max5938 Maxim Integrated Products, Inc., max5938 Datasheet - Page 8

• Manufacturer Part Number: max5938
• Description: Max5938 -48v Hot-swap Controller With Vin Step Immunity, No Rsense, And Overvoltage Protection
• Manufacturer: Maxim Integrated Products, Inc.

-48V Hot-Swap Controller with V
No R
capacitance (gate-to-drain) would pull up and turn on
the MOSFET gate when the MOSFET drain is rapidly
pulled up by the V
The MAX5938 GATE clamp can overcome the gate-to-
drain capacitance of large power MOSFETs with added
slew-rate control (C
the need for additional gate-to-source capacitance.
The MAX5938 keeps the MOSFET off indefinitely if the
supply voltage is below the user-set ON and OFF
thresholds, if the supply voltage is above the user-set
overvoltage (OV) threshold, or if a short circuit (user-
defined) is detected in the load connected to the drain
of the power MOSFET.
Figure 1. Functional Diagram
8
GND
V
_______________________________________________________________________________________
EE
SENSE
STEP_MON
POL_SEL
GND
OFF
V
ON
OV
EE
IN
SLEW
step during backplane contact.
LOGIC CONTROL
, and Overvoltage Protection
BANDGAP
POLARITY
) capacitors while eliminating
10V REG
ON, OFF,
V
AND OV
PGOOD
5V REG
LOGIC
BG
10µA
AND
REF
MAX5938
PG
+10V
+5V
V
BG
STEP
OV
(1.25V)
PG
CONTROLLER
SEQUENCER
DETECTION
FAULT
TIMER
COMPARATORS
V
LOAD-PROBE
75% OF V
SC
CONTROL
PGOOD
, V
LOGIC
GATE
TEST
CB
, AND
CB
The MAX5938 conducts a load-probe test after contact
transients from the hot plug-in have settled. This follows
the MAX5938 power-up (when the ON, OFF, and OV
conditions have been met for 220ms (t
the turn-on of the power MOSFET. This test pulls a user-
programmable current through the load (1A, max) for up
to 220ms (t
the load at V
external resistor, R
When the voltage across the load exceeds 200mV, the
test is truncated and the GATE turn-on sequence is start-
ed. If at the end of the 200ms (t
age across the load has not reached 200mV, the load is
assumed to be shorted and the current to the load from
CURRENT SOURCE
COMPENSATED
50µA TEMP
LP
52µA
OUT
) and tests for a voltage of 200mV across
IN
LP
(Figure 3). This current is set by an
Step Immunity,
2V AND
CLAMP
(Figure 17) between V
2kΩ
R
15V
INT
PGOOD
V
CB_ADJ
GATE
LP
OUT
LP
) test period the volt-
LP
R
)) and prior to
LOAD
OUT
and LP.
C
LOAD