8

LTC1643AL

LTC1643AL-1/LTC1643AH

1643afa

+

–

LOGIC

9.5V

UVL

+

–

62

µA

200

µA

Q5

ON/ON

FAULT

22

µA

GATE

TIMER

GND

2.5V

UVL

2.5V

UVL

REF

REF

REF

LTC1643AH/LTC1643AL

ONLY

LTC1643AH/LTC1643AL

ONLY

Q2

Q8

REF

1643A BD

Q3

Q4

5

13

1

16

4

2

15

8

12

11

10

9

3

14

6

7

PWRGD

Q7

Q1

Q9

Q10

Q6

Hot Circuit Insertion

When a circuit board is inserted into a live PCI slot, the

supply bypass capacitors on the board can draw huge

transient currents from the PCI power bus as they charge

up. The transient currents can cause permanent damage

to the connector pins and cause glitches on the power bus,

causing other boards in the system to reset.

The LTC1643A is designed to turn a board’s supply

voltages on and off in a controlled manner, allowing the

board to be safely inserted or removed from a live PCI slot

without glitching the system power supplies. The chip

also protects the PCI supplies from shorts and monitors

the supply voltages.

The LTC1643AH is designed for motherboard applica-

tions, while the LTC1643AL/LTC1643AL-1 are designed

for CompactPCI applications where the chip resides on

the plug-in board.

exceed –10.8V before the PWRGD signal can go high on

the LTC1643AH and LTC1643AL.

exceed 11.4V before the PWRGD signal can go high on the

LTC1643AH and LTC1643AL.