PROGRAMMABLE SYNCHRONOUS DC/DC
CONVERTER, DUAL LOW DROPOUT
REGULATOR CONTROLLER
PRELIMINARY - December 2, 1999
SC1186
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
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 optimum compromise between
size, efficiency and cost in the intended application
areas. The integrated D/A converter 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.
The SC1186 linear sections are low dropout regula-
tors 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.
FEATURES
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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
®
ORDERING INFORMATION
Part Number
(1)
Package
Linear
Voltage
Temp.
Range (T
J
)
SC1186CSW
SO-24
1.5V/2.5V 0° to 125°C
Note:
(1) Add suffix ‘TR’ for tape and reel.
PIN CONFIGURATION
BLOCK DIAGRAM
Top View
AGND
GATE1
LDOS1
LDOS2
VCC
REF
LDOEN
CS-
CS+
PGNDH
DH
PGNDL
1
2
3
4
5
6
7
8
9
10
11
12
24
23
22
21
20
19
18
17
16
15
14
13
GATE2
LDOV
VID0
VID1
VID2
VID3
VID4
VOSENSE
EN
BSTH
BSTL
DL
REF
VCC
CS-
CS+
CURRENT
LIMIT
EN
BSTH
70mV
+
-
VID4
VID3
VID2
VID1
VID0
VOSENSE
LEVEL SHIFT AND
HIGH SIDE DRIVE
DH
+
D/A
-
-
ERROR
AMP
+
PGNDH
R
OSCILLATOR
Q
S
SHOOT-THRU
CONTROL
AGND
LDOEN
LDOS1
GATE1
2.5V FET
CONTROLLER
1.265V
REF
1.5V FET
CONTROLLER
SYNCHRONOUS
MOSFET DRIVE
BSTL
DL
(24 Pin SOIC)
LDOV
REF
GATE2 LDOS2
PGNDL
Pentium is a registered trademark of Intel Corporation
1
© 1999 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SEMTECH [ SEMTECH CORPORATION ]
