SC2453 Datasheet, PDF (1/14 Pages) Semtech Corporation – High Performance Quad Output Switching Regulator

POWER MANAGEMENT
Description
SC2453 is a high performance multi-output converter
controller that can be configured for a variety of applica-
tions. The SC2453 utilizes synchronous rectified buck
topologies where efficiency is most important. It also
provides dedicated programmable positive and negative
linear regulators using external transistors in conjunction
with coupled windings to generate positive and negative
voltages. Power up sequencing prevents converter latch-
ups.
The two buck converters are out of phase, reducing in-
put ripple, allowing for fewer input capacitors. All con-
verters are synchronized to prevent beat frequencies.
High frequency operation will reduce ripple and minimize
noise. It also reduces the size of output inductors and
capacitors. Other features include soft start, power-good
signaling, bootstrapping for high side MOSFETs, and fre-
quency synchronization.
Typical Application Circuit
SC2453
High Performance Quad Output
Switching Regulator
PRELIMINARY
Features
‹ Two synchronized converters for low noise
‹ Power up sequencing to prevent latch-ups
‹ Out of phase operation for low input ripple
‹ Over current protection
‹ Wide input range, 4.5 to 30V
‹ Programmable frequency up to 700KHz
‹ Two synchronous bucks for high efficiency at high
current
‹ One dedicated programmable positive linear
regulator and one dedicated programmable nega-
tive linear regulator
‹ –40 to 105 degree C operating temperature
‹ Output voltage as low as 0.5V
‹ Small package TSSOP-28
Applications
‹ DSL applications with multiple input voltage re-
quirements
‹ Mixed-Signal applications requiring positive and
negative voltages
‹ Cable modem power management
‹ Base station power management
+8-30V
Q1
C29
C30
C29
R28
C32
16 22
28 27
C29
6
AVCC
SS
PVCC
BDI
VIN
BST2
17
+3.3V
R31
C29
9 _OSC
7 _SYNC/SHDN
8 _POK
GD2H ¹⁸
PH2 ¹⁹
GD2L ²⁰
+2.5V
C32
Q2
R31
R31
C32
R31 ⁴ BD4
5 _FB4
11 _BD3
SC2453
FB2 ¹³
EO2 ¹²
BST1 ²⁶
GD1H ²⁵
PH1 ²⁴
GD1L ²³
-12V
Q12 ^R32
C32 C32
R32
C31
FB1 ²
10 _FB3
EO1 ³
AGND PGND ILIM2 ILIM1
15
21
14
1
R28 R28
D10
D11
C31
R32 C34
C35
C31
C41
C42
R39
Q11
Q11
Q14
Q15
D11
L8
L9
C30
C33
+3.3V
R30
R33
+1.5V
C38
R35
R38
R32
+3.3V
Revision 5, August 2002
1
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