The TPS721xx family of LDO regulators is available in fixed voltage options that are commonly used to power the latest DSPs and microcontrollers with an adjustable option ranging from 1.22 V to 2.5 V. These regulators can be used in a wide variety of applications ranging from portable, battery-powered equipment to PC peripherals. The family features operation over a wide range of input voltages (1.8 V to 5.5 V) and low dropout voltage (150 mV at full load). Therefore, compared to many other regulators that require 2.5-V or higher input voltages for operation, these regulators can be operated directly from two AAA batteries. Also, the typical quiescent current (ground pin current) is low, starting at 85 µA during normal operation and 1 µA in shutdown mode. These regulators can be operated very efficiently and, in a battery-powered application, help extend the longevity of the device.
Similar LDO regulators require 1-µF or larger output capacitors for stability. However, this regulator uses an internal compensation scheme that stabilizes the feedback loop over the full range of input voltages and load currents with output capacitances as low as 0.1-µF. Ceramic capacitors of this size are relatively inexpensive and available in small footprints.
This family of regulators is particularly suited as a portable power supply solution due to its minimal board space requirement and 1.8-V minimum input voltage. Being able to use two off-the-shelf AAA batteries makes system design easier and also reduces component cost. Moreover, the solution will be more efficient than if a regulator with a higher input voltage is used.