The input buffer amplifiers for the MCP492X devicesprovide low offset voltage and low noise. A configurationbit for each DAC allows the VREF input to bypassthe input buffer amplifiers, achieving a Buffered orUnbuffered mode. The default value for this bit isunbuffered. Buffered mode provides a very high inputimpedance, with only minor limitations on the inputrange and frequency response. Unbuffered modeprovides a wide input range (0V to VDD), with a typicalinput impedance of 165 k[ch937] w/7 pF.
The MCP492X utilizes a 3-wire syncronous serialprotocol to transfer the DACs' setup and output valuesfrom the digital source. The serial protocol can be interfacedto SPI? or Microwire peripherals common onmany microcontrollers, including Microchip'sPICmicro® MCUs & dsPICTM DSC family of microcontrollers.In addition to the three serial connections (CS,SCK and SDI), the LDAC signal syncronizes when theserial settings are latched into the DAC's output fromthe serial input latch. Figure 6-1 illustrates the requiredconnections. Note that LDAC is active-low. If desired,this input can be tied low to reduce the required connectionsfrom 4 to 3. Write commands will be latcheddirectly into the output latch when a valid 16 clocktransmission has been received and CS has beenraised.
maybe it's not a voltage divider at all, and that is simply a bypass capacitor to reduce noise on the voltage reference line.
It wants an imaginary number and the radian frequency of the input voltage.
With a single dac, I'm not sure what the point of the buffer being there is.
I guess all I need to know now is how the DAC can output 2x the input voltage.
All writes to the MCP492X are 16-bit words. Anyclocks past 16 will be ignored. The most significantfour bits are configuration bits. The remaining 12 bitsare data bits. No data can be transferred into thedevice with CS high. This transfer will only occur if 16clocks have been transferred into the device. If the risingedge of CS occurs prior, shifting of data into theinput registers will be aborted.
The DAC also has a Vref input, this is the reference voltage that it uses to define the maximum analog value it can generate. There is a very low low-pass filter connected to it (C6 and R8) so that any digital noise (there is -a lot-) will not make it into the audio signal.