Electronic Design

Power Op Amp Features Voltage-Programmable Output Current

A new class of precision amplifier, the LT1970, features a voltage-programmable output current limit with guaranteed 2% accuracy. While more rigid designs require a resistor to set the output current limit, this amplifier simplifies the task of supplying a precisely controlled amount of voltage and/or current to a load. With the LT1970, source and sink current limits are easily set and adjusted using a 0- to 5-V dc control signal.

The LT1970 guarantees an output current up to 500 mA. Also, the IC can directly drive external power transistors to boost the output current to any level. The precision amplifier provides three diagnostic flags. The open collector status flags can directly drive LEDs to signal that one amplifier has entered current limit (sourcing or sinking) as well as current shutdown. The op amp offers a 600-µV maximum input offset voltage and a 3.6-MHz gain-bandwidth with a 1.6-V/µs slew rate.

Additional features include a wide total supply range of 5 to 36 V, a shutdown/enable control input, a built-in self-current limit of 800 mA if the source resistor is lost, and thermal shutdown protection. The LT1970 is housed in a 20-pin thermally enhanced TSSOP package to handle power dissipation and operates over the ×40°C to 85°C industrial temperature range.

Pricing for the LT1970 starts at $4.95 in 1000-unit quantities.

Linear Technology Corp.
www.linear.com; (800) 800-4LINEAR

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