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AD420:  Serial Input 16-Bit, 4-20 mA, 0-20 mA DAC

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. ...More

AD420:  Serial Input 16-Bit, 4-20 mA, 0-20 mA DAC

Product Description

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.

A new revision of the AD420 datasheet, Rev F, 10/99, containing some new applications information, is now available.

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TECHNICAL DOCUMENTATION

  • 4mA-20 mA, 0 mA-20 or 0 mA-24
    Current Output
  • 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 Reference (25 ppm/°C Max)
  • Asynchronous CLEAR Function
  • Maximum Power Supply Range of 32 V
  • Output Loop Compliance of
    0 V to Vcc-2.5 V
  • 24-Lead SOIC and PDIP Packages
  • Resolution (Bits): 16bit
  • DAC Update Rate: 400SPS
  • DAC Settling Time: 2.5ms
  • # DAC Outputs: 1
  • DAC Type: Current Out
  • DAC Input Format: Ser,SPI
  • Output FSR: (0-20mA),(0-24mA),(4-20mA)
  • Ref Int/Ext: Int/Ext
  • Supply Vnom: Single(+12),Single(+15),Single(+24),Single(+32)
  • Pwr Diss: 176mW
  • Package: DIP,SOIC

Functional Block Diagram for AD420

AD420 Diagram
Functional Block Diagram for AD420

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Pricing, Packaging & Availability

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Package Description
The package for this IC (i.e. DIP, SOIC, BGA). An Evaluation Board is a board engineered to show the performance of the model, the part is included on the board.

For detailed drawings and chemical composition please consult our  Package Site

Pin Count
Pin Count is the number of pins, balls, or pads on the device. Pin-out diagrams & pin function descriptions may be found in the datasheet.

Temperature Range
This is the acceptable operating range of the device. The various ranges specified are as follows:
  • Commercial: 0 to +70 degrees Celsius
  • Military : -55 to +125 degrees Celsius
  • Industrial: Temperature ranges may vary by model. Please consult the datasheet for more information.
  • Automotive: -40 to +125 degrees Celsius
Price
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.

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This is the date Analog Devices, Inc. anticipates that the product will ship from the warehouse. Most orders ship within 48 hours of this date.Once an order has been placed, Analog Devices, Inc. will send an Order Acknowledgement email to confirm your delivery date. It is important to note the scheduled dock date on the order entry screen. We do take orders for items that are not in stock, so delivery may be scheduled at a future date. Also, please note the warehouse location for the product ordered. We have warehouses in the United States, Europe and Southeast Asia. Transit times from these sites may vary.
Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.

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Due to environmental concerns, ADI offers many of our products in lead-free versions. For more information about lead-free parts, please consult our Pb (Lead) free information page.

View PCN
This is the list of Product Change Notifications (PCN) published on the web for this model. Click on the link to access PCN Information.Only select pre-2009 PCN�s are available on-line. To obtain a pre-2009 PCN, contact your ADI Sales Rep. For more information on ADI's PCN process, please visit our PCN Policy Statement page

*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.
**Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.