MAX5960

19-0856; Rev 0; 7/07 KIT ATION EVALU E L B A AVAIL Quad PCI Express, Hot-Plug Controllers General Description The MAX5959/MAX5960 quad hot-plug controllers are designed for PCI Express® (PCIe) applications. These devices provide hot-plug control for the main 12V, 3.3V, and 3.3V auxiliary supplies of four PCIe slots. The MAX5959/MAX5960s’ logic inputs/outputs allow interfacing directly with the system hot-plug management controller or through an SMBus™ with an external I/O expander such as the MAX7313. An integrated debounced attention switch and present-detect signals simplify system design. The MAX5959/MAX5960 drive eight external n-channel MOSFETs to control the 12V and 3.3V main outputs. The 3.3V auxiliary outputs are controlled through 0.2Ω n-channel MOSFETs. Internal charge pumps provide the gate drive for the 12V outputs while the gate drive of the 3.3V output is driven by the 12V input supply clamped to 5.5V above the respective 3.3V main supply rail. The 3.3V auxiliary outputs are completely independent from the main outputs with their own charge pumps. At power-up, the MAX5959/MAX5960 keep all the MOSFETs off until the supplies rise above their respective undervoltage lockout (UVLO) thresholds. Upon a turn-on command, the MAX5959/MAX5960 enhance the external and internal MOSFETs slowly with a constant gate current to limit the power-supply inrush current. The MAX5959/MAX5960 actively limit the current to protect all outputs at all times and shut down if an overcurr...