1 Features
1• Integrated Current Limiter
– Input Voltage Range: 1.62 V to 4.5 V
– Low ON-Resistance
– rON = 300-mΩ at VIN = 4.5 V
– r ON = 350-mΩ at VIN = 3.3 V
– rON = 400-mΩ at VIN = 2.5 V
– r ON = 600-mΩ at VIN = 1.8 V
– Integrated 100-mA Minimum Current Limit
– Undervoltage Lockout
– Fast-Current Limit Response Time
– Integrated Fault Blanking and Auto Restart
• Stable Without Current Limiter Output Capacitor
(TPS22949A Only)
• Integrated Low-Noise RF LDO
– Input Voltage Range: 1.62 V to 4.5 V
– Low Noise: 50 μVrms (10 Hz to 100 kHz)
– 80-dB VIN PSRR (10 Hz to 10 kHz)
– Fast Start-Up Time: 130 μs
– Low Dropout 100 mV at I load =100 mA
– Integrated Output Discharge
– Stable With 2.2-μF Output Capacitor
• 1.8-V Compatible Control Input Threshold
• ESD Performance Tested Per JESD 22
– 3500 V Human Body Model
(A114-B, Class II)
– 1000 V Charged Device Model
(C101)
• Tiny 8-Terminal YZP Package (1.9 mm × 0.9 mm,
0.5-mm Pitch, 0.5-mm Height) and WSON-8
(DRG) 3.0 mm × 3.0 mm

2 Applications
• Fingerprint Module Protection
• Portable Consumer Electronics
• Smart Phones
• Notebooks
• Control Access Systems

3 Description
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.