zlnb2004 Zetex Semiconductors plc., zlnb2004 Datasheet - Page 8

• Manufacturer Part Number: zlnb2004
• Description: Zlnb2004 - Dual Tone And Polarity Switch Lnb Multiplex Controller
• Manufacturer: Zetex Semiconductors plc.

FURTHER INFORMATION
1) Inputs V
2) The ZLNB2001/2 includes the circuitry
3) The ZLNB2003 / 4 includes the circuitry
wired to the power inputs of an LNB via
high value (10k) resistors. Input V
controls outputs HVout1 and Enable1.
Input V
Enable2. With either input voltage set at
or below 14V, the corresponding HVout
pin will be in active. With either input
v o l ta g e a t or a b ov e 1 5 .5 V, t he
corresponding HVout pin will be active.
Should the voltage applied to either V
input fall below 8V, the corresponding
Enable pin will be low, otherwise these
outputs will be high.Any input or output
not required may be left open-circuit.
necessary to detect the presence of 22kHz
tones modulated on either of two supply
inputs to the lnb. The main elements of
the detectors in each channel are an
op-amp enabling the construction of a
Sallen Key filter, a rectifier/smoother and
a comparator. Full user control is given
over the centre frequency and bandwidth
of the filter using two external resistors
and capacitors (one of these resistors
shares the function of overvoltage
protection of the corresponding V
i.e. the 10k referenced in note 1). The
comparator circuit utilises no external
components. The presence of a 22kHz
tone applied to pin Fin1 or Fin2 switches
the corresponding output Tout1 or Tout2
high.
necessary to detect the presence of 22kHz
tones modulated on either of two supply
inputs to the LNB. The main elements of
the detectors in each channel are an
op-amp enabling the construction of a
Sallen Key filter, a rectifier/smoother and
a comparator. Full user control is given
over the centre frequency and bandwidth
of the filter using two external resistors
and capacitors (one of these resistors
shares the function of overvoltage
protection of the corresponding Vpol pin,
i.e. the 10k referenced in note 1). The
comparator circuit utilises no external
components. The presence of a 22kHz
tone applied to pin Fin1 or Fin2 switches
the corresponding output Tout1 or Tout2
POL2
POL1
controls outputs HVout2 and
and V
POL2
are designed to be
POL
POL1
pin,
POL
87
high. Pins Crec1 and Crec2 make
accessible the outputs of the tone switch
rectifiers and provides a means of
c o n tr o l l i n g t o n e s w i tc h d e l a y s.
Significant switching delays may be
necessary to avoid incorrect operation in
the presence of unwanted interference
(e.g. switching tones intended for other
s i g n a l l i n g sy st e m s ). F or cor re ct
operation of the IC, a capacitor and a
parallel connected resistor should be
connected between each Crec pin and
ground. The Tout low to high delays are
set solely by the added capacitors at
approximately 22ms/uF. The high to low
delays are set by the time constant of
each resistor capacitor combination at
a p p r o x i m a t e l y 0 . 2 CR s e c o nd s . A
capacitor of 100nF and resistor of 1MW
will give a low to high delay of around
2.2ms and a high to low delay of 20ms,
providing immunity to the 60Hz square
wave signal occasionally used for
switching between multiple LNB units.
ZLNB2001 ZLNB2002
ZLNB2003 ZLNB2004