Power Opamp with Programmable Output Current

The LT1970 from Linear Technology (www.linear-tech.com/pdf/1970f.pdf) is a power opamp with adjustable current limit, available in a 20 pin TSSOP package. As well as the usual opamp connections the component sports a range of extra pins for the current limiting feature. The first thing that catches the eye is the current sense resistor RCS, set at 1 ?. DC voltages VCSRC and VCSNK set the current limit value, for the two polarities separately: the maximum allowable current flowing from the positive supply through the output OUT and RCS into the load is set via VCSRC.