Order this document by SG3526/D
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
PULSE WIDTH MODULATION
CONTROL CIRCUIT
SEMICONDUCTOR
TECHNICAL DATA
18
1
•
•
•
•
•
•
•
•
•
•
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
N SUFFIX
PLASTIC PACKAGE
CASE 707
PIN CONNECTIONS
+Error
–Error
Compensation
1
2
3
4
5
6
7
8
9
(Top View)
18 Vref
17 VCC
16 Output B
15 Ground
14 VC
13 Output A
12 Sync
11 RDeadtime
10 CT
Representative Block Diagram
CSoft–Start
Vref
VCC
Ground
Sync
RDeadtime
RT
CT
Reset
CSoft–Start
18
17 Reference
Regulator
15
12
11
9 Oscillator
10
Under–
Voltage
Lockout
To Internal
Circuitry
14
VC
13
Output
A
5
4
3
VCC
1
2
7
6
8
+
–
+
–
Amp
–
+
SQ
D
Q
Soft
Start
Memory
F/F
S
RQ
Toggle
F/F
Q
T
Q
16
Output
B
Reset
–CS
+CS
Shutdown
RT
Compensation
+Error
–Error
+C.S.
–C.S.
Shutdown
ORDERING INFORMATION
Device
SG3526N
Operating
Temperature Range
TJ = 0° to +125°C
Package
Plastic DIP
Rev 2
Metering
F/F
©
Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICE DATA
1
SG3526
MAXIMUM RATINGS
(Note 1)
Rating
Supply Voltage
Collector Supply Voltage
Logic Inputs
Analog Inputs
Output Current, Source or Sink
Reference Load Current (VCC = 40 V, Note 2)
Logic Sink Current
Power Dissipation
TA = +25°C (Note 3)
TC = +25°C (Note 4)
Thermal Resistance Junction–to–Air
Thermal Resistance Junction–to–Case
Operating Junction Temperature
Storage Temperature Range
Lead Temperature (Soldering, 10 Seconds)
PD
1000
3000
R
θJA
R
θJC
TJ
Tstg
TSolder
100
42
+150
–65 to +150
±300
°C/W
°C/W
°C
°C
°C
IO
Iref
Symbol
VCC
VC
Value
+40
+40
–0.3 to +5.5
–0.3 to VCC
±200
50
15
Unit
Vdc
Vdc
V
V
mA
mA
mA
mW
NOTES:
1. Values beyond which damage may occur.
2. Maximum junction temperature must be observed.
3. Derate at 10 mW/°C for ambient temperatures above +50°C.
4. Derate at 24 mW/°C for case temperatures above +25°C.
RECOMMENDED OPERATING CONDITIONS
Characteristics
Supply Voltage
Collector Supply Voltage
Output Sink/Source Current (Each Output)
Reference Load Current
Oscillator Frequency Range
Oscillator Timing Resistor
Oscillator Timing Capacitor
Available Deadtime Range (40 kHz)
Operating Junction Temperature Range
Symbol
VCC
VC
IO
Iref
fosc
RT
CT
–
TJ
Min
8.0
4.5
0
0
0.001
2.0
0.001
3.0
0
Max
35
35
±100
20
400
150
20
50
+125
Unit
Vdc
Vdc
mA
mA
kHz
kΩ
µF
%
°C
2
MOTOROLA ANALOG IC DEVICE DATA
SG3526
ELECTRICAL CHARACTERISTICS
(VCC = +15 Vdc, TJ = Tlow to Thigh [Note 5], unless otherwise noted.)
Characteristics
REFERENCE SECTION
(Note 6)
Reference Output Voltage (TJ = +25°C)
Line Regulation (+8.0 V
≤
VCC
≤
+35 V)
Load Regulation (0 mA
≤
IL
≤
20 mA)
Temperature Stability
Total Reference Output Voltage Variation
(+8.0 V
≤
VCC
≤
+35 V, 0 mA
≤
IL
≤
20 mA)
Short Circuit Current (Vref = 0 V) (Note 2)
UNDERVOLTAGE LOCKOUT
Reset Output Voltage (Vref = +3.8 V)
Reset Output Voltage (Vref = +4.8 V)
OSCILLATOR SECTION
(Note 7)
Initial Accuracy (TJ = +25°C)
Frequency Stability over Power Supply Range
(+8.0 V
≤
VCC
≤
+35 V)
Frequency Stability over Temperature
(∆TJ = Tlow to Thigh)
Minimum Frequency
(RT = 150 kΩ, CT = 20
µF)
Maximum Frequency
(RT = 2.0 kΩ, CT = 0.001
µF)
Sawtooth Peak Voltage (VCC = +35 V)
Sawtooth Valley Voltage (VCC = +8.0 V)
ERROR AMPLIFIER SECTION
(Note 8)
Input Offset Voltage (RS
≤
2.0 kΩ)
Input Bias Current
Input Offset Current
DC Open Loop Gain (RL
≥
10 MΩ)
High Output Voltage
(VPin 1–VPin 2
≥
+150 mV, Isource = 100
µA)
Low Output Voltage
(VPin 2–VPin 1
≥
+150 mV, Isink = 100
µA)
Common Mode Rejection Ratio (RS
≤
2.0 kΩ)
Power Supply Rejection Ratio (+12 V
≤
VCC
≤
+18 V)
NOTES:
2. Maximum junction temperature must be observed.
5. Tlow = 0°C
Thigh = +125°C
6. IL = 0 mA unless otherwise noted.
7. fosc = 40 kHz (RT = 4.12 kΩ
±
1%, CT = 0.01
µF ±
1%, RD = 0
Ω)
8. 0 V
≤
VCM
≤
+5.2 V.
