According to Texas Instruments, the LM27403 is the first analog dc-dc step-down controller with temperature-compensated inductor current sensing. Such resistance sensing improves current-limit accuracy to 10% over temperature by using a low-cost bipolar junction transistor (BJT) to measure real-time temperature shifts, allowing the device to maintain a consistent current-limit threshold across the operating temperature range. The 20-V dc-dc synchronous buck controller delivers over 85% efficiency from a 12-V input at 25 A of output current. A 3- to 20-V input voltage range converts 3.3-, 5-, and 12-V input voltage rails to point-of-load (POL) as low as 0.6 V. A 30-ns minimum on-time allows for higher switching frequencies at lower duty cycles. In addition, a 15-ns adaptive dead-time control helps boost efficiency in high-frequency operation. When used with the company WEBENCH online design tool, the device simplifies dc-dc conversion and helps speed design. Applications include communications infrastructure, industrial, medical, and power-module designs.
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