lnbh23qtr STMicroelectronics, lnbh23qtr Datasheet - Page 5

• Manufacturer Part Number: lnbh23qtr
• Description: Lnbs Supply And Control Ic With Step-up And I??c Interface
• Manufacturer: STMicroelectronics

2
Note:
2.1
2.2
2.3
Application information
This IC has a built-in DC/DC step-up converter with integrated NMOS that, from a single
source from 8 V to 15 V, generates the voltages (V
work at a minimum dissipated power of 0.375 W Typ. @ 500 mA load (the linear post-
regulator drop voltage is internally kept at V
circuit will disable the whole circuit when the supplied V
V typically).
In this document the output voltage (V
post-regulator output (V
DiSEqC
The new internal 22 kHz tone generator (patent pending) is factory trimmed in accordance
to the standards, and can be selected by I²C interface TTX bit (or TTX pin) and activated by
a dedicated pin (DSQIN) that allows immediate DiSEqC
I²C bit in case the 22 kHz presence is requested in continuous mode. In stand-by condition
(EN bit LOW) The TTX function must be disabled setting TTX to LOW.
DiSEqC
The built-in 22 kHz tone detector completes the fully bi-directional DiSEqC
(see
extracted PWK data are available on the DSQOUT pin. To comply to the bi-directional
DiSEqC
provided with two output pins, one for the dc voltage output (V
tone transmission (V
while the V
without any losses due to the R-L filter impedance (see
During the 22 kHz transmission, in DiSEqC
by the TEN bit, the V
controlled both through the TTX pin and by I²C bit. As soon as the tone transmission is
expired, the V
kHz receiving mode. The 13/18 V power supply is always provided to the LNB from the V
pin through the R-L filter.
DiSEqC
When the LNBH23 is used in DiSEqC
the proper operation of the new 22 kHz tone generator (patent pending. See application
circuit). Also in this case, the TTX function must be preventively enabled before to start the
22 kHz data transmission and disabled as soon as the data transmission has been expired.
The tone can be activated both with the DSQIN pin or the TEN I²C bit. The DSQIN internal
circuit activates the 22 kHz tone on the V
TTL signal presence on the DSQIN pin, and it stops with 1 cycles ±25 µs delay after the TTL
signal is expired.
Note:
TM
oRX
1). It’s input pin (DETIN) must be AC coupled to the DiSEqC
2.0 bus hardware requirements an output R-L filter is needed. The LNBH23 is
TM
TM
TM
oTX
provides the 13/18 V output voltage. This allows the 22 kHz Tone to pass
data encoding and decoding
2.0 implementation
1.X implementation
must be disabled by setting the TTX to LOW to set the device in the 22
oTX
oTX
ORX
). The V
pin must be preventively set ON by the TTX function. This can be
pin).
oTX
must be activated only during the tone transmission
TM
O
) is intended as the voltage present at the linear
oTX
1.x applications the R-L filter is always needed for
TM
UP
output with 0.5 cycles ±25 µs delay from the
-V
2.0 applications, activated by DSQIN pin or
ORX
UP
=0.75 V typ.). An under voltage lockout
) that let the linear post-regulator to
CC
TM
Figure 4
drops below a fixed threshold (6.7
data encoding, or through TEN
oRX
typ. application circuit).
) and one for the 22 kHz
TM
TM
BUS, and
2.0 interfacing
oRX
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