Simplified Block Diagram
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- PCIe Compliant
- Hot Swap 12V, 3.3V, and 3.3V Auxiliary for 3 PCIe Slots
- Integrated Power MOSFETs for Auxiliary Supply Rails
- Controls di/dt and dV/dt
- Active Current Limiting Protects Against Overcurrent/Short-Circuit Conditions
- Programmable Current-Limit Timeout
- Active-Low PWRGD Signal Outputs with Programmable Power-On Reset (POR) (160ms Default)
- Latched Active-Low FAULT Signal Output After Overcurrent or Overtemperature Fault
- Attention Switch Inputs/Outputs with 4ms Debounce
- Present-Detect Inputs
- Force-On Inputs Facilitate Testing/Debug
- Thermal Shutdown
- Allow Control Through SMBus with an I/O Expander
- Desktop/Mobile Server Platforms
- Embedded Devices
The MAX5957/MAX5958 drive six 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 MAX5957/MAX5958 keep all the MOSFETs (internal and external) off until the supplies rise above their respective undervoltage lockout (UVLO) thresholds. Upon a turn-on command, the MAX5957/MAX5958 enhance the external and internal MOSFETs slowly with a constant gate current to limit the power-supply inrush current.
The MAX5957/MAX5958 actively limit the current to protect all outputs at all times and shut down if an overcurrent condition occurs. After an overcurrent fault condition, the MAX5957L/MAX5958L latch off while the MAX5957A/MAX5958A automatically restart after a restart time delay. The MAX5957/MAX5958 are offered in latch-off or autorestart versions (see the Selector Guide located in the full data sheet).
The MAX5957/MAX5958 are available in a 56-pin TQFN package and operate over the -40°C to +85°C temperature range.