This reference design is part of an analog front-end for 50Ω-input oscilloscope application. System designers can readily use this evaluation platform to process input signals from DC to 2 GHz in both frequency-domain and time-domain applications.
Merkmale
- 50-Ω input, analog front-end with input signal bandwidth of 2 GHz
- System ENOB of 6 to 8 bits is achieved with this signal chain
- Supports a maximum input signal of ± 3V, with user-selectable options for input AC or DC coupling
- DC-offset correction feature available in DC-coupled input mode
- Three input-amplitude voltage adjustment settings provided by the front-end π-attenuator: 1:1, 2:1 and 5:1
- Low noise, high-performance fully-differential amplifier (LMH5401) used for single-ended to differential conversion
- High performance digitally-controlled variable-gain amplifier (LMH6401) programmable from 26dB to -6dB gain in 1-dB steps to maintain full-scale input at the ADC
- 12-bit ADC12J4000 operating at 4GSPS for sampling input signals
- Design supports +5 V supply using wall-mount power adapter or +12 V using internal FMC connection