SC1156SW.TRT [SEMTECH]
Switching Controller, Voltage-mode, 220kHz Switching Freq-Max, PDSO20, SOIC-20;
| 型号： | SC1156SW.TRT |
| 厂家： | 
SEMTECH CORPORATION |
| 描述： | Switching Controller, Voltage-mode, 220kHz Switching Freq-Max, PDSO20, SOIC-20 开关 光电二极管 |
| 文件： | 总7页 (文件大小：162K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SC1156
Programmable Synchronous DC/DC
Controller for Advanced Microprocessors
POWER MANAGEMENT
Features
Description
The SC1156 is a low-cost, full featured synchronous,
voltage-mode controller designed for use in single ended
power supply applications where efficiency is of primary
concern. Synchronous operation allows for the
elimination of heat sinks in many applications. The
SC1156 is ideal for implementing DC/DC converters
needed to power advanced microprocessors such as
Pentium® ll (Klamath), in both single and multiple
processor configurations. Internal level-shift, high-side
drive circuitry, and preset shoot-thru control, allows for
use of inexpensive n-channel power switches.
u Low cost / full featured
u Synchronous operation
u 5 Bit VID DAC programmable output
u On-chip power good and OVP functions
u Designed to meet Intel VRM8.1 (Klamath)
SC1156 features include an integrated 5-bit VID DAC, tem-
perature compensated voltage reference, triangle wave
oscillator, current limit comparator, frequency shift
over-current protection, and an accessible, internally
compensated error amplifier. Power good signaling, logic
compatible shutdown, and over voltage protection are
also provided.
Applications
u Pentium® II (Klamath) Core Supply
u Multiple MicroProcessor Supplies
u Voltage Regulation Modules (VRM)
u Programmable Power Supplies
u High Efficiency DC/DC Conversion
The SC1156 operates at a fixed 200KHz, providing an
optimum compromise between efficiency, external com-
ponent size, and cost.
Typical Application Circuit
L1
C3
820uF
R1
5mOhm
Q1
C6
1500uF
C8
1500uF
IRL3302S
12V IN
4uH
C1
+
+
+
0.1uF
R2
C10
0.1uF
3.9
Q2
IRL3302S
+
+
+
+
R3
C2
820uF
C4
820uF
3.9
C7
1500uF
C5
1500uF
C9
0.1uF
D1
R4
1.00k
R6
10
R7
10k
1N4148
U1
C11
R5
2
3
6
2.32k
VCC
OVP
VID0
VID1
VID2
VID3
VID4
EN
CS+
0.1uF
O V P
VID0
5
CS-
VOSENSE
P W R G O O D
BSTH
20
19
18
17
16
14
1
15
4
VID1
VID2
13
8
VID3
DH
VID4
7
PGNDH
BSTL
ENABLE
P O W E R G O O D
12
11
10
GND
DL
C12
0.1uF
9
NC
PGNDL
SC1156CS
Pentium® ll Power Supply
Revision 4/01
1
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SC1156
POWER MANAGEMENT
Absolute Maximum Ratings
Parameter
Symbol
Maximum
Units
VCC to GND
VIN
-0.3 to +15
+1
V
V
PGND to GND
BST to GND
-0.3 to +26
0 to +70
0 to +125
-65 to +50
30
V
Operating Temperature Range
Junction Temperature Range
Storage Temperature Range
Thermal Resistance Junction to Case
Thermal Resistance Junction to Ambient
Lead Temperature (Soldering) 10 Sec.
TA
TJ
°C
°C
TSTG
θJC
°C
°C/W
°C/W
°C
95
θJA
TLEAD
300
Electrical Characteristics
(Unless otherwise noted: VCC = 11.4V to 12.6V; GND = PGND = 0V; FB = VO; 0mV < (CS+ - CS-) < 60mV; TJ = 25oC )
Parameter
Conditions
Min
Typ
Max
Units
Output Voltage
IO = 2A (1)
VCC
See Output Voltage Table
Supply Voltage
4.2
15
V
mA
%
Supply Current
VCC = 12.0V
5
1
Load Regulation
IO = 0.3A to 15A (1)
All VID codes (1)
VOSENSE to VO
Line Regulation
0.5
35
70
200
95
%
Gain (AOL)
dB
mV
kHz
%
Current Limit Voltage
Oscillator Frequency
Oscillator Max Duty Cycle
DH Sink/Source Current
DL Sink/Source Current
OVP threshold Voltage
OVP source current
Power good threshold voltage
Dead time
60
80
180
220
BSTH - DH = 4.5V, DH - PGNDH = 2V
BSTL - DL = 4.5V, DL - PGNDL = 2V
1
1
A
A
120
100
%
VOVP = 3V
10
90
50
mA
%
110
ns
NOTE:
(1) Specification refers to Typical Application Circuit
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2000 Semtech Corp.
2
SC1156
POWER MANAGEMENT
Ordering Information
Pin Configuration
TOP VIEW
Device (1)
Package
SO-20
Temp Range (TJ)
SC1156SW.TR
0° to 125°C
GND
VCC
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
VID0
VID1
VID2
VID3
VID4
VOSENSE
EN
Note:
OVP
(1) Only available in tape and reel packaging. A reel
contains 1000 devices.
