MAX5902ABEUT 데이터 시트보기 (PDF) - Maxim Integrated
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MAX5902ABEUT Datasheet PDF : 14 Pages
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+72V, SOT23/TDFN, Simple Swapper Hot-Swap
Controllers
Pin Description
PIN
MAX5902 MAX5903
1
1
2
2
3
3
4
4
5
—
—
5
6
6
—
—
NAME
VS
DRAIN
GATE
GND
PGOOD
PGOOD
ON/OFF
EP
FUNCTION
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
coupling between the MAX5902/MAX5903 and the MOSFET. See Layout Guidelines
Section.
Gate Drive Output for External p-Channel MOSFET
Ground Connection
Power-Good Output. PGOOD is an n-channel, open-drain, active-low output,
referenced to GND.
Power-Good Output. PGOOD is an n-channel, open-drain, active-high output,
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.
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.)
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-
ages. They allow a board to be safely hot-plugged into
a live backplane without causing a glitch on the power-
supply rail. They are well suited for +48V power sys-
tems allowing cost-effective, simple, and compact
design. The MAX5902/MAX5903 operate from +9V to
+72V to cover a wide range of end equipment hot-swap
needs. They require only an external p-channel power
MOSFET to provide hot-swap control. Figure 1 shows a
functional block diagram of the MAX5902/MAX5903.
The MAX5902/MAX5903 controls an external p-channel
power MOSFET placed in the positive power-supply
pathway. When power is first applied, the MAX5902/
MAX5903 keep the MOSFET turned off. The
MAX5902/MAX5903 hold the MOSFET off indefinitely if
ON/OFF is held low, if the supply voltage is below the
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
turn on the MOSFET. During this turn-on phase, the
MAX5902/MAX5903 slowly enhance the MOSFET,
allowing the voltage on the load, i.e. the drain of the
MOSFET, to rise at a rate of 9V/ms (typ). The inrush cur-
rent to the load is thus limited to a level proportional to
the load capacitance, and the constant slew rate. After
MAX5902
MAX5903
VS
*
828kΩ
ON/OFF
GND
1kΩ
*
34.5kΩ
3V
CONTROL
LOGIC
GND
*900kΩ
*650kΩ
PGOOD
(PGOOD)
GND
DRAIN
GATE
( ) ARE FOR THE MAX5903 ONLY
* RELATIVE TOLERANCE ±1%, ABSOLUTE TOLERANCE ±50% (TYP)
Figure 1. Functional Block Diagram
the MOSFET is fully enhanced, and the load voltage is
settled to its final value, the MAX5902A/ MAX5903A and
MAX5902L/MAX5903L monitor the voltage drop across
the MOSFET. If the voltage drop exceeds the circuit-
breaker threshold the MAX5902A/MAX5903A and
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