The TPS22949 and TPS22949A are devices that provide protection to systems and loads in
high-current conditions. The device contains a 500-mΩ current-limited P-channel MOSFET that can
operate over an input voltage range of 1.62 V to 4.5 V as well as a low-dropout (LDO) regulator
with a fixed output voltage of 1.8 V.
The switch is controlled by an on/off input (EN1), which can interface directly with
low-voltage control signals. When the switch current reaches the maximum limit, the
TPS22949/TPS22949A operates in a constant-current mode to prohibit excessive currents from causing
damage. If the constant current condition persists after 12 ms, these devices shut off the switch
and pull the fault signal pin (OC) low. The TPS22949/TPS22949A has an auto-restart feature that
turns the switch on again after 70 ms if the EN1 pin is still active.
The output of the current limiter is internally connected to an RF low-dropout (LDO)
regulator that offers good AC performance with very low ground current, good power supply rejection
ratio (PSRR), low noise, fast start-up, and excellent line and load transient response. The output
of the regulator is stable with ceramic capacitors. This LDO uses a precision voltage reference and
feedback loop to achieve overall accuracy of 2% over all load, line, process, and temperature
variations.
The TPS22949A integrates additional internal circuitry that increases the current limit
of the switch during the power-up sequence. This feature allows the TPS22949A to operate without a
storage capacitor at the input of the LDO.
The TPS22949 and TPS22949A are available in a space-saving 8-terminal WCSP (YZP) or in an
8-pin WSON package (DRG). Both devices are characterized for operation over the free-air
temperature range of –40°C to 85°C.
