SG1842/SG1843
Current Mode PWM Controller
Features
Description
The SG1842/43 family of control IC's provides all the
necessary features to implement off-line fixed
frequency, current-mode switching power supplies
with a minimum number of external components.
Current-mode architecture demonstrates improved
line regulation, improved load regulation, pulse-bypulse current limiting and inherent protection of the
power supply output switch. The bandgap reference
is trimmed to ±1% over temperature.
Oscillator discharge current is trimmed to less than
±10%. The SG1842/43 has under-voltage lockout,
current limiting circuitry and start-up current of less
than 1mA. The totem-pole output is optimized to drive
the gate of a power MOSFET. The output is low in
the off state to provide direct interface to an
N-channel device. The SG1842/43 is specified for
operation over the full military ambient temperature
range of -55°C to 125°C. The SG2842/43 is specified
for the industrial range of -25°C to 85°C, and the
SG3842/43 is designed for the commercial range of
0°C to 70°C.
Product Highlight
Optimized For Off-Line Control
Low Start-Up Current (<1mA)
Automatic Feed Forward Compensation
Trimmed Oscillator Discharge Current
Pulse-By-Pulse Current Limiting
Enhanced Load Response Characteristics
Under-Voltage Lockout with 6V Hysteresis (SG1842
only)
Double-Pulse Suppression
High-Current Totem-Pole Output (1A Peak)
Internally Trimmed Bandgap Reference
500kHz Operation
Undervoltage Lockout
SG1842 - 16 volts
SG1843 - 8.4 volts
Low Shoot-Through Current <75mA Over
Temperature
Application
Available To MIL-STD – 883, ¶ 1.2.1
Available to DSCC
- Standard Microcircuit Drawing (SMD)
RST
IST
AC
INPUT
Vcc
SG3842/43
Figure 1 · Product Highlight
October 2014 Rev. 1.7
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