OPA541SM

The OPA541 high-power monolithic operational amplifier is capable of delivering continuous output currents up to 5A.

The OPA541 operational amplifier is available in two types of packages: an 11-pin power plastic package and an industry-standard 8-pin TO-3 hermetic package. The power plastic package features a copper-lead frame to maximize heat transfer, while the TO-3 package is isolated from all circuitry, allowing it to be mounted directly to a heat sink without special insulators. The key features of the OPA541 operational amplifier include power supplies up to ±40V, output current up to 10A peak, programmable current limit up to 5A, an industry-standard pinout, FET input, and low-cost power plastic packages. The OPA541 uses a single current-limit resistor to set both the positive and negative current limits, making it convenient for applications such as motor drivers, servo amplifiers, synchro excitation, audio amplifiers, and programmable power supplies.

The internal current limit of the OPA541 device can be programmed by using a single external resistor, RCL. The current limit is activated when the voltage across this resistor is approximately a base-emitter turn-on voltage. The value of the current limit resistor is calculated by Equation 1. The actual current limit depends on whether the current is positive or negative, with the RCL providing an average value. For a given RCL, the output current will be limited at approximately 10% below the expected level for positive current and approximately 10% above the expected level for negative current. The current limit value varies with temperature, decreasing with increasing temperature and increasing at low temperatures due to the temperature coefficient of a base-emitter junction voltage. The current limit resistor sets both the positive and negative current limits of the amplifier, ensuring protection for the amplifier and load from fault conditions.