LTC1642C LINER [Linear Technology], LTC1642C Datasheet - Page 3

• Manufacturer Part Number: LTC1642C
• Description: Hot Swap Controller
• Manufacturer: LINER [Linear Technology]

DC ELECTRICAL CHARACTERISTICS
The
V
SYMBOL
V
I
V
V
V
V
I
V
I
V
V
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
CRWBR (Pin 1): Combination Overvoltage Timer and
Crowbar Circuit Trigger. The timer sets the overvoltage
time needed to trigger the crowbar circuit. To use the timer
connect a capacitor C to ground; the trigger time is
9ms•C( F). When the timer is off an internal N-channel
pulls the pin to ground. The timer is started when the OV
comparator trips. A 45 A current source is connected
from V
a rate of 45/C( F) Volts/second. When the voltage reaches
410mV the current sourced by the pin increases to 1.5mA.
Boost this current with an NPN emitter follower to trigger
a crowbar SCR.
BRK TMR (Pin 2): Analog Timer which Limits the Time the
Part Remains In Current Limit. To use the timer connect a
capacitor from BRK TMR to ground. BRK TMR is pulled to
ground until the sense resistor current reaches its limit,
PI FU CTIO S
CP
PU
RSC
CB
ONHI
ONLO
ONHYST
OL
REF
COS
CHYST
CC
V
V
V
GATE
LNR
LDR
U
= 5V unless otherwise specified.
denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T
CC
to the CRWBR pin, and the voltage increases at
PARAMETER
Circuit Breaker Trip Voltage
GATE Pin Output Current
External N-Channel Gate Drive
ON Pin Threshold (Low to High)
ON Pin Threshold (High to Low)
ON Pin Hysteresis
Output Low Voltage
Logic Output Pull-Up Current
Reference Output Voltage
Reference Line Regulation
Reference Load Regulation
Reference Short-Circuit Current
Comparator Offset Voltage
Comparator Hysteresis
U
U
CONDITIONS
V
V
Charge Pump On, V
Charge Pump Off, V
V
V
V
RESET, FAULT, COMPOUT I
RESET, FAULT = GND
No Load
2.97V V
I
V
V
V
O
CB
CB
GATE
GATE
GATE
REF
CM
CM
= 0mA to –1mA, Sourcing Only
= (V
= (V
= V
= 0V
= V
– V
– V
– V
REF
CC
CC
REF
CC,
CC,
CC,
CC
– V
– V
when the pin begins sourcing 20 A and the pin voltage
increases at a rate of 20/C( F) Volts/second. When the pin
reaches 1.23V the GATE pin is pulled to ground and the
FAULT output is asserted until the chip is reset. To allow
the part to remain in current limit indefinitely ground BRK
TMR.
RST TMR (Pin 3): Analog System Timer. To use the timer
connect a capacitor from RST TMR to ground. This timer
sets the delay from the ON pin going high to the start of the
GATE pin’s ramp; it also sets the delay from output voltage
good, as sensed by the FB pin, to RESET going high. When
the timer is off, an internal N-channel shorts RST TMR to
ground. When the timer is turned on a 2 A current from
V
ramp up at a rate of 2/C( F) Volts/second. The timer trips
when the voltage reaches 1.23V.
V
V
V
CC
CC
CC
CC
SENSE
SENSE
16.5V, No Load
= 3V
= 5V
= 15V
is connected and the RST TMR pin voltage starts to
GATE
GATE
), V
), V
FB
FB
= GND
= 5V
= GND
= 1V
O
= 1.5mA
1.208
1.30
1.20
MIN
– 30
4.5
4.5
15
45
10
1.220
52.5
11.5
1.34
1.22
TYP
– 25
– 15
110
5.9
8.5
2.5
4.5
25
10
5
3
LTC1642
1.232
MAX
1.38
1.26
– 20
8.0
0.4
7.5
A
36
60
14
18
15
10
= 25 C.
UNITS
3
mV
mV
mA
mV
mV
mV
mA
mV
mV
A
V
V
V
V
V
V
A
V