5

FN9104.4

October 2, 2008

ISL6161 Description and Operation

The ISL6161 is a multi-featured +12V and +3.3V dual power

supply distribution controller. Its features include programmable

current regulation (CR) limiting and time to latch off.

At turn-on, the gate capacitor of each external N-Channel

MOSFET is charged with a 10µA current source. These

capacitors create a programmable ramp (soft turn-on). A

charge pump supplies the gate drive for the 12V supply control

FET switch driving that gate to 17V.

The load currents pass through two external current sense

resistors. When the voltage across either resistor quickly

exceeds the user programmed Current Regulation voltage

threshold (CRVth) level, the controller enters current regulation.

10µA current source and the controller enters the time-out

period. The length of the time-out period is set by the single

(pin 10) to ground and is characterized by a lowered gate drive

voltage to the appropriate external N-Channel MOSFET. Once

in both N-Channel MOSFETs being latched off. If the voltage

across the sense resistors rises slowly in response to an OC

condition, then the CR mode is entered at ~95% of the

programmed CR level. This difference is due to the necessary

hysteresis and response time in the CR control circuitry.

resulting CR level for the PCI-Express add-in card connector

sizes specified.

±1% Current Limit Response Time

(Current within 1% of Regulated Value)

-10

-

µs

Response Time To Dead Short

-

500

ns

Gate Turn-On Time

-

5

-

ms

Gate Turn-On Current

8

10

12

µA

3x Gate Discharge Current

3xdisI

0.75

-

A

3.3V Undervoltage Threshold

2.7

2.85

3.0

V

3.3VG High Voltage

3VG

11.2

11.9

-

V

SUPPLY CURRENT AND IO SPECIFICATIONS

48

10

mA

9.5

10.0

10.7

V

9.0

9.4

9.8

V

Current Limit Time-Out

-

20

-

ms

ENABLE Pull-up Voltage

PWRN_V

ENABLE pin open

1.8

2.4

3.2

V

ENABLE Rising Threshold

PWR_Vth

1.1

1.5

2

V

ENABLE Hysteresis

PWR_hys

0.1

0.2

0.3

V

ENABLE Pull-Up Current

PWRN_I

60

80

100

µA

1.8

2

2.2

V

8

10

12

µA

1.7

2.6

3.5

mA

3.556.5

mA

90

100

110

µA

Charge Pump Output Current

Qpmp_Io

320

560

900

µA

Charge Pump Output Voltage

Qpmp_Vo

No load

17.2

17.4

-

V

Charge Pump Output Voltage - Loaded

Qpmp_VIo

Load current = 100µA

16.2

16.7

-

V

Charge Pump POR Rising Threshold

Qpmp + Vth

15.6

16

16.5

V

Charge Pump POR Falling Threshold

Qpmp - Vth

15.2

15.7

16.2

V

Electrical Specifications

+85°C, Unless Otherwise Specified. Parameters with MIN and/or MAX limits are 100% tested at +25°C,

unless otherwise specified. Temperature limits established by characterization and are not

production tested. (Continued)

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNITS

ISL6161