SC4611 Datasheet, PDF (1/11 Pages) Semtech Corporation – Wide Input Range High Performance Synchronous Buck Switching Regulator

POWER MANAGEMENT
SC4611
Wide Input Range High Performance
Synchronous Buck Switching Regulator
Description
SC4611 is a high performance synchronous buck controller
that can be configured for a wide range of applications.
The SC4611 utilizes synchronous rectified buck topologies
where high efficiency is the primary consideration. It is
optimized for applications involving multiple and redundant
convertors connected together. The startup is
asynchronous, which keeps the lower side FET off during
soft start. This is a desired feature when a convertor is
turned on with a preset external voltage or pre-bias voltage
already present across its output. With the lower FET off,
external bus is not discharged which avoids latch-up of
modern ASIC circuits.
SC4611 comes with a rich set of features like regulated
Vcc supply, soft start, power-good signaling, high current
gate drivers, bootstrapped supply for driving high side N-
channel MOSFETs, shoot through protection, frequency
synchronization and the option for overvoltage crowbar. It
also features multi mode overload protection that includes
continuous current limiting, hiccup mode followed by latch
off. The user has the option of bypassing the hiccup mode
and latch off the output if required.
Typical Application Circuit
Features
‹ Wide input range, 4.5 to 30V
‹ Output voltage as low as 0.5V
‹ 2A output drive capability
‹ Asynchronous start up mode
‹ Multimode overcurrent protection with current limit,
hiccup mode and latched shutdown
‹ Overvoltage crowbar protection
‹ Power OK signal
‹ Programmable frequency up to 1 MHz with external
synchronization
‹ –40 to +85 degree C operating temperature
‹ Thermal shutdown
‹ Small package TSSOP-20
Applications
‹ Distributed power architectures
‹ Telecommunication equipment
‹ Servers/work stations
‹ Mixed signal applications
‹ Paralleled synchronous buck convertors
‹ Base station power management
VIN (30V MAX)
Cin
RTN
4
VIN
3
BST
5
BDI
2
GDH
17
AVC C
1
PH
20 _{P VC C}
G D L ¹⁹
14 _{S S /S H}
CS+ ⁷
13
OS C
6
CS-
RT
16 _{S Y N C}
OVP ¹¹
12 _{C L M}
AG N D ¹⁵
9 _EAO
P G N D ¹⁸
8
FB
10
P OK
QH
Lout
QL
VOUT (0.5V MIN)
Rcs
Cout
Rclset
RTN
Revision: November 10, 2004
1
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