Moteur de recherche de fiches techniques de composants électroniques
  French  ▼

Delete All
ON OFF
ALLDATASHEET.FR

X  

Preview PDF Download HTML

IRU1150 Fiches technique(PDF) 5 Page - International Rectifier

No de pièce IRU1150
Description  4A ULTRA LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR
Download  6 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  IRF [International Rectifier]
Site Internet  http://www.irf.com
Logo IRF - International Rectifier

IRU1150 Fiches technique(HTML) 5 Page - International Rectifier

  IRU1150 Datasheet HTML 1Page - International Rectifier IRU1150 Datasheet HTML 2Page - International Rectifier IRU1150 Datasheet HTML 3Page - International Rectifier IRU1150 Datasheet HTML 4Page - International Rectifier IRU1150 Datasheet HTML 5Page - International Rectifier IRU1150 Datasheet HTML 6Page - International Rectifier  
Zoom Inzoom in Zoom Outzoom out
 5 / 6 page
background image
IRU1150
5
Rev. 1.6
03/18/02
www.irf.com
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 121
V resistor so
that it automatically satisfies this condition. Notice that
since the IADJ is typically in the range of 50
mA 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.
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 100m
V and an output
capacitance of 500 to 1000
mF. 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.
For most applications a minimum of 100
mF 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 150
8C, 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:
Calculate the maximum power dissipation using the fol-
lowing equation:
Using table below select the proper package and the
amount of copper board needed.
Pkg
Copper
θJA(°C/W)
Max Pd
Max Pd
Area
(TA=25
°C)
(TA=45
°C)
TO-263 1.4"X1.4"
25
4.4W
3.6W
TO-263 1.0"X1.0"
30
3.7W
3.0W
TO-263 0.7"X0.7"
35
3.1W
2.6W
TO-263 Pad Size
45
2.4W
2.0W
SO-8
1.0"X1.0"
55
2.0W
1.63W
Note: Above table is based on the maximum junction
temperature of 135
8C.
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.
VOUT = 2.7V
VIN = 3.3V
VCTRL = 5V
IOUT = 2A (DC Avg)
PD = 2
3 (3.3 - 2.7) +
oo pp3(5-2.7)=1.28W
2
60
PD = IOUT
3 (VIN - VOUT) +
oo pp3(V
CTRL
- VOUT)
IOUT
60
R1
R2
VIN
VCTRL
R L
IRU1150
VSENSE
Adj
VOUT
VCTRL
Vin


Html Pages

1  2  3  4  5  6 


Fiches technique Télécharger

Go To PDF Page


Lien URL




Politique de confidentialité
ALLDATASHEET.FR
ALLDATASHEET vous a-t-il été utile ?  [ DONATE ] 

À propos de Alldatasheet   |   Publicité   |   Contactez-nous   |   Politique de confidentialité   |   Echange de liens   |   Fabricants
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn