JAJSDZ9 October 2017 ADS54J64
PRODUCTION DATA.
The ADS54J64 analog signal inputs are designed to be driven differentially. The analog input pins have internal analog buffers that drive the sampling circuit. As a result of the analog buffer, the input pins present a high-impedance input across a very wide frequency range to the external driving source that enables great flexibility in the external analog filter design as well as excellent 50-Ω matching for RF applications. The buffer also helps isolate the external driving circuit from the internal switching currents of the sampling circuit, resulting in a more constant SFDR performance across input frequencies. The common-mode voltage of the signal inputs is internally biased to 1.3 V using 2-kΩ resistors to allow for ac-coupling of the input drive network. Each input pin (INP, INM) must swing symmetrically between (VCM + 0.275 V) and (VCM – 0.275 V), resulting in a 1.1-VPP (default) differential input swing. The input sampling circuit has a 3-dB bandwidth that extends up to 1000 MHz.