Symbol
Min
Typ
Max
Unit
Vref
Regline
Regload
∆V
ref/∆T
∆V
ref
ISC
4.90
–
–
–
4.85
25
5.00
10
10
10
5.00
80
5.10
30
50
–
5.15
125
V
mV
mV
mV
V
mA
–
2.4
0.2
4.8
±3.0
0.5
0.4
–
±8.0
1.0
V
V
–
∆f
osc
∆
V
CC
∆f
osc
∆
TJ
fmin
fmax
Vosc(P)
Vosc(V)
–
%
%
–
2.0
–
%
–
400
–
0.45
0.5
–
3.0
0.8
–
–
3.5
–
Hz
kHz
V
V
VIO
IIB
IIO
AVOL
VOH
VOL
CMRR
PSRR
–
–
–
60
3.6
–
70
66
2.0
–350
35
72
4.2
0.2
94
80
10
–2000
200
–
–
0.4
–
–
mV
nA
nA
dB
V
V
dB
dB
MOTOROLA ANALOG IC DEVICE DATA
3
SG3526
ELECTRICAL CHARACTERISTICS (continued)
Characteristics
PWM COMPARATOR SECTION
(Note 7)
Minimum Duty Cycle
(VCompensation = +0.4 V)
Maximum Duty Cycle
(VCompensation = +3.6 V)
DIGITAL PORTS (SYNC, SHUTDOWN, RESET)
Output Voltage
(High Logic Level) (Isource = 40
µA)
(Low Logic Level) (Isink = 3.6 mA)
Input Current
High Logic Level
(High Logic Level) (VIH = +2.4 V)
(Low Logic Level) (VIL = +0.4 V)
CURRENT LIMIT COMPARATOR SECTION
(Note 9)
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)
OUTPUT DRIVERS
(Each Output, VC = +15 Vdc, unless otherwise noted.)
Output High Level
Isource = 20 mA
Isource = 100 mA
Output Low Level
Isink = 20 mA
Isink = 100 mA
Collector Leakage, VC = +40 V
Rise Time (CL = 1000 pF)
Fall Time (CL = 1000 pF)
Supply Current
(Shutdown = +0.4 V, VCC = +35 V, RT = 4.12 kΩ)
NOTES:
7. fosc = 40 kHz (RT = 4.12 kΩ
±
1%, CT = 0.01
µF ±
1%, RD = 0
Ω)
8. 0 V
≤
VCM
≤
+5.2 V
9. 0 V
≤
VCM
≤
+12 V
Symbol
Min
Typ
Max
Unit
DCmin
DCmax
–
45
–
49
0
–
%
%
V
VOH
VOL
IIH
IIL
2.4
–
–
–
4.0
0.2
–125
–225
–
0.4
µA
–200
–360
Vsense
IIB
80
100
–3.0
120
–10
mA
µA
–
ICS
50
0.1
100
0.4
150
V
µA
VOH
12.5
12
VOL
–
–
IC(leak)
tr
tf
ICC
–
–
–
–
0.2
1.2
50
0.3
0.1
18
0.3
2.0
150
0.6
0.2
30
13.5
13
–
–
V
V
µA
µs
µs
mA
4
MOTOROLA ANALOG IC DEVICE DATA
SG3526
Figure 2. Reference Voltage as a
Function Supply Voltage
Figure 1. Reference Stability over Temperature
V ref , REFERENCE VOLTAGE (V)
–50
–25
0
25
50
75 100 125
TJ, JUNCTION TEMPERATURE (°C)
150
5.0
4.0
3.0
2.0
1.0
1.0
2.0
3.0 4.0 5.0
10
20 30 40
VCC, SUPPLY VOLTAGE (V)
50 mV
Spec
Limit
–75
Figure 3. Error Amplifier Open Loop
Frequency Response
8.0
7.0
A Vol , VOLTAGE GAIN (dB)
SHUTDOWN VOLTAGE (V)
CComp
Figure 4. Current Limit Comparator Threshold
80
60
40
20
0
10
100
1
2
+
_
100 pF
3
6.0
5.0
4.0
3.0
2.0
1.0
1.0 k
10 k
100 k
1.0 M
10 M
0
25
50
75
100
125
150
175
200
DIFFERENTIAL INPUT VOLTAGE (mV)
f, FREQUENCY (Hz)
8.0
7.0
RESET VOLTAGE (V)
6.0
5.0
4.0
3.0
2.0
1.0
0
0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Vref, REFERENCE VOLTAGE (V)
V sat , OUTPUT DRIVER SATURATION VOLTAGE (V)
Figure 5. Undervoltage Lockout Characteristic
Figure 6. Output Driver Saturation Voltage as a
Function of Sink Current
2.5
2.0
1.5
1.0
0.5
0
2.0
5.0
10
20
50
100
200
OUTPUT DRIVER SINK CURRENT (mA)
MOTOROLA ANALOG IC DEVICE DATA
5
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