lnbh25pqr STMicroelectronics, lnbh25pqr Datasheet - Page 7

• Manufacturer Part Number: lnbh25pqr
• Description: Lnb Supply And Control Ic With Step-up And I²c Interface
• Manufacturer: STMicroelectronics

LNBH25
2.6
2.7
2.8
requirements an output RL filter is needed. In order to avoid 22 kHz waveform distortion
during tone transmission, LNBH25 is provided with the BPSW pin to be connected to an
external transistor, which allows to bypass the output RL filter in DiSEqC 2.x applications
while in transmission mode. Before starting tone transmission by means of the DSQIN pin,
make sure that the TEN bit is preventively set to “1” and after ending tone transmission,
make sure that the TEN bit is set to “0”.
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
with ISET=0
Equation 2
with ISET=1
(Refer also to the ISET bit description in
where RSEL is the resistor connected between ISEL and GND expressed in kΩ and
I
Output voltage selection
The linear regulator output voltage level can be easily programmed in order to accomplish
application specific requirements, using 4 bits of an internal DATA 1 register (see
registers
I²C bus.
Diagnostic and protection functions
LNBH25 has 8 diagnostic internal functions provided via the I²C bus, by reading 8 bits on
two STATUS registers (in read mode). All the diagnostic bits are, in normal operation (that is
no failure detected), set to LOW. Two diagnostic bits are dedicated to the overtemperature
and overload protection status (OTF and OLF) while the remaining 6 bits are dedicated to
the output voltage level (VMON), to 22 kHz tone characteristics (TMON), to the minimum
load current (IMON), to external voltage source presence on the V
input voltage Power Not Good function (PNG) and to the 22 kHz tone presence on the
DETIN pin (TDET). Once the OLF (or OTF or PNG) bit has been activated (set to “1”), it is
latched to “1” until relevant cause is removed and a new register reading operation is done.
MAX
I
I
MAX
MAX
(typ.) is the typical current limit threshold expressed in mA. I
(
(
typ
typ
and
.)
.)
=
=
Table 14
RSEL
RSEL
13915
6808
. 1
. 1
068
111
for exact programmable values). Register writing is accessible via the
Doc ID 022433 Rev 3
Table 9
).
MAX
OUT
Application information
can be set up to 1 A.
pin (PDO), to the
7.3: Data
7/34