FPF2123: Full Function Load Switch with Adjustable Current Limit

The FPF2123, FPF2124, and FPF2125 are a series of load switches which provides full protection to systems and loads which may encounter large current conditions. These devices contain a 0.125Ω current-limited P-channel MOSFET which can operate over an input voltage range of 1.8-5.5V. The current limit is settable using an external resistor. Internally, current is prevented from flowing when the MOSFET is off and the output voltage is higher than the input voltage. Switch control is by a logic input (ON) capable of interfacing directly with low voltage control signals. Each part contains thermal shutdown protection which shuts off the switch to prevent damage to the part when a continuous over-current condition causes excessive heating.     When the switch current reaches the current limit, the parts operate in a constant-current mode to prohibit excessive currents from causing damage. For the FPF2123 and FPF2124 if the constant current condition still persists after 10ms, these parts will shut off the switch. The FPF2123 has an auto-restart feature which will turn the switch on again after 160ms if the ON pin is still active. The FPF2124 does not have this auto-restart feature so the switch will remain off after a current limit fault until the ON pin is cycled. The FPF2125 will not turn off after a current limit fault, but will rather remain in the constant current mode indefinitely. The minimum current limit is 150mA. These parts are available in a space-saving 5 pin SOT23 package

Features

• 1.8 to 5.5V Input Voltage Range
• Controlled Turn-On
• 0.15-1.5A Adjustable Current Limit
• Undervoltage Lockout
• Thermal Shutdown
• < 2uA Shutdown Current
• Auto Restart
• Fast Current limit Response Time
• 3us to Moderate Over Currents
• 20ns to Hard Shorts
• Fault Blanking
• Reverse Current Blocking

Application Notes