CS5171, CS5172, CS5173,
CS5174
1.5 A 280 kHz/560 kHz
Boost Regulators
The CS5171/2/3/4 products are 280 kHz/560 kHz switching
regulators with a high efficiency, 1.5 A integrated switch. These parts
operate over a wide input voltage range, from 2.7 V to 30 V. The
flexibility of the design allows the chips to operate in most power
supply configurations, including boost, flyback, forward, inverting,
and SEPIC. The ICs utilize current mode architecture, which allows
excellent load and line regulation, as well as a practical means for
limiting current. Combining high frequency operation with a highly
integrated regulator circuit results in an extremely compact power
supply solution. The circuit design includes provisions for features
such as frequency synchronization, shutdown, and feedback controls
for either positive or negative voltage regulation. These parts are
pin−to−pin compatible with LT1372/1373.
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SOIC−8
D SUFFIX
CASE 751
MARKING DIAGRAM AND
PIN CONNECTIONS
1
CS5171/3
8
V
SW
517xy
ALYW
G
PGND
AGND
V
CC
Part Number
CS5171
CS5172
CS5173
CS5174
Frequency
280 kHz
280 kHz
560 kHz
560 kHz
Feedback Voltage Polarity
positive
negative
positive
negative
V
C
FB
Test
SS
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
Integrated Power Switch: 1.5 A Guaranteed
Wide Input Range: 2.7 V to 30 V
High Frequency Allows for Small Components
Minimum External Components
Easy External Synchronization
Built in Overcurrent Protection
Frequency Foldback Reduces Component Stress During an
Overcurrent Condition
Thermal Shutdown with Hysteresis
Regulates Either Positive or Negative Output Voltages
Shut Down Current: 50
mA
Maximum
Pin−to−Pin Compatible with LT1372/1373
Wide Temperature Range
♦
Industrial Grade: −40°C to 125°C
♦
Commercial Grade: 0°C to 125°C
Pb−Free Packages are Available
1
V
C
Test
NFB
SS
CS5172/4
8
V
SW
517xy
ALYW
G
PGND
AGND
V
CC
517xy = Device Code
x= 1, 2, 3, or 4
y= E, G
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
G
= Pb−Free Package
ORDERING INFORMATION
See detailed ordering and shipping information in the
package dimensions section on page 20 of this data sheet.
©
Semiconductor Components Industries, LLC, 2006
1
October, 2006 − Rev. 22
Publication Order Number:
CS5171/D
CS5171, CS5172, CS5173, CS5174
R2
3.72 k
1
D1
V
C
CS5171/3
V
SW
PGND
AGND
V
CC
8
V
OUT
5V
2
FB
Test
SS
7
MBRS120T3
C1
0.01
mF
SS
3.3 V
R1
5k
R3
3
6
L1
4
5
+
22
mH
C3
22
mF
+
1.28 k
C2
22
mF
Figure 1. Applications Diagram
MAXIMUM RATINGS
Rating
Junction Temperature Range, T
J
Storage Temperature Range, T
STORAGE
Package Thermal Resistance, Junction−to−Case, R
qJC
Junction−to−Ambient, R
qJA
Lead Temperature Soldering: Reflow (Note 1)
ESD, Human Body Model
Value
−40 to +150
−65 to +150
45
165
230 Peak
1.2
Unit
°C
°C
°C/W
°C/W
°C
kV
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. 60 second maximum above 183°C.
MAXIMUM RATINGS
Pin Name
IC Power Input
Shutdown/Sync
Loop Compensation
Voltage Feedback Input
Pin Symbol
V
CC
SS
V
C
FB
(CS5171/3 only)
NFB
(CS5172/4 only)
Test
PGND
AGND
V
SW
V
MAX
35 V
30 V
6.0 V
10 V
V
MIN
−0.3 V
−0.3 V
−0.3 V
−0.3 V
I
SOURCE
N/A
1.0 mA
10 mA
1.0 mA
I
SINK
200 mA
1.0 mA
10 mA
1.0 mA
Negative Feedback Input
(transient, 10 ms)
Test Pin
Power Ground
Analog Ground
Switch Input
−10 V
10 V
1.0 mA
1.0 mA
6.0 V
0.3 V
0V
40 V
−0.3 V
−0.3 V
0V
−0.3 V
1.0 mA
4A
N/A
10 mA
1.0 mA
10 mA
10 mA
3.0 A
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2
CS5171, CS5172, CS5173, CS5174
ELECTRICAL CHARACTERISTICS
(2.7 V< V
CC
< 30 V; Industrial Grade: −40°C < T
J
< 125°C;
Commercial Grade: 0°C < T
J
< 125°C; For all CS5171/2/3/4 specifications unless otherwise stated.)
