SEMTECH SC1150

PROGRAMMABLE DC/DC
CONTROLLER
March 11, 1998
SC1150
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
DESCRIPTION
FEATURES
The SC1150 voltage mode controller contains most of
the circuitry necessary to implement a DC/DC converter
®
for powering the Intel Pentium Pro microprocessor,
both in single and multiple processor configurations.
•
•
•
•
The SC1150 features an integrated D/A converter,
pulse by pulse current limiting, integrated power good
signaling, logic compatible shutdown and on-board over
voltage protection (OVP).
APPLICATIONS
The SC1150 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 converter provides programmability
of output voltage from 2.0V to 3.5V in 100mV increments with no external components. Both the range
and the increment value may be changed by adding external components.
•
•
•
•
85% efficiency
4 bit DAC for output programmability
On chip power good and OVP functions
®
Meets Intel Pentium Pro VRM8.0 specifications
®
Pentium Pro Processor supplies
®
Pentium Pro Processor VRM modules
2.0V to 3.5V microprocessor supplies
Programmable power supplies
ORDERING INFORMATION
(1)
DEVICE
PACKAGE
TEMP RANGE (TJ)
SC1150CS
SO-16
0 - 125°C
The SC1150 provides an OVP output which can be
used to trigger a crowbar circuit for true over voltage
protection.
Note:
(1) Add suffix ‘TR’ for tape and reel.
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
VCC
1.25V REF
CSm
SHUTDOWN
CSp
VCC
BST
+
LEVEL SHIFT
AND DRIVE
VID2
Maximum
Units
VCC to GND
VIN
-0.3 to 7
V
±1
V
-0.3 to 15
V
DH
R
D/A
1.00V to
1.75V
VID0
Symbol
-
70mV
VID3
VID1
Parameter
CURRENT LIMIT
Q
OSCILLATOR
S
PGND
PGND to GND
BST to GND
VOSENSE
+
+
+
-
-
ERROR
AMP
PWRGOOD
+
-
Operating
Temperature Range
TA
0 to 70
°C
Storage
Temperature Range
TSTG
-65 to +150
°C
Lead Temperature
(Soldering) 10 sec
TLEAD
300
°C
VCC
+
B16997B
-
OVP
GND
FB
PIN CONFIGURATION
GND
1
16
VID0
VCC
2
15
VID1
OVP
3
14
VID2
PWRGOOD
4
13
VID3
CSm
5
12
FB
CSp
6
11
VOSENSE
PGND
7
10
SHUTDOWN
DH
8
9
BST
Pentium is a registered trademark of Intel Corporation
© 1998 SEMTECH CORP.
1
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC
CONTROLLER
SC1150
March 11, 1998
ELECTRICAL CHARACTERISTICS
o
Unless specified: VCC = 4.75V to 5.25V; GND = PGND = 0V; VOSENSE = VO; 0mV < (CSp-CSm) < 60mV; TA = 25 C
PARAMETER
CONDITIONS
(2)
Output Voltage
IO = 2A in Application circuit 16935E
Load Regulation
Line Regulation
UV Lockout
Current Limit Voltage
Oscillator Frequency
Oscillator Max Duty
Cycle
DH Sink/Source Current
Output Voltage Tempco
IO = 0.3A to 13A
(1)
BST - DH = 4.5V, DH - PGND = 2V
VID
3210
1111
1110
1101
1100
1011
1010
1001
1000
0111
0110
0101
0100
0011
0010
0001
0000
xxxx
xxxx
xxxx
xxxx
xxxx
xxxx
xxxx
xxxx
MIN
TYP
MAX UNITS
1.980
2.079
2.178
2.277
2.376
2.475
2.574
2.673
2.772
2.871
2.970
3.069
3.168
3.267
3.366
3.465
2.000
2.100
2.200
2.300
2.400
2.500
2.600
2.700
2.800
2.900
3.000
3.100
3.200
3.300
3.400
3.500
1
0.5
2.020
2.121
2.222
2.323
2.424
2.525
2.626
2.727
2.828
2.929
3.030
3.131
3.232
3.333
3.434
3.535
60
180
90
70
200
95
1
65
4.2
80
220
V
%
%
V
mV
kHz
%
A
o
ppm/ C
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 16935E 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. xxxx refers to any valid VID code.
2
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC
CONTROLLER
SC1150
March 11, 1998
PIN DESCRIPTION
Pin # Pin Name
Pin Function
1
GND
Small Signal Analog and Digital Ground
2
VCC
Chip Supply Voltage
3
OVP
(1)
4
PWRGOOD
5
CSm
High Signal out if VO>setpoint + 20%
(1)
Open collector logic output, high if VO within
10% of setpoint
GND
1
16
VID0
Current Sense Input (negative)
VCC
2
15
VID1
OVP
3
14
VID2
6
CSp
Current Sense Input (positive)
PWRGOOD
4
13
VID3
7
PGND
Power Ground
CSm
5
12
FB
8
DH
High side Driver Output
CSp
6
11
VOSENSE
9
BST
Vcc for high side Driver
PGND
7
10
SHUTDOWN
DH
8
9
(1)
10
SHUTDOWN
11
VOSENSE
Top end of internal feedback chain
12
FB
Voltage Feedback Input
13
VID3
14
VID2
15
VID1
16
Logic low shuts down the converter
(1)
Programming Input (MSB)
(1)
Programming Input
(1)
Programming Input
(1)
Programming Input (LSB)
VID0
BST
NOTE:
(1) All logic level inputs and outputs are open collector TTL compatible
3
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC
CONTROLLER
SC1150
March 11, 1998
APPLICATION CIRCUIT
L1
4uH
Q1
BUK556
5V IN
R1
5mOhm
C6
1000uF
C8
1000uF
C10
1000uF
+
+
+
+
C1
0.1uF
C3
1000uF
+
C2
1000uF
+
R2
10k
D1
PSR16C30CT
R5
10
C4
1000uF
R3
12V IN
2.32k
3
VID0
16
VID1
15
VID2
14
VID3
13
SHUTDOWN
10
VCC
CSp
OVP
CSm
VID0
VOSENSE
VID1
PWRGOOD
VID2
FB
VID3
BST
SHUTDOWN
1
+
+
+
C5
1000uF
C7
1000uF
C9
1000uF
C12
0.1uF
R4
1.00k
C11
0.1uF
U1
2
OVP
VCCP
GND
DH
PGND
6
5
11
4
12
9
8
7
SC1150CS
PWRGD
C13
0.1uF
REF 16935E
MATERIALS LIST
Quantity Reference
Part/Description
Vendor
Notes
4
C1,C11-C13 0.1µF Ceramic
Various
9
C2-C10
1000µF/6.3V
SANYO
1
D1
PSR16C30CT
PHOTRON
1
L1
4µH
1
Q1
BUK556
PHILIPS
Logic level FET, ≤22mΩ, 30V
1
R1
5mΩ
IRC
OAR-1 Series
1
R2
10kΩ, 5%, 1/8W
Various
1
R3
2.32kΩ, 1%, 1/8W Various
1
R4
1kΩ, 1%, 1/8W
Various
1
R5
10Ω, 5%, 1/8W
Various
1
U1
SC1150CS
SEMTECH
MV-GX or equiv. Low ESR
8 Turns 16AWG on MICROMETALS T50-52D core
4
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC
CONTROLLER
SC1150
March 11, 1998
CHARACTERISTIC CURVES
SC1150 Efficiency in Application circuit 16935E
Application circuit 16935E Ripple, 3.1V, 10A out
100.0%
95.0%
Efficiency
90.0%
3.50V Set
3.00V Set
85.0%
2.40V Set
80.0%
2.00V Set
75.0%
70.0%
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Output Current (Amps)
Application circuit 16935E Transient Response, 3.1V, 0.3A to 10A
SC1150 Regulation in Application circuit 16935E
Vo at Io=300mA steady state
Vo at Io=10A steady state
Steady state voltage
levels are superimposed
for reference.
Voltage change (V) normalized at Io=2A
0.050
0.040
0.030
0.020
0.010
0.000
-0.010
-0.020
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
Output Current (Amps)
5
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA
PROGRAMMABLE DC/DC
CONTROLLER
SC1150
March 11, 1998
OUTLINE DRAWING SO-16
LAND PATTERN SO-16
6
© 1998 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA