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SC1151
1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC CONTROLLER
FOR ADVANCED MICROPROCESSORS
March 11, 1998
1
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Maximum
Units
V
CC
to GND
V
IN
-0.3 to 7
V
PGND to GND
1
V
BST to GND
-0.3 to 15
V
Operating
Temperature Range
T
A
0 to 70
C
Storage
Temperature Range
T
STG
-65 to +150
C
Lead Temperature
(Soldering) 10 sec
T
LEAD
300
C
Pentium is a registered trademark of Intel Corporation
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
The SC1151 voltage mode controller contains most of
the circuitry necessary to implement a DC/DC con-
verter for powering advanced microprocessors such
as Klamath, both in single and multiple processor con-
figurations.
The SC1151 features an integrated 5 bit D/A con-
verter, pulse by pulse current limiting, integrated
power good signaling, logic compatible shutdown and
on-board over voltage protection (OVP).
The SC1151 operates at a fixed frequency of 200kHz,
providing an optimum compromise between size, effi-
ciency and cost in the intended application areas.
The integrated D/A converter provides programmabil-
ity of output voltage from 2.0V to 3.5V in 100mV in-
crements and 1.80V to 2.05V in 50mV increments with
no external components.
The SC1151 provides an OVP output which can be
used to trigger a crowbar circuit for true over voltage
protection.
APPLICATIONS
Klamath microprocessor supplies
Klamath VRM modules
1.8V to 3.5V microprocessor supplies
Programmable power supplies
FEATURES
85% efficiency
5 bit DAC for output programmability
On chip power good and OVP functions
Designed for Intel Klamath VRM8.1 requirements
ORDERING INFORMATION
DEVICE
(1)
PACKAGE
TEMP RANGE (T
J
)
SC1151CS
SO-16
0 to 125C
BLOCK DIAGRAM
VCC
VCC
ERROR
AMP
D/A AND
SHUTDOWN
LOGIC
DECODED SHUTDOWN SIGNAL
OSCILLATOR
LEVEL SHIFT
AND DRIVE
1.25V REF
+
-
+
-
CURRENT LIMIT
+
-
+
-
CSm
VID0
VID2
VID1
VID3
VOSENSE
PWRGOOD
BST
DH
VCC
SHUTDOWN
OVP
GND
PGND
R
S
Q
+
-
70mV
CSp
+
-
VID4
A17043A
PIN CONFIGURATION
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PWRGOOD
VID0
VID1
VID2
VID3
BST
DH
VOSENSE
GND
SHUTDOWN
PGND
VCC
CSp
CSm
OVP
VID4
Note:
(1) Add suffix `TR' for tape and reel.
SC1151
1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC CONTROLLER
FOR ADVANCED MICROPROCESSORS
March 11, 1998
2
NOTES:
(1) Low output currents, below the continuous conduction threshold will cause an increase in output voltage beyond
the load regulation limit. For Application circuit 16935F see the regulation curve on sheet 5.
(2) All VID codes not specifically listed here are invalid and cause shutdown exactly as if the shutdown pin had been
asserted. xxxxx refers to any valid VID code.
ELECTRICAL CHARACTERISTICS
Unless specified: V
CC
= 4.75V to 5.25V; GND = PGND = 0V; V
OSENSE
= V
O
; 0mV < (CSp-CSm) < 60mV; T
A
= 25
o
C
PARAMETER
CONDITIONS
VID
43210
MIN
TYP
MAX
UNITS
Output Voltage
(2)
I
O
= 2A in Application circuit 16935F
00101 1.782 1.800 1.818
V
00100 1.832 1.850 1.868
00011 1.881 1.900 1.919
00010 1.931 1.950 1.969
00001 1.980 2.000 2.020
00000 2.030 2.050 2.070
11111 1.980 2.000 2.020
11110 2.079 2.100 2.121
11101 2.178 2.200 2.222
11100 2.277 2.300 2.323
11011 2.376 2.400 2.424
11010 2.475 2.500 2.525
11001 2.574 2.600 2.626
11000 2.673 2.700 2.727
10111 2.772 2.800 2.828
