|
|
PDF IRU1150CS Data sheet ( Hoja de datos )
| Número de pieza | IRU1150CS | |
| Descripción | 4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR | |
| Fabricantes | International Rectifier | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de IRU1150CS (archivo pdf) en la parte inferior de esta página. Total 6 Páginas | ||
|
No Preview Available !
FEATURES
0.7V Dropout at 4A
Fast Transient Response
1% Voltage Reference Initial Accuracy
Built-In Thermal Shutdown
APPLICATIONS
3.3V to 2.7V Intel I740 Chip Set
TYPICAL APPLICATION
Data Sheet No. PD94129
IRU1150
4A ULTRA LOW DROPOUT POSITIVE
ADJUSTABLE REGULATOR
DESCRIPTION
The IRU1150 is a 4A regulator with extremely low drop-
out voltage using a proprietary bipolar process that
achieves comparable equivalent on-resistance to that of
discrete MOSFETs. This product is specifically designed
to provide well regulated supply for applications requir-
ing 2.8V or lower voltages from 3.3V ATX power supplies
where high efficiency of a switcher can be achieved with-
out the cost and complexity associated with switching
regulators. One such application is the new graphic chip
sets that require anywhere from 2.4V to 2.7V supply
such as the Intel I740 chip set.
3.3V
C1
100uF
VIN 5
IRU1150
VCTRL 4
VOUT 3
Adj 2
VSENSE 1
5V
C2
100uF
2.7V
R1
102
C3
R2 100uF
118
Figure 1 - Typical application of IRU1150 in a 3.3V to 2.7V for I740 chip.
PACKAGE ORDER INFORMATION
TJ (°C)
0 To 125
5-PIN PLASTIC
TO-263 (M)
IRU1150CM
5-PIN PLASTIC
Ultra Thin-PakTM (P)
IRU1150CP
8-PIN PLASTIC
SOIC (S)
IRU1150CS
Rev. 1.6
03/18/02
www.irf.com
1
1 page  
IRU1150
The IRU1150 keeps a constant 1.25V between the VSENSE
pin and the VADJ pin. By placing a resistor R1 across
these two pins and connecting the VSENSE and VOUT pin
together, a constant current flows through R1, adding to
the Iadj current and into the R2 resistor producing a volt-
age equal to the (1.25/R1)3R2 + IADJ3R2. This voltage
is then added to the 1.25V to set the output voltage.
This is summarized in the above equation. Since the
minimum load current requirement of the IRU1150 is
10mA, R1 is typically selected to be a 121V resistor so
that it automatically satisfies this condition. Notice that
since the IADJ is typically in the range of 50mA it only
adds a small error to the output voltage and should be
considered when very precise output voltage setting is
required.
Load Regulation
Since the IRU1150 has separate pins for the output (VOUT)
and the sense (VSENSE), it is ideal for providing true re-
mote sensing of the output voltage at the load. This
means that the voltage drops due to parasitic resistance
such as PCB traces between the regulator and the load
are compensated for using remote sensing. Figure 4
shows a typical application of the IRU1150 with remote
sensing.
VI N
Vin
VOUT
For most applications a minimum of 100mF aluminum
electrolytic capacitor such as Sanyo, MVGX series,
Panasonic FA series as well as the Nichicon PL series
insures both stability and good transient response.
Thermal Design
The IRU1150 incorporates an internal thermal shutdown
that protects the device when the junction temperature
exceeds the allowable maximum junction temperature.
Although this device can operate with junction tempera-
tures in the range of 1508C, it is recommended that the
selected heat sink be chosen such that during maxi-
mum continuous load operation the junction tempera-
ture is kept below this number. The example below
shows the steps in selecting the proper surface mount
package.
Assuming, the following conditions:
VOUT = 2.7V
VIN = 3.3V
VCTRL = 5V
IOUT = 2A (DC Avg)
Calculate the maximum power dissipation using the fol-
lowing equation:
PD
=
IOUT
3
(VIN
-
VOUT)
+o
IOUT
60
p3
(VCTRL
-
VOUT)
VC T R L
IRU1150
V CTRL
V SENSE
Adj
R1
R2
RL
Figure 4 - Schematic showing connection
for best load regulation.
Stability
The IRU1150 requires the use of an output capacitor as
part of the frequency compensation in order to make the
regulator stable. Typical designs for the microprocessor
applications use standard electrolytic capacitors with
typical ESR in the range of 50 to 100mV and an output
capacitance of 500 to 1000mF. Fortunately as the ca-
pacitance increases, the ESR decreases resulting in a
fixed RC time constant. The IRU1150 takes advantage
of this phenomena in making the overall regulator loop
stable.
2
PD = 2 3 (3.3 - 2.7) +o60 p3 (5 - 2.7) = 1.28W
Using table below select the proper package and the
amount of copper board needed.
Pkg Copper θJA(°C/W)
Area
TO-263 1.4"X1.4" 25
TO-263 1.0"X1.0" 30
TO-263 0.7"X0.7" 35
TO-263 Pad Size 45
SO-8 1.0"X1.0" 55
Max Pd
(TA=25°C)
4.4W
3.7W
3.1W
2.4W
2.0W
Max Pd
(TA=45°C)
3.6W
3.0W
2.6W
2.0W
1.63W
Note: Above table is based on the maximum junction
temperature of 1358C.
As shown in the above table, any of the two packages
will do the job. For low cost applications the SO-8 pack-
age is recommended.
Rev. 1.6
03/18/02
www.irf.com
5
5 Page | ||
| Páginas | Total 6 Páginas | |
| PDF Descargar | [ Datasheet IRU1150CS.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| IRU1150CM | 4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR | International Rectifier |
| IRU1150CP | 4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR | International Rectifier |
| IRU1150CS | 4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR | International Rectifier |
| 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 |