SC2621
SC2621 is 500kHz Voltage Mode PWM Controller manufactured by SEMTECH.
Description
The SC2621 provides the control and protection Features necessary for a synchronous buck converter and a linear regulator in high performance graphic card applications. The SC2621 is designed to directly drive the top and bottom MOSFETs of the buck converter. It uses an internal 8.2V supply as the gate drive voltage for minimum driver power loss and MOSFET switching loss. It allows the converter to operate at 500k Hz 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 voltage 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.
Features u u u u u u u u u
500k Hz switching frequency 4V to 16V power rails Internal LDO for optimum gate drive voltage 1.5A gate drive current Programmable output voltages Internal soft start Power rail under voltage lockout Hiccup mode short circuit protection 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
PN LDOG LDFB OCS FB P NC
DH NC B ST DRV DL GND V CC
14 13 12 11 10 9 8 + 1 2
2 3 4 5 + 6 7
1.5V OUT
December 17, 2004
.semtech.
POWER MANAGEMENT w w w Maximum . D a t a S h e e t Absolute Ratings
Parameter Input Supply Voltage BST to GND BST to PN PN to GND PN to GND Negative Pulse (tpulse < 20ns) DL to GND DL to GND Negative Pulse (tpulse < 20ns) DH to PN DH to PN Negative Pulse (tpulse < 20ns) DRV to GND Operating Ambient Temperature Range Operating Junction Temperature Thermal Resistance Junction to Ambient Thermal Resistance Junction to Case...
