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16-Bit, Low-Power, 2-Channel, Sigma-Delta ADC

Product Details

Key Features

Parametric specs for Precision ADCs (< 5Msps)
Resolution (bits) (ADC) 16
# Input Channels 2
Conv. Rate (ksps) (max) 0.5
Data Bus SPI
ADC Architecture Sigma-Delta
Diff/S.E. Input Diff. Only
External VREF (V) (min) 1
External VREF (V) (max) 3.5
Unipolar VIN (V) (max) 2.5
Bipolar VIN (±V) (max) 2.5
INL (±LSB) 1.96608
Package/Pins PDIP/16
SOIC (W)/16
TSSOP/16
Budgetary
Price (See Notes)
4.83
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Simplified Block Diagram

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Parameters

Parametric specs for Precision ADCs (<u><</u> 5Msps)
Resolution (bits) (ADC) 16
# Input Channels 2
Conv. Rate (ksps) (max) 0.5
Data Bus SPI
ADC Architecture Sigma-Delta
Diff/S.E. Input Diff. Only
External VREF (V) (min) 1
External VREF (V) (max) 3.5
Unipolar VIN (V) (max) 2.5
Bipolar VIN (±V) (max) 2.5
INL (±LSB) 1.96608
Package/Pins PDIP/16
SOIC (W)/16
TSSOP/16
Budgetary
Price (See Notes)
4.83

Key Features

  • Pin Compatible and Software Compatible with the AD7705
  • 16-Bit Sigma-Delta ADC
  • Two Fully Differential Input Channels
  • 0.003% Integral Nonlinearity with No Missing Codes
  • Interface with Schmitt Triggers on Inputs
  • Internal Analog Input Buffers
  • PGA from 1 to 128
  • Single (2.7V to 3.6V) or (4.75V to 5.25V) Supply
  • Low Power
    • 1mW (max), 3V Supply
    • 2µA (typ) Power-Down Current
  • SPI-/QSPI-/MICROWIRE-Compatible 3-Wire Serial Interface

Applications/Uses

  • Flow and Gas Meters
  • Industrial Instruments
  • Loop-Powered Systems
  • Medical Instrumentation
  • Pressure Transducers
  • RTD Measurements
  • Strain-Gauge Measurements
  • Thermocouple Measurements
  • Weigh Scales

Description

The MX7705 low-power, 2-channel, serial-output analog-to-digital converter (ADC) includes a sigma-delta modulator with a digital filter to achieve 16-bit resolution with no missing codes. This ADC is pin compatible and software compatible with the AD7705. The MX7705 features an on-chip input buffer and programmable-gain amplifier (PGA). The device offers an SPI-/QSPI™-/MICROWIRE ®-compatible serial interface.

The MX7705 operates from a single 2.7V to 5.25V supply. The operating supply current is 320µA (typ) with a 3V supply. Power-down mode reduces the supply current to 2µA (typ).

Self-calibration and system calibration allow the MX7705 to correct for gain and offset errors. Excellent DC performance (±0.003% FSR INL) and low noise (650nV) make the MX7705 ideal for measuring low-frequency signals with a wide dynamic range. The device accepts fully differential bipolar/unipolar inputs. An internal input buffer allows for input signals with high source impedances. An on-chip digital filter, with a programmable cutoff and output data rate, processes the output of the sigma-delta modulator. The first notch frequency of the digital filter is chosen to provide 150dB rejection of common-mode 50Hz or 60Hz noise and 98dB rejection of normal-mode 50Hz or 60Hz noise. A PGA and digital filtering allow signals to be directly acquired with little or no signal-conditioning requirements.

The MX7705 is available in a 16-pin TSSOP package.

Simplified Block Diagram

MX7705: Functional Diagram MX7705: Functional Diagram Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .