Four way split

Analog Devices has introduced an active RF splitter IC that uses a four-way signal-splitting technology to resolve design challenges in multi-tuner cable set-top boxes.

Analog Devices has introduced an active RF splitter IC that uses a four-way signal-splitting technology to resolve design challenges in multi-tuner cable set-top boxes (STBs) and advanced televisions that need to simultaneously deliver video or data content to multiple applications, enabling features such as picture-in-picture capability and personal video recording.

Unlike existing solutions that require 20% more components to split the signal and amplify power while maintaining signal integrity, Analog Devices claims that its new ADA4302-4 active RF splitter offers these functions with a 2 dB lower noise figure and 16 dB better CSO (composite second order distortion), all within a compact (4 mm x 4 mm), single-chip solution.

“For cable set-top box manufacturers to achieve functionality beyond just receiving and decoding digital broadcast signals, RF system designers require advanced signal splitting technology,” said Curt Ventola, product line director, Analog Devices.

“For example, an STB equipped with Analog Devices’ ADA4302-4 can receive one incoming signal and divide and deliver it to four tuners, or three tuners and a cable modem, enabling a consumer to simultaneously view one televised program, set a digital video recorder for recording another program, use a cable modem to access the Internet, and run picture-in-picture settings.”

STB manufacturers depend on analog components to meet distortion and noise requirements and ensure that signals are received and processed properly. The ADA4302-4 active RF 1:4 splitter receives one incoming analog or digital video signal, boosts its strength by 4.5 dB, divides it into four differential outputs, and delivers each to a separate tuner or modem without degrading the signal quality.

The ADA4302-4 can also be configured for applications that require fewer than four outputs. Within an RF system, as the part splits a signal it strikes a unique balance between two fundamental performance trade offs – voltage noise and harmonic distortion – to maintain linearity. It receives downstream video channels and has a noise figure of only 4.5 dB. The device also sustains signal integrity by maintaining a CTB (composite triple beat) better than 70 dBc and a CSO better than 80 dBc.

The ADA4302-4 is available in a 4 mm x 4 mm LFCSP (lead frame chip-scale package). The device is priced at $2.60 per unit in 1,000-piece quantities.

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