ONSEMI SG3526

SG3526
Pulse Width Modulation
Control Circuit
The SG3526 is a high performance pulse width modulator
integrated circuit intended for fixed frequency switching regulators
and other power control applications.
Functions included in this IC are a temperature compensated
voltage reference, sawtooth oscillator, error amplifier, pulse width
modulator, pulse metering and steering logic, and two high current
totem pole outputs ideally suited for driving the capacitance of power
FETs at high speeds.
Additional protective features include soft start and undervoltage
lockout, digital current limiting, double pulse inhibit, adjustable dead
time and a data latch for single pulse metering. All digital control ports
are TTL and B−series CMOS compatible. Active low logic design
allows easy wired−OR connections for maximum flexibility. The
versatility of this device enables implementation in single−ended or
push−pull switching regulators that are transformerless or transformer
coupled. The SG3526 is specified over a junction temperature range of
0° to +125°C.
• 8.0 V to 35 V Operation
• 5.0 V ±1% Trimmed Reference
• 1.0 Hz to 400 kHz Oscillator Range
• Dual Source/Sink Current Outputs: ±100 mA
• Digital Current Limiting
• Programmable Dead Time
• Undervoltage Lockout
• Single Pulse Metering
• Programmable Soft−Start
• Wide Current Limit Common Mode Range
• Guaranteed 6 Unit Synchronization
Vref
VCC
Ground
Sync
RDeadtime
RT
CT
Reset
CSoft−Start
+C.S.
−C.S.
Shutdown
MARKING
DIAGRAM
18
17 Reference
Regulator
15
12
A
WL
YY
WW
1
18 Vref
−Error
2
17 VCC
Compensation
3
16 Output B
CSoft−Start
4
15 Ground
Reset
5
14 VC
−CS
6
13 Output A
+CS
7
12 Sync
Shutdown
8
11 RDeadtime
RT
9
10 CT
14
VC
13
Memory
F/F
S
3
VCC
Amp
100 mV
7
+
6
−
8
+Error
(Top View)
To Internal
Circuitry
Soft
Start
+
−
−
+
= Assembly Location
= Wafer Lot
= Year
= Work Week
PIN CONNECTIONS
Output
A
1
2
SG3526N
AWLYYWW
1
1
Under−
Voltage
Lockout
11
9 Oscillator
10
5
4
PDIP−18
N SUFFIX
CASE 707
18
18
Compensation
+Error
−Error
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SQ
R
RQ
ORDERING INFORMATION
Device
SG3526N
Toggle
F/F
Q
T
Q
Package
Shipping
PDIP−18
20 Units/Rail
16
Q
Output
B
Metering
F/F
Figure 1. Representative Block Diagram
© Semiconductor Components Industries, LLC, 2006
July, 2006 − Rev. 4
1
Publication Order Number:
SG3526/D
SG3526
MAXIMUM RATINGS (Note 1)
Rating
Symbol
Value
Unit
Supply Voltage
VCC
+40
Vdc
Collector Supply Voltage
VC
+40
Vdc
Logic Inputs
−0.3 to +5.5
V
Analog Inputs
−0.3 to VCC
V
Output Current, Source or Sink
IO
±200
mA
Reference Load Current (VCC = 40 V, Note 2)
Iref
50
mA
Logic Sink Current
15
Power Dissipation
TA = +25°C (Note 3)
TC = +25°C (Note 4)
PD
mA
mW
1000
3000
Thermal Resistance Junction−to−Air
RθJA
100
°C/W
Thermal Resistance Junction−to−Case
RθJC
42
°C/W
Operating Junction Temperature
TJ
+150
°C
Storage Temperature Range
Tstg
−65 to +150
°C
TSolder
±300
°C
Lead Temperature (Soldering, 10 Seconds)
RECOMMENDED OPERATING CONDITIONS
Characteristics
1.
2.
3.
4.
Symbol
Min
Max
Unit
Supply Voltage
VCC
8.0
35
Vdc
Collector Supply Voltage
VC
4.5
35
Vdc
Output Sink/Source Current (Each Output)
IO
0
±100
mA
Reference Load Current
Iref
0
20
mA
Oscillator Frequency Range
fosc
0.001
400
kHz
Oscillator Timing Resistor
RT
2.0
150
kΩ
Oscillator Timing Capacitor
CT
0.001
20
μF
Available Deadtime Range (40 kHz)
−
3.0
50
%
Operating Junction Temperature Range
TJ
0
+125
°C
Values beyond which damage may occur.
