AD7785
3通道，低噪声，低功耗， 20位⒉-ツADC，具有片内仪表放大器和基准 3-Channel, Low Noise, Low Power, 20-Bit ⒉-ツ ADC with On-Chip In-Amp and Reference
Product Details
The is a low power, low noise, complete analog front ends for high precision measurement applications. It contains a low noise 20-bit Σ-Δ ADC with three differential analog inputs. The on-chip, low noise instrumentation amplifier means that signals of small amplitude can be interfaced directly to the ADC. With a gain setting of 64, the rms noise is 40 nV when the update rate equals 4.17 Hz.
The device contains a precision low noise, low drift internal band gap reference and can also accept an external differential reference. Other on-chip features include programmable excitation current sources, burnout currents, and a bias voltage generator, the bias voltage generator being used to set the common-mode voltage of a channel to AVDD/2.
The device can be operated with either the internal clock or an external clock. The output data rate from the part is software-programmable and can be varied from 4.17 Hz to 470 Hz.
The part operates with a power supply from 2.7 V to 5.25 V. It consumes a current of 400 µA typical and is housed in 16-lead TSSOP packages.
**Applications**
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- Thermocouple measurements
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- RTD measurements
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- Thermistor measurements
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- Gas analysis
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- Industrial process control
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- Instrumentation
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- Portable instrumentation
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- Blood analysis
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- Smart transmitters
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- Liquid/gas chromatography
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- 6-digit DVM
### Features and Benefits
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- Up to 20 bits effective resolution
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- RMS noise
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- 40 nV @ 4.17 Hz
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- 85 nV @ 16.7 Hz
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- Current: 400 µA typ
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- Power-down: 1 µA max
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- Low noise programmable gain instrumentation amp
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- Band gap reference with 4 ppm/°C drift typ
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- Update rate: 4.17 Hz to 470 Hz
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- 3 differential inputs
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- Simultaneous 50 Hz/60 Hz rejection
