LTC4252A-1IMS#TR Linear Technology, LTC4252A-1IMS#TR Datasheet - Page 26

• Manufacturer Part Number: LTC4252A-1IMS#TR
• Description: IC CTRLR HOTSWAP NEG VOLT 10MSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC4252A-1IMS#TR

• Applications: General Purpose
• Internal Switch(s): No
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
• Family Name: LTC4252A-1
• Package Type: MSOP
• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 3mm
• Product Height (mm): 0.86mm
• Product Length (mm): 3mm
• Mounting: Surface Mount
• Pin Count: 10
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LTC4252-1/LTC4252-2
LTC4252A-1/LTC4252A-2
APPLICATIONS INFORMATION
the V
Figure 14b, when TIMER exceeds V
immediately and the LTC4252 shuts down. In Figure 14c,
multiple momentary faults cause the TIMER capacitor to
integrate and reach V
the LTC4252 shuts down. During shutdown, the LTC4252-1
latches TIMER high with a 5.8μA pull-up current source;
the LTC4252-2 activates a shutdown cooling cycle.
Resetting a Fault Latch (LTC4252-1)
The latched circuit breaker fault of LTC4252-1 benefits
from long cooling time. It is reset by pulling the UV pin
below V
pulling the V
third reset method involves pulling the TIMER pin below
V
skipped if TIMER is used for reset. An initial timing cycle
is generated if reset by the UV pin or the V
The duration of the TIMER reset pulse should be smaller
than the time taken to reach 0.2V at SS pin. With a single
26
TMRL
TMRH
(14a) Momentary Circuit-Breaker Fault
PWRGD
TIMER
SENSE
DRAIN
as shown in Figure 15. An initial timing cycle is
UVLO
GATE
V
OUT
SS
V
threshold, TIMER is discharged by 5.8μA. In
TMRH
IN
with a switch. Reset is also accomplished by
CB FAULT
1
pin momentarily below (V
2
TMRH
V
V
Figure 14. Circuit-Breaker Timing Behavior (All Waveforms Are Referenced to V
ACL
CB
. GATE pull down follows and
5.8μA
DRN
TMRH
, GATE pulls down
LKO
IN
pin.
(14b) Circuit-Breaker Time Out
PWRGD
– V
SENSE
TIMER
DRAIN
GATE
V
OUT
SS
LKH
V
TMRH
). A
1
CB FAULT
V
DRNCL
pole mechanical pushbutton switch, this may not be
feasible. A double pole, single throw pushbutton switch
removes this restriction by connecting the second switch
to the SS pin. With this method, both the SS and TIMER
pins are released at the same time (see Figure 24).
Shutdown Cooling Cycle (LTC4252-2)
Figure 16 shows the timer behavior of the LTC4252-2. At
time point 2, TIMER exceeds V
immediately and the LTC4252 shuts down. TIMER starts
a shutdown cooling cycle by discharging TIMER with
5.8μA to the V
5.8μA to the V
discharge phases and three 5.8μA charge phases in this
shutdown cooling cycle spanning time points 2 and 3. At
time point 3, the LTC4252 automatic retry occurs with a
start-up cycle. Good thermal management techniques are
highly recommended; power and thermal dissipation must
be carefully evaluated when implementing the automatic
retry scheme.
CB TIMES OUT
2
V
V
ACL
CB
DRN
TMRL
TMRH
PWRGD
SENSE
TIMER
DRAIN
(14c) Multiple Circuit-Breaker Fault
GATE
V
OUT
SS
threshold. TIMER then charges with
V
TMRH
threshold. There are four 5.8μA
CB FAULT
1
2
5.8μA
EE
V
TMRH
DRNCL
)
CB FAULT
3
425212 F14
, GATE pulls down
CB TIMES OUT
4
DRN
V
V
ACL
CB
DRN
425212fc