Voltage Mode PWM Controller With
Linear Power Regulator
POWER MANAGEMENT
Description
The SC2621A provides the control and protection fea-
tures necessary for a synchronous buck converter and a
linear regulator in high performance graphic card appli-
cations.
The SC2621A is designed to directly drive the top and
bottom MOSFETs of the buck converter. It uses an inter-
nal 8.2V supply as the gate drive voltage for minimum
driver power loss and MOSFET switching loss. It allows
the converter to operate with 4V to 25V power rail and
as low as 0.5V output. The SC2621A is capable to drive
a N-type MOSFET in a linear regulator with as low as 0.5V
output.
The SC2621A features soft-start, supply power under
voltage lockout, and hiccup mode over current protec-
tion. The SC2621A monitors the output current by using
the Rdson of the bottom MOSFET in the buck converter
that eliminates the need for a current sensing resistor.
The SC2621A is offered in SOIC-14 package.
SC2621A
Features
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4V to 25V power rails
Internal LDO for optimum gate drive voltage
1.5A gate drive current
Adaptive non-overlapping gate drives provide
shoot-through protection for MOSFETs
Programmable output voltages
Internal soft start for both outputs
Power rail under voltage lockout
Hiccup mode short circuit protection
SOIC-14 package, fully RoHS and WEEE compliant
Applications
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Graphics processor power supplies on PCI-Express
platform
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Embedded, low cost, high efficiency converters
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Point of load power supplies
Typical Application Circuit
12V IN
+
1.5V OUT
U2
1
B ST
OCS
COMP
FB
LDOG
LDFB
GND
S C2 621A
DH
PN
GND
DL
DRV
NC
V CC
14
13
12
11
10
9
8
+
1
2
3.3V IN
2
3
4
2.5V OUT
5
6
7
+
February 21, 2007
1
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SEMTECH [ SEMTECH CORPORATION ]
