SC1155(2000) Ver la hoja de datos (PDF) - Semtech Corporation
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SC1155
(Rev.:2000)
(Rev.:2000)
Semtech Corporation
SC1155 Datasheet PDF : 19 Pages
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PROGRAMMABLE SYNCHRONOUS
DC/DC HYSTERETIC CONTROLLER
WITH VRM 9.0 VID RANGE
SC1155
PRELIMINARY - August 7, 2000
DESCRIPTION
The SC1155 is a synchronous-buck switch-mode con-
troller designed for use in single ended power supply
applications where efficiency is the primary concern.
The controller is a hysteretic type, with a user se-
lectable hysteresis. The SC1155 is ideal for implement-
ing DC/DC converters needed to power advanced mi-
croprocessors such as Pentium® llI and Athlon®, in both
single and multiple processor configurations. Inhibit,
under-voltage lockout and soft-start functions are in-
cluded for controlled power-up.
SC1155 features include an integrated 5 bit D/A con-
verter, temperature compensated voltage reference,
current limit comparator, over-current protection, and
an adaptive deadtime circuit to prevent shoot-through
of the power MOSFET during switching transitions.
Power good signaling, logic compatible shutdown, and
over-voltage protection are also provided. The inte-
grated D/A converter provides programmability of out-
put voltage from 1.1V to 1.85V in 25mV increments.
The SC1155 high side driver can be configured as
either a grounded reference or as a floating bootstrap
driver. The high and low side MOSFET drivers have a
peak current rating of 2 amps.
TYPICAL APPLICATION CIRCUIT
FEATURES
•= Programmable hysteresis
•= 5 bit DAC programmable output (1.1V-1.85V)
•= On-chip power good and OVP functions
•= Designed to meet latest Intel specifications
•= Up to 95% efficiency
•= +1% voltage tolerance over temperature
APPLICATIONS
•= Server Systems and Workstations
•= Intel Pentium® III Core Supplies
•= AMD Athlon® Core Supplies
•= Multiple Microprocessor Supplies
•= Voltage Regulator Modules
ORDERING INFORMATION
DEVICE(1)
PACKAGE TEMP. RANGE (TJ)
SC1155CSW.TR SO-28
0 - 125°C
SC1155EVB
Evaluation Board
Note:
(1) Only available in tape and reel packaging. A reel
contains 1000 devices.
R1 R3
2k 2.7k
R2
1k
R4
1k
C3
0.01
C2
0.01
R5
100
C4
R6
0.01
20k
1 IOUT
U1
SC1155CSW
PWRGD 28
2 DROOP
VID0 27
3 OCP
VID1 26
4 VHYST
VID2 25
5 VREFB
C6
0.1
6 VSENSE
VID3 24
VID4 23
R9
10k
+5V
R10
10k
C5
0.001
7 AGND
INHIBIT 22
C12
8 SOFTST
IOUTLO 21
C7
0.33
0.1
C8
+5V
9 N/C
LOSENSE 20
0.01
10 LODRV
HISENSE 19
11 LOHIB
BOOTLO 18
R8
12 DRVGND
HIGHDR 17
R11
2.2
Q1
IRL3103S
10k
C13
13 LOWDR
BOOT 16
0.33
+12V
14 DRV
VIN12V 15
Q2
R12 IRL2203S
3.9
C8
2.2uF
C9
2.2uF
R7
150
PWRGD
INHIB
L1
1uH
C16
0.1
C17-C19
150uF/16V
Vin
C20
0.1 Vin +5 to +12V
GND
L2
1.5uH
Vout
C21-C26
150uF/4V
C27
0.1 Vout = 1.1 to 1.85V
GND
© 2000 SEMTECH CORP.
Athlon is a registered trademark of AMD Corporation
1
Pentium is a registered trademark of Intel Corporation
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
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