Maximum junction temperature must be observed.
Derate at 10 mW/°C for ambient temperatures above +50°C.
Derate at 24 mW/°C for case temperatures above +25°C.
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SG3526
ELECTRICAL CHARACTERISTICS (VCC = +15 Vdc, TJ = Tlow to Thigh [Note 6], unless otherwise noted.)
Symbol
Min
Typ
Max
Unit
Reference Output Voltage (TJ = +25°C)
Vref
4.90
5.00
5.10
V
Line Regulation (+8.0 V ≤ VCC ≤ +35 V)
Regline
−
10
30
mV
Load Regulation (0 mA ≤ IL ≤ 20 mA)
Regload
−
10
50
mV
Temperature Stability
ΔVref/ΔT
−
10
−
mV
ΔVref
4.85
5.00
5.15
V
ISC
25
80
125
mA
Reset Output Voltage (Vref = +3.8 V)
−
0.2
0.4
V
Reset Output Voltage (Vref = +4.8 V)
2.4
4.8
−
V
−
±3.0
±8.0
%
Characteristics
REFERENCE SECTION (Note 7)
Total Reference Output Voltage Variation
(+8.0 V ≤ VCC ≤ +35 V, 0 mA ≤ IL ≤ 20 mA)
Short Circuit Current (Vref = 0 V) (Note 5)
UNDERVOLTAGE LOCKOUT
OSCILLATOR SECTION (Note 8)
Initial Accuracy (TJ = +25°C)
Frequency Stability over Power Supply Range
(+8.0 V ≤ VCC ≤ +35 V)
Δfosc
Δ V
−
0.5
1.0
%
Frequency Stability over Temperature
(ΔTJ = Tlow to Thigh)
Δfosc
−
2.0
−
%
CC
Δ TJ
Minimum Frequency
(RT = 150 kΩ, CT = 20 μF)
fmin
−
0.5
−
Hz
Maximum Frequency
(RT = 2.0 kΩ, CT = 0.001 μF)
fmax
400
−
−
kHz
Sawtooth Peak Voltage (VCC = +35 V)
Vosc(P)
−
3.0
3.5
V
Sawtooth Valley Voltage (VCC = +8.0 V)
Vosc(V)
0.45
0.8
−
V
ERROR AMPLIFIER SECTION (Note 9)
5.
6.
7.
8.
9.
Input Offset Voltage (RS ≤ 2.0 kΩ)
VIO
−
2.0
10
mV
Input Bias Current
IIB
−
−350
−2000
nA
Input Offset Current
IIO
−
35
200
nA
DC Open Loop Gain (RL ≥ 10 MΩ)
AVOL
60
72
−
dB
High Output Voltage
(VPin 1−VPin 2 ≥ +150 mV, Isource = 100 μA)
VOH
3.6
4.2
−
V
Low Output Voltage
(VPin 2−VPin 1 ≥ +150 mV, Isink = 100 μA)
VOL
−
0.2
0.4
V
Common Mode Rejection Ratio (RS ≤ 2.0 kΩ)
CMRR
70
94
−
dB
Power Supply Rejection Ratio (+12 V ≤ VCC ≤ +18 V)
PSRR
66
80
−
dB
Maximum junction temperature must be observed.
Thigh = +125°C
Tlow = 0°C
IL = 0 mA unless otherwise noted.
fosc = 40 kHz (RT = 4.12 kΩ ± 1%, CT = 0.01 μF ± 1%, RD = 0 Ω)
