ZHCSIJ3C June 2008 – July 2018 ADS7950 , ADS7951 , ADS7952 , ADS7953 , ADS7954 , ADS7955 , ADS7956 , ADS7957 , ADS7958 , ADS7959 , ADS7960 , ADS7961
PRODUCTION DATA.
请参考 PDF 数据表获取器件具体的封装图。
In general applications, when the internal multiplexer is updated, the previously converted channel charge is stored in the 15-pF internal input capacitance that disturbs the voltage at the newly selected channel. This disturbance is expected to settle to 1 LSB during sampling (acquisition) time to avoid degrading converter performance. The initial absolute disturbance error at the channel input must be less than 0.5 V to prevent source current saturation or slewing that causes significantly long settling times. Fortunately, significantly reducing disturbance error is easy to accomplish by simply placing a large enough capacitor at the input of each channel. Specifically, with a 150-pF capacitor, instantaneous charge distribution keeps disturbance error less than 0.46 V because the internal input capacitance can only hold up to 75 pC (or 5 V × 15 pF). The remaining error must be corrected by the voltage source at each input, with impedance low enough to settle within 1 LSB. The following application examples explain the considerations for the input source impedance (RSOURCE).