The FPF2123, FPF2124, and FPF2125 are a series of load switches which provide 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.
The FPF2123, FPF2124, and FPF2125 are load‑switch ICs designed for portable electronics such as PDAs, cell phones, GPS devices, MP3 players and digital cameras. They provide a 0.125 Ω P‑channel MOSFET with a selectable current limit (150 mA‑1.5 A), controlled turn‑on, under‑voltage lockout, thermal shutdown, auto‑restart (FPF2123 only) and reverse‑current blocking.
The datasheet details absolute maximum ratings, recommended operating ranges, electrical characteristics, typical application circuits, and layout guidelines. Key parameters include input voltage range, turn‑on/off times, on‑resistance, shutdown current and thermal shutdown threshold. Designers can set the current limit via an external resistor on the ISET pin and should follow the recommended capacitor placement for optimal performance.
| Input voltage range | 1.8 V to 5.5 V |
|---|---|
| Adjustable current limit | 0.15 A to 1.5 A |
| Shutdown current (ISHDN) | 2 µA |
The devices operate with an input voltage from 1.8 V up to 5.5 V.
Yes, the FPF2123 automatically turns the switch back on after 160 ms when a current‑limit fault occurs.
The current limit is set by connecting an external resistor between the ISET pin and ground.
The shutdown current is specified as 2 µA.