SLVSDG6B May 2016 – April 2021 TPS54302
The TPS54302 device is a 28-V, 3-A, synchronous step-down (buck) converter with two integrated n-channel MOSFETs. To improve performance during line and load transients the device implements a constant-frequency, peak current-mode control which reduces output capacitance. The optimized internal compensation network minimizes the external component counts and simplifies the control loop design.
The switching frequency of the device is fixed to 400 kHz.
The TPS54302 device starts switching when VIN is 4.5 V. The operating current is 45 μA (typical) when not switching and under no load. When the device is disabled, the supply current is 2 µA (typical).
The integrated 85-mΩ high-side MOSFET and 40-mΩ low-side MOSFET allow for high-efficiency power-supply designs with continuous output currents up to 3 A.
The TPS54302 device reduces the external component count by integrating the boot recharge diode. The bias voltage for the integrated high-side MOSFET is supplied by an external capacitor on the BOOT to PH pins. The boot capacitor voltage is monitored by an UVLO circuit and turns off the high-side MOSFET when the voltage falls below a preset threshold of 2.1 V (typical).
The device minimizes excessive output overvoltage transients by taking advantage of the overvoltage comparator. When the regulated output voltage is greater than 108% of the nominal voltage, the overvoltage comparator is activated, and the high-side MOSFET is turned off and masked from turning on until the output voltage is lower than 104%.
The TPS54302 device has internal 5-ms soft-start time to minimize inrush currents.