TPS65321-Q1 Step-Down Converter

Texas Instruments' TPS65321-Q1 device is a combination of a high-V_IN DC-DC step-down converter, referred to as the buck regulator, with an adjustable switch-mode frequency from 100 kHz to 2.5 MHz, and a high-V_IN 280 mA low-dropout (LDO) regulator. The input range is 3.6 V to 36 V for the buck regulator, and 3 V to 36 V for the LDO regulator. The buck regulator has an integrated high-side MOSFET and an active-low, open-drain power-good output-pin (nRST). The LDO regulator also has an integrated MOSFET and features a low-input supply current of 35 μA typical in no-load condition. The low-voltage tracking feature enables the TPS65321-Q1 device to track the input supply during cold-crank conditions.

The buck regulator provides a flexible design to fit system needs. The external loop compensation circuit allows for optimization of the converter response for the appropriate operating conditions. A low-ripple pulse-skip mode reduces the no-load input-supply current to maximum 140 μA.

The device has built-in protection features such as soft start, current-limit, thermal sensing, and shutdown because of excessive power dissipation. Furthermore, the device has an internal undervoltage-lockout (UVLO) function that turns off the device when the supply voltage is too low.