IR2085S

Product Summary

The IR2085S is a self oscillating half-bridge driver IC with 50% duty cycle ideallysuited for 36V-75V half-bridge DC-bus converters. This product is also suitable forpush-pull converters without restriction on input voltage.Each channel frequency is equal to fosc, where fosc can be set by selecting RT & CT,where fosc ~ 1/(2*RT.CT). Dead-time can be controlled through proper selection of CTand can range from 50 to 200nsec. Internal soft-start increases the pulse width duringpower up and maintains pulse width matching for the high and low outputs throughout the start up cycle. The IR2085S initiates a soft start at power up and after every overcurrent condition. Undervoltage lockout preventsoperation if VCC is less than 7.5Vdc.

Parametrics

The absolute maximum ratings of IR2085S are (1)High side floating supply voltage:150V; (2)Low side supply voltage:25V; (3)High side floating supply offset voltage:Vb + 0.3V; (4)High side floating output voltage:Vb + 0.3V; (5)Low side output voltage:VCC + 0.3V; (6)OSC pin voltage:VCC + 0.3V; (7)Cs pin voltage:VCC + 0.3; (8)Allowable offset voltage slew rate:+50V/ns; (9)Supply current:20mA; (10)Package power dissipation:1.0W; (11)Thermal resistance, junction to ambient:200°C/W; (12)Junction temperature:150°C; (13)Storage temperature:150°C; (14)Lead temperature (soldering, 10 seconds):300°C

Features

The features of IR2085S can be summarized as (1)Simple primary side control solution to enable half-bridge DC-Bus Converters for 48V distributed systems with reducedcomponent count and board space.; (2)Integrated 50% duty cycle oscillator & half-bridge driver IC in asingle SO-8 package; (3)Programmable switching frequency with up to 500kHz max perchannel;(4) +/- 1A drive current capability optimized for low charge MOSFETs;(5) Adjustable dead-time 50nsec–200nsec; (6)Floating channel designed for bootstrap operation up to +100Vdc; (7)High and low side pulse width matching to +/-25nsec; (8)Adjustable overcurrent protection; (9)Undervoltage lockout and internal soft start;(10)Also available LEAD-FREE

Diagrams

<P><IMG alt="IR2085S Block Diagram" src="http://www.seekic.com/uploadfile/ic-mfg/201282201130856.jpg" border=0></P>