SG3845 Series

Current Mode PWMs Isolated Switching Reg Low Start-Up Current (<1mA) 0°C to70°C

Catalog

Current Mode PWMs Isolated Switching Reg Low Start-Up Current (<1mA) 0°C to70°C

Part	Frequency - Switching [Min]	Frequency - Switching [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Voltage - Supply (Vcc/Vdd) [Max]	Number of Outputs	Operating Temperature [Max]	Topology	Output Type	Function	Qualification	Duty Cycle (Max) [Max]	Supplier Device Package	Grade	Package / Case	Package / Case [y]	Package / Case [x]	Output Configuration	Mounting Type	Output Phases	Package / Case	Package / Case
Microchip Technology SG3845D-TR	100 Hz	500 kHz	7.6 V	30 V	1	70 °C	Flyback	Transistor Driver	Step-Up/Step-Down	MIL-STD-883	48 %	8-SOIC	Military	8-SOIC	3.9 mm	0.154 in	Isolation Capable Positive	Surface Mount	1
Microchip Technology SG3845D	100 Hz	500 kHz	7.6 V	30 V	1	70 °C	Flyback	Transistor Driver	Step-Up/Step-Down	MIL-STD-883	48 %	8-SOIC	Military	8-SOIC	3.9 mm	0.154 in	Isolation Capable Positive	Surface Mount	1
Microchip Technology SG3845M	1 Hz	500 kHz	7.6 V	30 V	1	70 °C	Flyback	Transistor Driver	Step-Up/Step-Down		48 %	8-DIP		8-DIP			Isolation Capable Positive	Through Hole	1	0.3 in	7.62 mm
Microchip Technology SG3845DM-TR	100 Hz	500 kHz	7.6 V	30 V	1	70 °C	Flyback	Transistor Driver	Step-Up/Step-Down	MIL-STD-883	48 %	8-SOIC	Military	8-SOIC	3.9 mm	0.154 in	Isolation Capable Positive	Surface Mount	1

Catalog

Current Mode PWMs Isolated Switching Reg Low Start-Up Current (<1mA) 0°C to70°C

Key Features

• + 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 -Undervoltage Lockout with 6V Hysteresis

• + Double-Pulse Suppression

• + High-Current Totem-Pole Output (1A Peak)

• + Internally Trimmed Band-gap Reference

• + 500kHz Operation SG1845 - 8.4 Volts

• + Low Shoot-Through Current <75mA Over Temperature

Description

The SG1844/45 family of control ICs provides all the required 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-by pulse 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 SG1844/45 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 Nchannel device. Both operate up to a maximum duty cycle range of zero to <50% due to an internal toggle flip-flop which blanks the output off every other clock cycle. The SG1844/45 is specified for operation over the full military ambient temperature range of -55°C to 125°C. The SG3844/45 is designed for the commercial range of 0°C to 70°C.