AD652AQ (ANALOG DEVICES)

The AD652AQ is a Synchronous Voltage-to-frequency Converter (SVFC), powerful building block for precision analog-to-digital conversion, offering typical nonlinearity of 0.002% (0.005% maximum) at a 100kHz output frequency. The inherent monotonicity of the transfer function and wide range of clock frequencies allow the conversion time and resolution to be optimized for specific applications. The AD652 uses a variation of the charge-balancing technique to perform the conversion function. The AD652 uses an external clock to define the full-scale output frequency, rather than relying on the stability of an external capacitor. The result is a more stable, more linear transfer function, with significant application benefits in both single- and multichannel systems. Gain drift is minimized using a precision low drift reference and low TC, on-chip, thin-film scaling resistors. Furthermore, initial gain error is reduced to less than 0.5% by the use of laser-wafer-trimming.