DAC8871EVM: Using the EVM

Nishant,

The minimal control pins required to interface the device are CS, SDI, and SCLK. In this case /LDAC would be tied to GND and /RST would be tied high. RSTSEL connection would be don't care since the reset cannot be actuated without the /RST pin being brought out to the controller.

It looks like the LaunchPad has the corresponding peripherals required to get this done, also to include the optional connections to GPIO pins as well.

Thanks.

Nishant,

VCC and VSS are the net aliases for the supplies to the DAC analog, the buffer amplifiers on the board (OPA211 & OPA227), INA105, and REF102. The DAC requires at least +/-13.5V supplies, but in order to protect the INA105 maximum supply this should not exceed +/-18V.

The only other rail is for the VDD pin on the DAC, 2.7V to 5.5V.

Nishant,

Having 500mA current capability on the supply is a reasonable configuration. The total power consumption on the board in normal operation should not encroach on such a high value, so there is plenty of overhead there to operate the EVM board.

If 500mA is actually pulled from the power supply when you connect the EVM, I would be checking for shorts somewhere or a damaged component. The current consumption should not be so high.

Nishant,

Your summation is correct. The supply is not injecting a fixed current to the EVM. It is providing a fixed voltage with a programmed current limit. If that current limit is reached, the supply voltage will begin to droop. Otherwise the supply has 500mA source current capability to provide load regulation to the board.