SC4502
SC4502 is 2MHz Step-Up Switching Regulator manufactured by SEMTECH.
Description
The SC4502/SC4502H is a high-frequency current-mode step-up switching regulator with an integrated 1.4A power transistor. Its high switching frequency (programmable up to 2MHz) allows the use of tiny surface-mount external passive ponents. Programmable soft-start eliminates high inrush current during start-up. The internal switch is rated at 32V (40V for the SC4502H) making the converter suitable for high voltage applications such as Boost, SEPIC and Flyback. .. The operating frequency of the SC4502/SC4502H can be set with an external resistor. The ability to set the operating frequency gives the SC4502/SC4502H design flexibilities. A dedicated P pin allows optimization of the loop response. The SC4502/SC4502H is available in thermally enhanced 10-pin MLPD package.
Features
Low saturation voltage switch: 210m V (250m V for the SC4502H) Constant switching frequency current-mode control Programmable switching frequency up to 2MHz Soft-Start function Input voltage ranges from 1.4V to 16V Output voltage up to 32V (40V for the SC4502H) Low shutdown current Adjustable undervoltage lockout threshold Small low-profile thermally enhanced lead free package. This product is fully WEEE and Ro HS pliant.
Applications
Flat screen LCD bias supplies TFT bias supplies XDSL power supplies Medical equipment Digital video cameras Portables devices White LED power supplies
Typical Application Circuit
VIN 5V 8 OFF ON C1 2.2 µF 3 10 IN SHDN SC4502 SS GND C3 47n F 4,5 P ROSC 9 R4 C4 6,7 SW FB 2 1 R3 C6 R2 100K C2 10 µF L1 D1 10BQ015 VOUT 12V R1 866K
Efficiency
95 90 85 10.5µH, 700KHz 5.3µH, 1.4MHz
Efficiency (%)
80 75 70 65 60 55 50 VIN = 5V VOUT = 12V 0.0 0.1 0.2 0.3 0.4 0.5 3.3µH, 2MHz
All Capacitors are Ceramic. f (MHz) 0.7 1.4 2
R3 (KΩ ) R4 (KΩ ) 33.2 59.0 73.2 23.7 9.53 5.36
C4 (p F) 1500 560 330
C6 (p F) 22
L1 (µH) 10.5 (Falco D08019) 5.3 (Sumida CDRH5D28) 3.3 (Coilcraf t DO1813P)
Load Current (A)
Figure 1(b). Efficiencies of 5V to...
