This paper introduces three designs using DACs, operational amplifiers and MOSFETs to build current sources with serial interface digital control.
The note presents several reference circuits that combine high‑resolution DACs (14‑bit AD5446, 16‑bit ADS343), precision op‑amps (OP1177) and MOSFET switches (CYTE4153N) to create programmable current sources. It explains the required supply voltages, component selection, and layout considerations for achieving low noise and high accuracy.
Additional sections cover load‑current calculations, common variations of the circuits, and a list of related Analog Devices tutorials (MT‑01S, MT‑031, MT‑087, MT‑101) and reference documents such as voltage‑reference selection guides.
| ADS343 DAC package | 8‑pin MSOP (3 mm × 4.7 mm) |
|---|---|
| AD5446 DAC package | 10‑pin MSOP |
| ADR423 reference | Low‑power precision voltage reference |
Both the 16‑bit ADS343 and the 14‑bit AD5446 support SPI, QSPI and Microwire interfaces.