SG1577 Datasheet, PDF (1/14 Pages) Fairchild Semiconductor – Dual Synchronous DC/DC Controller

April 2008
SG1577
Dual Synchronous DC/DC Controller
Features
ƒ Integrated Two Sets of MOSFET Drivers
ƒ Two Independent PWM Controllers
ƒ Constant Frequency Operation: Free-running Fixed
Frequency Oscillator Programmable: 60kHz to
320kHz
ƒ Wide Range Input Supply Voltage: 8~15V
ƒ Programmable Output as Low as 0.7V
ƒ Internal Error Amplifier Reference Voltage:
0.7V±1.5%
ƒ Two Soft-Start / EN Functions
ƒ Programmable Over-Current Protection (OCP)
ƒ 30V HIGH Voltage Pin for Bootstrap Voltage
ƒ Output Over-Voltage Protection (OVP)
ƒ SOP and DIP 20-pin
Description
The SG1577 is a high-efficiency, voltage-mode, dual-
channel, synchronous DC/DC PWM controller for two
independent outputs. The two channels are operated
out of phase. The internal reference voltage is trimmed
to 0.7V±1.5%. It is connected to the error amplifier’s
positive terminal for voltage feedback regulation. The
soft-start circuit ensures the output voltage can be
gradually and smoothly increased from zero to its final
regulated value. The soft-start pin can also be used for
chip-enable function. When two soft-start pins are
grounded, the chip is disabled and the total operation
current can be reduced to under 0.55mA. The fixed-
frequency is programmable from 60kHz to 320kHz. The
Over-Current Protection (OCP) level can be
programmed by an external current sense resistor. It
has two integrated sets of internal MOSFET drivers.
SG1577 is available in 20-pin SOP and DIP packages.
Applications
ƒ CPU and GPU Vcore Power Supply
ƒ Power Supply Requiring Two Independent Outputs
Ordering Information
Part Number
Operating
Temperature Range
Package
SG1577SZ
SG1577DZ
-40°C to +85°C
-40°C to +85°C
20-pin Small Outline Package (SOP)
20-pin Dual In-Line Package (DIP)
All packages are lead free per JEDEC: J-STD-020B standard.
Packing Method
Tape & Reel
Tube
© 2007 Fairchild Semiconductor Corporation
SG1577 • Rev. 1.0.1
www.fairchildsemi.com