Ad7768 / ad7768-4 are integrated for each channel respectively Σ-Δ 8-channel and 4-channel synchronous sampling of modulator and digital filter Σ-Δ A / D converter (ADC) supports synchronous sampling of AC and DC signals.
Ad7768 / ad7768-4 achieves 108db dynamic range under the maximum input bandwidth of 110.8khz, and has typical performance of ± 2ppminl, ± 50 µ V offset error and ± 30ppm gain error.
Ad7768 / ad7768-4 users can trade off input bandwidth, output data rate and power consumption, and select one of three power consumption modes to optimize noise target and power consumption. The flexibility of ad7768 / ad7768-4 makes it a reusable platform for low-power DC and High-Performance AC measurement modules.
The ad7768 / ad7768-4 has three operating modes: fast mode (maximum: 256ksps, 110.8khz input bandwidth, 51.5mw per channel), medium speed mode (maximum: 128ksps, 55.4khz input bandwidth, 27.5mw per channel) and ecological mode (maximum: 32ksps, 13.8khz input bandwidth, 9.375mw per channel).
Ad7768 / ad7768-4 provides rich digital filtering performance, such as broadband, ± 0.005db low-pass ripple, anti aliasing low-pass filter with integrated sharp roll off performance, and 105dB stopband attenuation at Nyquist frequency.
Broadband linear phase filter can be used for frequency domain measurement. The filter has a flat passband (± 0.005db ripple) in the following ranges: DC to 102.4khz (256ksps), DC to 51.2khz (128ksps), or DC to 12.8khz (32ksps).
The ad7768 / ad7768-4 also provides sinc response (through sinc5 filter), low bandwidth, low delay path and low noise measurement. Broadband and sinc5 filters can be selected and run for each channel.
Within these filter options, the user can extract the rate from the filter × 32、 × 64、 × 128、 × 256、 × 512 and × 1024 to increase the dynamic range. Changing the ability of decimation filtering can optimize the noise performance of the required input bandwidth.
The embedded analog function of each ADC channel can simplify the design. For example, the precharge buffer on the analog input can reduce the analog input current, and the reference precharge buffer of each channel can reduce the input current and burr at the reference voltage input.
The device is powered by 5vavdd1a and avdd1b power supply, 2.25V to 5.0vavdd2a and avdd2b power supply, and 2.5V to 3.3V or 1.8viovdd power supply (refer to “1.8viovdd power supply” for specific power supply requirements of 1.8viovdd). The device needs an external reference voltage source; The absolute input reference voltage range is 1V to avdd1 − AVSS.
In this document, for clarity, avdd1a and avdd1b power supplies are called avdd1, while avdd2a and avdd2b power supplies are called avdd2. For negative power supply, AVSS refers to avss1a, avss1b, avss2a, avss2b and AVSS pins.
The rated operating temperature range of the device is − 40 ° C to + 105 ° C, providing 10mm × 10mm, 64 pin LQFP package, printed circuit board (PCB) size is 12mm × 12mm。 In the whole data manual, the multi-functional pin (such as crystal oscillator 2 / MCLK) is represented by the whole pin name or a single function of the pin (for example, MCLK means that it is only related to this function).
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