MAX4370ESA+ Maxim Integrated Products, MAX4370ESA+ Datasheet - Page 10

• Manufacturer Part Number: MAX4370ESA+
• Description: IC CNTRLR HOT-SWAP 8-SOIC
• Manufacturer: Maxim Integrated Products
• Type: Hot-Swap Controllerr

Specifications of MAX4370ESA+

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: 2.7 V ~ 13.2 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Current-Regulating Hot-Swap Controller with
DualSpeed/BiLevel Fault Protection
The status output is an open-drain output that goes low
when the part is:
1) in start-up
2) forced off (on = GND)
3) in an overcurrent condition, or
4) latched off.
STAT is high only if the part is in normal mode and no
faults are present (Table 1). Figure 4 shows the STAT
timing diagram.
The undervoltage lockout prevents the MAX4370 from
turning on the external MOSFET until the input voltage
at V
least 150ms. The undervoltage lockout protects the
external MOSFET from insufficient gate drive voltage.
The 150ms timeout ensures that the board is fully
plugged into the backplane and that V
Voltage transients at V
will reset the device and initiate a start-up sequence.
The device also features a gate overvoltage lockout
that prevents the device from restarting after a fault
condition if the discharge has not been completed.
V
restarting. Since the MAX4370 does not monitor the
output voltage, a start-up sequence can be initiated
while the board capacitance is still charged.
Newer-generation MOSFETs have an absolute maxi -
mum rating of ±8V for the gate-to-source voltage (V
To protect these MOSFETs, the MAX4370 limits the
gate-to-drain (V
diode. No protection is provided for negative V
GATE can be discharged to GND faster than the output
voltage, an external small-signal protection diode (D1)
can be used, as shown in Figure 5.
Table 1. Status Output Truth Table
X = Don’t care
10
GATE
IN
______________________________________________________________________________________
START-UP
PART IN
exceeds the lockout threshold (2.25V min) for at
must be discharged to below 0.1V before
Yes
No
No
No
No
GD
Gate Overvoltage Protection
Over/Undervoltage Lockouts
) to +7.5V with an internal zener
IN
with voltages below the UVLO
ON PIN
High
High
High
Low
X
Status Output
IN
CONDITION ON V
OVERCURRENT
is stable.
GD
Yes
No
No
X
X
GS
. If
).
IN
Figure 4. Status Output (STAT) Timing Diagram
Figure 5. External Gate-Source Protection
CTIM
STAT
ON
1.2V
V
V
OV
OV
OV
PART IN LATCHED-OFF MODE
IN
IN
DUE TO OVERCURRENT
CHARGE PUMP
GATE DRIVE
MAX4370
CONDITION
Yes
No
X
X
X
V
V
GATE
IN
SEN
V
GD
V
NO FAULT CONDITIONS
PRESENT
GS
D1
M1
N
V
R
(STATUS)
STAT PIN
OUT
C
SENSE
BOARD
High
Low
Low
Low
Low
FAULT
CONDITION
OR ON
FALLING EDGE