Buck regulator for 2V-to-6V input rails
The TPS62273DRVT is a step-down buck converter from Texas Instruments, operating from a 2V minimum input up to 6V maximum. It delivers a programmable output at 400 mA continuous current, with a 2.25 MHz switching frequency that allows small external inductors and capacitors. Output is programmable via external resistors, with fixed options at 2.5V and 3.3V.
Output current and switching frequency trade-offs
At 400 mA output, the 2.25 MHz switching frequency keeps the inductor value in the 1 µH to 4.7 µH range, saving board area compared to lower-frequency parts. The trade-off is higher switching losses at light loads — expect efficiency to drop below 10 mA output. The programmable output covers 2.5V and 3.3V fixed options, but the part does not support a 1.2V output directly — the minimum fixed voltage is 2.5V. For sub-2V rails, an adjustable version or a different regulator is needed.
Input and output capacitors should be placed within 2 mm of the respective pins to minimize loop inductance at 2.25 MHz. The inductor should be a shielded type rated for at least 500 mA saturation current.