500mA Power Op Amp with Adjustable Precision Current Limit

The LT1970A is a ±500mA power op amp with precise externally controlled current limiting. Separate control voltages program the sourcing and sinking current limit sense thresholds with 1% accuracy. Output current may be boosted by adding external power transistors.

The circuit operates with single or split power supplies from 5V to 36V total supply voltage. In normal operation, the input stage supplies and the output stage supplies are connected (VCC to V+ and VEE to V–). To reduce power dissipation it is possible to power the output stage (V+, V–) from independent, lower voltage rails. The amplifier is unity-gain stable with a 3.6MHz gain-bandwidth product and slews at 1.6V/μs. The LT1970A can drive capacitive and inductive loads directly.

Open-collector status flags signal current limit circuit activation, as well as thermal shutdown of the amplifier. An enable logic input puts the amplifier into a low power, high impedance output state when pulled low. Thermal shutdown and a ±800mA fixed current limit protect the chip under fault conditions.

The LT1970A is packaged in a 20-lead TSSOP package with a thermally conductive copper bottom plate to facilitate heat sinking.

Applications

* Automatic Test Equipment

* Laboratory Power Supplies

* Motor Drivers

* Thermoelectric Cooler Driver

* ±500mA Minimum Output Current

* Independent Adjustment of Source and Sink Current Limits

* 1% Current Limit Accuracy

* Improved Reactive Load Driving Stability

* Operates with Single or Split Supplies

* Shutdown/Enable Control Input

* Open-Collector Status Flags:

* Sink Current Limit

* Source Current Limit

* Thermal Shutdown

* Fail-Safe Current Limit and Thermal Shutdown

* 1.6V/μs Slew Rate

* 3.6MHz Gain-Bandwidth Product

* Specified Temperature Range: –40°C to 85°C

* Available in a 20-Lead TSSOP Package