VCA2612 Datasheet | Burr-Brown

FEATURES q LOW NOISE PREAMP: - Low Input Noise: 1.25n V/√Hz - Active Termination Noise Reduction - Switchable Termination Value - 80MHz Bandwidth - 5d B to 25d B Gain - Differential Input /Output q LOW NOISE VARIABLE GAIN AMPLIFIER: - Low Noise VCA: 3.3n V/√Hz, Differential Programming Optimizes Noise Figure - 24d B to 45d B Gain - 40MHz Bandwidth - Differential Input /Output q LOW CROSSTALK: 52d B at Max Gain, 5MHz q HIGH-SPEED VARIABLE GAIN ADJUST q SWITCHABLE EXTERNAL PROCESSING DESCRIPTION The VCA2612 is a highly integrated, dual receive channel, signal processing subsystem. Each channel of the product consists of a low noise pre-amplifier (LNP) and a Variable Gain Amplifier (VGA). The LNP circuit provides the necessary connections to implement Active Termination (AT), a method of cable termination which results in up to 4.6d B noise figure improvement. Different cable termination characteristics can be acmodated by utilizing the VCA2612’s switchable LNA feedback pins. The LNP has the ability to accept both differential and single ended inputs, and generates a differential output signal. The LNP provides strappable gains of 5d B, 17d B, 22d B and 25d B. The output of the LNP can be accessed externally for further signal processing, or fed directly into the VGA. The VCA2612’s VGA section consists of two parts, the Voltage Controlled Attenuator (VCA) and the Programmable Gain Amplifier (PGA). The gain and gain range of the Programmable Gain Amplifier can be digitally programmed. The bination of these two programmable elements results in a variable gain ranging from 0d B up to a maximum gain as defined by the user through external connections. The output of the VGA can be used in either a single-ended or differential mode to drive high performance analog-to-digital converters. The VCA2612 also features low crosstalk and outstanding distortion performance. The bination of low noise, and gain range programmability make the VCA2612 a versatile building block in a number of...