The TPS2105 is a dual-input, single-output power switch designed to provide uninterrupted output voltage when transitioning between two independent power supplies. Both devices combine one N-channel (250 mΩ) and one P-channel (1.3-Ω) MOSFET with a single output. The P-channel MOSFET (IN2) is used with auxiliary power supplies that deliver lower current for standby modes. The N-channel MOSFET (IN1) is used with a main power supply that delivers higher current required for normal operation. Low on-resistance makes the N-channel the ideal path for higher main supply current when power-supply regulation and system voltage drops are critical. When using the P-channel MOSFET, quiescent current is reduced to 0.75 µA to decrease the demand on the standby power supply. The MOSFETs in the TPS2105 do not have the parasitic diodes, typically found in discrete MOSFETs, thereby preventing back-flow current when the switch is off.