TB435 Datasheet, PDF (1/2 Pages) Intersil Corporation – Using the EL7516 Demo Board

®
Technical Brief
Using the EL7516 Demo Board
May 13, 2005
TB435.0
The complete schematic of EL7516 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 Table 1, which
occupies less than 0.4 in² area with components on top side
only. Layout diagrams are given at the end of this document.
1. V_IN = 2.5V-5.5V. Can be higher with higher voltage rated
C₁
2. V_O = 12V. Can be set according to the following formula:
V_O
=
V_FB
×

1

+
R_{-----1- }
R_2
where V_FB is 1.294V.
3. I_O - up to 750mA 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 selected between 620KHz
(FSEL <0.6V) or 12.5MHz (FSEL >2.7V)
5. R₃ and C₅ are the compensation network.
SW
C₅
R₃
3.9kΩ
C₆
4.7nF
R₁
85.2kΩ ^R2
10kΩ
1 COMP
SS 8
2 FB
FSEL 7
3 SHDN VDD 6
4 GND
LX 5
C₄
R₄
27nF 10kΩ
R₅
10kΩ
C₂ + C₁
0.1µF 22µF
L₁
10µH
+ C₃
D₁
22µF
2.7V TO 5.5V
12V
REFERENCE
DESIGNATOR
R₁
R₂
R₃
R₄, R₅
C₁, C₃
C₂
C₄
C₅
C₆
L₁
D₁
FIGURE 1. 3.3V TO 12V CONVERTER
TABLE 1. EL7516 BILL OF MATERIALS FOR V_O = 12V
VALUE
MANUFACTURER
MANUFACTURER’S
PHONE NUMBER
85.2kΩ/1%, 0603
Any
10kΩ/1%, 0603
Any
3.9kΩ, 0603
Any
10kΩ/1%, 0603
Any
22µF, 16V, 1812
TDK
0.1µF, 16V, 0805
Any
27nF, 0603
Any
OPEN
4.7nF, 0603
Any
10µH
Coilcraft
847-639-6400
MBR0520
On Semiconductor
800-282-9855
MANUFACTURER’S
PART NUMBER
C4532X5R1C226M
DO1608C-103
MBR0520
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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