LNBH30

Application information

DocID023739 Rev 2

7/27

voltage power not good function (PNG). Once the OLF (or OTF or PNG) bit is active (set to

“1”), it is latched to “1” until the relevant cause is removed and a new register reading

operation is performed.

2.5

VMON: output voltage diagnostic

When the device output voltage is active (VOUT pin), its value is internally monitored and,

as long as the output voltage level is below the guaranteed limits, the relevant VMON I²C

bit is set to “1” (see Table 12: "Output voltage diagnostic (VMON bit, status register)

characteristics" for more details).

2.6

PDO: overcurrent detection on output pull-down stage

When an overcurrent occurs on the pull-down output stage due to an external voltage

ms typ.), the corresponding PDO I²C bit is set to “1”. This may happen due to an external

voltage source presence on the LNB output (VOUT pin).

For current threshold and deglitch time details, see Table 9: "Electrical characteristics".

2.7

Power-on I²C interface reset and undervoltage lockout

The I²C interface built into the LNBH30 is automatically reset at power-on. As long as the

not respond to any I²C command and all DATA register bits are initialized to zeroes,

interface becomes operative and the DATA registers can be configured by the main

microprocessor.

2.8

PNG: input voltage minimum detection

thresholds, the PNG I²C bit is set to “1”. Refer to Table 9: "Electrical characteristics" for

threshold details.

2.9

OLF: overcurrent and short-circuit protection and diagnostic

In order to reduce the total power dissipation during an overload or a short-circuit condition,

the device is provided with a dynamic short-circuit protection. The overcurrent protection

circuit works dynamically: as soon as an overload is detected, the output current is

typically 900 ms. Simultaneously, the corresponding diagnostic OLF I²C bit of the status

register is set to “1”. After this time has elapsed, the involved output is resumed for a time

operation is resumed and the OLF diagnostic bit is reset to LOW after register reading is

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

ensuring excellent power-on startup in most conditions.