CS51021A, CS51022A,
CS51023A, CS51024A
Enhanced Current Mode
PWM Controller
The CS51021A/2A/3A/4A Fixed Frequency PWM Current Mode
Controller family provides all necessary features required for AC−DC
or DC−DC primary side control. Several features are included
eliminating the additional components needed to implement them
externally. In addition to low startup current (75
mA)
and high
frequency operation capability, the CS51021A/2A/3A/4A family
includes overvoltage and undervoltage monitoring, externally
programmable dual threshold overcurrent protection, current sense
leading edge blanking, current slope compensation, accurate duty cycle
control and an externally available 5.0 V reference. The CS51021A
and CS51023A feature bidirectional synchronization capability, while
the CS51022A and CS51024A offer a sleep mode with 100
mA
maximum IC current consumption. The CS51021A/2A/3A/4A family
is available in a 16 lead narrow body SOIC package.
Device
CS51021A
CS51022A
CS51023A
CS51024A
Sleep/Synch
Synch
Sleep
Synch
Sleep
V
CC
Start/Stop
8.25 V/7.7 V
8.25 V/7.7 V
13 V/7.7 V
13 V/7.7 V
GATE
I
SENSE
SLEEP or SYNC
SLOPE
UV
OV
R
T
C
T
I
SET
CS5102xAG
AWLYWW
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16
1
SOIC−16
D SUFFIX
CASE 751B
16
1
TSSOP−16
DTB SUFFIX
CASE 948F
PIN CONNECTIONS AND
MARKING DIAGRAMS
1
16
V
C
PGND
V
CC
V
REF
LGND
SS
COMP
V
FB
Features
•
75
mA
Max. Startup Current
•
Fixed Frequency Current Mode Control
•
1.0 MHz Switching Frequency
•
Undervoltage Protection Monitor
•
Overvoltage Protection Monitor with Programmable Hysteresis
•
Programmable Dual Threshold Overcurrent Protection with
Delayed Restart
•
Programmable Soft Start
•
Accurate Maximum Duty Cycle Limit
•
Programmable Slope Compensation
•
Leading Edge Current Sense Blanking
•
1.0 A Sink/Source Gate Drive
•
Bidirectional Synchronization (CS51021A/3A)
•
50 ns PWM Propagation Delay
•
100
mA
Max Sleep Current (CS51022A/4A)
•
Pb−Free Packages are Available*
1
CS51
022A
ALYW
G
G
x
A
WL, L
Y
WW, W
G or
G
16
= Specific Device Code
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 9 of this data sheet.
*For additional information on our Pb−Free strategy and soldering details, please
download the ON Semiconductor Soldering and Mounting Techniques
Reference Manual, SOLDERRM/D.
©
Semiconductor Components Industries, LLC, 2006
1
February, 2006 − Rev. 8
Publication Order Number:
CS51021A/D
CS51021A, CS51022A, CS51023A, CS51024A
100
V
IN
(36 V to 72 V)
PGND
51 k
BAS21
18 V
100:1
FZT688
10
1.0
mF
SYNC/SLEEP
22
mF
11 V
200 k,
1.0%
2.49 k,
1.0%
BA521
2:5
10 k
24.3 k,
1.0%
4:1
V
OUT
(5 V/5 A)
0.01
mF
10 k
4700 pF
22 k
51 k
330 pF
V
C
V
REF
COMP
V
FB
R
T
C
T
SYNC/
SLEEP
C
SS
LGND
V
CC
UV
OV
I
SET
SLOPE
GATE
I
SENSE
PGND
470 pF
10
100
mF
100
mF
SGND
CS51021A/2A
680 pF
IRF6345
6.98 k,
1.0%
6.98 k,
1.0%
100
62
100 p
0.01
mF
0.1
mF
TL431
180
1.0 k
10 K
1.0 K
MOC81025
5.1 k
1000 pF
2.0 k,
1.0%
2.0 k, 1.0%
Figure 1. Typical Application Diagram, 36−72 V to 5.0 V, 5.0 A DC−DC Converter
MAXIMUM RATINGS*
Rating
Power Supply Voltage, V
CC
Driver Supply Voltage, V
C
SYNC, SLEEP, R
T
C
T
, SOFT−START, V
FB
, SLOPE, I
SENSE
, UV, OV, I
SET
(Logic Pins)
Peak GATE Output Current
Steady State Output Current
Operating Junction Temperature, T
J
Storage Temperature Range, T
S
ESD (Human Body Model)
Lead Temperature Soldering:
Reflow: (SMD styles only) (Note 1)
Value
−0.3, 20
−0.3, 20
0.25 to V
REF
1.0
±0.2
150
−65 to +150
2.0
230 peak
Unit
V
V
V
A
A
°C
°C
kV
°C
Maximum ratings are those values beyond which device damage can occur. Maximum ratings applied to the device are individual stress limit
values (not normal operating conditions) and are not valid simultaneously. If these limits are exceeded, device functional operation is not implied,
damage may occur and reliability may be affected.
*The maximum package power dissipation must be observed.
1. 60 second maximum above 183°C.
