AD7711: CMOS, 24-Bit Sigma-Delta, Signal Conditioning ADC with Matched RTD Excitation Currents
The AD7711 is a complete analog front end for low frequency measurement applications. The device accepts low level signals directly from a transducer and outputs a serial digital word. It employs a ...More
AD7711: CMOS, 24-Bit Sigma-Delta, Signal Conditioning ADC with Matched RTD Excitation Currents
Product Description
The AD7711 is a complete analog front end for low frequency measurement applications. The device accepts low level signals directly from a transducer and outputs a serial digital word. It employs a sigma-delta conversion technique to realize up to 24 bits of no missing codes performance. The input signal is applied to a proprietary programmable gain front end based around an analog modulator. The modulator output is processed by an on-chip digital filter. The first notch of this digital filter can be programmed via the on-chip control register allowing adjustment of the filter cutoff and settling time.
The part features one differential analog input and one single ended analog input as well as a differential reference input. Normally, one of the input channels will be used as the main channel with the second channel used as an auxiliary input to periodically measure a second voltage. It can be operated from a single supply (by tying the VSS pin to AGND) provided that the input signals on the analog inputs are more positive than -30 mV. By taking the VSS pin negative, the part can convert signals down to -VREF on its inputs. The part provides two current sources that can be used to provide excitation in three-wire and four-wire RTD configurations. The AD7711 thus performs all signal conditioning and conversion for a single or dual channel system.
The AD7711 is ideal for use in smart, microcontroller based systems. Gain settings, signal polarity, input channel selection and RTD current control can be configured in software using the bidirectional serial port. The AD7711 contains self-measurement calibration, system calibration and background calibration options and also allows the user to read and write the on-chip calibration registers.
CMOS construction ensures low power dissipation, and a software programmable power-down mode reduces the standby power consumption to only 7 mW typical. The part is available in a 24-pin, 0.3 inch wide, plastic and hermetic dual-in-line package (DIP) as well as a 24-lead small outline (SOIC) package.
Features
- Charge-Balancing ADC
- 24 Bits, No Missing Codes
- ±0.0015% Nonlinearity - 2-Channel Programmable Gain Front End
- Gains from 1 to 128
- 1 Differential Input
- 1 Single-Ended Input - Low-Pass Filter with Programmable Filter Cutoffs
- Ability to Read/Write Calibration Coefficients
- RTD Excitation Current Sources
- Bidirectional Microcontroller Serial Interface
- Internal/External Reference Option
- Single- or Dual-Supply Operation
- Low Power (25 mW typ) with Power-Down Mode (7 mW typ)
Diagrams
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- Symbols and Footprints
Functional Block Diagram for AD7711
CMOS, 24-Bit Sigma-Delta, Signal Conditioning ADC with Matched RTD Excitation Currents
Functional Block Diagram for AD7711
AD7264 - True Differential, Dual, 1 MSPS, 14-Bit/12-Bit, 2-Channel SAR ADC With PGA
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AD7658-1 - 250 kSPS, 6-Channel, Simultaneous Sampling, Bipolar 12-Bit ADC
| Part# | Res | Throughput Rate | # of Inputs | Operating Pwr Diss |
|---|---|---|---|---|
| AD7710 | 24 | 1.028KSPS | 2 | 53mW |
| AD7711 | 24 | 1.028KSPS | 2 | 53mW |
| AD7712 | 24 | 1.028KSPS | 2 | 53mW |
| AD7766 | 24 | 128KSPS | 1 | 18mW |
| AD7767 | 24 | 128KSPS | 1 | 18mW |
| AD7718 | 24 | 1.365KSPS | 10 | 8.75mW |
| AD7730 | 24 | 1.2KSPS | 2 | 65mW |
| AD1555 | 24 | 16KSPS | 2 | 96mW |
| AD7732 | 24 | 15.4KSPS | 2 | 100mW |
| AD7711A | 24 | 1KSPS | 2 | 53mW |
| AD7922 | 12 | 1MSPS | 2 | 15mW |
AD7711 Model Options
Help
- Pre-Release: The model has not been released to general production, but samples may be available.
- Production: The model is currently being produced, and generally available for purchase and sampling.
- 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).
For detailed drawings and chemical composition please consult our Package Site
- 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
Sample availability may be better than production availability. Please enter samples into your cart to check sample availability.
*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 iinto your cart to check sample availability.

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