4-bit I2C current DAC for trimming and margining
The Maxim DS4412U+ is a 4-bit, dual-channel, current-output digital-to-analog converter (DAC) controlled via an I2C interface. Resolution is 4 bits (16 steps per channel), with integral nonlinearity specified at ±1 LSB maximum and differential nonlinearity at ±0.5 LSB maximum — tight enough for the coarse-trim role it is designed for, not a precision waveform DAC. The analog and digital supply share the same 2.7 V to 5.5 V range, so a single 3.3 V or 5 V rail powers both the I2C bus and the output stage. The part is supplied in an 8-uMAX/uSOP package (equivalent to 8-TSSOP/MSOP), a small surface-mount footprint suited for space-constrained boards.
Because the DS4412U+ outputs current rather than voltage, it does not need an external op-amp to drive a trim node — the current can be injected directly into a feedback divider or an error-amplifier summing junction. This saves a few passives and an amplifier on the BOM, but the trade-off is that the output is unbuffered and the load impedance must be considered when setting the full-scale current range. The I2C interface runs at standard speeds; bus pull-up resistors are the only external components required for communication.