Application information

LNBH29

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DocID023065 Rev 3

2.3

LNBH29E: DISEQC data encoding by external 22 kHz signal

connected to the EXTM pin

In order to improve design flexibility, an analogic modulation input pin is available (EXTM) to

blocking capacitor must be used to couple the 22 kHz modulating signal source to the

capacitor, so that:

2.4

Output current limit selection

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

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

Equation 1

mA.

2.5

Output voltage selection

The linear regulator output voltage level can be easily programmed in order to accomplish

application specific requirements, using 3 bits of the internal DATA register (see Section 7.1:

Write mode transmission and Table 7 for exact programmable values). Register writing is

accessible via the I²C bus.

2.6

Diagnostic and protection functions

The LNBH29 series has 5 diagnostic internal functions provided via the I²C bus, by reading

5 bits on the STATUS register (in Read mode). All the diagnostic bits are, in normal

operation, set to LOW. Two diagnostic bits are dedicated to the overtemperature and

overload protection status (OTF and OLF) while the remaining 3 bits are dedicated to the

and to the input voltage power not good function (PNG). Once the OLF (or OTF or PNG) bit

has been activated (set to “1”), it is latched to “1” until the relevant cause is removed and a

new register reading operation is done (see Table 8).

111

.

1

MAX

RSEL

13915

.)

typ

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I

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