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2
CS51021A, CS51022A, CS51023A, CS51024A
ELECTRICAL CHARACTERISTICS
(Unless otherwise stated, specifications apply for −40°C < T
A
< 85°C, −40°C < T
J
< 150°C,
3.0 V < V
C
< 20 V, 8.2 V < V
CC
< 20 V, R
T
= 12 kW, C
T
= 390 pF)
Characteristic
Under Voltage Lockout
START Threshold (CS51021A/2A)
START Threshold (CS51023A/4A)
STOP Threshold
Hysteresis (CS51021A/2A)
Hysteresis (CS51023A/4A)
I
CC
@ Startup (CS51021A/2A)
I
CC
@ Startup (CS51023A/4A)
I
CC
Operating (CS51021A/3A)
I
CC
Operating (CS51022A/4A)
I
CC
Operating
Voltage Reference
Initial Accuracy
Total Accuracy
Line Regulation
Load Regulation
NOISE Voltage
OP Life Shift
FAULT Voltage
OK Voltage
OK Hysteresis
Current Limit
Error Amplifier
Initial Accuracy
Reference Voltage
V
FB
Leakage Current
Open Loop Gain
Unity Gain Bandwidth
COMP Sink Current
COMP Source Current
COMP High Voltage
COMP Low Voltage
PS Ripple Rejection
SS Clamp, V
COMP
I
LIM(SET)
Clamp
T
A
= 25°C, I
REF
= 2.0 mA, V
CC
= 14 V,
V
FB
= COMP, (Note 2)
V
FB
= COMP
V
FB
= 0 V
1.4 V < COMP < 4.0 V, (Note 2)
(Note 2)
COMP = 1.5 V, V
FB
= 2.7 V
COMP = 1.5 V, V
FB
= 2.3 V
V
FB
= 2.3 V
V
FB
= 2.7 V
FREQ = 120 Hz, (Note 2)
V
SS
= 2.5 V, V
FB
= 0 V, I
SET
= 2.0 V
(Note 2)
2.465
2.440
−
60
1.5
2.0
−0.2
4.35
0.4
60
2.4
0.95
2.515
2.515
−0.2
90
2.5
6.0
−0.5
4.8
0.8
85
2.5
1.0
2.565
2.590
−2.0
−
−
−
−
5.0
1.2
−
2.6
1.15
V
V
mA
dB
MHz
mA
mA
V
V
dB
V
V
T
A
= 25°C, I
REF
= 2.0 mA, V
CC
= 14 V, (Note 2)
1.0 mA < I
REF
< 10 mA
8.2 V < V
CC
< 18 V, I
REF
= 2.0 mA
1.0 mA < I
REF
< 10 mA
(Note 2)
T = 1000 Hours, (Note 2)
