LT1641 Datasheet, PDF (1/12 Pages) Linear Technology – Positive High Voltage Hot Swap Controller

FEATURES
s _{Allows Safe Board Insertion and Removal from a}
Live Backplane
s _{Controls Supply Voltage from 9V to 80V}
s _{Programmable Analog Foldback Current Limiting}
s _{High Side Drive for an External N-Channel}
s _{Automatic Retry or Latched Operation Mode}
s _{User Programmable Supply Voltage Power-Up Rate}
s _{Undervoltage Lockout}
s _{Overvoltage Protection}
U
APPLICATIO S
s _{Hot Board Insertion}
s _{Electronic Circuit Breaker}
s _{Industrial High Side Switch/Circuit Breaker}
s _{24V/48V Industrial/Alarm Systems}
Final Electrical Specifications
LT1641
Positive High Voltage
Hot Swap Controller
August 1999
DESCRIPTIO
The LT^®1641 is an 8-pin Hot Swap^TM controller that allows
a board to be safely inserted and removed from a live
backplane. Using an external N-channel pass transistor,
the board supply voltage can be ramped up at a program-
mable rate. A high side switch driver controls an N-channel
gate for supply voltages ranging from 9V to 80V.
The chip features a programmable analog foldback cur-
rent limit circuit. If the chip remains in current limit for
more than a programmable time, the N-channel pass
transistor latches off and is optionally set to automatically
restart after a time-out delay.
The PWRGD output indicates when the output voltage,
sensed by the FB pin, is within tolerance. The ON pin
provides programmable undervoltage lockout.
The LT1641 is available in the 8-lead SO package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
24V Input Voltage Application
V_IN
24V
R1
49.9k
1%
R_S
0.01Ω
Q1
IRF530
D1
R5
CMPZ R3
10Ω
5248B 59k
5%
1%
C1
R6, _10nF
1k, 5%
V_OUT
C_L
8
V_CC
1
ON
7
SENSE
6
GATE
LT1641
R2
3.4k
1%
2
FB
3
PWRGD
R7
24k
5%
R4
3.57k
1%
PWRGD
TIMER
GND
5
4
C2
0.68µF
GND
1641 TA01
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
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