LT1640L_15 Datasheet, PDF (1/16 Pages) Linear Technology – Negative Voltage Hot Swap Controller

FEATURES
s _{Allows Safe Board Insertion and Removal}
from a Live – 48V Backplane
s _{Operates from –10V to – 80V}
s _{Programmable Inrush Current}
s _{Programmable Electronic Circuit Breaker}
s _{Programmable Overvoltage Protection}
s _{Programmable Undervoltage Lockout}
s _{Power Good Control Output}
U
APPLICATIO S
s _{Central Office Switching}
s _{– 48V Distributed Power Systems}
s _{Negative Power Supply Control}
LT1640L/LT1640H
Negative Voltage
Hot Swap Controller
DESCRIPTIO
The LT^®1640L/LT1640H is an 8-pin, negative voltage Hot
Swap^TM controller that allows a board to be safely inserted
and removed from a live backplane. Inrush current is
limited to a programmable value by controlling the gate
voltage of an external N-channel pass transistor. The pass
transistor is turned off if the input voltage is less than the
programmable undervoltage threshold or greater than the
overvoltage threshold. A programmable electronic circuit
breaker protects the system against shorts. The PWRGD
(LT1640L) or PWRGD (LT1640H) signal can be used to
directly enable a power module. The LT1640L is designed
for modules with a low enable input and the LT1640H for
modules with a high enable input.
The LT1640L/LT1640H is available in 8-pin PDIP and SO
packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
GND
UV = 37V
OV = 71V
*
(SHORT PIN)
GND
R4^†
562k
1%
R5^†
9.09k
1%
R6^†
10k
1%
3
UV
2
OV
V_EE
4
SENSE
5
– 48V
R1^†
3
0.02Ω
5%
4
1
2
* DIODES INC. SMAT70A
† _{THESE COMPONENTS ARE APPLICATION}
SPECIFIC AND MUST BE SELECTED BASED
UPON OPERATING CONDITIONS AND DESIRED
PERFORMANCE. SEE APPLICATIONS
INFORMATION.
8
V_DD
LT1640L
1
PWRGD
GATE
6
DRAIN
7
1N4148
C1^†
150nF
25V
R2
10Ω
R3^†
18k
C2^†
5% _5% 3.3nF
100V
Q1
IRF530
C3 +
0.1µF
100V
C4
100µF
100V
2
1
ON/OFF
V_IN+
V_OUT+
SENSE ⁺
9
8
7
+
TRIM
SENSE ^{– 6}
4 _VIN–
V_OUT– ⁵
5V
C5
100µF
16V
LUCENT
JW050A1-E
1640 TA01
INRUSH
CURRENT
1A/DIV
GATE – V_EE
10V/DIV
DRAIN
50V/DIV
V_EE
50V/DIV
CONTACT
BOUNCE
Input Inrush Current
5ms/DIV
1640 F06b
1640lhfb
1