SG1526/SG2526/SG3526
REGULATING PULSE WIDTH MODULATOR
DESCRIPTION
The SG1526 is a high performance monolithic pulse width modulator
circuit designed for fixed-frequency switching regulators and other
power control applications. Included in an 18-pin dual-in-line package
are a temperature compensated voltage reference, sawtooth oscillator,
error amplifier, pulse width modulator, pulse metering and steering logic,
and two low impedance power drivers. Also included are protective
features such as soft-start and undervoltage lockout, digital current
limiting, double pulse inhibit, a data latch for single pulse metering,
adjustable deadtime, and provision for symmetry correction inputs. For
ease of interface, all digital control ports are TTL and B-series CMOS
compatible. Active LOW logic design allows wired-OR connections for
maximum flexibility. This versatile device can be used to implement
single-ended or push-pull switching regulators of either polarity, both
transformerless and transformer coupled. The SG1526 is characterized
for operation over the full military ambient junction temperature range of
-55°C to +150°C. The SG2526 is characterized for operation from -25°C
to +150°C, and the SG3526 is characterized for operation from 0°C to
+125°C.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
•
8 to 35 volt operation
5V reference trimmed to ±1%
1Hz to 350KHz oscillator range
Dual 100mA source/sink outputs
Digital current limiting
Double pulse suppression
Programmable deadtime
Undervoltage lockout
Single pulse metering
Programmable soft-start
Wide current limit common mode range
TTL/CMOS compatible logic ports
Symmetry correction capability
Guaranteed 6 unit synchronization
HIGH RELIABILITY FEATURES - SG1526
♦
Available to MIL-STD-883B and DESC SMD
♦
Radiation data available
♦
LMI level "S"processing available
BLOCK DIAGRAM
V
REF
+V
IN
GROUND
R
D
R
T
C
T
Reference
Regulator
Undervoltage
Lockout
SYNC
+V
C
To Internal
Circuitry
Oscillator
OUTPUT A
RESET
C
SOFTSTART
COMPENSATION
+ ERROR
Soft
Start
+V
IN
S
Amp
D
Q
METERING
F/F
Q
S
T
R
Q
Q
Q
TOGGLE
F/F
OUTPUT B
MEMORY
F/F
— ERROR
+ C.S.
— C.S.
SHUTDOWN
4/90 Rev 1.1 2/94
Copyright
©
1994
1
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
SG1526/SG2526/SG3526
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Input Voltage (V
IN
) ............................................................... 40V
Collector Supply Voltage (V
C
) ............................................. 40V
Logic Inputs ......................................................... -0.3V to 5.5V
Analog Inputs .......................................................... -0.3V to V
IN
Source/Sink Load Current (each output) ....................... 200mA
Reference Load Current .................................................. 50mA
Note 1. Exceeding these ratings could cause damage to the device.
Logic Sink Current ............................................................ 15mA
Operating Junction Temperature
Hermetic (J, L Packages) ............................................ 150°C
Plastic (N, DW Packages) ........................................... 150°C
Storage Temperature Range ............................ -65°C to 150°C
Lead Temperature (Soldering, 10 Seconds) ................... 300°C
THERMAL DATA
J Package:
Thermal Resistance-
Junction to Case
,
θ
JC
.................. 25°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
.............. 70°C/W
N Package:
Thermal Resistance-
Junction to Case
,
θ
JC
.................. 30°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
............. 60°C/W
DW Package:
Thermal Resistance-
Junction to Case
,
θ
JC
.................. 35°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
............. 90°C/W
L Package:
Thermal Resistance-
Junction to Case
,
θ
JC
................... 35°C/W
Thermal Resistance-
Junction to Ambient
,
θ
JA
........... 120°C/W
Note A. Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
Note B. The above numbers for
θ
JC
are maximums for the limiting
thermal resistance of the package in a standard mount-
ing configuration. The
θ
JA
numbers are meant to be
guidelines for the thermal performance of the device/pc-
board system. All of the above assume no ambient
airflow.
