Features and Benefits
- 4mA-20 mA, 0 mA-20 or 0 mA-24
- 16-Bit Resoluton and Monotonicity
- ±0.012% Max Integral Nonlinearity
- ±0.05% Max Offset (Trimmable)
- ±0.15% Max Total Output Error (Trimmable)
- Flexible Serial Digital Interface (3.3. MBPS)
- On-Chip Loop Fault Detection
- On-Chip 5 V Reference (25 ppm/°C Max)
- Asynchronous CLEAR Function
- Maximum Power Supply Range of 32 V
- Output Loop Compliance of
0 V to Vcc-2.75 V
- 24-Lead SOIC and PDIP Packages
The AD420 is a complete digital to current loop output converter, designed to meet the needs of the industrial control market. It provides a high precision, fully integrated, low cost single-chip solution for generating current loop signals in a compact 24-pin SOIC or PDIP package.
The output current range can be programmed to 4 mA-20 mA, 0 mA-20 mA or an overrange function of 0 mA-24 mA. The AD420 can alternatively provide a voltage output from a separate pin that can be configured to provide 0 V-5 V, 0 V-10 V, ±5 V or ±10 V with the addition of a single external buffer amplifier.
The 3.3 M Baud serial input logic design minimizes the cost of galvanic isolation and allows for simple connection to commonly used microprocessors. It can be used in three-wire or asynchronous mode and a serial-out pin is provided to allow daisy chaining of multiple DACs on the current loop side of the isolation barrier.
The AD420 uses sigma-delta (SD) DAC technology to achieve 16-bit monotonicity at very low cost. Full-scale settling to 0.1% occurs within 3 ms. The only external components that are required (in addition to normal transient protection circuitry) are three low cost capacitors which are used in the DAC output filter.
If the AD420 is going to be used at extreme temperatures and supply voltages, an external output transistor can be used to minimize power dissipation on the chip via the "BOOST" pin.
The FAULT DETECT pin signals when an open circuit occurs in the loop. The on-chip voltage reference can be used to supply a precision +5 V to external components in addition to the AD420 or, if the user desires temperature stability exceeding 25 ppm/°C, an external precision reference such as the AD586 can be used as the reference.
The AD420 is available in a 24-pin SOIC and PDIP over the industrial temperature range of -40°C to +85°C.
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Solutions Bulletins & Brochures (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.
Sample & Buy
The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.