ALLGEMEINE BESCHREIBUNG

The AD7768-1 is a low power, high performance, Σ-Δ analog-to-digital converter (ADC), with a Σ-Δ modulator and digital filter for precision conversion of both ac and dc signals. The AD7768-1 is a single-channel version of the AD7768, an 8-channel, simultaneously sampling, Σ-Δ ADC. The AD7768-1 provides a single configurable and reusable data acquisition (DAQ) footprint, which establishes a new industry standard in combined ac and dc performance and enables instrumentation and industrial system designers to design across multiple measurement variants for both isolated and nonisolated applications.
The AD7768-1 achieves a 108.5 dB dynamic range when using the low ripple, finite impulse response (FIR) digital filter at 256 kSPS, giving 110.8 kHz input bandwidth, combined with ±1.1 ppm integral nonlinearity (INL), ±30 µV offset error, and ±30 ppm gain error.
A wider bandwidth, up to 500 kHz Nyquist (filter −3 dB point of 204kHz), is available using the sinc5 filter, enabling a view of signals over an extended range.
The AD7768-1 offers the user the flexibility to configure and optimize for input bandwidth vs. output data rate (ODR) and vs. Power dissipation. The flexibility of the AD7768-1 allows dynamic analysis of a changing input signal, making the device particularly useful in general-purpose DAQ systems. The selection of one of three available power modes allows the designer to achieve required noise targets while minimizing power consumption. The design of the AD7768-1 is unique in that it becomes a reusable and flexible platform for low power dc and high performance ac measurement modules.
When using the AD7768-1, embedded analog functionality within the AD7768-1 greatly reduces the design burden over the entire application range. The precharge buffer on each analog input decreases the analog input current compared to competing products, simplifying the task of an external amplifier to drive the analog input.
A full buffer input on the reference reduces the input current, providing a high impedance input for the external reference device or in buffering any reference sense resistor scenarios used in ratiometric measurements.
The specified operating temperature range is −40°C to +125°C. The device is housed in a 4 mm × 5 mm, 28-lead LFCSP.
Note that, throughout this data sheet, multifunction pins, such as XTAL2/MCLK, are referred to either by the entire pin name or by a single function of the pin, for example, MCLK, when only that function is relevant.

 

FEATURES

► ADC for single-channel low power, platform DAQ designs
► Wide bandwidth
► Sinc filter bandwidth range: DC to 204 kHz
► Low ripple FIR bandwidth range: DC to 110.8 kHz
► Precision ac and dc performance
► 108.5 dB dynamic range typical
► −120 dB THD
► ±1.1 ppm of FSR INL, ±30 µV offset error, ±30 ppm of FSR gain error
► Programmable ODR, filter type, and latency
► ODR values up to 1024 kSPS
► Linear phase digital filter options
► Low ripple FIR filter: ±0.005 dB maximum pass-band ripple, dc to 102.4 kHz
► Low latency sinc5 filter
► Low latency sinc3 filter enabling 50 Hz/60 Hz rejection
► Programmable FIR filter option
► Programmable power consumption and bandwidth
► Fast, highest speed
► 52.224 kHz bandwidth, 26.4 mW (sinc5 filter)
► 110.8 kHz bandwidth, 36.8 mW (FIR filter)
► Median, half speed: 55.4 kHz bandwidth, 19.7 mW (FIR filter)
► Low power, low speed: 13.9 kHz bandwidth, 6.75 mW (FIR filter)
► Power supply
► AVDD1 − AVSS = 5.0 V typical
► AVDD2 − AVSS = 2.0 V to 5.0 V typical
► Analog supplies can run from split supply (true bipolar)
► IOVDD − DGND = 1.8 V to 3.3 V typical
► Low power mode can run from single 3.0 V supply
► Pin control or SPI interface configurable
► Suite of diagnostic check mechanisms
► Temperature, interface CRC, and memory map CRC
► Package: 28-lead, 4 mm × 5 mm, LFCSP
► Temperature range: −40°C to +125°C

 

ANWENDUNGEN

► Platform ADC to serve a superset of measurements and sensor types
► Sound and vibration, acoustic, and material science research and development
► Control and hardware in loop verification
► Condition monitoring for predictive maintenance
► Electrical test and measurement
► Audio testing and current and voltage measurement
► Clinical electroencephalogram (EEG), electromyogram (EMG), and electrocardiogram (ECG) vital signs monitoring
► USB-, PXI-, and Ethernet-based modular DAQ
► Channel to channel isolated modular DAQ designs