AD421 is a single chip, high performance, low cost solution for generating 4 mA to 20 mA signals for smart industrial control transmitters.
The AD421 is a complete, loop-powered digital-to-current converter designed for smart transmitter manufacturers in the industrial control industry. It provides a high precision, fully integrated solution that eliminates the need for discrete regulators and voltage references by including an on-chip selectable regulator (3 V, 3.3 V, or 5 V) and precision references (+1.25 V or +2.5 V).
The device features a sigma-delta architecture ensuring 16-bit monotonicity with an integral nonlinearity of +0.01%. It supports standard HART FSK protocol communication via a high-speed serial interface capable of operating at up to 10 Mbps. The AD421 is available in 16-lead plastic DIP and SOIC packages, specified for the industrial temperature range of -40°C to +85°C.
| Current Output Range | 4 mA to 20 mA |
|---|---|
| Resolution | 16 Bits |
| Integral Nonlinearity | +0.01 % of FS max |
| Full-Scale Settling Time | 8 ms typ |
| Data Rate | 10 Mbps max |
Yes, it is fully compatible with standard HART FSK protocol communication circuitry.
The device provides selectable regulated outputs of +5 V, +3.3 V, or +3 V.
It is available in 16-lead plastic DIP and 16-lead SOIC packages.