SC4501 Datasheet, PDF (1/21 Pages) Semtech Corporation – 2Amp, 2MHz Step-Up Switching Regulator with Soft-Start

POWER MANAGEMENT
Description
The SC4501 is a high-frequency current-mode step-up
switching regulator with an integrated 2A power transis-
tor. Its high switching frequency (programmable up to
2MHz) allows the use of tiny surface-mount external pas-
sive components. Programmable soft-start eliminates high
inrush current during start-up. The internal switch is rated
at 32V making the converter suitable for high voltage ap-
plications such as Boost, SEPIC and Flyback.
The operating frequency of the SC4501 can be set with an
external resistor. The ability to set the operating frequency
gives the SC4501 design flexibilities. A dedicated COMP
pin allows optimization of the loop response. The SC4501
is available in thermally enhanced 8-Pin MSOP and 10-pin
MLPD packages.
SC4501
2Amp, 2MHz Step-Up Switching
Regulator with Soft-Start
Features
u Low saturation voltage switch: 220mV at 2A
u Constant switching frequency current-mode control
u Programmable switching frequency up to 2MHz
u Soft-Start function
u Input voltage range from 1.4V to 16V
u Output voltage up to 32V
u Low shutdown current
u Adjustable undervoltage lockout threshold
u Small low-profile thermally enhanced packages
Applications
u Flat screen LCD bias supplies
u TFT bias supplies
u XDSL power supplies
u Medical equipment
u Digital video cameras
u Portables devices
u White LED power supplies
Typical Application Circuit
VIN
5V
C1
2.2µF
L1
D1
10BQ015
6
5
IN
OFF ON ³ _SHDN
SW
FB ²
SC4501
8
SS
COMP ¹
C3
47nF
GND
4
ROSC
7
R4
R3
C6
C4
R1
174K
R2
20K
VOUT
12V, 0.7A
C2
10µF
All Capacitors are Ceramic.
MSOP-8 Pinout
f / MHz R₃ / KΩ R₄ / KΩ C₄ / pF C₆ / pF
0.7
22.1
22.1 2200
-
L₁ / µH
10.5 (Falco D08019)
1.35 30.9
9.31
820
-
4.7 (Falco D08017)
2
63.4 4.75 470
22 3.3 (Coilcraft DO1813P)
Efficiency
95
10.5µH, 700KHz
90
4.7µH, 1.4MHz
85
80
3.3µH, 2MHz
75
70
65
60
55
VIN = 5V
VOUT = 12V
50
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Load Current (A)
Figure 1(a). 5V to 12V Boost Converter.
Revision: October 25, 2005
Figure 1(b). Efficiencies of 5V to 12V Boost Converters at
700KHz, 1.4MHz and 2MHz.
1
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