SC4503 Semtech Corporation, SC4503 Datasheet - Page 19

• Manufacturer Part Number: SC4503
• Description: 1.3MHz Step-Up Switching Regulator
• Manufacturer: Semtech Corporation

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 2007 Semtech Corp.
POWER MANAGEMENT
Typical Application Circuits
Figure 13(b).
CH1 : OUT1 Voltage, 5V/div
CH2 : OUT2 Voltage, 20V/div
CH3 : OUT3 Voltage, 5V/div
CH4 : RUN Voltage, 5V/div
TFT Power Supply Start-up Transient as
the RUN Voltage is Stepped from 0 to
3.3V
CH4
CH1
CH2
CH3
3.3V
400µs/div
OFF
4.7µF
C1
RUN
Figure 13(a). Triple-Output TFT Power Supply with Soft-Start
< 0.4V
ON
3.3V
17.8k
R3
4
C3
56nF
D2 - D7 : BAT54S
L1 : Sumida CDC5D23B-4R7M
C2: Murata GRM21BR61C475K
C1: Murata GRM188R61A105K
SHDN/SS
IN
5
SC4503
4.7µH
GND
L1
2
1
SW
D2
FB
19
3
C5
0.1µF
Upper Trace : Output Voltage, AC Coupled, 0.5V/div
Lower Trace : Inductor Current, 0.5A/div
D3
C9
10BQ015
0.1µF
D6
Figure 13(c).
D1
D7
C6
0.1µF
D4
C10
1µF
OUT3
C4
12pF
-8.5V (10mA)
C7
Load Transient Response. I
is switched between 50mA and
350mA
0.1µF
R1
309k
R2
49.9k
D5
40µs/div
C8
1µF
OUT1
C2
9V (0.3A)
4.7µF X 2
OUT2
26V (10mA)
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SC4503
OUT1