NCS5652, NCV5652

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10

microcontroller disables the outputs 1ms after detecting the

thermal shutdown. Note that at −40

°C thermal shutdown

with temperature and PCB characteristics.

It is possible that a short from low to high can disable the

outputs and not cause a thermal shutdown. When the short

is pulled significantly higher than VCC (8−9 V), the

high−side NPN protection circuit will be activated. This

protection circuitry will turn off the current source providing

the drive current to the output stage. This results in a very

is disabled until the short is removed.

When possible, it is recommended that the application use

current limiting resistors to limit the output current to 1 A

maximum when shorted to ground. This method helps

distribute the heat between the NCx5652 and the current

limiting resistors during normal operation and for a short to

ground condition. Say that Figure 22 application example

will have a 3 V maximum output with a full load of 300 mA.

W are chosen so the voltage drop

across them will be greater than 3 V at a full load of 300 mA.

∼ 11.3 V. So

maximum current = 11.3 V / 27

W ∼ 420 mA.

If the power dissipation exceeds the thermal shutdown

limit, the thermal shutdown circuit will disable the outputs.

As discussed with the low to high short above, the

microcontroller should disable the outputs within 5 ms and

not enable them again for 5 seconds.

Figure 22. NCx5652 Application Diagram

Thermal

Detection

1

2

4

5

3

12

11

7

8

VCC

−

+

10

9

VCC

6

Class

AB

Bias

VCC

VCC

−

+

Class

AB

Bias

VCC

EN

EN

EN

Exposed

Pad (13)

5 V

Load 1

500 mA

Max

Load 2

500 mA

Max

VC1

VC2

*Optional

0 to 3.8 V Input

To microcontroller

From microcontroller

NCx5652

0 to 3.8 V Input

5 V

D1

12 V

VC1

VC2

27

W

27

W

10 K

W

1

mF

1

mF

0.1

mF

1

mF

0.1

mF

10 K

W

10 K

W