Buck or Buck-Boost Current Mode Controller
Description
Buck or Buck-Boost(Inverting) Current Mode Controller
POWER MANAGEMENT Description
The SC4508 is a low voltage current mode switching regulator controller that drives a P-channel power MOSFET with programmable switching frequency.
It can be configured in either buck or buck boost (inverting) converters.
The converters can be operated from 2.
7V to 15V input voltage range.
The typical operating supply current is 3mA and a shutdown pin allows the user to turn the controller off reducing it to less than 200µA.
The output voltage can adjusted by external resistor divider.
The www.
DataSheet4U.
com switching frequency is programmable up to 1.
5MHz, allowing small inductor and capacitor values to minimize PCB space.
The operating current level is programmable via an external sense resistor.
Accessible reference voltage allows users to make output voltage as low as they want.
SC4508
Features
Wide input voltage range 2.
7V to 15V Programmable output voltage Programmable switching frequency up to 1.
5MHz Buck or buck boost(inverting) configuration Current mode control with slope compensation Very low quiescent current in shutdown mode Accessible reference voltage MLPQ-12 package
Applications
Low power point of use converters Single or multiple output low power converters Positive and/or negative output voltage DSL cards Graphic cards I/O cards Negative bias supplies
Typical Application Circuits
Vin Vin
VDD VDD VREF VREF FB+ FBCOMP CS FB+ OUT FB-
SC4508
SC4508
CS
COMP SS/SHDN GND OSC SS/SHDN GND OSC
OUT
Revision: November 30, 2004
1
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semtech.
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SC4508
POWER MANAGEMENT Absolute Maximum Rating
Exceeding the specifications below may result in permanent damage to the device, or device malfunction.
Operation outside of the parameters specified in the Electrical Characteristics section is not implied.
Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability.
Parameter VDD to GND SS/SHDN to GN...
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