ST SG3524 User Manual
®
REGULA TING P ULSE WIDTH MODULA TO RS
COMPLETE PWM POWER CONTROL CIRCUITRY
UNCOMMITTED OUTPUTS FOR SINGLEENDED OR PUSH PULL APPLICATIONS
LOW STANDBY CURRENT 8mA TYPICAL
OPERATION UP TO 300KHz
1% MAXIMUM TEMPERATURE VARIATION
OF REFERENCE VOLTAGE
SG3524
DESCRIPTION
The SG3524 incorporates on a single monolithic
chip all the function required for the construction
of regulating power suppies inverters or switching
regulators. They can also be used as the control
element for high power-output applications. The
SG3524 family was designed for switching regulators of either polarity, transformer-coupled dcto-dc converters, transformerless voltage doublers and polarity converter applications
employing fixed-frequency, pulse-width modulation techniques. The dual alternating outputs allows either single-ended or push-pull applications.
BLOCK DIAGRAM
DIP16 SO16
ORDERING NUMBERS:
SG3524P (SO16)
Each device includes an on-ship reference, error
amplifier, programmable oscillator, pulse-steering
flip flop, two uncommitted output transistors, a
high-gain comparator, and current-limiting and
shut-down circuitry.
SG3524N (DIP16)
July 2000
This is advanced information on a new product now in development or undergoing evaluation. Details are subject to change without notice.
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SG3524
ABSOLUTE MAXIMUM RATINGS
Symbol Parameter Value Unit
V
IN
I
C
I
R
I
T
P
tot
T
stg
T
op
Supply Voltage 40 V
Collector Output Current 100 mA
Reference Output Current 50 mA
Current Through CT Terminal – 5 mA
Total Power Dissipation at T
= 70°C1000mW
amb
Storage Temperature Range – 65 to 150 °C
Operating Ambient Temperature Range: 0 to 70 °C
PIN CONNECTION
(Top view)
THERMAL DATA
Symbol Parameter DIP16 SO16 Unit
R
th j-amb
R
th j-alumina
(*) Thermal resistance junction-alumina with the device soldered on the middle of an alumina supporting substrate measuring 15 x 20mm;
0.65mm thickness with infinite heatsink.
Thermal Resistance Junction-ambient Max.
Thermal Resistance Junction-alumina (*) Max.
80
–
50
–
°C/W
°C/W
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SG3524
ELECTRICAL CHARACTERISTICS
70°C, V
= 20V, and f = 20KHz).
IN
(unless otherwise stated, these specifications apply for Tj = 0 to
Symbol Parameter Test Condition Min. Typ. Max. Unit
REFERENCE SECTION
REF
REF
REF
Output Voltage 4.6 5 5.4 V
Line Regulation VIN = 8 to 40V 10 30 mV
Load Regulation IL = 0 to 20mA 20 50 mV
V
∆V
∆V
Ripple Rejection f = 120Hz, Tj = 25°C66dB
Short Circuit Current Limit V
∆V
/∆T Temperature Stability Over Operating Temperature range 0.3 1 %
REF
∆V
Long Term Stability Tj = 125°C, t = 1000Hrs 20 mV
REF
= 0, Tj = 25°C 100 mA
REF
OSCILLATOR SECTION
f
MAX
Maximum Frequency CT = 0.001µF, RT = 2KΩ 300 KHz
Initial Accuracy R
Voltage Stability V
and CT Constant 5 %
T
= 8 to 40V, Tj = 25°C1%
IN
∆f/∆T Temperature Stability Over Operating Temperature Range 2 %
Output Amplitude Pin 3, T
= 25°C 3.5 V
j
Output Pulse Width CT = 0.01µF, Tj = 25°C0.5µs
ERROR AMPLIFIER SECTION
V
G
CMV Common Mode Voltage T
Input Offset Voltage VCM = 2.5V 2 10 mV
OS
Input Bias Current 2 10 µA
I
b
Open Loop Voltage Gain 60 80 dB
V
= 25°C1.83.4V
j
CMR Common Mode Rejection Tj = 25°C70dB
B Small Signal Bandwidth A
V
Output Voltage Tj = 25°C0.53.8V
O
= 0dB, Tj = 25°C 3 MHz
V
COMPARATOR SECTION
Duty-cycle % Each Output On 0 45 %
V
Input Threshold Zero Duty-cycle 1 V
IT
Maximum Duty-cycle 3.5 V
Input Bias Current 1 µA
I
b
CURRENT LIMITING SECTION
Sense Voltage Pin 9 = 2V with Error Amp. Set for
180 200 220 mV
Max. Out.
Tj = 25°C
Sense Voltage T.C. 0.2 mV/°C
CMV Common Mode Voltage –1 1
OUTPUT SECTION
(each output)
Collector-emitter Voltage 40 V
Collector Leackage Curr. V
Saturation Voltage I
= 40V 0.1 50 µA
CE
= 50mA 1 2 V
C
Emitter Output Voltage VIN = 20V 17 18 V
Rise Time RC = 2KΩ, Tj = 25°C0.2µs
t
r
Fall Time RC = 2KΩ, Tj = 25°C0.1µs
t
f
I
(*) Total Standby Current VIN = 40V 8 10 mA
q
(*) Excluding oscillator charging current, error and current limit dividers, and with outputs open.
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