MAX14586 Datasheet, PDF(7/9 Page) Maxim Integrated Products – High-Current Overvoltage Protectors with Adjustable OVLO

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MAX14586/MAX14590

High-Current Overvoltage Protectors

with Adjustable OVLO

Functional Diagram

OUT

MAX14586

MAX14590

VBG

REFERENCE

TEMPERATURE

FAULTS

CHARGE

PUMP

LOGIC

CONTROL

OVLO

SEL

GND

Detailed Description

The MAX14586/MAX14590 overvoltage protection devices

feature a low on-resistance (RON) internal FET and protect

low-voltage systems against voltage faults up to +36V. If

the input voltage exceeds the overvoltage threshold, the

internal FET is turned off to prevent damage to the pro-

tected components. The 15ms debounce time prevents

false turn-on of the internal FET during startup.

Device Operation

The devices have timing logic that controls the turn-on

of the internal FET. If VIN < VOVLO_THRESH, the internal

charge pump is enabled. The charge-pump startup, after

a 15ms debounce delay, turns on the internal FET (see

the Functional Diagram). After the debounce time, soft-

start limits the FET inrush current for 15ms (typ). At any

time, if VIN rises above VOVLO_THRESH, OUT is discon-

nected from IN.

Internal Switch

The devices incorporate an internal FET with a 48mI

(typ) RON. The FET is internally driven by a charge pump

that generates a necessary gate voltage above IN. The

internal FET can pass more than 5A inrush current.

Overvoltage Lockout (OVLO)

The MAX14586 has a 7V (typ) overvoltage threshold. The

MAX14590 has a 15V (typ) overvoltage threshold.

Thermal Shutdown Protection

The devices feature thermal shutdown circuitry. The inter-

nal FET turns off when the junction temperature exceeds

+150NC (typ). The device exits thermal shutdown after

the junction temperature cools by 20NC (typ).

Applications Information

IN Bypass Capacitor

For most applications, bypass IN to GND with a 1FF

ceramic capacitor as close as possible to the device

to enable Q15kV (HBM) ESD protection on IN. If Q15kV

(HBM) ESD is not required, there is no capacitor required

at IN. If the power source has significant inductance due

to long lead length, take care to prevent overshoots due

to the LC tank circuit and provide protection if necessary

to prevent exceeding the +40V absolute maximum rating

on IN.

OUT Output Capacitor

The slow turn-on time provides a soft-start function that

allows the devices to charge an output capacitor up to

1000FF without turning off due to an overcurrent condition.

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