Characteristic
Positive and Negative Error Amplifiers
FB Reference Voltage (CS5171/3 only)
NFB Reference Voltage (CS5172/4 only)
FB Input Current (CS5171/3 only)
NFB Input Current (CS5172/4 only)
FB Reference Voltage Line Regulation
(CS5171/3 only)
NFB Reference Voltage Line Regulation
(CS5172/4 only)
Positive Error Amp Transconductance
Negative Error Amp Transconductance
Positive Error Amp Gain
Negative Error Amp Gain
V
C
Source Current
V
C
Sink Current
V
C
High Clamp Voltage
V
C
Low Clamp Voltage
V
C
Threshold
Oscillator
Base Operating Frequency
Reduced Operating Frequency
Maximum Duty Cycle
Base Operating Frequency
Reduced Operating Frequency
Maximum Duty Cycle
NFB Frequency Shift Threshold
FB Frequency Shift Threshold
Sync/ Shutdown
Sync Range
Sync Range
Sync Pulse Transition Threshold
SS Bias Current
CS5171/2
CS5173/4
Rise time = 20 ns
SS = 0 V
SS = 3.0 V
−
2.7 V
≤
V
CC
≤
12 V
12 V < V
CC
≤
30 V
320
640
2.5
−15
−
0.50
12
12
−
−
−
−3.0
3.0
0.85
80
36
500
1000
−
−
8.0
1.20
350
200
kHz
kHz
V
mA
mA
V
ms
ms
CS5171/2, FB = 1 V or NFB = −1.9 V
CS5171/2, FB = 0 V or NFB = 0 V
CS5171/2
CS5173/4, FB = 1 V or NFB = −1.9 V
CS5173/4, FB = 0 V or NFB = 0 V
CS5173/4
Frequency drops to reduced operating frequency
Frequency drops to reduced operating frequency
230
30
90
460
60
82
−0.80
0.36
280
52
94
560
104
90
−0.65
0.40
310
120
−
620
160
−
−0.50
0.44
kHz
kHz
%
kHz
kHz
%
V
V
V
C
tied to FB; measure at FB
V
C
= 1.25 V
FB = V
REF
NFB = NV
REF
V
C
= FB
V
C
= 1.25 V
I
VC
=
±
25
mA
I
VC
=
±
5
mA
(Note 2)
(Note 2)
FB = 1.0 V or NFB = −1.9 V, V
C
= 1.25 V
FB = 1.5 V or NFB = −3.1 V, V
C
= 1.25 V
FB = 1.0 V or NFB = −1.9 V;
V
C
sources 25
mA
FB = 1.5 V or NFB = −3.1 V, V
C
sinks 25
mA
Reduce V
C
from 1.5 V until switching stops
1.246
−2.55
−1.0
−16
−
1.276
−2.45
0.1
−10
0.01
1.300
−2.35
1.0
−5.0
0.03
V
V
mA
mA
%/V
Test Conditions
Min
Typ
Max
Unit
−
300
115
200
100
25
200
1.5
0.25
0.75
0.01
550
160
500
180
50
625
1.7
0.50
1.05
0.05
800
225
−
320
90
1500
1.9
0.65
1.30
%/V
mMho
mMho
V/V
V/V
mA
mA
V
V
V
Shutdown Threshold
Shutdown Delay
2. Guaranteed by design, not 100% tested in production.
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3
CS5171, CS5172, CS5173, CS5174
ELECTRICAL CHARACTERISTICS
(2.7 V< V
CC
< 30 V; Industrial Grade: −40°C < T
J
< 125°C;
Commercial Grade: 0°C < T
J
< 125°C; For all CS5171/2/3/4 specifications unless otherwise stated.)