0 V ≤ VCM ≤ +5.2 V.
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3
SG3526
ELECTRICAL CHARACTERISTICS (continued)
Characteristics
Symbol
Min
Typ
Max
Unit
Minimum Duty Cycle
(VCompensation = +0.4 V)
DCmin
−
−
0
%
Maximum Duty Cycle
(VCompensation = +3.6 V)
DCmax
45
49
−
%
VOH
VOL
2.4
−
4.0
0.2
−
0.4
IIH
IIL
−
−
−125
−225
−200
−360
Vsense
80
100
120
mV
IIB
−
−3.0
−10
μA
−
0.1
0.4
V
50
100
150
μA
12.5
12
13.5
13
−
−
−
−
0.2
1.2
0.3
2.0
IC(leak)
−
50
150
μA
Rise Time (CL = 1000 pF)
tr
−
0.3
0.6
μs
Fall Time (CL = 1000 pF)
tf
−
0.1
0.2
μs
ICC
−
18
30
mA
PWM COMPARATOR SECTION (Note 10)
DIGITAL PORTS (SYNC, SHUTDOWN, RESET)
Output Voltage
(High Logic Level) (Isource = 40 μA)
(Low Logic Level) (Isink = 3.6 mA)
V
Input Current ⎯ High Logic Level
(High Logic Level) (VIH = +2.4 V)
(Low Logic Level) (VIL = +0.4 V)
μA
CURRENT LIMIT COMPARATOR SECTION (Note 12)
Sense Voltage (RS ≤ 50 Ω)
Input Bias Current
SOFT−START SECTION
Error Clamp Voltage (Reset = +0.4 V)
CSoft−Start Charging Current (Reset = +2.4 V)
ICS
OUTPUT DRIVERS (Each Output, VC = +15 Vdc, unless otherwise noted.)
Output High Level
Isource = 20 mA
Isource = 100 mA
VOH
Output Low Level
Isink = 20 mA
Isink = 100 mA
VOL
Collector Leakage, VC = +40 V
Supply Current
(Shutdown = +0.4 V, VCC = +35 V, RT = 4.12 kΩ)
10. fosc = 40 kHz (RT = 4.12 kΩ ± 1%, CT = 0.01 μF ± 1%, RD = 0 Ω)
11. 0 V ≤ VCM ≤ +5.2 V
12. 0 V ≤ VCM ≤ +12 V
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4
V
V
V ref , REFERENCE VOLTAGE (V)
SG3526
50 mV
Spec
Limit
−75 −50
−25
0
25
50
75 100 125
TJ, JUNCTION TEMPERATURE (°C)
5.0
4.0
3.0
2.0
1.0
150
1.0
2.0
Figure 2. Reference Stability over Temperature
3.0 4.0 5.0
10
20 30 40
VCC, SUPPLY VOLTAGE (V)
Figure 3. Reference Voltage as a
Function Supply Voltage
8.0
SHUTDOWN VOLTAGE (V)
80
60
40
20
1
+
_
3
2
0
10
100
pF
100
CComp
1.0 k
10 k
100 k
1.0 M
4.0
3.0
2.0
0
10 M
25
50
75
100
125
150
175
200
f, FREQUENCY (Hz)
DIFFERENTIAL INPUT VOLTAGE (mV)
Figure 4. Error Amplifier Open Loop
Frequency Response
Figure 5. Current Limit Comparator Threshold
7.0
RESET VOLTAGE (V)
5.0
1.0
8.0
6.0
5.0
4.0
3.0
2.0
1.0
0
0
6.0
V sat , OUTPUT DRIVER SATURATION VOLTAGE (V)
A Vol , VOLTAGE GAIN (dB)
7.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
2.5
2.0
1.5
1.0
0.5
0
2.0
5.0
10
20
50
100
200
Vref, REFERENCE VOLTAGE (V)
OUTPUT DRIVER SINK CURRENT (mA)
Figure 6. Undervoltage Lockout Characteristic
Figure 7. Output Driver Saturation Voltage as a
Function of Sink Current
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5
SG3526
200
10
20
50
IC, SINK CURRENT (mA)
100
5.0
2.0
200
0.005
0.01
0.02
5.0
10
0.002
0
2.0
20
Figure 8. VC Saturation Voltage as a
Function of Sink Current
100
200
500
1000
0.5
50
5.0
10
20
50
1.0
RD = 0 Ω
1.0
2.0
1.5
100
0.05
0.1
0.2
0.5
2.0
R T, TIMING RESISTOR (k Ω )
V SAT , SATURATION VOLTAGE (V)
2.5
OSCILLATOR PERIOD (ms)
Figure 9. Oscillator Period
VCC
Q6
Vref
Q5
Vref
125
μA
Q11
Q3
Q4
50μA
50μA
14μA
14μA
100
μA
Q8
Q7
To Reset
Q12
100μA
R1
3 Compensation
Q10
100μA
Q9
Q1
Q2
1.0k
500
1.0k
+
1.2V
Bandgap
Reference
500
−
R2
1
+ Error
− Error
Figure 10. Error Amplifier
Figure 11. Undervoltage Lockout
Memory
F/F
Sync
S
S Q
PWM
The metering Flip−Flop is an asynchronous data latch
which suppresses high frequency oscillations by allowing
only one PWM pulse per oscillator cycle.
