Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

LTC3409A Datasheet(PDF) 14 Page - Linear Technology

Part No. LTC3409A
Description  600mA Low VIN Buck Regulator in 3mm 3mm DFN
Download  16 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  LINER [Linear Technology]
Homepage  http://www.linear.com
Logo 

LTC3409A Datasheet(HTML) 14 Page - Linear Technology

 
Zoom Inzoom in Zoom Outzoom out
 14 / 16 page
background image
LTC3409A
14
3409af
Design Example
As a design example, assume the LTC3409A is used in a
2-alkaline cell battery-powered application. The VIN will be
operating from a maximum of 3.2V down to about 1.8V.
The load current requirement is a maximum of 600mA
but most of the time it will be in standby mode, requiring
only 2mA. Efficiency at both low and high load currents is
important, so the minimum frequency setting of 1.7MHz
is chosen. Output voltage is 1.5V. With this information
we can calculate L using Equation 3:
L
=
1
f•
ΔIL
VOUT 1–
VOUT
VIN
⎝⎜
⎠⎟
(3)
Substituting VOUT = 1.5V, VIN = 3.2V, ΔIL = 240mA and
f = 1.7MHz in Equation 2 gives:
L
=
1
1.7MHz • 240mA
1.5V 1–
1.5V
3.2V
⎝⎜
⎠⎟
2.2µH
For best efficiency choose a 750mA or greater inductor
with less than 0.3Ω series resistance. CIN will require
an RMS current rating of at least 0.3A
≅ ILOAD(MAX)/2 at
temperature.
For the feedback resistors, choose R2 = 137k. R1 is then
calculated to be 200k from Equation 2. Figure 4 shows the
complete circuit along with its efficiency curve.
Table 2 below gives 1% resistor values for selected output
voltages.
VOUT
R1
R2
0.85V
53.6k
137k
1.2V
137k
143k
1.5V
200k
137k
1.8V
267k
137k
VFB
GND
VIN
VIN
SYNC
RUN
SW
MODE
LTC3409A
L1
2.2μH
R1
200k
C1
10pF
CIN
4.7μF
VIN
1.8V TO 3.2V
R2
137k
3409A F04
VOUT
1.5V
0.6A
COUT
22μF
2
L1: SUMIDA CDRH2D18/LD
Figure 4
Burst Mode Efficiency, 1.5VOUT
APPLICATIONS INFORMATION
LOAD CURRENT (mA)
30
90
100
20
10
80
50
70
60
40
0.1
10
100
1000
3409A F04b
0
1
1.8VIN
3.2VIN
2.5VIN


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16 


Datasheet Download




Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
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