Force V
REF
Force V
REF
Force V
REF
Force V
REF
4.95
4.9
−
−
−
−
0.90
×
V
REF
0.94
×
V
REF
75
−20
5.0
5.0
6.0
6.0
50
4.0
0.93
×
V
REF
0.96
×
V
REF
165
−
5.05
5.15
20
15
−
20
0.95
×
V
REF
0.985
×
V
REF
250
−
V
V
mV
mV
mV
mV
V
V
mV
mA
Includes 1.0 nF Load
−
−
−
−
−
V
CC
< UV
START
Threshold
V
CC
< UV
START
Threshold
−
−
7.95
12.4
7.4
0.50
4.0
−
−
−
−
−
8.25
13
7.7
0.75
5.0
40
45
7.0
6.0
7.0
8.8
13.4
8.2
1.00
6.0
75
75
9.0
8.0
12
V
V
V
V
V
mA
mA
mA
mA
mA
Test Conditions
Min
Typ
Max
Unit
2. Guaranteed by design, not 100% tested in production.
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3
CS51021A, CS51022A, CS51023A, CS51024A
ELECTRICAL CHARACTERISTICS
(Unless otherwise stated, specifications apply for −40°C < T
A
< 85°C, −40°C < T
J
< 150°C,
3.0 V < V
C
< 20 V, 8.2 V < V
CC
< 20 V, R
T
= 12 kW, C
T
= 390 pF)
Characteristic
Oscillator
Accuracy
Voltage Stability
Temperature Stability
Min Charge & Discharge Time
Duty Cycle Accuracy
Peak Voltage
Valley Voltage
Valley Clamp Voltage
Discharge Current
Discharge Current
Synchronization (CS51021A/3A)
Input Threshold
Output Pulsewidth
Output High Voltage
Input Resistance
Drive Delay
Output Drive Current
SLEEP (CS51022A/4A)
SLEEP Input Threshold
SLEEP Input Current
I
CC
@ SLEEP
GATE Driver
HIGH Voltage
LOW Voltage
HIGH Voltage Clamp
LOW Voltage Clamp
Peak Current
UVL Leakage
RISE Time
FALL Time
SLOPE Compensation
Charge Current
COMP Gain
Discharge Voltage
SLOPE = 2.0 V
Fraction of slope voltage added to I
SENSE
,
(Note 3)
SYNC = 0 V
−63
0.095
−
−53
0.100
0.1
−43
0.105
0.2
mA
V/V
V
Measure V
C
− GATE, V
C
= 10 V, 150 mA Load
Measure GATE − PGND, 150 mA SINK
V
C
= 20 V, 1.0 nF
Measured at 10 mA Output Current
V
C
= 20 V, 1.0 nF, (Note 3)
V
C
= 20 V measured at 0 V
Load = 1.0 nF, 1.0 V < GATE < 9.0 V,
V
C
= 20 V, T
A
= 25°C
Load = 1.0 nF, 9.0 V > GATE > 1 .0 V,
V
C
= 20 V
−
−
11
−
−
−
−
−
1.5
1.2
13.5
0.6
1.0
−1.0
60
15
2.2
1.5
16
0.8
−
−50
100
40
V
V
V
V
A
mA
ns
ns
Active High
V
SLEEP
= 4.0 V
V
CC
≤
15 V
1.0
11
−
1.5
25
50
2.7
46
100
V
mA
mA
I
SYNC
= 100
mA
(Note 3)
SYNC to GATE RESET
1.0 k Load
−
−
1.0
160
3.5
35
80
1.25
1.5
260
4.3
70
120
2.0
2.7
400
4.8
140
150
3.5
V
ns
V
kW
ns
mA
TA = 25°C, Note 3
R
T
= 12 k, C
T
= 390 pF
Delta Frequency 8.2 V < V
CC
< 20 V
T
MIN
< T
A
< T
MAX,
(Note 3)
(Note 3)
R
T
= 12 k, C
T
= 390 pF
(Note 3)
(Note 3)
10 k Resistor to ground on R
T
C
T
−
230
−
−
0.333
70
−
−
1.2
0.8
0.925
255
2.0
8.0
−
77
3.0
1.5
1.4
1.0
1.0
280
3.0
−
−
83
−
−
1.6
1.2
1.075
kHz
%
%
ms
%
V
V
V
mA
mA
Test Conditions
Min
Typ
Max
Unit
3. Guaranteed by design, not 100% tested in production.
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4
CS51021A, CS51022A, CS51023A, CS51024A
ELECTRICAL CHARACTERISTICS
(Unless otherwise stated, specifications apply for −40°C < T
A
< 85°C, −40°C < T
J
< 150°C,
3.0 V < V
C
< 20 V, 8.2 V < V
CC
< 20 V, R
T
= 12 kW, C
T
= 390 pF)
Characteristic
Current Sense
OFFSET Voltage
Blanking Time
Blanking Disable Voltage
Second Current Threshold Gain
I
SENSE
Input Resistance
Minimum On Time
Gain
OV & UV Voltage Monitors
OV Monitor Threshold
OV Hysteresis Current
UV Monitor Threshold
UV Monitor Hysteresis
SOFT START (SS)
Charge Current
Discharge Current
Charge Voltage, V
SS
Discharge Voltage, V
SS
4. Guaranteed by design, not 100% tested in production.
SS = 2.0 V
SS = 2.0 V
−
−
−70
250
4.4
0.25
−55
1000
4.7
0.27
−40
−
5.0
0.30
mA
mA
V
V
−
−
−
−
2.4
−10
1.38
25
2.5
−12.5
1.45
75
2.6
−15
1.52
100
V
mA
V
mV
GATE High to Low
(Note 4)
Adjust V
FB
−
−
(Note 4)
−
0.09
−
1.8
1.21
−
30
0.78
0.10
55
2.0
1.33
5.0
70
0.80
0.11
160
2.2
1.45
−
110
0.82
V
ns
V
V/V
kW
ns
V/V
Test Conditions
Min
Typ
Max
Unit
PACKAGE PIN DESCRIPTION
PIN #
PIN SYMBOL
FUNCTION
16 Lead SO Narrow
1
2
3
3
4
5
6
7
8
9
10
GATE
I
SENSE
SYNC (CS51021A/3A)
SLEEP (CS51022A/4A)
SLOPE
UV
OV
R
T
C
T
I
SET
V
FB
COMP
External power switch driver with 1.0 A peak capability.
Current sense amplifier input.
Bi−directional synchronization. Locks to the highest frequency.
Active high chip disable. In sleep mode, V
REF
and GATE are turned off.
Additional slope to the current sense signal. Internal current source charges the external capacitor.
Undervoltage protection monitor.
Overvoltage protection monitor.
Timing resistor R
T
and capacitor C
T
determine oscillator frequency and maximum duty cycle, D
MAX.
Voltage at this pin sets pulse−by−pulse overcurrent threshold, and second threshold (1.33 times
higher) with Soft Start retrigger (hiccup mode).
Feedback voltage input. Connected to the error amplifier inverting input.
Error amplifier output. Frequency compensation network is usually connected between COMP and
V
FB
pins.
Charging external capacitor restricts error amplifier output voltage during the start or fault
conditions (hiccup).
Logic ground.
5.0 V reference voltage output.
Logic supply voltage.
Output power stage ground connection.
Output power stage supply voltage.
11
12
13
14
15
16
SS
LGND
V
REF
V
CC
PGND
V
C
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