A new step-down µModule regulator has been released by Linear Technology that offers 36V input, 5A and an adjustable and precise (+/-10 percent) accurate current limit. The current limit enables designers to set the maximum amount of power drawn from the supply, preventing input voltage droop caused by overcurrent conditions. When multiple LTM8026 are configured with the outputs tied together, each converter can be programmed with a unique maximum current limit to meet its specific input supply limitations for greater output power, a technique known as asymmetric power sharing. In contrast, common regulators must current share, a feature where each input supply contributes equally to the load, which is restricted by the least powerful input rail. Applications for the LTM8026 include point of load regulation in systems with 24V and 12V supplies such as VXI bus, for automotive, medical and industrial end-markets.
The device includes a DC/DC controller, power switches, power inductor, compensation and a modest amount of input and output capacitance in a surface mount package. The current limit is adjustable by applying a voltage or resistor divider and can be automatically decreased with rising junction or ambient temperature using a thermistor to prevent the LTM8026 or load from overheating.
The regulator operates from an input voltage between 6V to 36V and regulates an output voltage between 1.2V to 24V set by a single resistor. In a 12V to 3.3V output application, it achieves an operating efficiency of 89 percent at 2A. For noise-sensitive applications, the regulator can be synchronised to an external clock frequency in the range of 100kHz to 1MHz. Additional features include externally adjustable soft start, adjustable switching frequency and thermal shutdown.