L7987L datasheet(19/41 Pages) STMICROELECTRONICS

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L7987L

Functional description

The peak current limit threshold (ILIM) can be programmed in the range 0.85 A - 3.0 A by

selecting the proper RILIM resistor, as suggested in Equation 6:

Equation 6

In any case, the maximum high-side MOS RMS current must not be allowed to exceed the

value shown in Table 2 on page 7.

Figure 9. Current limit and programming resistor

The minimum programmed current limit can't be lower than ISKIP = 0.5 A (typical), also in

case of foldback detection.

4.6

Overtemperature protection

It is recommended that the device never exceeds the maximum allowable junction

temperature. This temperature increase is mainly caused by the total power dissipated from

the integrated power MOSFET.

To avoid any damage to the device when reaching high temperature, the L7987L device

implements a thermal shutdown feature: when the junction temperature reaches 170 °C

(typ.) the device turns off the power MOSFET and shuts down.

When the junction temperature drops to 155 °C (typ.), the device restarts with a new soft-

start sequence.

RILIM

20k



IPK

ILIM

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L7987L データシート(PDF) 19 Page - STMicroelectronics