MAX5931AEEP+ Maxim Integrated Products, MAX5931AEEP+ Datasheet - Page 13

• Manufacturer Part Number: MAX5931AEEP+
• Description: IC HOT-SWAP CTRLR TRPL 20-QSOP
• Manufacturer: Maxim Integrated Products
• Type: Hot-Swap Controllerr

Specifications of MAX5931AEEP+

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: 1 V ~ 15 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SSOP (0.154", 3.91mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 4. Power-Sequencing Fault Turn-Off
The MAX5930A/MAX5931A/MAX5931B limit the load
current if an overcurrent fault occurs during startup
instead of completely turning off the external MOSFETs.
The slow comparator is disabled during the startup
period and the load current can be limited in two ways:
1) Slowly enhancing the MOSFETs by limiting the
2) Limiting the voltage across the external current-
During the startup period, the gate-drive current is limit-
ed to 100µA and decreases with the increase of the gate
voltage (see the Typical Operating Characteristics sec-
tion). This allows the controller to slowly enhance the
MOSFETs. If the fast comparator detects an overcurrent,
the MAX5930A/MAX5931A/MAX5931B regulate the gate
*
ON1 = ON2 = ON3
OVERCURRENT
FAULT
CONDITION
OUT1
OUT2
OUT3
OF THE LOAD RESISTANCE AND CAPACITANCE.
THE OUT_ DISCHARGE RATE IS A RESULT OF NATURAL DECAY
MOSFET gate-charging current.
sense resistor.
Low-Voltage, Triple, Hot-Swap Controllers/
______________________________________________________________________________________
Power Sequencers/Voltage Trackers
*
*
*
voltage to ensure that the voltage across the sense resis-
tor does not exceed V
the inrush current during startup.
Figure 6 shows the startup waveforms. STAT_ is assert-
ed immediately after the startup period if no fault condi-
tion is present.
VariableSpeed/BiLevel fault protection incorporates
comparators with different thresholds and response
times to monitor the load current (Figure 7). During the
startup period, protection is provided by limiting the
load current. Protection is provided in normal operation
(after the startup period has expired) by discharging
the MOSFET gates with a strong 3mA/50mA pulldown
current in response to a fault condition. After a fault,
STAT_ is deasserted. Use the LATCH input to control
whether the STAT_ outputs latch off or autoretry (see
the Latched and Autoretry Fault Management section).
The slow comparator is disabled during the startup
period while the external MOSFETs are turning on.
Disabling the slow comparator allows the device to
ignore the higher-than-normal inrush current charging
the board capacitors when a card is first plugged into a
live backplane.
After the startup period is complete, the slow comparator
is enabled and the device enters normal operation. The
comparator threshold voltage (V
25mV to 100mV. The slow-comparator response time is
3ms for a 1mV overdrive. The response time decreases
to 100µs with a large overdrive. The variable-speed
response time allows the MAX5930A/MAX5931A/
MAX5931B to ignore low-amplitude momentary glitches,
thus increasing system noise immunity. After an extend-
ed overcurrent condition, a fault is generated, STAT_ out-
puts are deasserted and the MOSFET gates are
discharged with a 3mA pulldown current.
During the startup period, the fast comparator regu-
lates the gate voltages to ensure that the voltage
across the sense resistor does not exceed the startup
fast-comparator threshold voltage (V
scaled to two times the slow-comparator threshold
(V
SC,TH
VariableSpeed/BiLevel Fault Protection
).
Slow-Comparator Normal Operation
Slow-Comparator Startup Period
Fast-Comparator Startup Period
SU,TH
. This effectively regulates
SC,TH
) is adjustable from
SU,TH
), V
SU,TH
13
is