
Analog Devices
GENERAL DESCRIPTION†
The AD7714 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.
FEATURES
Charge Balancing ADC 24 Bits No Missing Codes 0.0015% Nonlinearity
Five-Channel Programmable Gain Front End Gains from 1 to 128 Can Be Configured as Three Fully Differential Inputs or Five Pseudo-Differential Inputs
Three-Wire Serial Interface SPI™, QSPI™, MICROWIRE™ and DSP Compatible
3 V (AD7714-3) or 5 V (AD7714-5) Operation
Low Noise (<150 nV rms)
Low Current (350␣ mA typ) with Power-Down (5 mA typ)
AD7714Y Grade:
+2.7 V to 3.3 V or +4.75 V to +5.25 V Operation 0.0010% Linearity Error –40°C to +105°C Temperature Range Schmitt Trigger on SCLK and DIN
Low Current (226␣ mA typ) with Power-Down (4 mA typ)
Lower Power Dissipation than Standard AD7714 Available in 24-Lead TSSOP Package
Low-Pass Filter with Programmable Filter Cutoffs
Ability to Read/Write Calibration Coefficients
APPLICATIONS
Portable Industrial Instruments
Portable Weigh Scales
Loop-Powered Systems
Pressure Transducers