The MP118 is a low quiescent, high power dissipation operational amplifier that integrates several new layers of onboard circuit protection including over current shut down. Designed as an open frame product form factor with a footprint measuring just 26cm2 (4in2), the MP118FD exhibits just 25mA of quiescent current and is capable of 100W of internal power dissipation. In addition to temperature shut down and external shut down, the device provides a new twist that replaces over current limit functionality with the ability to completely shut down the device’s output drivers when put into an over current situation. This will protect the power amplifier from over stress due to excessive current and unsafe power dissipation. Onboard temperature monitoring circuitry, also new, enables the MP118 to shut down the system before any permanent damage can occur. In terms of electrical performance, the MP118 does not disappoint. The product is compatible with supplies up to 200V, is capable of 10A of continuous output current, or 12A PEAK, and has a power bandwidth of 140kHz.
MP118 Over Current Shut Down Protection
Two current sense lines are to be connected directly across the current sense resistor. For the over-current protection to work correctly, pin 28 must be connected to the amplifier output side and pin 27 connected to the load side of the current sense resistor RLIM as shown in Figure 6. This connection will bypass any parasitic resistances RP, formed by socket and solder joints as well as internal amplifier losses. The current sense resistor may not be placed anywhere in the output circuit except where shown in the figure. The value of the current sense resistor can be calculated as follows: RLIM = 0.65V/ISD