+72V, SOT23/TDFN, Simple Swapper Hot-Swap

Controllers

6

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MAX5902L/MAX5903L turn off the MOSFET, discon-

necting the load immediately. If no circuit-breaker fault

exists, the MAX5902/MAX5903 assert the power-good

output. Then, if any of four conditions exist, the power-

good output deasserts and the MAX5902/MAX5903

turn off the MOSFET. The four conditions are: the volt-

age across the MOSFET exceeds the circuit-breaker

threshold; the supply voltage falls below the undervolt-

age lockout level; the die temperature exceeds

+125°C; or ON/OFF is forced low. After a circuit-break-

er fault, the MAX5902L/MAX5903L keep the MOSFET

off until the power is cycled, or the part is reset by tog-

gling ON/OFF low for 10ms (typ). After a circuit-breaker

fault, the MAX5902A/MAX5903A automatically restarts

in 150ms (typ). All versions automatically restart after a

thermal fault, or an undervoltage shutdown, if the fault

condition goes away for at least 150ms (typ).

ON/OFF offers external control of the MAX5902/

MAX5903, facilitating power-supply sequencing, and

may also be used to change the undervoltage lockout

(UVL) level. UVLO keeps the external MOSFET

switched off as long as the input voltage is below the

desired level.

A power-good output, PGOOD (MAX5902) or PGOOD

(MAX5903), asserts when the external MOSFET is fully

enhanced and the source-drain voltage is below the

circuit-breaker threshold. PGOOD and PGOOD are

open-drain outputs referenced to GND, and can with-

stand up to +72V.

GND

GATE

DRAIN

50kΩ

50Ω

50kΩ

50kΩ

MAX5902

ON/OFF

PGOOD

V

I

GND

GATE

DRAIN

MAX5902

ON/OFF

PGOOD

V

V

GND

GATE

DRAIN

MAX5902

ON/OFF

PGOOD

V

V

0 TO 0.5V

GND

GATE

DRAIN

MAX5902A

ON/OFF

PGOOD

SCOPE

SCOPE

48V

GND

GATE

DRAIN

IRFR5410

MAX5902

ON/OFF

PGOOD

SCOPE

SCOPE

SCOPE

SCOPE

48V

GND

GATE

DRAIN

MAX5902

ON/OFF

PGOOD

SCOPE

SCOPE

SCOPE

48V

(a) SUPPLY CURRENT

(d) RETRY TIMEOUT

(d) STARTUP WAVEFORMS

(d) CIRCUIT-BREAKER EVENT

(b) GATE DRIVE VOLTAGE

Figure 2. Test Circuits