SC2659
Programmable Synchronous DC/DC
Hysteretic Controller with VRM 8.5 VID Range
POWER MANAGEMENT
Description
Features
The SC2659 is a synchronous-buck switch-mode controller designed for use in single ended power supply applications where efficiency is the primary concern. The
controller is a hysteretic type, with a user selectable hysteresis. The SC2659 is ideal for implementing DC/DC
converters needed to power advanced microprocessors
such as Pentium® llI and Athlon®, in both single and multiple processor configurations. Inhibit, under-voltage lockout and soft-start functions are included for controlled
power-up.
Programmable hysteresis
5 bit DAC programmable output (1.050V-1.825V)
On-chip power good and OVP functions
Designed to meet latest Intel specifications
Up to 95% efficiency
VIDs pulled up to +3.3V
Applications
Server Systems and Workstations
Pentium® III Core Supplies
AMD Athlon® Core Supplies
Multiple Microprocessor Supplies
Voltage Regulator Modules
SC2659 features include an integrated 5 bit D/A converter, 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 integrated D/A
converter provides programmability of output voltage
from 1.050V to 1.825V in 25mV increments.
The SC2659 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 current rating of 2 amps.
Typical Application Circuit
+5V
R1
*
R3
*
1
IOUT
R10
1k
R9
10k
U1
SC2659
PWRGD
PWRGD
28
"POWER GOOD"
R2
1k
C6
0.1
2
R4
1k
DROOP
VID0
OCP
VID1
27
INHIB
3
4
R5
*
5
C1
0.1
R6
20k
C2
0.001
6
7
8
VHYST
VID2
VREFB
VID3
VSENSE
VID25
AGND
INHIBIT
SOFTST
IOUTLO
26
"INHIBIT"
C7
0.1
R11
1k
25
24
L1
0.5uH
+
23
Cin
HF
22
Cin
Bulk
Vin +5V/12V
_
21
C8
0.033
C3
0.1
9
+5V
10
C4
0.01
11
12
13
N/C
LOSENSE
LODRV
HISENSE
LOHIB
BOOTLO
DRVGND
LOWDR
HIGHDR
BOOT
20
19
Q1
FDB6035AL
18
R12
1.0
17
L2
1.0uH
16
+12V
14
DRV
VIN12V
C9
1.0
15
C5
+
Q2
FDB7030BL
R14
1.6
Cout
Bulk
Cout
HF
1.05 to 1.825V
C10
_
R8
10k
Revision: December 10, 2003
R7
*
*) for the values see specific application circuit somewhere else in the datasheet
1
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