AD7763 24-Bit, 625 kSPS, 109 dB Sigma-Delta ADC with On-Chip Buffers, Serial Interface

The AD7763 high performance, 24-bit, Σ-Δ analog-to-digital converter (ADC) combines wide input bandwidth and high speed with the benefits of Σ-Δ conversion, as well as performance of 107 dB SNR at 625 kSPS, making it ideal for high speed data acquisition. A wide dynamic range, combined with significantly reduced antialiasing requirements, simplifies the design process. An integrated buffer to drive the reference, a differential amplifier for signal buffering and level shifting, an overrange flag, internal gain and offset registers, and a low-pass, digital FIR filter make the AD7763 a compact, highly integrated data acquisition device requiring minimal peripheral component selection. In addition, the device offers programmable decimation rates and a digital FIR filter, which can be user-programmed to ensure that its characteristics are tailored for the user’s application. The AD7763 is ideal for applications demanding high SNR without necessitating the design of complex, front-end signal processing.

The differential input is sampled at up to 40 MSPS by an analog modulator. The modulator output is processed by a series of low-pass filters, the final filter having default or user-programmable coefficients. The sample rate, filter corner frequencies, and output word rate are set by a combination of the external clock frequency and the configuration registers of the AD7763.

The reference voltage supplied to the AD7763 determines the analog input range. With a 4 V reference, the analog input range is ±3.2 V differential-biased around a common mode of 2 V. This common-mode biasing can be achieved using the on-chip differential amplifiers, further reducing the external signal conditioning requirements.

The AD7763 is available in an exposed paddle, 64-lead TQFP_EP and is specified over the industrial temperature range from −40°C to +85°C.

Applications

Data acquisition systems
Vibration analysis
Instrumentation

Features and Benefits

120 dB dynamic range at 78 kHz output data rate
109 dB dynamic range at 625 kHz output data rate
112 dB SNR at 78 kHz output data rate
107 dB SNR at 625 kHz output data rate

625 kHz maximum fully filtered output word rate
Programmable oversampling rate (32× to 256×)
Flexible serial interface
Please see data sheet for additional features.

Analog to Digital Converters

A/D Converters

Data Sheets

Document	note
AD7763: 24-Bit, 625 kSPS, 109 dB Sigma-Delta ADC with On Chip Buffers, Serial Interface Data Sheet (Rev. B)	PDF 678 kB

Application Notes

Document	note
AN-282: Fundamentals of Sampled Data Systems	PDF 2131 kB
AN-342: Analog Signal-Handling for High Speed and Accuracy	PDF 468 kB
AN-280: Mixed Signal Circuit Technologies	PDF 2101 kB
AN-389: Using Sigma-Delta Converters-Part 2	PDF 590 kB
AN-388: Using Sigma-Delta Converters-Part 1	PDF 590 kB
AN-311: How to Reliably Protect CMOS Circuits Against Power Supply Overvoltaging	PDF 217 kB
AN-283: Sigma-Delta ADCs and DACs	PDF 1699 kB