Data Sheet ADA4304-2
Rev. A | Page 9 of 10
APPLICATIONS INFORMATION
The ADA4304-2 active splitter is primarily intended for use in
the downstream path of television set-top boxes (STBs) that
contain multiple tuners. It is typically located directly after the
diplexer in a bidirectional CATV customer premise unit. The
ADA4304-2 provides a single-ended input and two single-
ended outputs that allow the delivery of the RF signal to two
different signal paths. These paths can include, but are not
limited to, a main picture tuner, the picture-in-picture (PIP)
tuner, an out-of-band (OOB) tuner, a digital video recorder
(DVR), and a cable modem (CM).
The ADA4304-2 exhibits composite second order (CSO) and
composite triple beat (CTB) products that are −62 dBc and
−72 dBc, respectively. The use of the SiGe bipolar process also
allows the ADA4304-2 to achieve a noise figure (NF) of 4 dB.
CIRCUIT DESCRIPTION
The ADA4304-2 consists of a low noise buffer amplifier followed
by a resistive power divider. This arrangement provides 2.8 dB
of gain relative to the RF signal present at the input of the device.
The input and each output must be properly matched to a 75 Ω
environment for distortion and noise performance to match the
data sheet specifications. AC coupling capacitors of 0.01 µF are
recommended for the input and outputs.
A 1 µH RF choke (Coilcraft chip inductor 0805LS-102X) is
required to correctly bias internal nodes of the ADA4304-2. It
should be connected between the 5 V supply and the IL pin
(Pin 14). The choke should be placed as close as possible to
the ADA4304-2 to minimize parasitic capacitance on the
IL pin, which is critical for achieving the specified bandwidth
and flatness.
