SC4508A
Buck or Buck-Boost (Inverting)
Current Mode Controller
POWER MANAGEMENT
Description
The SC4508A 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) con-
verters. 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 di-
vider. The switching frequency is programmable up to
1.5MHz, allowing small inductor and capacitor values to
minimize PCB space. The operating current level is pro-
grammable via an external sense resistor. Accessible ref-
erence voltage allows users to make output voltage as
low as they want.
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
Hiccup mode after 32 cycle-by-cycle OCP
4mm x 4mm MLPQ-12 lead free package. This
product is fully WEEE and RoHS compliant
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
V+
VREF
FB+
FB-
COMP
SC4508A
CS
OUT
SS/EN
GND OSC
Vout
V+
VREF
FB+
FB-
COMP
SC4508A
CS
OUT
SS/EN
GND OSC
Vout
Revision: July 25, 2007
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