LNBH23L

Application information

Doc ID 15335 Rev 4

7/25

system register is set to "1". After this time has elapsed, the output is resumed for a time

overload is detected, normal operation is resumed and the OLF diagnostic bit is reset to

operation can greatly reduce the power dissipation in short circuit condition, still ensuring

excellent power-on start-up in most conditions. However, there could be some cases in

which a highly capacitive load on the output may cause a difficult start-up when the dynamic

protection is chosen. This can be solved by initiating any power start-up in static mode (PCL

= 1) and, then, switching to the dynamic mode (PCL = 0) after a chosen amount of time

depending on the output capacitance. When in static mode, the diagnostic OLF bit goes to

"1" when the current clamp limit is reached and returns LOW when the overload condition is

cleared.

2.9

Thermal protection and diagnostic

The LNBH23L is also protected against overheating: when the junction temperature

exceeds 150 °C (typ.), the step-up converter and the liner regulator are shut-off, and the

diagnostic OTF SR bit is set to "1". Normal operation is resumed and the OTF bit is reset to

LOW when the junction is cooled down to 135 °C (typ.)

2.10

Output current limit selection

The linear regulator current limit threshold can be set by an external resistor connected to

ISEL pin. The resistor value defines the output current limit by the equation:

threshold value.

Note:

External components are needed to comply DiSEqC™ bus hardware requirements. Full

compliance of the whole application with DiSEqC™ specifications is not implied by the bare

use of this IC. NOTICE: DiSEqC™ is a trademark of EUTELSAT.