Datasheet MAX5902, MAX5903 (Maxim) - 5

+72V, SOT23/TDFN, Simple Swapper Hot-Swap Controllers MAX5902/MAX5903 Pin Description PIN NAME FUNCTION MAX5902 MAX5903
1 1 VS Positive Supply Voltage Input and External p-Channel MOSFET Source Connection Drain Sense Input for External p-Channel MOSFET. Connect DRAIN as close as possible to the MOSFET’s drain and use wide circuit traces to assure good thermal 2 2 DRAIN coupling between the MAX5902/MAX5903 and the MOSFET. See Layout Guidelines Section. 3 3 GATE Gate Drive Output for External p-Channel MOSFET 4 4 GND Ground Connection Power-Good Output. PGOOD is an n-channel, open-drain, active-low output, 5 — PGOOD referenced to GND. Power-Good Output. PGOOD is an n-channel, open-drain, active-high output, — 5 PGOOD referenced to GND. ON/OFF Control Input. ON/OFF is referenced to GND. Drive ON/OFF above 1.38V or leave unconnected to enable the device. Drive ON/OFF below 1V to disable the device. 6 6 ON/OFF ON/OFF is also used to adjust the UVLO threshold. Internally clamped to nominally 3V through a 1kΩ resistor (See Figure 1). (See the Undervoltage Lockout section in the Applications Information.) — — EP Exposed Pad (TDFN only). Connect to GND.
Detailed Description
The MAX5902/MAX5903 are integrated hot-swap con- troller ICs contained in 6-pin SOT23 and TDFN pack- MAX5902 ages. They allow a board to be safely hot-plugged into MAX5903 VS a live backplane without causing a glitch on the power- * supply rail. They are well suited for +48V power sys- 828kΩ tems allowing cost-effective, simple, and compact design. The MAX5902/MAX5903 operate from +9V to ON/OFF +72V to cover a wide range of end equipment hot-swap 1kΩ CONTROL PGOOD needs. They require only an external p-channel power * LOGIC (PGOOD) 34.5kΩ MOSFET to provide hot-swap control. Figure 1 shows a 3V functional block diagram of the MAX5902/MAX5903. GND The MAX5902/MAX5903 controls an external p-channel GND GND *900kΩ power MOSFET placed in the positive power-supply pathway. When power is first applied, the MAX5902/ *650kΩ MAX5903 keep the MOSFET turned off. The MAX5902/MAX5903 hold the MOSFET off indefinitely if DRAIN GATE ON/OFF is held low, if the supply voltage is below the ( ) ARE FOR THE MAX5903 ONLY * RELATIVE TOLERANCE ±1%, ABSOLUTE TOLERANCE ±50% (TYP) undervoltage lockout level, or if the die temperature exceeds +125°C. If none of these conditions exist for 150ms (typ), the MAX5902/MAX5903 begin to gradually Figure 1. Functional Block Diagram turn on the MOSFET. During this turn-on phase, the MAX5902/MAX5903 slowly enhance the MOSFET, the MOSFET is fully enhanced, and the load voltage is allowing the voltage on the load, i.e. the drain of the settled to its final value, the MAX5902A/ MAX5903A and MOSFET, to rise at a rate of 9V/ms (typ). The inrush cur- MAX5902L/MAX5903L monitor the voltage drop across rent to the load is thus limited to a level proportional to the MOSFET. If the voltage drop exceeds the circuit- the load capacitance, and the constant slew rate. After breaker threshold the MAX5902A/MAX5903A and
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