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PI2002

Recalculate based on calculated Junction

temperature, 115°C.

At 115°C Rds(on) will increase by 32%.

Ω

=

∗

Ω

=

m

m

on

Rds

62

.

4

32

.

1

5

.

3

)

(

C

m

A

W

C

C

T

J

°

=

⎟

⎠

⎞

⎜

⎝

⎛

Ω

∗

∗

°

+

°

=

5

.

116

62

.

4

)

15

(

40

75

2

max

3. Vaux: Make sure Vaux voltage is higher than Vin

(power source output) by the voltage required to

fully enhance the MOSFET. Minimum required

Vaux = Vin + Vgs + 0.5V = 3.3V + 4.5V + 0.5V =

8.3V. Since 8.3V is less than the 11V minimum

Aux supply voltage, there is sufficient voltage

available to drive the gate of the MOSFET.

4. SP and SN pins: Connect the SP pin to the

MOSFET drain pin at the input and the SN pin to

the MOSFET drain pin at the load side.

5. OCT pin: Connect 18nF capacitor between OCT

pin and the GND pin to achieve the maximum off

time after forward over-current condition occurs.

6. SCD pin: Connect the SCD pin to the GND pin

for fast MOSFET enhancement.

7.

logic power supply via a 10KΩ resistor.

8. Program UV and OV to monitor input voltage:

Program UV at 3.0V and OV at 3.6V

Use the three-resistor divider configuration:

A

I

Ra

μ

200

=

Ω

=

=

=

k

A

mV

I

UV

V

Ra

Ra

TH

5

.

2

200

500

)

(

μ

or 2.49kΩ 1%

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−

=

1

)

(

)

(

UV

V

OV

V

Ra

Rb

Ω

=

⎟

⎠

⎞

⎜

⎝

⎛

−

Ω

=

498

1

0

.

3

6

.

3

49

.

2

V

V

k

or 499Ω 1%

()

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−

+

=

1

)

(

)

(

TH

UV

V

UV

V

Rb

Ra

Rc

()

Ω

=

⎟

⎠

⎞

⎜

⎝

⎛

−

Ω

+

Ω

=

k

mV

V

k

95

.

14

1

500

0

.

3

499

49

.

2

or 15kΩ 1%

Figure 19: High side Active ORing function.

Figure 20: PI2002 performance in example 1, applied short at Vin1.