MAX6397SATA+T Maxim Integrated Products, MAX6397SATA+T Datasheet - Page 7

• Manufacturer Part Number: MAX6397SATA+T
• Description: IC SW OVERVOLT PROT 8-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX6397SATA+T

• Voltage - Working: 72V
• Technology: Mixed Technology
• Power (watts): 1.45W
• Number Of Circuits: 1
• Applications: General Purpose
• Package / Case: 8-TDFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Clamping: -

The MAX6397/MAX6398 are ultra-small, low-current,
high-voltage protection circuits for automotive applica-
tions that must survive load dump and high-voltage
transient conditions. These devices monitor the input/
output voltages and control an external n-channel
MOSFET to isolate the load or to regulate the output
voltage from overvoltage transient energy. The con-
troller allows system designers to size the external
MOSFET to their load current and board size.
The MAX6397/MAX6398 drive the MOSFET’s gate high
when the monitored input voltage is below the adjustable
overvoltage threshold. An internal charge-pump circuit
provides a 5V to 10V gate-to-source drive (see the
Typical Operating Characteristics ) to ensure low input-to-
load voltage drops in normal operating modes. When the
input voltage rises above the user-adjusted overvoltage
threshold,
the MOSFET.
MAX6397
—
1
2
3
4
5
6
7
8
PIN
GATE
MAX6398
—
—
—
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1
2
3
4
5
6
Detailed Description
pulls
Overvoltage Protection Switch/Limiter
NAME
SHDN
GATE
GND
POK
OUT
REG
SET
to
EP
IN
OUT,
Supply Voltage Input. Bypass with a minimum 10µF capacitor to GND.
Shutdown Input. Drive SHDN low to force GATE low, turning off the external n-channel
MOSFET. REG remains active when in shutdown mode. SHDN is internally pulled down
to GND with a 1µA source. Connect to IN for normal operation.
Overvoltage Threshold Adjustment Input. Connect SET to an external resistor voltage-
divider network to OUT (overvoltage limiter) or IN (overvoltage switch) to adjust the
desired overvoltage limit threshold. Use SET to monitor a system input or output voltage.
Open-Drain Output. POK remains low until REG exceeds 92.5% or 87.5% of REG
nominal output voltage. Connect to an external pullup resistor.
Ground
Gate-Drive Output. Connect GATE to the gate of an external n-channel MOSFET. GATE
is a charge pump with a 75µA pullup current to 10V (typ) above IN during normal
operation. GATE is quickly shorted to OUT during an overvoltage condition. GATE pulls
low when SHDN is low.
Output-Voltage-Sense Input. Connect to the source of the external n-channel MOSFET.
Regulator Output. Fixed 5.0V, 3.3V, 2.5V, or 1.8V output. REG sources up to 100mA.
Bypass with a minimum 4.7µF capacitor to GND.
Exposed Pad. Connect to ground plane.
turning
Controllers Operate Up to 72V
off
The MAX6397/MAX6398 are configurable to operate as
overvoltage protection switches or as closed-looped volt-
age limiters. In overvoltage protection switch mode, the
input voltage is monitored. When an overvoltage condi-
tion occurs at IN, GATE pulls low, disconnecting the load
from the power source, and then slowly enhances upon
removal of the overvoltage condition. In overvoltage
limit mode, the output voltage is monitored and the
MAX6397/MAX6398 regulate the source of the external
MOSFET at the adjusted overvoltage threshold, allowing
devices within the system to continue operating during an
overvoltage condition.
The MAX6397/MAX6398 undervoltage lockout (UVLO)
function disables the devices as long as the input
remains below the 5V (typ) UVLO turn-on threshold. The
MAX6397/MAX6398 have an active-low SHDN input to
turn off the external MOSFET, disconnecting the load and
reducing power consumption. After power is applied and
SHDN is driven above its logic-high voltage, there is a
100µs delay before GATE enhancement commences.
FUNCTION
Pin Description
7