Simple, Synchronous
Voltage Mode PWM Controller
POWER MANAGEMENT
Description
The SC2608 is a versatile voltage-mode PWM controller
designed for use in step down DC/DC power supply appli-
cations. A simple, fixed frequency, highly efficient buck
regulator can be implemented using the SC2608 with mini-
mal external components. The input voltage range is from
+3.3V to +12V. Internal level shift and drive circuitry elimi-
nates the need for an expensive P-channel, high-side
MOSFET. The small device footprint allows for compact
circuit design.
SC2608 features include temperature compensated volt-
age reference, triangle wave oscillator, current limit com-
parator, and an externally compensated error amplifier.
Current limit is implemented by sensing the voltage drop
across the bottom MOSFET R
DS(ON)
.
The SC2608 operates at a fixed frequency of 200kHz
providing an optimum compromise between efficiency ,
external component size, and cost.
SC2608 has a thermal protection circuit, which is
activated if the junction temperature exceeds 150
O
C.
SC2608
Features
+3.3V or +5V or +12V input voltage
200kHz operation
High efficiency (>90%)
1% Reference voltage accuracy
Hiccup mode over current protection
Robust output drive
R
DS(ON)
Current sensing for protection
Industrial temperature range
SO-8 package
Integrated boot strap diode
Thermal Shut down
Fully WEEE and RoHS Compliant
Applications
Termination supplies
Low cost microprocessor supplies
Peripheral card supplies
Industrial power supplies
High density DC/DC conversion
Typical Application Circuit
SC2608
sense
COMP/SS SENSE
+12V/+5V/+3.3V
+12V
GND
VCC
DL
PHASE
DH
BST
VOUT
sense
Figure 1
Revision 4: October, 2005
1
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