Moteur de recherche de fiches techniques de composants électroniques
  French  ▼

Delete All
ON OFF
ALLDATASHEET.FR

X  

Preview PDF Download HTML

IRU1015 Fiches technique(PDF) 6 Page - International Rectifier

No de pièce IRU1015
Description  1.5A LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR
Download  8 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Fabricant  IRF [International Rectifier]
Site Internet  http://www.irf.com
Logo IRF - International Rectifier

IRU1015 Fiches technique(HTML) 6 Page - International Rectifier

  IRU1015 Datasheet HTML 1Page - International Rectifier IRU1015 Datasheet HTML 2Page - International Rectifier IRU1015 Datasheet HTML 3Page - International Rectifier IRU1015 Datasheet HTML 4Page - International Rectifier IRU1015 Datasheet HTML 5Page - International Rectifier IRU1015 Datasheet HTML 6Page - International Rectifier IRU1015 Datasheet HTML 7Page - International Rectifier IRU1015 Datasheet HTML 8Page - International Rectifier  
Zoom Inzoom in Zoom Outzoom out
 6 / 8 page
background image
IRU1015
6
Rev. 1.1
06/29/01
2) With the output capacitance being 1500µF:
Where:
∆t = 2µs is the regulator response time
To set the output voltage, we need to select R1 and R2:
3) Assuming R1 = 121Ω, 1%
Select R2 = 215Ω, 1%
Selecting both R1 and R2 resistors to be 1% toler-
ance results in the least amount of error introduced
by the resistor dividers leaving a
≈ ±2.5% error bud-
get for the IRU1015 reference which is well within the
initial accuracy of the device.
Finally, the input capacitor is selected as follows:
4) Assuming that the input voltage can drop 150mV be-
fore the main power supply responds, and that the
main power supply response time is
≈ 50ms, then
the minimum input capacitance for a 1.2A load step
is given by:
The ESR should be less than:
Where:
VDROP L Input voltage drop allowed in step 4
∆V L Maximum regulator dropout voltage
∆I L Load current step
Select a single 1500µF the same type as the output
capacitors exceeds our requirements.Figure 6 shows
the completed schematic for our example.
Figure 5 - Typical regulator response to the
fast load current step
An example of a regulator design to meet the AMD speci-
fication for 486DX4-120MHz is given below.
Assume the specification for the processor as shown in
Table 1:
Type of
Vout
Imax
Max Allowed
Processor
Nominal
Output Tolerance
AMD 486DX4
3.45 V
1.2 A
±150 mV
Table 1 - GTL+ specification for Pentium Pro
The first step is to select the voltage step allowed in the
output due to the output capacitor’s ESR:
1) Assuming the regulator’s initial accuracy plus the re-
sistor divider tolerance is
≈ ±86mV (±2.5% of 3.45V
nominal), then the total step allowed for the ESR and
the ESL, is -64mV.
Assuming that the ESL drop is -10mV, the remaining
ESR step will be -54mV. Therefore the output ca-
pacitor ESR must be:
The Sanyo MVGX series is a good choice to achieve
both price and performance goals. The 6MV1500GX,
1500µF, 6.3V has an ESR of less than 36mΩ typi-
cal. Selecting a single capacitor achieves our design
goal.
The next step is to calculate the drop due to the ca-
pacitance discharge and make sure that this drop in
voltage is less than the selected ESL drop in the
previous step.
V ESR
V ESL
V C
T
LOAD
CURRENT
LOAD CURRENT RISE TIME
1015plt1-1.0
CIN =
= 400µF
1.2 × 50
0.15
ESR =
= 0.167Ω
(5 - 3.45 - 1.2 - 0.15)
1.2
ESR =
(VIN - VOUT - ∆V - VDROP)
∆I
∆Vc =
=
= 1.6mV
∆t × ∆I
2 × 1.2
C
1500
ESR ≤
= 45mΩ
54
1.2
R2 =o
o
o
o
o
- 1p
p
p
p
p
× 121 =o
o
o
o
o
- 1p
p
p
p
p
× 121 = 213Ω
VOUT
VREF
3.45
1.25


Html Pages

1  2  3  4  5  6  7  8 


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