SC2621 Datasheet, PDF (1/10 Pages) Semtech Corporation – 500kHz Voltage Mode PWM Controller With Linear Power Regulator

SC2621
500kHz Voltage Mode PWM Controller
With Linear Power Regulator
POWER MANAGEMENT
Description
Features
The SC2621 provides the control and protection features
necessary for a synchronous buck converter and a lin-
ear regulator in high performance graphic card applica-
tions.
The SC2621 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 at 500kHz switching frequency
with 4V to 16V power rail and as low as 0.5V output. The
SC2621 is capable to drive a N-type MOSFET in a linear
regulator with as low as 0.5V output.
The SC2621 features soft-start, supply power under volt-
age lockout, and hiccup mode over current protection.
The SC2621 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
SC2621 is offered in a SOIC-14 package.
u 500kHz switching frequency
u 4V to 16V power rails
u Internal LDO for optimum gate drive voltage
u 1.5A gate drive current
u Programmable output voltages
u Internal soft start
u Power rail under voltage lockout
u Hiccup mode short circuit protection
u SOIC-14 package
Applications
u Graphics processor power supplies on PCI-Express
platform
u Embedded, low cost, high efficiency converters
u Point of load power supplies
Typical Application Circuit
12V IN
3.3V IN
2.5V OUT
+
1
PN
2 _LDOG
3
LDFB
4 _OCS
5 _FB
6 _COMP
7
NC
14
DH
NC ¹³
12
B ST
DRV ¹¹
DL ¹⁰
GND ⁹
8
V CC
S C 2 62 1
+
1
2
1.5V OUT
+
December 17, 2004
1
www.semtech.com