LTC4224IMS-2#TRPBF Linear Technology, LTC4224IMS-2#TRPBF Datasheet - Page 9

• Manufacturer Part Number: LTC4224IMS-2#TRPBF
• Description: IC CNTRLR HOT SWAP DUAL 10-MSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC4224IMS-2#TRPBF

• Applications: General Purpose
• Internal Switch(s): No
• Voltage - Supply: 1 V ~ 6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS INFORMATION
time, a 5ms start-up blanking delay begins during which
the circuit breaker is not allowed to latchoff the MOSFET.
If the ECB is tripped at the end of 5ms (time point t
MOSFET is latched off by pulling GATE down with 1.5mA
and FAULT is latched low. The waveform in Figure 6 shows
an unsuccessful start-up due to a short circuit at the output.
To ensure start-up, the load capacitor must be charged
up suffi ciently to exit current limit before the end of the
5ms blanking delay. For large load capacitors, it may be
necessary to connect an external capacitor from GATE to
GND as described in the Turn-On Sequence section.
After start-up, any transient overcurrent faults lasting
less than 100μs are ignored. Any overcurrent condition
lasting more than 100μs will initiate the 5ms ECB blank-
ing delay (time point t
the ECB is armed for the following 5ms (time point t
t
off the MOSFET. In summary, for 5ms to 10ms after a
100μs or greater overcurrent fault is detected, a second
100μs fault condition causes the MOSFET to latchoff. If
no overcurrent condition is detected during this time, the
part re-enters the IDLE state and another blanking delay
following an overcurrent condition is again required before
the MOSFET latches off. Figure 7 shows how the output
latches off following an overcurrent fault.
During a severe short-circuit (see Figure 8), the output load
current can briefl y surge to tens of amperes. The LTC4224
rapidly brings the current under control by discharging
6
). Any 100μs overcurrent pulse during this time latches
2V/DIV
5V/DIV
1A/DIV
5V/DIV
GATE1
FAULT
I
OUT1
ON1
Figure 6. Start-Up with Short at Output
4
). After the ECB blanking delay,
5ms/DIV
422412 F06
3
), the
5
to
the MOSFET’s gate with 125mA towards ground. After a
short delay, the ACL amplifi er regulates the gate voltage
until the ECB trips at the end of 5ms.
Undervoltage Fault
An undervoltage fault occurs if either V
below 0.8V for longer than 8μs. This turns off the affected
supply’s switch by discharging GATE with 1.5mA and
clears its fault latch. An undervoltage fault on one supply
does not affect the operation of the other supply. If V
the higher of V
than 12μs, all supply switches are turned off and all fault
latches are cleared.
5V/DIV
5V/DIV
1A/DIV
5V/DIV
5V/DIV
8A/DIV
GATE1
GATE2
V
V
I
I
OUT1
OUT1
OUT2
OUT2
Figure 8. Severe Short-Circuit on Output
Figure 7. Overcurrent Fault on Output
LTC4224-1/LTC4224-2
CC1
and V
0.5μs/DIV
2ms/DIV
CC2
, falls below 2.4V for more
CC1
422412 F07
422412 F08
or V
CC2
422412fa
falls
9
CC
,