SC4540 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SC4540' PDF : 15 Pages View PDF
SC4540
Applications Information (continued)
Application Circuit for Alternate Input voltages
The typical applications circuit for the SC4540 is shown in
Figure 2. The performance data and specifications included
in this document are for the typical application circuit
(Figure 2). The SC4540 can be used with input voltages
lower than 4.5V (see Figure 3). The Inductor, L1, will need
to be adjusted to allow proper operation for input volt-
ages between to 2.8V to 5.5V. The SC4538 datasheet
should be consulted for the performance of the lower
input voltage circuit.
L1
D
5 6 μH
1 μF
LX
C OUT
4.5 to 12V
IN
OUT
C IN
2.2μF
SC 4540
Enable and
PWM
dimming
R IS E T
CCOMP
RCOMP
1 .2 7 k Ω
47nF
EN
IS E T
COMP
BL
GND
L1
D
2 2 μH
2.8V to 5.5V
C IN
2.2μF
LX
IN
OUT
SC 4540
Enable and
PWM
dimming
R IS E T
C C OM P
RCOMP
1 .2 7 k Ω
47nF
EN
IS E T
COMP
BL
GND
COUT
1 μF
Figure 2 — Typical Application Circuit
Figure 3 — Low Input Voltage Application Circuit
13
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