin.
Note 6: Dropout voltage is the minimum input/output voltage required to
maintain regulation at the specified output current. In dropout the output
voltage will be equal to (VIN – VDROPOUT). Dropout voltage is measured
between the input pin and the output pin. External voltage drops between
the output pin and the sense pin will add to the dropout voltage.
Note 7: Ground pin current is tested with VIN = VOUT (nominal) and a
current source load. This means that the device is tested while operating in
its dropout region. This is the worst case ground pin current. The ground
pin current will decrease slightly at higher input voltages.
Note 8: Adjust pin bias current flows into the adjust pin.
Note 9: Shutdown pin current at VSHDN = 0V flows out of the shutdown pin.
Note 10: Quiescent current in shutdown is equal to the sum total of the
shutdown pin current (6μA) and the ground pin current (9μA).
Note 11: Reverse output current is tested with the input pin grounded. The
output pin and the sense pin are forced to the rated output voltage. This
current flows into the sense pin and out of the ground pin. For the LT1129
(adjustable version) the sense pin is internally tied to the output pin.
Note 12: The LT1129 regulators are tested and specified under pulse load
conditions such that TJ ≅ TA. The LT1129C regulators are 100% tested at
TA = 25°C. For C-grade devices, Regulated Output Voltage, Line Regulation
and Load Regulation performance at –40°C and 125°C is assured by
design, characterization and correlation with statistical process controls.
The LT1129I regulators are guaranteed over the full –40°C to 125°C
operating junction temperature range. The LT1129MP regulators are 100%
tested and guaranteed over the –55°C to 125°C temperature range.
TYPICAL PERFORMANCE CHARACTERISTICS
Guaranteed Dropout Voltage
0.7
0.6
TJ ≤ 125°C
0.5
0.4 TJ ≤ 25°C
0.3
0.2
0.1
0
0
= TEST POINTS
0.1 0.2 0.3 0.4 0.5
OUTPUT CURRENT (A)
0.6 0.7
112935 G01
Dropout Voltage
0.7
A. ILOAD = 700mA
0.6 B. ILOAD = 500mA
C. ILOAD = 300mA
0.5
D. ILOAD = 100mA
E. ILOAD = 10mA
0.4
0.3
0.2
A
B
C
D
E
0.1
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
112935 G02
Quiescent Current
70
60
50 VSHDN = OPEN (HI)
40
30
20 VSHDN = 0V
10
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
112935 G03
112935ff
5
5 Page 
LT1129/LT1129-3.3/LT1129-5
OPERATION
copper. This data can be used as a rough guideline in
estimating thermal resistance. The thermal resistance for
each application will be affected by thermal interactions
with other components as well as board size and shape.
Some experimentation will be necessary to determine the
actual value.
Table 1. Q Package, 5-Lead DD
COPPER AREA
THERMAL RESISTANCE
TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 2500 sq. mm
25°C/ W
1000 sq. mm 2500 sq. mm 2500 sq. mm
27°C/W
125 sq. mm 2500 sq. mm 2500 sq. mm
35°C/W
* Tab of device attached to topside copper
Table 2. ST Package, 3-Lead SOT-223
COPPER AREA
THERMAL RESISTANCE
TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 2500 sq. mm
45°C/ W
1000 sq. mm 2500 sq. mm 2500 sq. mm
45°C/W
225 sq. mm 2500 sq. mm 2500 sq. mm
53°C/W
100 sq. mm 2500 sq. mm 2500 sq. mm
59°C/W
* Tab of device attached to topside copper
Table 3. S8 Package, 8-Lead Plastic SOIC
COPPER AREA
THERMAL RESISTANCE
TOPSIDE* BACKSIDE BOARD AREA (JUNCTION-TO-AMBIENT)
2500 sq. mm 2500 sq. mm 2500 sq. mm
55°C/ W
1000 sq. mm 2500 sq. mm 2500 sq. mm
55°C/W
225 sq. mm 2500 sq. mm 2500 sq. mm
63°C/W
100 sq. mm 2500 sq. mm 2500 sq. mm
69°C/W
* Device attached to topside copper
T Package, 5-Lead TO-220
Thermal Resistance (Junction-to-Case) = 5°C/W
Calculating Junction Temperature
Example: Given an output voltage of 3.3V, an input voltage
range of 4.5V to 5.5V, an output current range of 0mA to
500mA, and a maximum ambient temperature of 50°C,
what will the maximum junction temperature be?
The power dissipated by the device will be equal to:
IOUT MAX • (VIN MAX – VOUT) + (IGND • VIN MAX)
where, IOUT MAX = 500mA
VIN MAX = 5.5V
IGND at (IOUT = 500mA, VIN = 5.5V) = 25mA
so, P = 500mA • (5.5V – 3.3V) + (25mA • 5.5V)
= 1.24W
If we use a DD package, then the thermal resistance will be
in the range of 25°C/W to 35°C/W depending on copper
area. So the junction temperature rise above ambient will
be approximately equal to:
1.24W • 30°C/W = 37.2°C
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
TJMAX = 50°C + 37.2°C = 87.2°C
Output Capacitance and Transient Performance
The LT1129 is designed to be stable with a wide range
of output capacitors. The minimum recommended value
is 3.3μF with an ESR of 2Ω or less. The LT1129 is a
micropower device and output transient response will
be a function of output capacitance. See the Transient
Response curves in the Typical Performance Character-
istics. Larger values of output capacitance will decrease
the peak deviations and provide improved output transient
response. Bypass capacitors, used to decouple individual
components powered by the LT1129, will increase the
effective value of the output capacitor.
Protection Features
The LT1129 incorporates several protection features
which make it ideal for use in battery-powered circuits.
In addition to the normal protection features associated
with monolithic regulators, such as current limiting and
thermal limiting, the device is protected against reverse
input voltages, and reverse voltages from output to input.
For fixed voltage devices the output and sense pins are
tied together at the output.
112935ff
11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet LT1129-3.3.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LT1129-3.3 | Micropower Low Dropout Regulators | Linear |
| 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 |