ZHCS814H March 2012 – July 2021 TPS709
PRODUCTION DATA
The TPS709 use a PMOS pass transistor to achieve low dropout voltage. When (VIN – VOUT) is less than the dropout voltage (VDO), the PMOS pass device is in the linear region of operation and the input-to-output resistance is the RDS(ON) of the PMOS pass element. VDO approximately scales with the output current because the PMOS device functions like a resistor in dropout.
The ground pin current of many linear voltage regulators increases substantially when the device is operated in dropout. This increase in ground pin current while operating in dropout can be several orders of magnitude larger than when the device is not in dropout. The TPS709 employs a special control loop that limits the increase in ground pin current while operating in dropout. This functionality allows for the most efficient operation while in dropout conditions that can greatly increase battery run times.