R
Q
Clock
D
Q
The memory Flip−Flop prevents double pulsing in a
push−pull configuration by remembering which output
produced the last pulse.
PWM
Metering
F/F
Figure 12. Pulse Processing Logic
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To Driver A
To Driver B
SG3526
APPLICATIONS INFORMATION
Negative
Output
Voltage
R1
Vref
R3
1 +
Vref
2 −
R2
R3
Positive
Output
Voltage
R1
27
1 +
2 −
C*
17
VCC
R2
18
Reference
Regulator
Vref
Gnd
Gnd
+
15
10μF
Vout = Vref
R1 + R2
R2
R1
R2
Vout = Vref
Gnd
R1R2
R1 + R2
R3 =
* May be required with some types of transistors
Figure 13. Extending Reference
Output Current Capability
Figure 14. Error Amplifier Connections
Output to Load
+
RS
11
12
SG3526
− 6
Sync
8
RD
9
Vout
R1
+ 7
10
R2
Gnd
CT
RT
0.1 V +
I(max) =
Figure 15. Oscillator Connections
−
Vout R1
R1 + R2
ISC =
RS
0.1 V
RS
Figure 16. Foldback Current Limiting
+12V
Vref
+ Error
− Error
Reset
1
2
+
14
VC
100
μA
Ramp
−
PWM
Error
− Amp
SG3526
+
Gnd
Q2
5
A 13
B
16
Q1
Q3
To
Undervoltage
Lockout
CSoft−Start
The totem pole output drivers of the SG3526 are ideally
suited for driving the input capacitance of power FETs at
high speeds.
Figure 17. Soft−Start Circuity
Figure 18. Driving VMOS Power FETs
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7
SG3526
+V
Supply
R1
14
VC
+V
Supply
5
R
8
C1
14
VC
13
4
Gnd
15
B
CS
T2
SG3526
C2
Q2
16
A
B
S
Q1
A
R4
SG3526
R1
C1
T1
C2
+CS
−CS
Gnd
15
13
D1
16
D2
Q1
7
R3
6
R2
T1
In the above circuit, current limiting is accomplished by using the
current limit comparator output to reset the soft−start capacitor.
Figure 19. Half−Bridge Configuration
Q1
+V Supply
Figure 20. Flyback Converter with
Current Limiting
To
Output
Filter
R1
+V Supply
R1
C1
R2
14
VC
A
SG3526
B
14
VC
13
A
13
Gnd
Gnd
B
Q1
C2
SG3526
16
R2
16
R3
Q2
15
15
Figure 21. Single−Ended Configuration
Figure 22. Push−Pull Configuration
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8
T1
SG3526
PACKAGE DIMENSIONS
PDIP−18
N SUFFIX
CASE 707−02
ISSUE D
J
18
NOTES:
1. POSITIONAL TOLERANCE OF LEADS (D), SHALL
BE WITHIN 0.25 mm (0.010) AT MAXIMUM
MATERIAL CONDITION, IN RELATION TO SEATING
PLANE AND EACH OTHER.
2. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.
3. DIMENSION B DOES NOT INCLUDE MOLD FLASH.
4. CONTROLLING DIMENSION: INCH.
10
B
1
L
9
M
A
DIM
A
B
C
D
F
G
H
J
K
L
M
N
C
N
F
H
D
G
K
SEATING
PLANE
INCHES
MIN
MAX
0.875
0.915
0.240
0.260
0.140
0.180
0.014
0.022
0.050
0.070
0.100 BSC
0.040
0.060
0.008
0.012
0.115
0.135
0.300 BSC
0_
15_
0.020
0.040
MILLIMETERS
MIN
MAX
22.22
23.24
6.10
6.60
3.56
4.57
0.36
0.56
1.27
1.78
2.54 BSC
1.02
1.52
0.20
0.30
2.92
3.43
7.62 BSC
0_
15 _
0.51
1.02
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability
arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages.
“Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over time. All
operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under its patent rights
nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body, or other applications
intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death may occur. Should
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SG3526/D