FireWire Current Limiter and Low-Drop

ORing Switch Controller

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9

Pin Description

PIN

NAME

FUNCTION

1ON

On/Off-Control Input. ON sets the undervoltage lockout threshold and resets the part after a fault latch.

Drive ON high to enable the device. Drive ON low to disable the device. Connect ON to IN for the default

undervoltage lockout threshold. Connect a resistor-divider from IN to ON and GND to program the desired

undervoltage lockout threshold.

2

FAULT

Current-Fault, Active-Low, Open-Drain Output. FAULT asserts and latches low after a current-limit/circuit-

breaker fault has exceeded the current-limit/circuit-breaker timeout period (see the FAULT section).

3

TIM

Current-Limit/Circuit-Breaker Timeout Adjustment Input. Connect TIM to IN for the default timeout period or

connect a resistor from TIM to GND to program the current-limit/circuit-breaker timeout period.

4

ILIM

Current-Limit/Circuit-Breaker Threshold Input. Leave ILIM open for a 40mV circuit-breaker threshold,

connect to GND for a 50mV circuit-breaker threshold, or connect to IN for a 60mV circuit-breaker threshold

(see the Current Limiting section).

5

LATCH

Latch or Autoretry Fault Management Selection Input. Connect LATCH to IN to select latch-off mode

after a current-limit/circuit-breaker timeout. Connect LATCH to GND for autorestart mode after a current-

limit/circuit-breaker timeout.

6

OR_ADJ

ORing Switch Turn-On Current Threshold Adjustment Input. Select one of three ORing switch turn-on

threshold settings: connect OR_ADJ to GND, connect OR_ADJ to IN, or leave OR_ADJ floating (see the

Power-Supply ORing section).

7, 10, 13

N.C.

No Connection. Not internally connected.

8

ONQ1

ORing Switch Manual Turn-On Input. Drive ONQ1 low to enable power-supply ORing. Drive ONQ1 high

9

GND

Ground

11

OUT

Output Voltage Sense. Connect to the output.

12

GATE2

Current-Limiter Switch Gate Drive Output. Connect GATE2 to the gate of the 2nd n-channel MOSFET.

GATE2 is a charge pump with a 45µA pullup current to 5.5V (typ) above OUT when active (see the Typical

Operating Circuit).

14

GATE1

ORing Switch Gate-Drive Output. Connect GATE1 to the gate of the 1st n-channel MOSFET. GATE1 is a

charge pump with a 45µA pullup current to 5.5V (typ) above SENSE when active (see the Typical

Operating Circuit).

15

SENSE

Typical Operating Circuit).

16

IN

Input Power and Current-Sense Positive Input. Connect IN to the positive terminal of the current-sense

resistor and to the power source (see the Typical Operating Circuit).