ZHCSGI8A April 2017 – October 2021 ADC12D1620QML-SP
PRODUCTION DATA
The full-scale analog-differential input range (VIN_FSR) of the ADC12D1620 is derived from an internal bandgap reference. In Non-ECM, this full-scale range has two settings controlled by the FSR pin; see Full-Scale Input-Range Pin (FSR). The FSR Pin operates on both I and Q channels. In ECM, the full-scale range may be independently set with 15 bits of precision for each channel through the I- and Q-channel Full-Scale Range Adjust Registers (Addr: 3h and Addr: Bh, respectively); see Table 7-16 and Table 7-24 for information about the registers. The best SNR is obtained with a higher full-scale input range, but better distortion and SFDR are obtained with a lower full-scale input range. It is not possible to use an external analog reference voltage to modify the full-scale range, and this adjustment should only be done digitally, as described.
A buffered version of the internal bandgap reference voltage is made available at the VBG pin for the user. The VBG pin can drive a load of up to 80-pF and source or sink up to 100 μA. It must be buffered if current higher than 100 μA is required. This pin remains as a constant reference voltage regardless of what full-scale range is selected and may be used for a system reference. VBG is a dual-purpose pin and it may also be used to select a higher LVDS output common-mode voltage; see LVDS Output Common-Mode Pin (VBG).