RECOMMENDED OPERATING CONDITIONS
(Note 2)
Input Voltage ............................................................. 8V to 35V
Collector Supply Voltage ........................................ 4.5V to 35V
Sink/Source Load Current (each output) ................ 0 to 100mA
Reference Load Current ........................................... 0 to 20mA
Oscillator Frequency Range .............................. 1Hz to 350KHz
Oscillator Timing Resistor .................................. 2KΩ to 150KΩ
Note 2. Range over which the device is functional.
Oscillator Timing Capacitor .................................... 1nF to 20µF
Available Deadtime Range at 40KHz ...................... 3% to 50%
Operating Ambient Temperature Range:
SG1526 ......................................................... -55°C to 125°C
SG2526 ........................................................... -25°C to 85°C
SG3526 ............................................................... 0°C to 70°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1526 with -55°C
≤
T
A
≤
125°C, SG2526 with
-25°C
≤
T
A
≤
85°C, SG3526 with 0°C
≤
T
A
≤
70°C, and V
IN
= 15V. Low duty cycle pulse testing techniques are used which maintains junction and case
temperatures equal to the ambient temperature.)
Parameter
Reference Section
(Note 3)
Output Voltage
Line Regulation
Load Regulation
Temperature Stability
(Note 9)
Total Output Voltage Range
(Note 9)
Short Circuit Current
Undervoltage Lockout Section
RESET Output Voltage
RESET Output Voltage
Test Conditions
T
J
= 25°C
V
IN
= 8 to 35V
I
L
= 0 to 20mA
Over Operating T
J
Over Recommended Operating Conditions
V
REF
= 0V
V
REF
= 3.8V
V
REF
= 4.8V
SG1526/2526
SG3526
Units
Min. Typ. Max. Min. Typ. Max.
4.95 5.00 5.05 4.90 5.00 5.10
10
30
10
30
30
10
50
10
15
50
15
50
4.90 5.00 5.10 4.85 5.00 5.15
50 125
50 125
0.2
4.8
0.4
2.4
0.2
4.8
0.4
V
mV
mV
mV
V
mA
V
V
2.4
4/90 Rev 1.1 2/94
Copyright
©
1994
2
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
SG1526/SG2526/SG3526
ELECTRICAL CHARACTERISTICS
Parameter
Oscillator Section
(Note 4)
Initial Accuracy
Voltage Stability
Temperature Stability
(Note 9)
Minimum Frequency
(Note 9)
Maximum Frequency
Sawtooth Peak Voltage
Sawtooth Valley Voltage
Error Amplifier Section
(Note 5)
Input Offset Voltage
Input Bias Current
Input Offset Current
DC Open Loop Gain
High Output Voltage
Low Output Voltage
Common Mode Rejection
Supply Voltage Rejection
PWM Comparator Section
(Note 4)
Minimum Duty Cycle
Maximum Duty Cycle
(continued)
Test Conditions
T
J
= 25°C
V
IN
= 8 to 35V
Over Operating T
J
R
T
= 150KΩ, C
T
= 20µF
R
T
= 2KΩ, C
T
= 1.0nF
V
IN
= 35V
V
IN
= 8V
R
S
≤
2KΩ
R
L
≥
10MΩ, T
J
= 25°C
V
PIN1
- V
PIN2
≥
150mV, I
SOURCE
= 100µA
V
PIN2
- V
PIN1
≥
150mV, I
SINK
= 100µA
R
S
≤
2KΩ
V
IN
= 8V to 35V
V
COMPENSATION
= 0.4V
V
COMPENSATION
= 3.6V
SG1526/2526
SG3526
Units
Min. Typ. Max. Min. Typ. Max.
