SC2655 Semtech Corporation, SC2655 Datasheet

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SC2655

Manufacturer Part Number
SC2655
Description
Programmable Synchronous DC/DC Hysteretic Controller
Manufacturer
Semtech Corporation
Datasheet
The SC2655 is a synchronous-buck switch-mode con-
troller designed for use in single ended power supply ap-
plications where efficiency is the primary concern. The
controller is a hysteretic type, with a user selectable hys-
teresis. The SC2655 is ideal for implementing DC/DC
converters needed to power advanced microprocessors
such as Pentium
tiple processor configurations. Inhibit, under-voltage lock-
out and soft-start functions are included for controlled
power-up.
SC2655 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-volt-
age protection are also provided. The integrated D/A
converter provides programmability of output voltage
from 1.1V to 1.85V in 25mV increments.
The SC2655 high side driver can be configured as either
a ground-referenced or as a floating bootstrap driver.
The high and low side MOSFET drivers have a peak cur-
rent rating of 2 amps.
Revision: December 10, 2003
POWER MANAGEMENT
Description
Typical Application Circuit
www.DataSheet4U.com
®
llI and Athlon
+5V
C4
0.01
R6
20k
®
R2
1k
0.001
R4
1k
R5
*
C2
, in both single and mul-
R8
10k
C3
0.1
R7
R1
*
*
R3
*
C1
0.1
C5
10
11
12
13
14
1
2
3
4
5
6
7
8
9
Hysteretic Controller with VRM 9.0 VID Range
IOUT
DROOP
OCP
VHYST
VREFB
VSENSE
AGND
SOFTST
N/C
LODRV
LOHIB
DRVGND
LOWDR
DRV
*) for the values see specific application circuit somewhere else in the datasheet
U1
SC2655
LOSENSE
HISENSE
BOOTLO
HIGHDR
PWRGD
IOUTLO
INHIBIT
VIN12V
BOOT
VID0
VID1
VID2
VID3
VID4
28
27
26
25
24
23
22
21
20
19
18
17
16
15
C10
+12V
R9
10k
Programmable Synchronous DC/DC
C9
1.0
R14
1.6
0.033
R12
1.0
1
C8
+5V
Features
FDB6035AL
FDB7030BL
Q1
Q2
Applications
R10
1k
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
VIDs pulled up to +3.3V
Server Systems and Workstations
Pentium
AMD Athlon
Multiple Microprocessor Supplies
Voltage Regulator Modules
R11
1k
Cin
HF
C6
0.1
C7
0.1
1.0uH
L2
PWRGD
INHIB
®
Cout
Bulk
Cin
Bulk
III Core Supplies
"POWER GOOD"
"INHIBIT"
®
0.5uH
L1
Core Supplies
Cout
HF
Vin +5V/12V
1.10 to 1.825V
+
_
+
_
SC2655
www.semtech.com

Related parts for SC2655

SC2655 Summary of contents

Page 1

... The integrated D/A converter provides programmability of output voltage from 1.1V to 1.85V in 25mV increments. The SC2655 high side driver can be configured as either a ground-referenced floating bootstrap driver. The high and low side MOSFET drivers have a peak cur- rent rating of 2 amps. ...

Page 2

... SC2655 ± ...

Page 3

... SC2655 ...

Page 4

... V < < I < SC2655 ...

Page 5

... ° SC2655 µ ...

Page 6

... SC2655 ...

Page 7

... POWER MANAGEMENT Test Circuit www.DataSheet4U.com Timing Diagram Simplified Block Diagram 2003 Semtech Corp. 7 SC2655 www.semtech.com ...

Page 8

... SC2655 ° ...

Page 9

... SC2655 ...

Page 10

... POWER MANAGEMENT Block Diagram www.DataSheet4U.com 2003 Semtech Corp. 10 SC2655 www.semtech.com ...

Page 11

... SC2655 ...

Page 12

... DS(ON) to VREF • (1+R7/R8) (see Typ. App. Circuit external resistor divider from VOUT to the VSENSE pin to reduce the undershoot on VOUT during a low to high load current transient. The overshoot during a high to low load current transient is reduced by subtracting the volt- 12 SC2655 www.semtech.com ...

Page 13

... The minimum drive voltage is 7V. The minimum short circuit current is can remain the same 100mA. 13 SC2655 SS is the current flowing out of the REFB pin. It www.semtech.com = I /5. ...

Page 14

... POWER MANAGEMENT Application Circuit www.DataSheet4U.com 2003 Semtech Corp. 14 SC2655 www.semtech.com ...

Page 15

... Disabled V = 1.8V OUT -1% -2% - 1.5V OUT -1% -2% - 1.1V OUT -1% -2% - SC2655 Current Current Current, A www.semtech.com ...

Page 16

... Disabled V = 1.8V OUT -1% -2% - 1.5V OUT -1% -2% - 1.1V OUT -1% -2% - SC2655 Current Current Current, A www.semtech.com ...

Page 17

... POWER MANAGEMENT Evaluation Board Artwork www.DataSheet4U.com Top Layer Bottom Layer Mid Layer 2003 Semtech Corp. 17 SC2655 www.semtech.com ...

Page 18

... POWER MANAGEMENT Evaluation Board Artwork (Cont.) www.DataSheet4U.com Top Overlay Bottom Overlay 2003 Semtech Corp. 18 SC2655 www.semtech.com ...

Page 19

... SC2655 , ...

Page 20

... In order to prevent substrate glitching, a small (0.5A) Schottky diode should be placed in close proximity to the chip with the cathode connected to BOOTLO and anode connected to DRVGND. Semtech Corporation Power Management Products Division 200 Flynn Road, Camarillo, CA 93012 Phone: (805)498-2111 FAX (805)498-3804 20 SC2655 www.semtech.com ...

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