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With the new NXP silicon bipolar double poly BFG400W series, it is possible to design low noise amplifiers for high frequency applications with a low current and a low supply voltage. These amplifiers are well suited for the new generation low voltage high frequency wireless applications.
In this note a first study of such an amplifier will be given. This amplifier is designed for a wideband working frequency from 40MHz to 1GHz. It is designed for DVB-C application, so the solution need provide a pretty good Gain flatness.
DVB-C stands for "Digital Video Broadcasting - Cable" and it is the DVB European consortium standard for the broadcast transmission of digital television over cable. This system transmits a MPEG-2 or MPEG-4 family digital audio/digital video stream, using a QAM modulation with channel coding. The standard was first published by the ETSI in 1994, and subsequently became the most widely used transmission system for digital cable television in Europe. It is deployed worldwide in systems ranging from the larger cable television networks (CATV) down to smaller satellite master antenna TV (SMATV) systems.
The circuit shown in this application note is intended to demonstrate the performance of the BFG425W in a 40M ~ 1GHz LNA for DVB-C applications.
Key requirements for this application are:
• Frequency Band 40M – 1GHz
• Gain
• Input/output Match
• Linearity
• NF
• Gain Flatness
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