
1
www.semtech.com
SC4510
High Performance Synchronous Buck
Controller With Reference Tracking
POWER MANAGEMENT
Description
The SC4510 can be configured as a synchronous buck
convertor capable of sourcing and sinking current from load
without losing output regulation. The output can be set to
track an internal reference or an external voltage. The
actual reference used by the error amplifier is buffered
and brought out as a reference. It is the ideal choice for
externally referenced or tracking buck convertors such as
those for DDR memory applications.
United States Patent #6,441,597
Features
Applications
u
Externally referenced buck convertors
u
DDR memory terminators
u
Point of use power supplies
Revision: Jan 0
7
, 2005
Typical Application Circuit
u
Synchronous buck operation with current sink or
source without loss of regulation
u
Output can track internal or external reference
u
Buffered reference output from external reference
u
Combi-Sense mode lossless current sensing
u
2.5V to 16V operation with 4.75V minimum V
CC
u
Direct drive for high side N-channel MOSFETs with
diode and capacitor bootstrap
u
Undervoltage lockout, Soft Start, Enable and Power
Good functions
u
Fast transient response with external compensation
u
Current mode control with transconductance error
amplifier
u
Programmable oscillator frequency with external sync
The controller is also designed for point of use DC-DC
convertors with 2.5-16V power sources with a Vcc of 4.5V
or higher. Soft start, current limit, programmable oscillator
and external compensation functions are provided to
ensure high degree of integration and low external
component count. Semetch’s patented Combi-Sense
technique is utilised for lossless current sening and
maximising efficiency. Both high and low side MOSFET
drivers are built in and rated for substantial peak currents
to minimise switching losses. The SC4510 is offered in a
space saving TSSOP-20 package.
C1
C7
C2
C6
C11
R3
R7
R6
Q1
Q2
L1
REFOUT
PGOOD
SYNC
D1
C8
C12
RTN
R5
C10
C5
C4
C3
VOUT
R2
0.5V MIN
EXT REF
INT REF
RTN
15V MAX
C9
C13
V
1
P
8
A
7
P
1
G
9
G
1
B
1
A
2
C
1
I
1
S
1
R
1
R
2
C
4
V
1
R
1
R
3
C
5
P
6
S
1
U1
SC4510
R1
R4
IN+
VIN