1
TB429
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 321-724-7143
|
Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2004. All Rights Reserved. Elantec is a registered trademark of Elantec Semiconductor, Inc.
All other trademarks mentioned are the property of their respective owners.
Using the EL7515 Demo Board
The complete schematic of EL7515
demo board is shown in Figure 1. With
different components stuffed, this
demo board can easily be configured into the applications
shown in this technical brief. The standard demo board
being sent out is the complete 5V to 12V converter shown in
Figure 2, which occupies less than 0.4 in
2
area with
components on top side only. Layout diagrams are given at
the end of this document.
1. V
IN
= 2V-5.5V. Can be higher with higher voltage rated
C
1
2. V
O
= 12V. Can be set according to the following formula:
where V
FB
is shown in the V
FB
vs V
DD
curve.
3. I
O
- up to 600mA depending on input voltage, provided
that diode and inductor can handle the corresponding
currents (refer to data sheet for the chart)
4. Switching frequency - can be set by R
3
5. R
4
can be 10
- 51 if V
O
is less than 10V. If V
O
is larger
than 12V, it can be calculated by:
where I
DD
is a function of switching frequency, as shown
in the I
DD
vs F
S
curve.
V
O
V
FB
1
R
2
R
1
-------
+
=
R
4
V
O
10
I
DD
---------------------
=
1
2
3
4
10
9
8
7
5
6
PGND
SGND
RT
EN
LBI
LX
VDD
FB
SS
LBO
C
3
R
1
R
2
C
5
C
6
C
4
R
4
D
1
L
1
C
1
R
3
V
IN
V
O11
C
7
R
7
R
8
R
6
EN
C
8
LBO
V
O1
L
2
C
12
C
13
V
O2
C
15
V
O3
V
O4
C
22
C
21
C
14
C
11
D
11
D
12
D
21
Q
1
R
9
FIGURE 1. COMPLETE SCHEMATIC OF EL7515 DEMO BOARD
FIGURE 2. 5V TO 12V CONVERTER
1
2
3
4
10
9
8
7
5
6
PGND
SGND
RT
EN
LBI
LX
VDD
FB
SS
LBO
C
3
R
1
R
2
C
5
C
6
C
4
R
4
D
1
L
1
C
1
R
3
V
IN
V
O1
C
10
R
6
Technical Brief
June 7, 2004
7
Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to
verify that the Application Note or Technical Brief is current before proceeding.
For information regarding Intersil Corporation and its products, see www.intersil.com
Demo Board Layout
FIGURE 8. TOP LAYER
2000 mil
2000 mil
FIGURE 9. TOP SILKSCREEN
2 in
2 in
FIGURE 10. BOTTOM LAYER
2000 mil
2000 mil
Technical Brief 429
PDF 
ZIP
