Low-Power Buffered Voltage-Output DAC
Created: Feb 15, 2016
No description available.
A digital-to-analog converter (DAC) converts digital data into an analog signal in terms of either current or voltage output. Nowadays, most DACs are implemented as integrated circuits. This reference design utilizes the DAC8562, which is a 16-bit, dual, low power, ultra-low glitch, buffered voltage output DAC. This IC includes a 2.5V, 4-ppm/°C internal reference, giving a full-scale output voltage range of 2.5V or 5V. The internal reference has an initial accuracy of ±5mV and can source or sink up to 20mA at the VREFIN/VREFOUT pin. This converter can operate up to 50MHz.
This device is powered from a +5V power supply, but can also be powered within a range of voltages from +2.7V to +5.5V. In this design, the DAC8562 is controlled through a serial peripheral interface (SPI) using the pins available on the J2 header. The 4 SPI signals are connected to the DAC I/O signals through 33-Ω series resistors. There are two static I/O pins, /LDAC and /CLR, from the DAC8562 that are routed to the J2 header. Both of signals have weak pull-up resistors to the AVDD power-supply voltage. Either of these signals can be pulled down using hardware jumpers or applying signals to the J2 header. The DAC8562 has two analog outputs that are available at the J1 header. Each of these outputs is referenced to the board ground. Additionally, this design contains an OPA379 op amp in a buffer configuration to condition the internal reference if the user would like to use the signal to drive another component. The buffered signal is routed to pin 15 of J1 connector.
There are several of fields wherein DACs are used. Some of these are in portable instrumentation, PLC analog output module, closed-loop servo control, and voltage controlled oscillator tuning, data acquisition systems, and programmable gain and offset adjustment. The DACs are also used on music players in which it converts digital data into analog audio signals.