20-Bit DAC board

We have developed another board (CMIDAC11001) that has same form factor as the Main board and can be used separately or in combination with the Main board. It is featuring three DA converters from Texas Instruments namely the DAC11001, which are single channel DAC with 20-Bit resolution, 1-LSB DNL and  4-LSB  INL. We chose LTC6655LN from Analog Devices as references, one for each channel. The board requires ±12 V and 3.3 V power supplies. Output voltages are jumper configurable to ±10 V, 0–10 V, ±5 V and 0–5 V, respectively. In current setup we use SPI communication which is implemented directly in the FPGA of Red Pitaya. This ensures much faster and non-interrupted transfers compared to CPU SPI link. All three DACs are connected in a daisy-chain, hence all voltages can be set within a single SPI message. Nevertheless, we have provided a separated connector for communication with only one of the converters, if needed. All the voltages are accessible via SMA connectors or via the Euro96 connector if used in combination with the Main board.

The three 20-Bit DACs were designed to be used to control the scanning process, i.e. the x, y and z positions of the scanner, to be applied on the piezoelectric scanner elements, after appropriate amplification. Nevertheless, the they can be used as a general purpose high resolution DAC. Voltage in each channel can be set independently via API.

Electronic board schematics drawing, layout and prototype boards manufacturing was done by Petr Dvořák (email: hw@idvorak.cz) who also cooperated with us on the design, together with colleagues from the Nenovision company.