8-bit current-output DAC with SPI — what it does on the board
The LTC1329ACS8-50#PBF is an 8-bit, single-channel, current-output digital-to-analog converter from Analog Devices, controlled via a standard SPI data interface. Its output is unbuffered and non-differential, meaning the DAC's current output drives a load directly without an internal buffer stage — useful in applications where the load impedance is well-defined and the designer wants to minimise added offset or noise from a buffer. The part integrates its own internal voltage reference, so no external reference IC is needed for the conversion. This simplifies the bill of materials for trim, calibration, or set-point generation in embedded control loops.
A DNL below ±1 LSB means the DAC is monotonic — every increase in the digital code produces a positive or zero step in the output current, with no missing codes. For a trim DAC or a control-loop set point, this monotonicity prevents the output from jumping backwards as the code increments, which would cause oscillation or hunting in the loop.
The analog and digital supply rails both accept 2.7 V to 6.5 V, with no separate rail needed. The 0°C to 70°C temperature grade suits commercial and most indoor industrial environments, but not extended-temperature or automotive under-hood duty.