SG1526B/SG2526B/SG3526B
REGULATING PULSE WIDTH MODULATOR
DESCRIPTION
The SG1526B is a high-performance pulse width modulator
for switching power supplies which offers improved
functional and electrical characteristics over the industry-
standard SG1526. A direct pin-for-pin replacement for the
earlier device with all its features, it incorporates the
following enhancements: a bandgap reference circuit for
improved regulation and drift characteristics, improved
undervoltage lockout, lower temperature coefficients on
oscillator frequency and current-sense threshold, tighter
tolerance on softstart time, much faster SHUTDOWN
response, improved double-pulse supperession logic for
higher speed operation, and an improved output driver
design with low shoot-through current, and faster rise and
fall times. This versatile device can be used to implement
single-ended or push-pull switching regulators of either
polarity, both transformerless and transformer-coupled. The
SG1526B is specified for operation over the full military
ambient temperature range of -55°C to 150°C. The
SG2526B is characterized for the industrial range of -25°C
to 150°C, and the SG3526B is designed for the commercial
range of 0°C to 125°C.
FEATURES
8V to 35V Operation
5V Low drift 1% Bandgap Reference
1Hz to 500kHz Oscillator Range
Dual 100mA Source/Sink
Digital Current Limiting
Double Pulse Suppression
Programmable Deadtime
Improved 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
Shoot-through Currents Less than 100mA
Improved Shutdown Delay
Improved Rise and Fall Time
HIGH RELIABILITY FEATURES
Available To MIL-STD-883, ¶ 1.2.1
Available to DSCC - Standard Microcircuit
Drawing (SMD)
MIL-M38510/12603BVA - SG1526BJ-JAN
Radiation data available
MSC-AMS Level "S" Processing Available
BLOCK DIAGRAM
V
REF
+V
IN
GROUND
R
D
R
T
Reference
Regulator
Undervoltage
Lockout
+V
C
To Internal
Circuitry
Oscillator
SYNC
OUTPUT A
C
T
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
December
2014 Rev1.2
www.microsemi.com
© 2014 Microsemi Corporation
1
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
RoHS Peak Package Solder Reflow Temp. (40 sec. max. exp.)...... 260°C (+0, -5)
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 500kHz
Oscillator Timing Resistor .................................. 2kΩ to 150kΩ
Note 2. Range over which the device is functional.
Oscillator Timing Capacitor ............................... 470pF to 20µF
Available Deadtime Range at 40kHz ...................... 5% to 50%
Operating Junction Temperature Range:
SG1526B ....................................................... -55°C to 125°C
SG2526B ......................................................... -25°C to 85°C
SG3526B ............................................................ 0°C to 70°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1526B with -55°C
≤
T
A
≤
125°C, SG2526B with
-25°C
≤
T
A
≤
85°C, SG3526B 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
V
REF
= 0V
V
REF
= 3.8V
V
REF
= 4.8V
SG1526B/2526B
SG3526B
Units
Min. Typ. Max. Min. Typ. Max.
4.95 5.00 5.05 4.90 5.00 5.10
20
10
10
7
10
20
10
25
15
50
50
15
4.90 5.00 5.10 4.85 5.00 5.15
25
50 125 25
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
2
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
SYNC Pulse Width
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
= 470pF
V
IN
= 35V
V
IN
= 8V
R
L
= 2.0kΩ to V
REF
R
S
≤
2kΩ
R
L
≥
10MΩ
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
SG3526B
SG1526B/2526B
Units
Min. Typ. Max. Min. Typ. Max.
±3
0.5
7
500
2.5
0.5
±8
1.0
10
1.0
3.5
1.1
2
500
2.5
0.5
±3
0.5
3
±8
1.0
5
1.0
3.5
1.1
2
%
%
%
Hz
kHz
V
V
µs
mV
nA
nA
dB
V
V
dB
dB
%
%
V
V
µA
µA
ns
mV
µA
ns
V
µA
V
V
V
V
µA
µs
µs
mA
3.0
1.0
1.0
3.0
1.0
1.0
64
3.6
70
66
5
2
-350 -1000
35 100
72
60
3.6
4.2
0.4
0.2
70
94
66
80
0
2
10
-350 -2000
35 200
72
4.2
0.2 0.4
94
80
0
45
2.4
49
4
0.2 0.4
-125 -200
-225 -360
200
100
-3
110
-10
400
0.4.
150
45
2.4
49
4
0.2 0.4
-125 -200
-225 -360
200
100
-3
120
-10
400
0.4.
150
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
(Note9)
SHUTDOWN Delay to Output
Current Limit Comparator Section
(Note 6)
Sense Voltage
R
S
≤
50Ω
Input Bias Current
Delay to Output
(Note 9)
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
0.1
100
50
0.1
100
12.5 13.5
12.5 13.5
12
13
12
13
0.2 0.3
0.2 0.3
2
1.2
1.2
2
50 150
50 150
0.3 0.4
0.3 0.4
0.1 0.15
0.1 0.15
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.
3
CHARACTERISTIC CURVES
FIGURE 1.
REFERENCE VOLTAGE VS. SUPPLY VOLTAGE
FIGURE 2.
REFERENCE TEMPERATURE STABILITY
FIGURE 3.
REFERENCE SHORT CIRCUIT
1k
10k
100k
1k
10k
100k
FIGURE 4.
REFERENCE RIPPLE REJECTION
FIGURE 5.
UNDER VOLTAGE LOCKOUT
FIGURE 6.
ERROR AMPLIFIER OPEN LOOP GAIN
VS. FREQUENCY
FIGURE 7.
SOFTSTART TIME CONSTANT VS. C
S
FIGURE 8.
CURRENT LIMIT TRANSFER FUNCTION
FIGURE 9.
COMPARATOR INPUT TO DRIVER OUTPUT DELAY
4
CHARACTERISTIC CURVES
(continued)
R
t
= 2.7k
R
D
=
0Ω
F
OSC
=
40kHz
C
T
=
0.01µF
FIGURE 10.
STANDBY CURRENT VS. SUPPLY VOLTAGE
FIGURE 11.
OUTPUT DRIVER DEADTIME VS. C
T
VALUE
FIGURE 12.
OUTPUT DRIVER DEADTIME VS. R
D
VALUE
R
t
= 2.2k - 155k
R
t
= 2.2k - 155k
R
t
= 2.2k - 155k
(kHz)
FIGURE 13.
SUPPLY CURRENT VS. OUTPUT FREQUENCY
(kHz)
FIGURE 14.
SUPPLY CURRENT VS. OUTPUT FREQUENCY
kHz
FIGURE 15.
SUPPLY CURRENT VS. OUTPUT FREQUENCY
F
OSC
=
40kHz
R
t
=
4.12k
FIGURE 16.
OSCILLATOR FREQUENCY
TEMPERATURE STABILITY
FIGURE 17.
OUTPUT DRIVER SATURATION VOLTAGE
FIGURE 18.
SHUTDOWN INPUT TO DRIVER OUTPUT DELAY
5
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