±3
0.5
7
350
0.5
3.0
1.0
3.5
0.5
±8
1.0
10
1.0
350
3.0
1.0
3.5
±3
0.5
5
±8
1.0
10
1.0
%
%
%
Hz
KHz
V
V
mV
nA
nA
dB
V
V
dB
dB
%
%
V
V
µA
µA
mV
µA
V
µA
V
V
V
V
µA
µs
µs
mA
64
3.6
70
66
2
5
-350 -1000
35 100
72
60
3.6
4.2
0.2 0.4
94
70
80
66
0
10
2
-350 -2000
35 200
72
4.2
0.2 0.4
94
80
0
45
2.4
49
4
0.2 0.4
-125 -300
-225 -500
100
-3
0.1
100
110
-10
0.4
200
45
2.4
49
4
0.2 0.4
-125 -300
-225 -500
100
-3
0.1
100
120
-10
0.4
200
Digital Ports (SYNC, SHUTDOWN, and RESET)
HIGH Output Voltage
I
SOURCE
= 40µA
LOW Output Voltage
I
SINK
= 3.6mA
V
IH
= 2.4V
HIGH Input Current
V
IL
= 0.4V
LOW Input Current
Current Limit Comparator Section
(Note 6)
R
S
≤
50Ω, T
J
= 25°C
Sense Voltage
Input Bias Current
Soft-Start Section
Error Clamp Voltage
RESET = 0.4V
C
S
Charging Current
RESET = 2.4V
Output Drivers (each output)
(Note 7)
HIGH Output Voltage
I
SOURCE
= 20mA
I
SOURCE
= 100mA
LOW Output Voltage
I
SINK
= 20mA
I
SINK
= 100mA
Collector Leakage
V
C
= 40V
Rise Time
C
L
= 1000pF
Fall Time
C
L
= 1000pF
Power Consumption Section
(Note 8)
Standby Current
SHUTDOWN = 0.4V
Note 3.
Note 4.
Note 5.
Note 6.
I
L
= 0mA
F
OSC
= 40KHz (R
T
= 4.12KΩ
±1%,
C
T
= .01µF
±1%,
R
D
= 0Ω)
V
CM
= 0 to 5.2V
V
CM
= 0 to 12V
90
80
50
50
12.5 13.5
12.5 13.5
12
13
12
13
0.2 0.3
0.2 0.3
2
1.2
2
1.2
50 150
50 150
0.3 0.6
0.3 0.6
0.1 0.2
0.1 0.2
18
30
18
30
Note 7. V
C
= 15V
Note 8. V
IN
= 35V
Note 9. These parameters, although guaranteed over the recom-
mended operating conditions, are not tested in production.
4/90 Rev 1.1 2/94
Copyright
©
1994
3
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
SG1526/SG2526/SG3526
CHARACTERISTIC CURVES
FIGURE 1.
REFERENCE VOLTAGE VS. SUPPLY VOLTAGE
FIGURE 2.
REFERENCE TEMPERATURE STABILITY
FIGURE 3.
REFERENCE SHORT CIRCUIT CURRENT
FIGURE 4.
REFERENCE RIPPLE REJECTION
FIGURE 5.
OSCILLATOR FREQUENCY TEMPERATURE
STABILITY
FIGURE 6.
OUTPUT DRIVER DEADTIME VS. R
D
VALUE
FIGURE 7.
OSCILLATOR PERIOD VS. R
T
AND C
T
4/90 Rev 1.1 2/94
Copyright
©
1994
4
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
SG1526/SG2526/SG3526
CHARACTERISTIC CURVES
(continued)
FIGURE 8.
UNDERVOLTAGE LOCKOUT CHARACTERISTIC
FIGURE 9.
ERROR AMPLIFIER OPEN LOOP GAIN
VS. FREQUENCY
FIGURE 10.
SOFTSTART TIME CONSTANT VS. C
S
FIGURE 11.
CURRENT LIMIT TRANSFER FUNCTION
FIGURE 12.
COMPARATOR INPUT TO DRIVER OUTPUT DELAY
FIGURE 13.
SHUTDOWN INPUT TO DRIVER OUTPUT DELAY
FIGURE 14.
OUTPUT DRIVER SATURATION VOLTAGE VS. I
SINK
FIGURE 15.
OUTPUT SUPPLY SATURATION VOLTAGE VS. I
SINK
FIGURE 16.
STANDBY CURRENT VS. SUPPLY VOLTAGE
4/90 Rev 1.1 2/94
Copyright
©
1994
5
11861 Western Avenue
∞
Garden Grove, CA 92841
(714) 898-8121
∞
FAX: (714) 893-2570
L
INFINITY
Microelectronics Inc.
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