LTC4252A-2IMS Linear Technology, LTC4252A-2IMS Datasheet - Page 29

• Manufacturer Part Number: LTC4252A-2IMS
• Description: IC CTRLR HOTSWAP NEG VOLT 10MSOP
• Manufacturer: Linear Technology
• Type: Hot-Swap Controllerr

Specifications of LTC4252A-2IMS

• 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-2
• 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

APPLICATIONS INFORMATION
current begins to decline below V
loop shuts off and GATE releases at time point 8. At time
point 9, the SENSE voltage falls below V
deactivates.
Large values of C
time out as V
the circuit breaker delay. The load capacitor is unable to
achieve full charge in one GATE start-up cycle. A more
serious side effect of large C
may be exceeded during soft-start into a low impedance
load. A soft-start voltage below V
circuit breaker TIMER.
Power Limit Circuit Breaker
Figure 19 shows the LTC4252A-1 in a power limit circuit
breaking application. The SENSE pin is modulated by the
board supply voltage, V
is set to be the same as the low supply operating voltage,
V
operating voltage, V
power at V
selected using the ratio:
SUPPLY(MIN)
SUPPLY(MIN)
ACL
= 43V. If the goal is to have the high supply
PWRGD
(t) may exceed the V
SENSE
TIMER
DRAIN
SS
GATE
SS
can cause premature circuit breaker
SUPPLY(MAX)
V
END OF INTIAL TIMING CYCLE
(18a) Without External C
12 34 567
GS(th)
, then resistors R4 and R6 are
SUPPLY
ACL
V
V
TMRH
TMRL
+ V
58μA
OS
Figure 18. Soft-Start Timing (All Waveforms Are Referenced to V
SS
)
. The D1 Zener voltage, V
OS
7a
values is SOA duration
ACL
= 71V giving the same
CB
CB
(t). The current limit
will not activate the
+ V
CB
DRN
OS
potential during
)
8 9
CB
58μA
SS
V
V
V
and TIMER
10
ACL
CB
DRNCL
5.8μA
V
DRNL
11
V
IN
– V
GATEH
Z
PWRGD
SENSE
TIMER
DRAIN
If R6 is 27Ω, R4 is 38.3k. The peak circuit breaker power
limit is:
when
The peak power at the fault current limit occurs at the supply
overvoltage threshold. The fault current limited power is:
GATE
POWER
SS
V
V
POWER
R6
R4
SUPPLY
SUPPLY
END OF INTIAL TIMING CYCLE
V
R
12 3 4 5 6
GS(th)
LTC4252A-1/LTC4252A-2
=
(18b) With External C
S
V
V
V
TMRH
TMRL
SUPPLY(MAX)
FAULT
58μA
MAX
= 0.5 • (V
• V
LTC4252-1/LTC4252-2
⎛
⎝ ⎜
V
CB
=
OS
=1.064 •POWER
ACL
=
ACL
(
4 • V
•POWER
V
7
+ V
SUPPLY(MIN)
– V
SUPPLY(MIN)
DRN
OS
(
SUPPLY(MIN)
)
SUPPLY
8 9
EE
SS
58μA
)
SUPPLY(MIN)
V
V
V
10
ACL
CB
DRNCL
5.8μA
V
425212 F18
DRNL
CB
–V
11
V
+V
+ V
IN
+ V
SUPPLY(MIN)
• V
– V
OS
Z
SUPPLY(MAX)
)
)
SUPPLY(MAX)
GATEH
SUPPLY(MAX)
•
R6
R4
⎞
⎠ ⎟
)
) = 57V.
2
29
425212fc
(16)
(17)
(18)