LT1641_15 Datasheet, PDF (1/12 Pages) Linear Technology – Positive High Voltage Hot Swap Controller

FEATURES
■ _{Allows Safe Board Insertion and Removal from a}
Live Backplane
■ _{Controls Supply Voltage from 9V to 80V}
■ _{Programmable Analog Foldback Current Limiting}
■ _{High Side Drive for an External N-Channel}
■ _{Automatic Retry Capability}
■ _{User Programmable Supply Voltage Power-Up Rate}
■ _{Undervoltage Lockout}
■ _{Overvoltage Protection}
■ _{Available in 8-Lead SO Package}
U
APPLICATIO S
■ _{Hot Board Insertion}
■ _{Electronic Circuit Breaker}
■ _{Industrial High Side Switch/Circuit Breaker}
■ _{24V/48V Industrial/Alarm Systems}
LT1641
Positive High Voltage
Hot Swap Controller
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 turns 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 LT1641-1/LT1641-2 are recommended for new
designs.
The LT1641 is available in the 8-lead SO package.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
24V Input Voltage Automatic Restart Application
V_IN
24V
SHORT
PIN
R1
49.9k
1%
R_S
0.01Ω
Q1
IRF530
R5
10Ω
5%
10nF
D1
CMPZ R3
5248B 59k
1%
V_OUT
C_L
*SMAT70A
R2
3.4k
1%
V_CC SENSE GATE
ON
FB
LT1641
TIMER
PWRGD
GND
R7
24k
5%
R4
3.57k
1%
PWRGD
GND
*DIODES, INC.
C2
0.68µF
1641 TA01
1641fd
1