SC1186_04 Datasheet, PDF (1/15 Pages) Semtech Corporation – Programmable Synchronous DC/DC Converter, Dual LDO Controller

SC1186
Programmable Synchronous DC/DC
Converter, Dual LDO Controller
POWER MANAGEMENT
Description
Features
The SC1186 combines a synchronous voltage mode
controller with two low-dropout linear regulators
providing most of the circuitry necessary to implement three
DC/DC converters for powering advanced microprocessors
such as Pentium^® II & III.
The SC1186 switching section features an integrated 5
bit D/A converter, latched drive output for enhanced noise
immunity, pulse by pulse current limiting and logic
compatible shutdown. The SC1186 switching section
operates at a fixed frequency of 140kHz, providing an op-
timum compromise between size, efficiency and cost in
the intended application areas. The integrated D/A con-
verter provides programmability of output voltage from 2.0V
to 3.5V in 100mV increments and 1.30V to 2.05V in
50mV increments with no external components.
‹ Synchronous design, enables no heatsink solution
‹ 95% efficiency (switching section)
‹ 5 bit DAC for output programmability
‹ Designed for Intel Pentium^® ll & III requirements
‹ 1.5V, 2.5V short circuit protected linear controllers
‹ 1.265V ± 1.5% Reference available
Applications
‹ Pentium^® ll & III microprocessor supplies
‹ Flexible motherboards
‹ 1.3V to 3.5V microprocessor supplies
‹ Programmable triple power supplies
The SC1186 linear sections are low dropout regulators
with short circuit protection, supplying 1.5V for GTL bus
and 2.5V for non-GTL I/O. The Reference voltage is made
available for external linear regulators.
Typical Application Circuit
12V
+
5V
47uF
0.1uF
+
1500uF
10
x4
VID0
VID1
VID2
VID3
VID4
EN
0.1uF
3.3V
5 _VCC
7 _LDOEN
22 _VID0
21 _VID1
20 _VID2
19 _VID3
18 _VID4
16 _EN
1 _AGND
23 _LDOV
24 _GATE2
4 _LDOS2
CS+
CS-
VOSENSE
BSTH
DH
BSTL
DL
PGNDH
PGNDL
REF
GATE1
LDOS1
SC1186CS
9
8 ^0.1uF
17
15
11
14
13
10
12
6
2
3
IRLR3103N
2R2
IRLR3103N
2R2
0.1uF
1.9uH
1k
12V
8
3+
2-
1
LM358
+
330uF
1.5V
IRLR024N
+
330uF
2.5V
4
IRLR024N
+
330uF
1.00k
2.32k
5mOhm
VCC_CORE
3.3V
+
1500uF
x6
0.1uF
IRLR024N
VLIN3
+
330uF
Revision: December 2, 2004
1
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