SG2845M Microchip

SG1844/SG1845 /SG3844/SG3845 Current Mode PWM Controller Features Description Optimized for Off-Line Control The SG1844/45 family of control ICs provides all the Low Start-Up Current (<1mA) required features to implement off-line Fixed Frequency, Current-mode switching power supplies Automatic Feed Forward Compensation with a minimum number of external components. Trimmed Oscillator Current-mode architecture demonstrates improved line Discharge Current regulation, improved load regulation, pulse-by pulse Pulse-By-Pulse Current Limiting current limiting and inherent protection of the power Enhanced Load Response Characteristics supply output swi tch. Undervoltage Lockout with 6V Hysteresis The Bandgap reference is trimmed to 1% over (SG1844 only) temperature. Oscillator discharge current is trimmed to Double Pulse Suppression less than 10%. The SG1844/45 has under-voltage High-Current Totem-Pole Output lockout, current-limiting circuitry and start-up current of Internally Trimmed Bandgap Reference less than 1mA. The totem-pole output is optimized to 500kHz Operation drive the gate of a power MOSFET. The output is low in the off state to provide direct interface to an N- Under-voltage Lockout channel device. Both operate up to a maximum duty SG1844 - 16 Volts cycle range of zero to <50% due to an internal toggle SG1845 - 8.4 Volts flip-flop which blanks the output off every other clock Low Shoot-through Current <75mA Over cycle. The SG1844/45 is specified for operation over Temperature the full military ambient temperature range of -55C to 125C. The SG3844/45 is designed for the commercial Application range of 0C to 70C. Available to MIL-STD-883 Available to DSCC Standard Microcircuit Drawing (SMD) SGR1844/45 Rad-Tolerant Version Available Product Highlight R ST I AC ST INPUT V cc SG3844 Figure 1 Product Highlight November 2014 Rev. 1.7 www.microsemi.com 1 2014 Microsemi Corporation- Analog Mixed Signal Group Current Mode PWM Controller Connection Diagrams and Ordering Information Ambient Type Packaging Package Part Number Connection Diagram Temperature Type COM V REF V V FB CC SG3844M OUTPUT I SENSE 8-PIN PLASTIC GND R /C M T T DUAL INLINE 0C to 70C PDIP PACKAGE M PACKAGE (Top View) SG3845M M Package: RoHS / Pb-free 100% Matte Tin Lead Finish SG1844Y V COM REF V SG1845Y V FB CC OUTPUT I SENSE 8-PIN SG1844Y-883B GND -55C to CERAMIC R /C T T Y CERDIP 125C DUAL INLINE SG1845Y-883B Y PACKAGE PACKAGE (Top View) SG1844Y-DESC PbSn Tin Lead Finish SG1845Y-DESC COM V REF V FB V SG3844DM CC 8-PIN SMALL I SENSE OUTPUT OUTLINE 0C to 70C DM SOIC R /C GND T T INTEGRATED CIRCUIT DM PACKAGE SG3845DM (Top View) RoHS / Pb-free 100% Matte Tin Lead Finish COM V REF N.C. N.C. SG3844D V V CC FB V 14-PIN SMALL C N.C. OUT UT OUTLINE I SENSE 0C to 70C D SOIC GND N.C. INTEGRATED WR GND R /C T T CIRCUIT SG3845D D PACKAGE (Top View) RoHS / Pb-free 100% Matte Tin Lead Finish 2