1

LTC1642

1642fb

Hot Swap Controller

The LTC

allows a board to be safely inserted and removed from a

live backplane. Using an external N-Channel pass transis-

tor, the board supply voltage can be ramped up at an

adjustable rate. A high side switch driver controls the

N-Channel gate for supply voltages above 2.97V.

The SENSE pin allows foldback limiting of the load current,

with circuit breaker action after an adjustable delay time.

The delay allows the part to power-up in current limit. The

CRWBR output can be used to trigger an SCR for crowbar

protection of the load if the input supply exceeds an

adjustable threshold. The RESET output can generate a

system reset with adjustable delay when the supply

voltage falls below an adjustable threshold. The ON

pin cycles the board power. The LTC1642 is available in

the 16-pin SSOP package.

Protection

1N4705

18V

12V

BACKPLANE

(SHORT PIN)

PLUG-IN CARD

SENSE

GATE

GND BRK TMR

LTC1642

RST TMR

ON

FAULT

OV

RESET

FB

CRWBR

0.33

µF

0.33

µF

2N2222

MCR

12DC

REF

0.1

µF

2.87k

1%

110k

1%

100

Ω

5%

107k

1%

13k

1%

FDS6630A

0.01

µF

0.047

µF

12V

AT 2.5A

330

Ω

5%

0.010

Ω

5%

11.3k

1%

POWER-GOOD = 11.4V

1642 TA01

+

COMPOUT

GND

UV = 10.8V

OV = 13.2V

APPLICATIO S

FEATURES

TYPICAL APPLICATIO

DESCRIPTIO

, LTC and LT are registered trademarks of Linear Technology Corporation. Hot Swap is

a trademark of Linear Technology Corporation. All other trademarks are the property of

their respective owners.