Characteristic
Power Switch
Switch Saturation Voltage
I
SWITCH
= 1.5 A, (Note 3)
I
SWITCH
= 1.0 A, 0°C
≤
T
J
≤
85°C
I
SWITCH
= 1.0 A, −40°C
≤
T
J
≤
0°C
I
SWITCH
= 10 mA
50% duty cycle, (Note 3)
80% duty cycle, (Note 3)
FB = 0 V or NFB = 0 V, I
SW
= 4.0 A, (Note 3)
2.7 V
≤
V
CC
≤
12 V, 10 mA
≤
I
SW
≤
1.0 A
12 V < V
CC
≤
30 V, 10 mA
≤
I
SW
≤
1.0 A
2.7 V
≤
V
CC
≤
12 V, 10 mA
≤
I
SW
≤
1.5 A, (Note 3)
12 V < V
CC
≤
30 V, 10 mA
≤
I
SW
≤
1.5 A, (Note 3)
V
SW
= 40 V, V
CC
= 0V
−
−
−
−
1.6
1.5
200
−
−
−
−
−
0.8
0.55
0.75
0.09
1.9
1.7
250
10
−
17
−
2.0
1.4
−
−
0.45
2.4
2.2
300
30
100
30
100
100
V
V
V
V
A
A
ns
mA/A
mA/A
mA/A
mA/A
mA
Test Conditions
Min
Typ
Max
Unit
Switch Current Limit
Minimum Pulse Width
DI
CC
/
DIV
SW
Switch Leakage
General
Operating Current
Shutdown Mode Current
Minimum Operation Input Voltage
Thermal Shutdown
Thermal Hysteresis
I
SW
= 0
V
C
< 0.8 V, SS = 0 V, 2.7 V
≤
V
CC
≤
12 V
V
C
< 0.8 V, SS = 0 V, 12 V
≤
V
CC
≤
30 V
V
SW
switching, maximum I
SW =
10 mA
(Note 3)
(Note 3)
−
−
−
−
150
−
5.5
12
−
2.45
180
25
8.0
60
100
2.70
210
−
mA
mA
V
°C
°C
3. Guaranteed by design, not 100% tested in production.
PACKAGE PIN DESCRIPTION
Package
Pin #
1
Pin
Symbol
V
C
Function
Loop compensation pin. The V
C
pin is the output of the error amplifier and is used for loop compensation,
current limit and soft start. Loop compensation can be implemented by a simple RC network as shown in the
application diagram on page 2 as R1 and C1.
Positive regulator feedback pin. This pin senses a positive output voltage and is referenced to 1.276 V. When
the voltage at this pin falls below 0.4 V, chip switching frequency reduces to 20% of the nominal frequency.
These pins are connected to internal test logic and should either be left floating or tied to ground. Connection
to a voltage between 2 V and 6 V shuts down the internal oscillator and leaves the power switch running.
2
(CS5171/3
only)
2
(CS5172/4)
3
CS5171/3)
3
(CS5172/4)
4
FB
Test
NFB
SS
Negative feedback pin. This pin senses a negative output voltage and is referenced to −2.5 V. When the
voltage at this pin goes above −0.65 V, chip switching frequency reduces to 20% of the nominal frequency.
Synchronization and shutdown pin. This pin may be used to synchronize the part to nearly twice the base
frequency. A TTL low will shut the part down and put it into low current mode. If synchronization is not used,
this pin should be either tied high or left floating for normal operation.
Input power supply pin. This pin supplies power to the part and should have a bypass capacitor connected to
AGND.
Analog ground. This pin provides a clean ground for the controller circuitry and should not be in the path of
large currents. The output voltage sensing resistors should be connected to this ground pin. This pin is
connected to the IC substrate.
Power ground. This pin is the ground connection for the emitter of the power switching transistor. Connection
to a good ground plane is essential.
High current switch pin. This pin connects internally to the collector of the power switch. The open voltage
across the power switch can be as high as 40 V. To minimize radiation, use a trace as short as practical.
5
6
V
CC
AGND
7
8
PGND
V
SW
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CS5171, CS5172, CS5173, CS5174
V
CC
Shutdown
Delay
Timer
SS
Sync
2.0 V
Regulator
Thermal
Shutdown
V
SW
Oscillator
S PWM
Latch
R
Q
Driver
Switch
Frequency
Shift 5:1
×5
200 k
2.0 V
Negative
Error Amp
+
−
Slope
Compensation
63 mW
Ramp
Summer
PWM
Comparator
+
−
NFB
CS5172/4
only
250 k
PGND
−0.65 V Detector
0.4 V Detector
FB
CS5171/3
only
1.276 V
−
+
Positive
Error Amp
AGND
V
C
Figure 2. Block Diagram
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