5

ISL6160 Description and Operation

The ISL6160 is the first power supply sequencer for the

emerging InfiniBand module (IM) hot swap application. This IC

controls both the +12V VB(ulk) and +5V VA(ux) supplies

providing soft start during hot insertion and overcurrent (OC)

protection during operation.

For VB control and protection, the ISL6160 features include an

accurate current detecting comparator, current limiting for the

range of both 25W and 50W capable power ports, a current

regulated time delay to latch off and soft start turn-on ramp.

These features are all programmable with a minimum of

external passive components. The ISL6160 also includes

severe overcurrent protection that immediately shuts down the

MOSFET switch should there be a shorted IM load.

The VB_ON pin provides on-off control of the external VB

switch once VB_IN > 9V. Driving this pin high causes the gate

pin to charge the external gate capacitor with a 10uA current

setting the soft start ramp rate. Large capacitive loads can thus

be safely turned on with no inrush current spiking nor disruption

of the voltage supply rail.

The VB load current passes through an external current sense

resistor. When the voltage across the sense resistor exceeds

the user programmed ISET voltage threshold, the controller

enters current regulation (CR). The regulated current level is

CR threshold voltage.

During CR, the CTIM pin starts charging the time-out capacitor

with a 20

µA current source and the controller enters the delay

time to latch-off period. This feature allows transient currents

that exceed the designed limit to pass without immediately

CTIM PARAMETERS

16

20

23

µA

5

8

11

mA

Current Limit Time-Out Threshold Voltage

CTIM Voltage

1.3

1.8

2.3

V

+5V AUXILIARY SUPPLY CONTROL

VA Integrated Switch On Resistance

-

0.125

0.150

Ω

-

0.160

0.200

Ω

Disabled Output Voltage

-

300

450

mV

t_vout_rt

-

8

-

V/mS

Toff_svout

-

8

-

V/mS

Toff_fvout

-

4

-

V/uS

CURRENT CONTROL

Current Limit

Ilim

0.75

1

1.25

A

OC Regulation Settling Time

Tsett_ocr

-

1.5

-

ms

Severe OC Regulation Settling Time

Tsett_socr

-

100

-

µs

Over Current Latch-off Time

-12

ms

I/O PARAMETERS

Fault Output Voltage

Vfault_hi

-

-

0.3

V

ENABLE High Threshold

Ven_vih

2.0

-

-

V

ENABLE Low Threshold

Ven_vil

-

-

0.8

V

ENABLE Input Current

Ien_i

-0.5

-

0.5

µA

BIAS PARAMETERS

Enabled VA_Iin Current

-

120

200

µA

Disabled VA_Iin Current

Switches Open, VA_Out = OPEN

-

1

5

µA

Undervoltage Lockout Threshold

VIN Rising, Switch Enabled

1.7

2.25

2.5

V

UV Hysteresis

50

100

-

mV

Electrical Specifications

PARAMETER

SYMBOL

TEST CONDITIONS

MIN

TYP

MAX

UNIT

S

TABLE 1.

NOMINAL REGULATION LEVEL

RESISTOR

NOMINAL

OC Vth

CURRENT (A)

POWER (W)

1.0k

Ω

20mV

1

12

2.8k

Ω

56mV

2.8

33.6

3.48k

Ω

70mV

3.5

42

5.6k

Ω

112mV

5.6

67.2

ISL6160