General Description
The AAT4621 SmartSwitch is a current limited P-channel MOSFET power switch designed for high-side load-switching applications in PC Card GSM/GPRS/3G modem cards. Used in conjunction with a super capacitor, the AAT4621 will ensure that the power ratings of the PCMCIA host are not exceeded at any time. Featuring two independent, programmable current limits and a power loop, the AAT4621 can ensure that the super capacitor can be charged without exceeding PCMCIA specifications. 

Features
• VIN Range: 3.0V to 5.5V
• Dual Independent Current Limits
   — 75mA to 1200mA
   — ±10% Current Accuracy
   — 20°C Temperature Band
• Reverse Current Blocking Protection
• Power Loop
• Low Quiescent Current
   — 40µA Typical
   — 1.0µA Max with Switch Off
• 65mΩ Typical RDS(ON) at 3V
• Only 1.4V Needed for Enable Control Pin
• System READY Output with Externally
   Programmable Hysteresis
• Under-Voltage Lockout
• Temperature Range: -40 to 85°C
• 12-Pin TSOPJW Package or 14-Pin TDFN33
   Package

Applications
• Capacitor Charger
• CF Card Port Power Protection
• Express Card GSM/GPRS/3G Modems
• PC Card GSM/GPRS Class 10/12 Modems
• WiMAX Cards