10110 2.871 2.900 2.929
10101 2.970 3.000 3.030
10100 3.069 3.100 3.131
10011 3.168 3.200 3.232
10010 3.267 3.300 3.333
10001 3.366 3.400 3.434
10000 3.465 3.500 3.535
Load Regulation
I
O
= 0.3A to 13A
(1)
xxxxx
1
%
Line Regulation
xxxxx
0.5
%
UV Lockout
xxxxx
4.2
V
Current Limit Voltage
xxxxx
60
70
80
mV
Oscillator Frequency
xxxxx
180
200
220
kHz
Oscillator Max Duty Cycle
xxxxx
90
95
%
DH Sink/Source Current
BST - DH = 4.5V, DH - PGND = 2V
xxxxx
1
A
Output Voltage Tempco
xxxxx
65
ppm/
o
C
SC1151
1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC CONTROLLER
FOR ADVANCED MICROPROCESSORS
March 11, 1998
3
NOTE:
(1) All logic level inputs and outputs are
open collector TTL compatible
PIN DESCRIPTION
Pin # Pin Name
Pin Function
1
GND
Small Signal Analog and Digital Ground
2
V
CC
Chip Supply Voltage
3
OVP
High Signal out if V
O
>setpoint + 20%
4
PWRGOOD
(1)
Open collector logic output, high if V
O
within
10% of setpoint
5
CSm
Current Sense Input (negative)
6
CSp
Current Sense Input (positive)
7
PGND
Power Ground
8
DH
High Side Driver Output
9
BST
Vcc for High Side Driver
10
SHUTDOWN
(1)
Logic low shuts down the converter
11
V
OSENSE
Top end of internal feedback chain
12
VID4
(1)
Programming Input (MSB)
13
VID3
(1)
Programming Input
14
VID2
(1)
Programming Input
15
VID1
(1)
Programming Input
16
VID0
(1)
Programming Input (LSB)
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
PWRGOOD
VID0
VID1
VID2
VID3
BST
DH
VOSENSE
GND
SHUTDOWN
PGND
VCC
CSp
CSm
OVP
VID4
SC1151
1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC CONTROLLER
FOR ADVANCED MICROPROCESSORS
March 11, 1998
4
MATERIALS LIST
APPLICATION CIRCUIT
C12
0.1uF
C1
0.1uF
C5
1000uF
+
C6
1000uF
+
C7
1000uF
+
C8
1000uF
+
Q1
BUK556
C4
1000uF
+
C3
1000uF
+
C2
1000uF
+
L1
4uH
R2
10k
R3
2.32k
R4
1.00k
C9
1000uF
+
C10
1000uF
+
R1
5mOhm
D1
PSR16C30CT
U1
SC1151CS
GND
1
VCC
2
OVP
3
PWRGOOD
4
CSm
5
CSp
6
PGND
7
DH
8
BST
9
SHUTDOWN
10
VOSENSE
11
VID4
12
VID3
13
VID2
14
VID1
15
VID0
16
R5
10
C13
0.1uF
C11
0.1uF
REF 16935F
5V IN
12V IN
OVP
VID0
VID1
VID2
VID3
VID4
SHUTDOWN
PWRGD
VCCP
Quantity Reference
Part/Description
Vendor
Notes
4
C1,C11-C13 0.1F Ceramic
Various
9
C2-C10
1000F/6.3V
SANYO
MV-GX or equiv. Low ESR
1
D1
PSR16C30CT
PHOTRON
1
L1
4H
8 Turns 16AWG on MICROMETALS T50-52D core
1
Q1
BUK556
PHILIPS
Logic level FET,
22m
, 30V
1
R1
5m
IRC
OAR-1 Series
1
R2
10k
, 5%, 1/8W
Various
1
R3
2.32k
, 1%, 1/8W Various
1
R4
1k
, 1%, 1/8W
Various
1
R5
10
, 5%, 1/8W
Various
1
U1
SC1151CS
SEMTECH
SC1151
1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC CONTROLLER
FOR ADVANCED MICROPROCESSORS
March 11, 1998
5
-0.020
-0.010
0.000
0.010
0.020
0.030
0.040
0.050
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Voltage change (V) normalized at Io=2A
Output Current (Amps)
SC1151 Regulation in Application circuit 16935F
Application circuit 16935F Ripple, 3.1V, 10A out
70.0%
75.0%
80.0%
85.0%
90.0%
95.0%
100.0%
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
3.50V Set
3.00V Set
2.40V Set
2.00V Set
Efficiency
Output Current (Amps)
SC1151 Efficiency in Application circuit 16935F
Application circuit 16935F Transient Response, 3.1V, 0.3A to 10A
Vo at Io=300mA steady state
Vo at Io=10A steady state
Steady state voltage
levels are superimposed
for reference.
CHARACTERISTIC CURVES
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