PROGRAMMABLE SYNCHRONOUS DC/DC
CONVERTER, DUAL LOW DROPOUT
REGULATOR CONTROLLER
August 25, 1998
SC1182/3
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC1182/3 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 (Klamath) or
Deschutes.
The SC1182/3 switching section features an integrat-
ed 5 bit D/A converter, pulse by pulse current limiting,
integrated power good signaling, and logic compatible
shutdown. The SC1182/3 switching section operates
at a fixed frequency of 200kHz, providing an optimum
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 compo-
nents.
The SC1182/3 linear sections are low dropout regula-
tors. The SC1182 supplies 1.5V for GTL bus and 2.5V
for non-GTL I/O.
For the SC1183 both LDO’s are adjustable.
FEATURES
•
•
•
•
•
•
•
•
•
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Synchronous design, enables no heatsink solution
95% efficiency (switching section)
5 bit DAC for output programmability
On chip power good function
®
Designed for Intel Pentium ll VRM8.1 require-
ments
1.5V, 2.5V or Adj. @ 1% for linear section
APPLICATIONS
Pentium ll or Deschutes 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
)
SC1182CSW
SC1183CSW
SO-24
SO-24
1.5V/2.5V 0° to 125°C
Adj.
0° to 125°C
Note:
(1) Add suffix ‘TR’ for tape and reel.
PIN CONFIGURATION
BLOCK DIAGRAM
REF.
Top View
AGND
GATE1
LDOS1
LDOS2
VCC
OVP
PWRGOOD
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
(24 Pin SOIC)
FET
CONTROLLER
2.5V/ADJ.
1.265V
REF.
FET
CONTROLLER
1.5V/ADJ.
LDOV
Pentium is a registered trademark of Intel Corporation
1
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320
SEMTECH [ SEMTECH CORPORATION ]
