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LTC1643AL

LTC1643AL-1/LTC1643AH

1643afa

PCI-Bus Hot Swap

Controller

Hot Swappable PCI Supply

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Allows Safe Board Insertion and Removal from a

Live PCI Slot

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Works on either a Motherboard (LTC1643AH) or

CompactPCI

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Controls –12V, 3.3V, 5V, 12V Supplies

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Programmable Foldback Current Limit with

Circuit Breaker

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User-Programmable Supply Voltage Power-Up Rate

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High Side Drive for External N-Channel MOSFETs

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–12V and 12V On-Chip Switches

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Fault and Power-Good Outputs

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Available in a Narrow 16-Lead SSOP Package

The LTC

to be safely inserted and removed from a live PCI-Bus slot.

Two external N-channel transistors control the 3.3V and 5V

supplies while on-chip switches control the –12V and 12V

supplies. All supply voltages can be ramped up at a program-

mable rate. An electronic circuit breaker protects all four

suppliesagainstovercurrentfaults.Thefoldbackcurrentlimit

feature limits current spikes and power dissipation when

shorts occur and allows boards with large capacitances to be

powered up without tripping the circuit breaker. The PWRGD

output indicates when all of the supply voltages are within

tolerance and the FAULT output indicates an overcurrent

condition. The ON(LTC1643AH)/ON (LTC1643AL/

LTC1643AL-1) pin is used to cycle the board power or reset

the circuit breaker. The LTC1643AL-1 has the

±12V power

good comparators disabled.

The LTC1643A is available in a 16-pin narrow SSOP package.

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PCI-Based Servers

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CompactPCI Compliant Boards

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

Hot Swap is a trademark of Linear Technology Corporation.

CompactPCI is a trademark of PCI Industrial Computer Manufacturing Group.

FEATURES

DESCRIPTIO

APPLICATIO S

R2

0.005

Ω

Q2

IRF7413

Q1

IRF7413

R1

0.007

Ω

R5

10

Ω

R6

10

Ω

R7

100

Ω

C1

0.047

µF

5V

5A

3.3V

7.6A

GND

–12V

100mA

12V

500mA

R3

10k

R4

10k

11

3

13

12

14

16

15

4

10

9

8

1

2

5

6

7

GND

ON

FAULT

PWRGD

LTC1643AH

TIMER

GATE

1643A TA01

SYSTEM

POWER

SUPPLY

PCI

POWER

SYSTEM

CONTROLLER

C2

0.1

µF

RESET

LOGIC

RESET