PWRGOOD
CS-
CS+
PGNDH
DH
BSTH
BSTL
DL
NC
PGNDL
(20 Pin SOIC)
Pin Descriptions
Pin #
Pin Name
Pin Function
1
2
GND
VCC
Small Signal Analog and Digital Ground
Chip Supply Voltage
3
OVP
High Signal out if VO>setpoint + 20%
Open collector logic output, high if VO within 10% of setpoint
Current Sense Input (negative)
Current Sense Input (positive)
Power Ground for High Side Switch
High Side Driver Output
4
PWRGOOD(1)
CS-
5
6
CS+
7
PGNDH
DH
8
9
NC
Not Connected
10
11
12
13
14
15
16
17
18
19
20
PGNDL
DL
Power Ground for Low Side Switch
Low Side Driver Output
BSTL
Vcc for Low Side Driver (Boost)
Vcc for High Side Driver (Boost)
Logic low shuts down the converter
Feedback
BSTH
EN (1)
VOSENSE
VID4 (1)
VID3 (1)
VID2 (1)
VID1 (1)
VID0 (1)
Programming Input (MSB)
Programming Input
Programming Input
Programming Input
Programming Input (LSB)
NOTE:
(1) All logic inputs and outputs are open collector TTL compatible.
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2000 Semtech Corp.
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SC1156
POWER MANAGEMENT
Block Diagram
VCC
CS- CS+
EN
CURRENT LIMIT
1.25V REF
+
-
70mV
BSTH
DH
SHUTDOWN
LEVEL SHIFT
AND DRIVE
VID4
VID3
VID2
VID1
VID0
R
S
D/A
Q
OSCILLATOR
PGNDH
VOSENSE
-
SHOOT-THRU
CONTROL
+
-
OPEN
COLLECTORS
+
+
-
PWRGOOD
ERROR
A M P
BSTDL
DL
+
-
VCC
LOW SIDE
DRIVE
+
-
PGNDL
OVP
GND
Theory of Operation
The D/A Converter generates an output voltage determined its input voltage exceeds approximately 70mV, this sets
by an internal trimmed bandgap voltage reference and the current limit latch, immediately terminating the cur-
the status of the VID0 through VID4 inputs. This voltage is rent ON time. The current limit latch is reset in the middle
applied to the non-inverting input of the error amplifier, of the OFF time when the triangular wave oscillator reaches
the inverting input of the error amplifier is fed from the its highest point .
VOSENSE pin via a precision resistor divider. The error When the output of the PWM comparator is high, output
amplifier itself is a transconductance amplifier with an in- DH is driven high, provided that the VID code is valid, the
ternal load resistor. The open loop gain is internally set to current limit latch has not been set and the Enable (EN)
approximately 40 dB.
pin is not pulled low. When the PWM comparator output is
The internal oscillator uses an on-chip capacitor and a low DL is always driven high.
trimmed precision current source to set the frequency of The Shoot-through control circuitry modifies the DH and
oscillation to 200 kHz. The triangular output of the oscil- DL waveforms slightly, ensuring that there is a short delay
lator is compared to the output of the error amplifier. The between one turning OFF and the other turning ON. This
output of the PWM comparator is a pulse width modu- ensures that the ON times of the external FETs driven by
lated signal whose duty cycle increases as the voltage at DH and DL do not overlap.
the VOSENSE pin decreases.
The output of the current limit comparator goes high when
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2000 Semtech Corp.
4
SC1156
POWER MANAGEMENT
Output Voltage Table
Unless otherwise noted: VCC = 4.75V to 5.25V; GND = PGND = 0V; FB = VO; 0mV < (CS+ - CS-) < 60mV; TJ = 25°C
Parameter
Conditions
VID
Min
Typ
Max
Units
43210
Output Voltage (1)
IO = 2A in Application circuit (Figure 1)
00101
00100
00011
00010
00001
00000
11111
11110
11101
11100
11011
11010
11001
11000
10111
10110
10101
10100
10011
10010
10001
10000
1.782
1.832
1.881
1.931
1.980
2.030
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
1.800
1.850
1.900
1.950
2.000
2.050
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
1.818
1.868
1.919
1.969
2.020
2.070
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
V
NOTE:
(1) All VID codes not specifically listed are invalid and cause shutdown exactly as if the shutdown pin had been
asserted.
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2000 Semtech Corp.
5
SC1156
POWER MANAGEMENT
Characteristic Curves
SC1156 Efficiency in Application Circuit
SC1156 Regulation in Application Circuit
90%
85%
80%
75%
70%
0
-2
-4
3.5V
-6
3.1V
2.8V
-8
2.4V
2.1V
-10
-12
-14
-16
1.8V
0
4
8
12
16
0
4
8
12
16
Output Current (A)
Output Current (A)
Transient at Vo=2.00V; Io= 0 to 15A in App. circuit
Ripple at Vo=2.00V; Io=15A in Application circuit
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2000 Semtech Corp.
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SC1156
POWER MANAGEMENT
Outline Drawing - SO-20
Ref. MS-013AC
Land Pattern - SO-20
Contact Information
Semtech Corporation
Power Management Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
www.semtech.com
2000 Semtech Corp.
7
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