MAX5909EEE Maxim Integrated Products, MAX5909EEE Datasheet - Page 16

• Manufacturer Part Number: MAX5909EEE
• Description: Hot Swap & Power Distribution
• Manufacturer: Maxim Integrated Products

Specifications of MAX5909EEE

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

The MAX5905–MAX5909 monitor the output voltages
with the MON1 and MON2 window comparator inputs.
These voltage monitors are enabled after the startup
period. Once enabled, the voltage monitor detects a
fault if V
687mV. If an output voltage fault is detected PGOOD
pulls low. When the MAX5906/MAX5907 detect an out-
put voltage fault on either MON1 or MON2, the fault is
latched and both external MOSFET gates are dis-
charged at 3mA. When the MAX5908/MAX5909 detect
an output voltage fault the external MOSFET gates are
not affected. The MAX5908/MAX5909 PGOOD goes
high impedance when the output voltage fault is
removed. The voltage monitors do not react to output
glitches of less than 20µs. A capacitor from MON_ to
GND increases the effective glitch filter time. Connect
MON1 to IN1 and MON2 to IN2 to disable the output
voltage monitors.
The status output is an open-drain output that pulls low
in response to one of the following conditions:
• Forced off (ON < 0.8V)
• Overcurrent fault
• Output voltage fault
PGOOD goes high impedance 0.75ms after the device
enters normal operation and no faults are present
(Table 1).
Select the external MOSFETs according to the applica-
tion’s current levels. Table 2 lists some recommended
components. The MOSFET’s on-resistance (R
Low-Voltage, Dual Hot-Swap Controllers/Power
Sequencers
Table 1. Status Output Truth Table
X = Don’t care.
16
UVLO DELAY
DEVICE IN
PERIOD
______________________________________________________________________________________
Yes
No
X
X
X
X
X
MON
_ is less than 543mV or greater than
Applications Information
DEVICE IN
STARTUP
PERIOD
Yes
No
X
X
X
X
X
Output Voltage Monitor
Status Output (PGOOD)
Component Selection
High
Low
ON
X
X
X
X
X
n-Channel MOSFET
OVERCURRENT
FAULT
Yes
No
X
X
X
X
X
DS(ON)
)
OVER/UNDER-
VOLTAGE
should be chosen low enough to have a minimum volt-
age drop at full load to limit the MOSFET power dissipa-
tion. High R
pulsating load. Determine the device power rating to
accommodate a short-circuit condition on the board at
startup and when the device is in automatic-retry mode
(see the MOSFET Thermal Considerations section).
Using the MAX5905/MAX5907/MAX5909 in latched
mode allows the use of MOSFETs with lower power rat-
ings. A MOSFET typically withstands single-shot pulses
with higher dissipation than the specified package rat-
ing. Table 3 lists some recommended manufacturers
and components.
The slow-comparator threshold voltage is set at 25mV
for the MAX5904/MAX5905 and is adjustable from
25mV to 100mV for the MAX5906–MAX5909. Select a
sense resistor that causes a drop equal to the slow-
comparator threshold voltage at a current level above
the maximum normal operating current. Typically, set
the overload current at 1.2 to 1.5 times the nominal load
current. The fast-comparator threshold is four times the
slow-comparator threshold in normal operating mode.
Choose the sense resistor power rating to be greater
than (I
The slow-comparator threshold voltage of the
MAX5904/MAX5905 is fixed at 25mV and adjustable
from 25mV to 100mV for the MAX5906–MAX5909.
The adjustable slow-comparator threshold of the
MAX5906–MAX5909 allows designers to fine-tune the
current-limit threshold for use with standard value
sense resistors. Low slow-comparator thresholds allow
for increased efficiency by reducing the power dissipat-
ed by the sense resistor. Furthermore, the low 25mV
FAULT
Yes
No
X
X
X
X
X
OVERLOAD
DS(ON)
PERIOD OR LATCHED OFF
PART IN RETRY-TIMEOUT
)
2
x V
Slow-Comparator Threshold, R
causes output ripple if there is a
SC,TH
Yes
No
X
X
X
X
X
.
Sense Resistor
impedence
PGOOD
High
Low
Low
Low
Low
Low
Low
LIM