AD421
PRODUCTIONLoop-Powered 4-20 mA DAC
- Part Models
- 4
- 1ku List Price
- Starting From $9.24
Overview
- 4mA to 20 mA Current Output
- HART@ Compatible
- 16-Bit Resolution and Monotonicity
- ±0.01% Integral Nonlinearity
- 5 V or 3 V Regulator Output
- 2.5 V and 1.25 V Precision Reference
- 750 µA Quiescent Current max
- Programmable Alarm Current Capability
- Flexible High Speed Serial Interface
- 16-Lead SOIC and PDIP Packages
The AD421 is a complete, loop-powered, digital to 4-20 mA converter, designed to meet the needs of smart transmitter manufacturers in the Industrial Control industry. It provides a high precision, fully integrated, low cost solution in a compact 16-pin package. The AD421 is ideal for extending the resolution of smart 4-20 mA transmitters at very low cost.
The AD421 includes a selectable regulator that is used to power itself and other devices in the transmitter. This regulator provides either a +5 V, +3.3 V or +3 V regulated output voltage. The part also contains +1.25 V and +2.5 V precision references. The AD421 thus eliminates the need for a discrete regulator and voltage reference. The only external components required are a number of passive components and a pass transistor to span large loop voltages.
The AD421 can be used with standard HART FSK protocol communication circuitry without any degradation in specified performance. The high speed serial interface is capable of operating at 10 Mbps and allows for simple connection to commonly-used microprocessors and microcontrollers via a standard three-wire serial interface.
The sigma-delta architecture of the DAC guarantees 16-bit monotonicity while the integral nonlinearity for the AD421 is ±0.01%. The part provides a zero scale 4 mA output current with ±0.1% offset error and a 20 mA full-scale output current with ±0.2% gain error.
The AD421 is available in a 16-pin, 0.3 inch-wide, plastic DIP and a 16-lead, 0.3 inch-wide, SOIC package. The part is specified over the industrial temperature range of -40°C to +85°C.
Documentation
Data Sheet 1
Application Note 2
Solutions Bulletin & Brochure 1
Analog Dialogue 1
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| AD421BNZ | 16-Lead PDIP | ||
| AD421BRZ | 16-Lead SOIC Wide | ||
| AD421BRZRL | 16-Lead SOIC Wide | ||
| AD421BRZRL7 | 16-Lead SOIC Wide |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Mar 29, 2021 - 21_0033 Assembly Site Transfer for 14/16L 300_MIL PDIP to Cirtek |
||
| AD421BNZ | ||
|
Aug 19, 2009 - 07_0024 Package Material Changes for SOT23, MiniSO, MQFP, PDIP, PLCC, SOIC (narrow and wide body), SSOP, TSSOP and TSSOP exposed pad |
||
| AD421BNZ | ||
|
Aug 4, 2010 - 10_0117 Halogen Free Material Change for SOIC_W Products at Carsem |
||
| AD421BRZ | PRODUCTION | |
| AD421BRZRL | ||
| AD421BRZRL7 | ||
This is the most up-to-date revision of the Data Sheet.
Software Resources
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| Parts | Product Life Cycle | Description |
|---|---|---|
| AD5421 | PRODUCTION | 16-Bit, Serial Input, Loop-Powered, 4mA to 20mA DAC |