AD7843:  Touch Screen Digitizer

The AD7843 is a 12-bit successive-approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The part operates from a single 2.2 V to 5.25 V power ...More

AD7843:  Touch Screen Digitizer

Product Description

The AD7843 is a 12-bit successive-approximation ADC with a synchronous serial interface and low on resistance switches for driving touch screens. The part operates from a single 2.2 V to 5.25 V power supply and features throughput rates greater than 125 kSPS. The external reference applied to the AD7843 can be varied from 1 V to +VCC, while the analog input range is from 0 V to VREF. The device includes a shutdown mode that reduces the current consumption to less than 1 µA. This part is available in a 16-lead 0.15" Quarter Size Outline (QSOP) package and a 16-lead Thin Shrink Small Outline (TSSOP) package. (View the QSOP Package Dimensions.)

Also see the AD7843 sister part, which is the AD7873. This part is similar to the AD7843 but has added functionality such as an on-chip temperature sensor (-40°C to + 85°C), on-chip 2.5 V reference and direct battery and touch-pressure measurement.

Features

  • 4-wire touch screen interface
  • Specified throughput rate of 125 kSPS
  • Low power consumption:
    1.37 mW max at 125 kSPS with VCC = 3.6 V
  • Single supply, VCC of 2.2 V to 5.25 V
  • Ratiometric conversion
  • High speed serial interface
  • Programmable 8-bit or 12-bit resolution
  • 2 auxiliary analog inputs
  • Shutdown mode: 1 µA max
  • 16-lead QSOP and TSSOP packages

Diagrams

AD7843 Diagram
Functional Block Diagram for AD7843

Specifications

Resolution (Bits) 12bit
T-Put Rate 125kSPS
# Chan 4
Supply V Single(+3),Single(+3.3)
Pwr Diss (max) 1.4mW
Interface Ser
Ain Range Uni (Vref)
SNR (dB) n/a
Pkg Type SOP

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AD7450 12 1MSPS 1 1.3mW
AD7466 12 200KSPS 1 900µW
AD7994 12 188KSPS 4 6mW
AD7923 12 200KSPS 4 7.5mW
AD7924 12 1MSPS 4 13.5mW
AD7934 12 1.5MSPS 4 16mW
AD7866 12 1MSPS 4 24mW
AD7862 12 250KSPS 4 75mW
AD7366 12 1MSPS 4 88.8mW
AD7864 12 520KSPS 4 120mW
AD9228-65 12 65MSPS 4 510mW
Pricing, Packaging & Availability

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Model
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Status
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  • Pre-Release: The model has not been released to general production, but samples may be available.
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  • Last Time Buy: The model has been scheduled for obsolescence, but may still be purchased for a limited time.
  • Obsolete: The specific part is obsolete and no longer available. Other models listed in the table may still be available (if they have a status that is not obsolete).
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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RoHS Compliant
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.

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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