Datasheet MAX5902, MAX5903 (Maxim) - 7

+72V, SOT23/TDFN, Simple Swapper Hot-Swap Controllers MAX5902/MAX5903 No Circuit Breaker
For the versions without a circuit breaker, MAX5902N (MAX5903N), PGOOD (PGOOD) are asserted when the HOT-SWAP CONTROLLER MOSFET is fully enhanced. Once powered up the +24V MAX5902N/MAX5903N ignore the MOSFET drain-to- OPTIONAL MAX5902 R2 source voltage for applications where a circuit-breaker MAX5903 ON/OFF 40.2k V Ω S function is not desired. ON/OFF
Applications Information
R1 GND DGND 3.01kΩ
ON/
OFF
Control Input
GND The ON/OFF control input provides three functions: external ON/OFF control; setting of the UVLO level; and resetting after a circuit-breaker event has caused the MAX5902L/MAX5903L to turn off the external MOSFET. Figure 3. Programmed +18V Lockout, with Optional Optocoupler Pulling ON/OFF to GND for at least 10ms (tOFF) forces On/Off Control. the MAX5902/MAX5903 to turn off the external MOSFET (see Figure 3 for a circuit example). To reset the MAX5902L/MAX5903L after a circuit-breaker event, A thermal shutdown feature protects the external MOS- toggle ON/OFF to GND for at least 10ms (tOFF). FET by turning it off if the die temperature of the ON/OFF can be used to sequence power supplies. MAX5902/MAX5903 exceeds +125°C. The MAX5902/ Connecting a capacitor from ON/OFF to GND will delay MAX5903 must be in good thermal contact with the the rise of ON/OFF proportional to the capacitance and external MOSFET. See Layout Guidelines in the Appli- input impedance of ON/OFF, typically 33kΩ (Figure 4). cations section of the data sheet. The MAX5902/MAX5903 can be controlled by logic- A circuit-breaker function monitors the voltage across level signals. Logic-level signals of 3.3V or 1.8V may be the external MOSFET, VSD, and turns off the MOSFET if directly connected to ON/OFF. For 5V logic level control, VSD exceeds the circuit-breaker threshold, VCB. The insert a series 47kΩ resistor as shown in Figure 5. circuit-breaker function is enabled after the MOSFET is fully enhanced. Three threshold voltage options are available—300mV, 400mV, and 500mV. One version is HOT-SWAP CONTROLLER #1 available with no circuit-breaker function. Fault man- V agement for the MAX5902/MAX5903 is offered with two S MAX5902 different configurations; latched and automatic retry. MAX5903 VS
Latched Circuit Breaker
ON/OFF After a circuit-breaker trip event, the latched C GND versions (MAX5902L/MAX5903L) drive GATE to VS, turning off the external MOSFET, and PGOOD (PGOOD) is deasserted. A latched off condition needs to be reset by toggling ON/OFF low for at least 10ms, or by cycling the power supply, VS. HOT-SWAP CONTROLLER #2
Automatic Retry Circuit Breaker
MAX5902 After a circuit-breaker trip event, the automatic retry MAX5903 VS versions (MAX5902A/MAX5903A) drive GATE to VS, turning off the external MOSFET, and PGOOD ON/OFF (PGOOD) is deasserted. If the start conditions are met 2C GND for a full 150ms (tRS) the start sequence is re-initiated. The start conditions are: the device is not in UVLO; GND ON/OFF is not driven low; and the device is not in ther- mal shutdown. Figure 4. Power-Supply Sequencing
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